/* ============================================================
   Die (Diane) Hu — Academic Personal Website
   styles.css
   ============================================================ */

/* ============================================================
   1. CSS CUSTOM PROPERTIES (Design Tokens)
   ============================================================ */
:root {
  /* Colors */
  --color-primary: #1B6CA8;
  --color-primary-dark: #134e7a;
  --color-primary-light: #e8f2fb;
  --color-accent: #D4845A;
  --color-accent-dark: #b86b40;
  --color-accent-light: #fdf0e8;
  --color-earth: #7B9E87;
  --color-earth-light: #edf4ef;
  --color-bg: #F8F6F2;
  --color-surface: #FFFFFF;
  --color-surface-alt: #F2F0EC;
  --color-text: #2C2C2C;
  --color-text-secondary: #5A5A5A;
  --color-text-muted: #888888;
  --color-border: #E0DDD8;
  --color-border-light: #EDE9E4;

  /* Typography */
  --font-heading: 'DM Sans', sans-serif;
  --font-body: 'Source Serif 4', serif;
  --font-mono: 'JetBrains Mono', monospace;
  --leading-relaxed: 1.7;
  --leading-snug: 1.35;

  /* Font sizes */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;
  --text-6xl: 3.75rem;
  --text-7xl: 4.5rem;

  /* Spacing (8px base) */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Border radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
  --shadow-xl: 0 16px 40px rgba(0, 0, 0, 0.14);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;

  /* Layout */
  --nav-height: 68px;
  --container-max: 1200px;
  --container-padding: var(--space-6);
}


/* ============================================================
   2. MODERN CSS RESET
   ============================================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text);
  background-color: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img,
picture,
video,
canvas,
svg {
  display: block;
  max-width: 100%;
  height: auto;
}

input,
button,
textarea,
select {
  font: inherit;
}

p,
h1,
h2,
h3,
h4,
h5,
h6 {
  overflow-wrap: break-word;
}

a {
  color: inherit;
  text-decoration: none;
}

ul,
ol {
  list-style: none;
}

button {
  background: none;
  border: none;
  cursor: pointer;
}

/* Selection */
::selection {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

/* Focus visible */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}

::-webkit-scrollbar-track {
  background: var(--color-border-light);
}

::-webkit-scrollbar-thumb {
  background: var(--color-primary);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-primary-dark);
}


/* ============================================================
   3. LAYOUT UTILITIES
   ============================================================ */
.container {
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
}

.section {
  padding-top: var(--space-24);
  padding-bottom: var(--space-24);
}

.section-label {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.section-title {
  font-family: var(--font-heading);
  font-size: var(--text-4xl);
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.2;
  margin-bottom: var(--space-4);
}

.section-subtitle {
  font-family: var(--font-body);
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.section-header {
  margin-bottom: var(--space-12);
}

/* ============================================================
   4. NAVIGATION
   ============================================================ */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(248, 246, 242, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: box-shadow var(--transition-base);
  height: var(--nav-height);
}

.nav.scrolled {
  box-shadow: var(--shadow-md);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav__brand {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: var(--text-xl);
  color: var(--color-primary);
  text-decoration: none;
  letter-spacing: -0.02em;
  flex-shrink: 0;
}

.nav__brand:hover {
  color: var(--color-primary-dark);
}

.nav__links {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  list-style: none;
}

.nav__links a {
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  text-decoration: none;
  position: relative;
  padding-bottom: 2px;
  transition: color var(--transition-fast);
}

.nav__links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width var(--transition-base);
  border-radius: var(--radius-full);
}

.nav__links a:hover {
  color: var(--color-primary);
}

.nav__links a:hover::after,
.nav__links a.active::after {
  width: 100%;
}

.nav__links a.active {
  color: var(--color-primary);
}

.nav__cta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-shrink: 0;
}

.nav__hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  cursor: pointer;
  border: none;
  background: none;
  padding: var(--space-2);
  border-radius: var(--radius-md);
  transition: background var(--transition-fast);
}

.nav__hamburger:hover {
  background: var(--color-primary-light);
}

.nav__hamburger-icon {
  font-size: var(--text-xl);
  color: var(--color-text);
  line-height: 1;
  display: block;
}

/* Hamburger bars */
.nav__toggle-bar {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.nav__toggle-bar + .nav__toggle-bar {
  margin-top: 5px;
}

/* X state */
.nav__hamburger.is-open .nav__toggle-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav__hamburger.is-open .nav__toggle-bar:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}
.nav__hamburger.is-open .nav__toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile nav drawer */
.nav__mobile-menu {
  display: none;
  position: fixed;
  top: var(--nav-height);
  left: 0;
  right: 0;
  background: rgba(248, 246, 242, 0.98);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-6);
  z-index: 99;
  transform: translateY(-110%);
  opacity: 0;
  transition: transform 0.3s ease, opacity 0.3s ease;
  box-shadow: var(--shadow-lg);
  will-change: transform, opacity;
}

.nav__mobile-menu.open {
  transform: translateY(0);
  opacity: 1;
}

.nav__mobile-menu.is-visible {
  display: block;
}

.nav__mobile-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  list-style: none;
  margin-bottom: var(--space-6);
}

.nav__mobile-links li a {
  display: block;
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  text-decoration: none;
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
  transition: color var(--transition-fast), background var(--transition-fast);
}

.nav__mobile-links li a:hover,
.nav__mobile-links li a.active {
  color: var(--color-primary);
  background: var(--color-primary-light);
}

.nav__mobile-cta {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}


/* ============================================================
   5. BUTTONS
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 12px 24px;
  border-radius: var(--radius-full);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: var(--text-sm);
  text-decoration: none;
  border: 2px solid transparent;
  cursor: pointer;
  transition: all var(--transition-base);
  white-space: nowrap;
  line-height: 1;
}

.btn--primary {
  background: var(--color-primary);
  color: #ffffff;
  border-color: var(--color-primary);
}

.btn--primary:hover {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn--secondary {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn--secondary:hover {
  background: var(--color-primary-light);
  transform: translateY(-2px);
}

.btn--accent {
  background: var(--color-accent);
  color: #ffffff;
  border-color: var(--color-accent);
}

.btn--accent:hover {
  background: var(--color-accent-dark);
  border-color: var(--color-accent-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn--ghost {
  background: transparent;
  color: var(--color-text-secondary);
  border-color: var(--color-border);
}

.btn--ghost:hover {
  background: var(--color-surface-alt);
  color: var(--color-text);
  border-color: var(--color-border);
}

.btn--sm {
  padding: 8px 16px;
  font-size: var(--text-xs);
}

.btn--white {
  background: #ffffff;
  color: var(--color-primary);
  border-color: #ffffff;
}

.btn--white:hover {
  background: var(--color-primary-light);
  color: var(--color-primary-dark);
}


/* ============================================================
   6. HERO SECTION
   ============================================================ */
.hero {
  min-height: 100vh;
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  /* UCSB diorama blended background */
  background:
    linear-gradient(
      105deg,
      rgba(248, 246, 242, 1.00)  0%,
      rgba(248, 246, 242, 0.97) 38%,
      rgba(248, 246, 242, 0.80) 55%,
      rgba(248, 246, 242, 0.30) 75%,
      rgba(248, 246, 242, 0.08) 100%
    ),
    url('../assets/images/ucsb-diorama-v2.png') right center / cover no-repeat;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle at 20% 50%, rgba(27, 108, 168, 0.05) 0%, transparent 50%),
    linear-gradient(rgba(27, 108, 168, 0.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(27, 108, 168, 0.02) 1px, transparent 1px);
  background-size: 100% 100%, 40px 40px, 40px 40px;
  pointer-events: none;
}

.hero__content {
  position: relative;
  z-index: 1;
  padding-top: var(--space-20);
  padding-bottom: var(--space-32);
  width: 100%;
}

.hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: var(--text-sm);
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-5);
}

.hero__eyebrow::before {
  content: '';
  display: inline-block;
  width: 24px;
  height: 2px;
  background: var(--color-primary);
  border-radius: var(--radius-full);
}

.hero__name {
  font-family: var(--font-heading);
  font-size: var(--text-6xl);
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-4);
}

.hero__name-highlight {
  color: var(--color-primary);
}

.hero__tagline-wrap {
  margin-bottom: var(--space-6);
  min-height: 2.5em;
  display: flex;
  align-items: center;
}

.hero__tagline {
  font-family: var(--font-body);
  font-style: italic;
  font-size: var(--text-3xl);
  color: var(--color-accent);
  line-height: 1.3;
  display: inline;
}

.hero__tagline .cursor {
  display: inline-block;
  width: 3px;
  height: 1em;
  background: var(--color-accent);
  margin-left: 3px;
  vertical-align: text-bottom;
  animation: blink 1s step-end infinite;
  border-radius: 1px;
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

.hero__desc {
  font-family: var(--font-body);
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  line-height: 1.8;
  max-width: 620px;
  margin-bottom: var(--space-8);
}

.hero__ctas {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  margin-bottom: var(--space-8);
}

.hero__badges {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-6);
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-3);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-text-secondary);
  white-space: nowrap;
}

.hero__badge i {
  color: var(--color-primary);
  font-size: 10px;
}

.hero__scroll {
  position: absolute;
  bottom: var(--space-8);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-text-muted);
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  letter-spacing: 1px;
  text-transform: uppercase;
  cursor: pointer;
  text-decoration: none;
  z-index: 2;
}

.hero__scroll-arrow {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  animation: bounce 2s ease infinite;
}

.hero__scroll-arrow::before,
.hero__scroll-arrow::after {
  content: '';
  display: block;
  width: 10px;
  height: 10px;
  border-right: 2px solid var(--color-text-muted);
  border-bottom: 2px solid var(--color-text-muted);
  transform: rotate(45deg);
}

.hero__scroll-arrow::after {
  opacity: 0.4;
  margin-top: -6px;
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(8px); }
}

/* Hero photo area */
.hero__photo {
  aspect-ratio: 4 / 5;
  border-radius: var(--radius-xl);
  background: linear-gradient(135deg, var(--color-primary-light) 0%, var(--color-accent-light) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  overflow: hidden;
  position: relative;
  box-shadow: var(--shadow-xl);
}

.hero__photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero__photo-placeholder {
  text-align: center;
  padding: var(--space-6);
  color: var(--color-text-muted);
}

.hero__photo-placeholder i {
  font-size: 3rem;
  display: block;
  margin-bottom: var(--space-3);
  color: var(--color-primary);
  opacity: 0.4;
}

.hero__layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-16);
  align-items: center;
}

.hero__left {
  grid-column: 1;
}

.hero__right {
  grid-column: 2;
}


/* ============================================================
   7. ABOUT SECTION
   ============================================================ */
.about {
  background: var(--color-surface);
}

.about__grid {
  display: grid;
  grid-template-columns: 6fr 4fr;
  gap: var(--space-16);
  align-items: start;
}

.about__text {
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin-bottom: var(--space-6);
}

.about__quote {
  border-left: 4px solid var(--color-accent);
  padding-left: var(--space-6);
  margin: var(--space-8) 0;
  font-family: var(--font-body);
  font-style: italic;
  font-size: var(--text-xl);
  color: var(--color-accent);
  line-height: 1.6;
}

.about__stats {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-8);
  margin-top: var(--space-8);
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-border-light);
}

.about__stat {
  flex: 1;
  min-width: 80px;
}

.about__stat-number {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-3xl);
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1;
  margin-bottom: var(--space-1);
}

.about__stat-label {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
  line-height: 1.4;
}

.about__photo-col {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

.about__photo {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

/* Journey pair — stacked hometown + UCSB */
.about__journey-pair {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

/* UCSB diorama card */
.about__diorama {
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  position: relative;
  aspect-ratio: 4 / 5;
}

.about__diorama--hometown {
  aspect-ratio: 16 / 10;
}

.about__diorama--hometown img {
  filter: grayscale(1);
  opacity: 0.85;
}

.about__diorama--hometown:hover img {
  filter: grayscale(0.3);
  opacity: 1;
}

.about__diorama--ucsb {
  aspect-ratio: 16 / 10;
}

.about__diorama img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  transition: transform 0.6s ease;
}

.about__diorama:hover img {
  transform: scale(1.03);
}

.about__diorama-caption {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: var(--space-3) var(--space-4);
  background: linear-gradient(to top, rgba(20,40,60,0.75) 0%, transparent 100%);
  color: rgba(255,255,255,0.92);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.about__diorama-caption i {
  color: var(--color-accent);
  font-size: 0.7rem;
}

/* Collapsible story */
.about__story {
  margin-top: var(--space-6);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.about__story-toggle {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4) var(--space-5);
  cursor: pointer;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text-secondary);
  background: var(--color-surface-alt);
  list-style: none;
  transition: background var(--transition-fast), color var(--transition-fast);
  user-select: none;
}

.about__story-toggle::-webkit-details-marker { display: none; }

.about__story-toggle:hover {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

.about__story-chevron {
  margin-left: auto;
  font-size: 0.7rem;
  transition: transform 0.25s ease;
}

.about__story[open] .about__story-chevron {
  transform: rotate(180deg);
}

.about__story-body {
  padding: var(--space-5) var(--space-6);
  background: var(--color-surface);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.about__story-body p {
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  line-height: var(--leading-relaxed);
  margin: 0;
}

.about__photo-caption {
  text-align: center;
  font-family: var(--font-body);
  font-style: italic;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  padding: var(--space-4);
}

.about__contact-quick {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  padding: var(--space-5);
  background: var(--color-bg);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
}

.about__contact-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

.about__contact-item i {
  color: var(--color-primary);
  width: 16px;
  text-align: center;
  flex-shrink: 0;
}

.about__contact-item a {
  color: var(--color-primary);
  transition: color var(--transition-fast);
}

.about__contact-item a:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}


/* ============================================================
   8. RESEARCH INTERESTS SECTION
   ============================================================ */
.interests {
  background: var(--color-bg);
}

/* Collapsible story — "What Fuels Me" */
.interests__story {
  max-width: 780px;
  margin: var(--space-8) 0 var(--space-12);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-xl);
  overflow: hidden;
}

.interests__story-toggle {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  width: 100%;
  padding: var(--space-4) var(--space-6);
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: 600;
  color: var(--color-text-secondary);
  background: var(--color-surface);
  cursor: pointer;
  list-style: none;
  transition: background var(--transition-fast), color var(--transition-fast);
  user-select: none;
}

.interests__story-toggle::-webkit-details-marker { display: none; }

.interests__story-toggle:hover {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

.interests__story-arrow {
  margin-left: auto;
  font-size: 0.7rem;
  transition: transform 0.25s ease;
}

.interests__story[open] .interests__story-arrow {
  transform: rotate(180deg);
}

.interests__story-body {
  padding: var(--space-6) var(--space-8);
  background: var(--color-surface);
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

.interests__story-body p {
  font-family: var(--font-body);
  font-size: var(--text-lg);
  line-height: var(--leading-relaxed);
  color: var(--color-text-secondary);
  margin: 0;
}

.interests__story-body em {
  font-style: italic;
  color: var(--color-primary-dark);
  font-weight: 600;
}

.interests__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

.interest-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  transition: all var(--transition-base);
  cursor: default;
}

.interest-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
  border-color: var(--color-primary-light);
}

.interest-card__icon {
  font-size: var(--text-2xl);
  color: var(--color-primary);
  margin-bottom: var(--space-4);
  display: block;
}

.interest-card__title {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: var(--text-xl);
  color: var(--color-text);
  margin-bottom: var(--space-2);
  line-height: 1.3;
}

.interest-card__desc {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
}

.interest-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin-top: var(--space-4);
}


/* ============================================================
   9. PROJECTS SECTION
   ============================================================ */
.projects {
  background: var(--color-surface);
}

.projects__filter {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-8);
}

.filter-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  background: transparent;
  border: 1px solid var(--color-border);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-primary-light);
}

.filter-btn.active {
  background: var(--color-primary);
  color: #ffffff;
  border-color: var(--color-primary);
}

.projects__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

.project-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  background: var(--color-surface);
  transition: all var(--transition-base);
  display: flex;
  flex-direction: column;
}

.project-card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}

.project-card[data-filter-hidden] {
  display: none;
}

.project-card__header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}

.project-card__badges {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  flex-shrink: 0;
}

.project-card__badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 600;
  white-space: nowrap;
  line-height: 1;
}

.project-card__badge--funding {
  background: var(--color-accent);
  color: #ffffff;
}

.project-card__badge--conference {
  background: var(--color-earth);
  color: #ffffff;
}

.project-card__badge--featured {
  background: var(--color-primary);
  color: #ffffff;
}

.project-card__badge--status {
  background: var(--color-surface-alt);
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
}

.project-card__title {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: var(--text-lg);
  color: var(--color-text);
  line-height: 1.35;
  margin-bottom: var(--space-2);
}

.project-card__meta {
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-bottom: var(--space-3);
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.project-card__meta-sep {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--color-border);
  display: inline-block;
}

.project-card__desc {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.7;
  flex-grow: 1;
  margin-bottom: var(--space-4);
}

.project-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
  margin-top: auto;
}

.tag {
  display: inline-block;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-primary);
  background: var(--color-primary-light);
  border: 1px solid rgba(27, 108, 168, 0.2);
  border-radius: var(--radius-full);
  padding: 2px var(--space-2);
  white-space: nowrap;
}

.tag--link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  text-decoration: none;
  cursor: pointer;
  transition: background var(--transition-fast), border-color var(--transition-fast), transform var(--transition-fast);
}

.tag--link:hover {
  background: rgba(27, 108, 168, 0.15);
  border-color: rgba(27, 108, 168, 0.4);
  transform: translateY(-1px);
}

.tag--earth {
  color: var(--color-earth);
  background: var(--color-earth-light);
  border-color: rgba(123, 158, 135, 0.2);
}

.tag--accent {
  color: var(--color-accent-dark);
  background: var(--color-accent-light);
  border-color: rgba(212, 132, 90, 0.2);
}

.project-card__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: var(--space-4);
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-border-light);
}

.project-card__link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-primary);
  text-decoration: none;
  transition: gap var(--transition-fast), color var(--transition-fast);
}

.project-card__link:hover {
  gap: var(--space-2);
  color: var(--color-primary-dark);
}


/* ============================================================
   10. PUBLICATIONS SECTION
   ============================================================ */
.publications {
  background: var(--color-bg);
}

.pub-tabs {
  display: flex;
  gap: 0;
  border-bottom: 2px solid var(--color-border);
  margin-bottom: var(--space-8);
}

.pub-tab {
  padding: var(--space-3) var(--space-6);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text-muted);
  cursor: pointer;
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: all var(--transition-fast);
}

.pub-tab:hover {
  color: var(--color-primary);
}

.pub-tab.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

.pub-panel {
  display: none;
}

.pub-panel.active {
  display: block;
}

.pub-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.pub-item {
  padding: var(--space-5) var(--space-6);
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  border-left: 4px solid var(--color-primary);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

.pub-item:hover {
  box-shadow: var(--shadow-md);
  transform: translateX(2px);
}

.pub-item__top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-4);
  margin-bottom: var(--space-2);
}

.pub-item__badge {
  display: inline-flex;
  align-items: center;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 600;
  white-space: nowrap;
  flex-shrink: 0;
  line-height: 1;
}

.pub-item__badge--journal {
  background: var(--color-earth-light);
  color: var(--color-earth);
  border: 1px solid rgba(123, 158, 135, 0.3);
}

.pub-item__badge--conference {
  background: var(--color-accent-light);
  color: var(--color-accent-dark);
  border: 1px solid rgba(212, 132, 90, 0.3);
}

.pub-item__badge--oral {
  background: var(--color-primary-light);
  color: var(--color-primary);
  border: 1px solid rgba(27, 108, 168, 0.3);
}

.pub-item__badge--forthcoming {
  background: var(--color-accent-light);
  color: var(--color-accent-dark);
  border: 1px solid rgba(212, 132, 90, 0.3);
}

.pub-item__title {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: var(--text-base);
  color: var(--color-text);
  line-height: 1.4;
  margin-bottom: var(--space-1);
}

.pub-item__title a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast);
}

.pub-item__title a:hover {
  color: var(--color-primary);
}

.pub-item__authors {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-1);
  line-height: 1.5;
}

.pub-item__authors strong {
  color: var(--color-primary);
  font-weight: 600;
}

.pub-item__venue {
  font-family: var(--font-body);
  font-style: italic;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.pub-item__links {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-top: var(--space-3);
}

.pub-item__link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.pub-item__link:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

/* Conference items — accent left border */
.pub-item--conference {
  border-left-color: var(--color-accent);
}

/* Forthcoming — earth left border */
.pub-item--forthcoming {
  border-left-color: var(--color-earth);
}


/* ============================================================
   11. TEACHING SECTION
   ============================================================ */
.teaching {
  background: var(--color-surface);
}

.teaching__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
}

.course-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-surface);
  transition: all var(--transition-base);
}

.course-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  border-color: var(--color-primary-light);
}

.course-card__header {
  background: var(--color-primary);
  padding: var(--space-3) var(--space-5);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.course-card__code {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 600;
  color: #ffffff;
  letter-spacing: 0.05em;
}

.course-card__role {
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 500;
  color: rgba(255, 255, 255, 0.75);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.course-card__body {
  padding: var(--space-5);
}

.course-card__title {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: var(--text-base);
  color: var(--color-text);
  margin-bottom: var(--space-2);
  line-height: 1.35;
}

.course-card__meta {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}

.course-card__meta-item {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.course-card__meta-item i {
  color: var(--color-primary);
  font-size: 12px;
}

.course-card__note {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  font-style: italic;
  line-height: 1.6;
}


/* ============================================================
   12. SKILLS SECTION
   ============================================================ */
.skills {
  background: var(--color-bg);
}

.skills__tiers {
  display: flex;
  flex-direction: column;
  gap: var(--space-10);
}

.skill-tier {
  /* individual tier */
}

.skill-tier__header {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}

.skill-tier__label {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 2px;
  text-transform: uppercase;
}

.skill-tier__line {
  flex: 1;
  height: 1px;
  background: var(--color-border);
}

.skill-tier__chips {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

/* Tier 1 — Primary expertise */
.skill-chip--tier1 {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: var(--color-primary);
  color: #ffffff;
  border-radius: var(--radius-full);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  border: none;
  white-space: nowrap;
}

/* Tier 2 — Proficient */
.skill-chip--tier2 {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  background: var(--color-surface);
  color: var(--color-primary);
  border: 1px solid var(--color-primary);
  border-radius: var(--radius-full);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 500;
  white-space: nowrap;
}

/* Tier 3 — Familiar */
.skill-chip--tier3 {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  background: var(--color-surface-alt);
  color: var(--color-text-secondary);
  border: 1px dashed var(--color-border);
  border-radius: var(--radius-full);
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 500;
  opacity: 0.8;
  white-space: nowrap;
}

.skills__categories {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-8);
  margin-top: var(--space-12);
}

.skills__category-title {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-2);
  border-bottom: 2px solid var(--color-border);
}


/* ============================================================
   13. AWARDS / TIMELINE SECTION
   ============================================================ */
.awards {
  background: var(--color-surface);
}

.timeline {
  position: relative;
  max-width: 720px;
}

.timeline__list {
  position: relative;
  padding-left: var(--space-8);
}

.timeline__list::before {
  content: '';
  position: absolute;
  left: 8px;
  top: 8px;
  bottom: 0;
  width: 2px;
  background: var(--color-border-light);
}

.timeline__item {
  position: relative;
  padding-bottom: var(--space-6);
}

.timeline__item:last-child {
  padding-bottom: 0;
}

.timeline__marker {
  position: absolute;
  left: calc(-1 * var(--space-8) + 4px);
  top: 4px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--color-primary);
  outline: 3px solid var(--color-primary-light);
  z-index: 1;
}

.timeline__year {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 1px;
  text-transform: uppercase;
  margin-bottom: var(--space-1);
}

.timeline__title {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: var(--text-base);
  color: var(--color-text);
  margin-bottom: var(--space-1);
  line-height: 1.35;
}

.timeline__subtitle {
  font-family: var(--font-body);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.5;
}

.timeline__amount {
  display: inline-block;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-accent-dark);
  background: var(--color-accent-light);
  border: 1px solid rgba(212, 132, 90, 0.2);
  border-radius: var(--radius-full);
  padding: 2px var(--space-2);
  margin-top: var(--space-1);
}


/* ============================================================
   13b. GITHUB / OPEN SOURCE SECTION
   ============================================================ */
.github-section {
  background: var(--color-bg);
}

.github-section__cta {
  text-align: center;
  margin-top: var(--space-10);
}

/* Repo grid: 2 columns → 1 */
.repo-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-6);
  margin-top: var(--space-10);
}

/* Repo card */
.repo-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

.repo-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary-light);
}

.repo-card--featured {
  background: linear-gradient(135deg, var(--color-surface) 0%, rgba(27, 108, 168, 0.05) 100%);
  border-color: rgba(27, 108, 168, 0.3);
  position: relative;
}

.repo-card--featured::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, rgba(27,108,168,0.08) 0%, transparent 60%);
  pointer-events: none;
}

/* Card preview thumbnail */
.repo-card__preview {
  margin: calc(var(--space-5) * -1) calc(var(--space-5) * -1) var(--space-4);
  border-radius: var(--radius-md) var(--radius-md) 0 0;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  background: var(--color-bg);
}

.repo-card__preview img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform 0.4s ease;
}

.repo-card:hover .repo-card__preview img {
  transform: scale(1.03);
}

/* Card header */
.repo-card__header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-3);
}

.repo-card__icon {
  width: 2.5rem;
  height: 2.5rem;
  background: var(--color-primary-light);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  font-size: 1.1rem;
  flex-shrink: 0;
}

.repo-card--featured .repo-card__icon {
  background: rgba(27, 108, 168, 0.15);
}

.repo-card__meta {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: var(--space-1);
}

/* Badges */
.repo-card__badge {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 2px var(--space-2);
  border-radius: var(--radius-full);
  white-space: nowrap;
}

.repo-card__badge--featured {
  background: rgba(27, 108, 168, 0.12);
  color: var(--color-primary);
  border: 1px solid rgba(27, 108, 168, 0.25);
}

.repo-card__badge--viz {
  background: rgba(123, 158, 135, 0.12);
  color: var(--color-earth);
  border: 1px solid rgba(123, 158, 135, 0.25);
}

.repo-card__badge--fun {
  background: rgba(212, 132, 90, 0.1);
  color: var(--color-accent);
  border: 1px solid rgba(212, 132, 90, 0.2);
}

.repo-card__stars {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  display: flex;
  align-items: center;
  gap: 3px;
}

.repo-card__stars .fa-star {
  color: #f5c842;
  font-size: 0.7rem;
}

/* Card content */
.repo-card__name {
  font-family: var(--font-mono);
  font-size: var(--text-base);
  font-weight: 600;
  color: var(--color-text);
  margin: 0;
}

.repo-card--featured .repo-card__name {
  color: var(--color-primary-dark);
}

.repo-card__desc {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: var(--leading-relaxed);
  flex: 1;
  margin: 0;
}

/* Topics */
.repo-card__topics {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.repo-topic {
  font-size: 0.65rem;
  font-weight: 500;
  font-family: var(--font-mono);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  border-radius: var(--radius-full);
  padding: 2px var(--space-2);
  white-space: nowrap;
}

/* Card link button */
.repo-card__link {
  align-self: flex-start;
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  margin-top: auto;
}

.repo-card__link .fa-external-link-alt {
  font-size: 0.65rem;
  opacity: 0.7;
}


/* ============================================================
   14. CONTACT SECTION
   ============================================================ */
.contact {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: #ffffff;
  position: relative;
  overflow: hidden;
}

.contact::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle at 10% 90%, rgba(212, 132, 90, 0.12) 0%, transparent 50%),
    radial-gradient(circle at 90% 10%, rgba(255, 255, 255, 0.05) 0%, transparent 50%);
  pointer-events: none;
}

.contact .section-label {
  color: rgba(255, 255, 255, 0.7);
}

.contact .section-title {
  color: #ffffff;
}

.contact .section-subtitle {
  color: rgba(255, 255, 255, 0.8);
}

/* Legacy grid — replaced by centered layout */
.contact__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-16);
  position: relative;
  z-index: 1;
}

/* New centered display-only contact layout */
.contact__centered {
  position: relative;
  z-index: 1;
  text-align: center;
  max-width: 680px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-8);
}

.contact__subtitle {
  color: rgba(255, 255, 255, 0.85) !important;
  line-height: 1.7;
}

.contact__primary {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
}

.btn--light {
  background: rgba(255, 255, 255, 0.15);
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(8px);
}

.btn--light:hover {
  background: rgba(255, 255, 255, 0.25);
  border-color: rgba(255, 255, 255, 0.5);
  color: #ffffff;
}

.btn--lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-lg);
  min-height: 52px;
}

.contact__location {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.65);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.contact__location i {
  color: var(--color-accent);
  font-size: 0.75rem;
}

/* Social cards grid */
.contact__social-grid {
  display: flex;
  gap: var(--space-4);
  flex-wrap: wrap;
  justify-content: center;
}

.contact__social-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-4) var(--space-6);
  background: rgba(255, 255, 255, 0.10);
  border: 1px solid rgba(255, 255, 255, 0.20);
  border-radius: var(--radius-lg);
  color: rgba(255, 255, 255, 0.85);
  text-decoration: none;
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 500;
  transition: background 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
  min-width: 90px;
}

.contact__social-card i {
  font-size: 1.5rem;
  color: rgba(255, 255, 255, 0.9);
}

.contact__social-card:hover {
  background: rgba(255, 255, 255, 0.20);
  border-color: rgba(255, 255, 255, 0.40);
  color: #ffffff;
  transform: translateY(-3px);
}

.contact__info {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

.contact__info-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-4);
}

.contact__info-icon {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  color: #ffffff;
  font-size: var(--text-base);
}

.contact__info-text {
  flex: 1;
}

.contact__info-label {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 600;
  color: rgba(255, 255, 255, 0.6);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: var(--space-1);
}

.contact__info-value {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: #ffffff;
}

.contact__info-value a {
  color: #ffffff;
  text-decoration: none;
  transition: opacity var(--transition-fast);
}

.contact__info-value a:hover {
  opacity: 0.8;
  text-decoration: underline;
}

.contact__socials {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-top: var(--space-6);
}

.contact__social {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.4);
  color: #ffffff;
  font-size: var(--text-base);
  text-decoration: none;
  transition: all var(--transition-fast);
}

.contact__social:hover {
  background: #ffffff;
  border-color: #ffffff;
  color: var(--color-primary);
  transform: translateY(-2px);
}

/* Contact Form */
.contact-form {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.contact-form__row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
}

.contact-form__group {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.contact-form__label {
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 600;
  color: rgba(255, 255, 255, 0.75);
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.contact-form input,
.contact-form textarea {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.3);
  color: #ffffff;
  border-radius: var(--radius-md);
  padding: var(--space-3) var(--space-4);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  transition: border-color var(--transition-fast), background var(--transition-fast);
  width: 100%;
}

.contact-form input::placeholder,
.contact-form textarea::placeholder {
  color: rgba(255, 255, 255, 0.5);
}

.contact-form input:focus,
.contact-form textarea:focus {
  outline: none;
  border-color: rgba(255, 255, 255, 0.7);
  background: rgba(255, 255, 255, 0.15);
}

.contact-form textarea {
  resize: vertical;
  min-height: 140px;
  line-height: 1.6;
}

.contact-form__submit {
  align-self: flex-start;
}


/* ============================================================
   15. FOOTER
   ============================================================ */
.footer {
  background: var(--color-text);
  color: rgba(255, 255, 255, 0.7);
  padding: var(--space-8) 0;
}

.footer__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.footer__brand {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: var(--text-base);
  color: #ffffff;
}

.footer__copy {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.5);
}

.footer__links {
  display: flex;
  align-items: center;
  gap: var(--space-5);
  list-style: none;
}

.footer__links a {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.6);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer__links a:hover {
  color: var(--color-primary-light);
}

.footer__heart {
  color: var(--color-accent);
}


/* ============================================================
   16. SCROLL ANIMATIONS (AOS-style)
   ============================================================ */
[data-aos] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

[data-aos].visible {
  opacity: 1;
  transform: translateY(0);
}

[data-aos-delay="1"] { transition-delay: 0.1s; }
[data-aos-delay="2"] { transition-delay: 0.2s; }
[data-aos-delay="3"] { transition-delay: 0.3s; }
[data-aos-delay="4"] { transition-delay: 0.4s; }
[data-aos-delay="5"] { transition-delay: 0.5s; }
[data-aos-delay="6"] { transition-delay: 0.6s; }

/* Fade-in from left variant */
[data-aos="fade-right"] {
  opacity: 0;
  transform: translateX(-24px);
}

[data-aos="fade-right"].visible {
  opacity: 1;
  transform: translateX(0);
}

/* Fade-in from right variant */
[data-aos="fade-left"] {
  opacity: 0;
  transform: translateX(24px);
}

[data-aos="fade-left"].visible {
  opacity: 1;
  transform: translateX(0);
}

/* Scale-in variant */
[data-aos="zoom-in"] {
  opacity: 0;
  transform: scale(0.92);
}

[data-aos="zoom-in"].visible {
  opacity: 1;
  transform: scale(1);
}


/* ============================================================
   17. MISC / UTILITY CLASSES
   ============================================================ */

/* Divider */
.divider {
  height: 1px;
  background: var(--color-border);
  margin: var(--space-8) 0;
}

/* Text utilities */
.text-primary { color: var(--color-primary); }
.text-accent { color: var(--color-accent); }
.text-muted { color: var(--color-text-muted); }
.text-secondary { color: var(--color-text-secondary); }

/* Font utilities */
.font-heading { font-family: var(--font-heading); }
.font-body { font-family: var(--font-body); }
.font-mono { font-family: var(--font-mono); }

/* Loading / skeleton */
.skeleton {
  background: linear-gradient(
    90deg,
    var(--color-border-light) 25%,
    var(--color-border) 50%,
    var(--color-border-light) 75%
  );
  background-size: 200% 100%;
  animation: skeleton-shimmer 1.5s infinite;
  border-radius: var(--radius-md);
}

@keyframes skeleton-shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* Card base */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
}

/* Back to top */
.back-to-top {
  position: fixed;
  bottom: var(--space-8);
  right: var(--space-8);
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-lg);
  text-decoration: none;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: all var(--transition-base);
  z-index: 50;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--color-primary-dark);
  transform: translateY(-2px);
}


/* ============================================================
   18. RESPONSIVE — TABLET (768px – 1024px)
   ============================================================ */
@media (max-width: 1024px) {
  .section {
    padding-top: var(--space-16);
    padding-bottom: var(--space-16);
  }

  .section-title {
    font-size: var(--text-3xl);
  }

  .hero__layout {
    grid-template-columns: 1fr;
    gap: var(--space-12);
  }

  .hero__right {
    grid-column: 1;
    max-width: 480px;
  }

  .hero__name {
    font-size: var(--text-5xl);
  }

  .hero__tagline {
    font-size: var(--text-2xl);
  }

  .about__grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-10);
  }

  .interests__grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .projects__grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .skills__categories {
    grid-template-columns: repeat(2, 1fr);
  }

  .contact__grid {
    gap: var(--space-10);
  }

  /* Repo grid stays 2-col on tablet */

  .nav__links {
    gap: var(--space-4);
  }
}


/* ============================================================
   19. RESPONSIVE — MOBILE (<768px)
   ============================================================ */
@media (max-width: 767px) {
  :root {
    --container-padding: var(--space-4);
  }

  .section {
    padding-top: var(--space-12);
    padding-bottom: var(--space-12);
  }

  .section-title {
    font-size: var(--text-3xl);
  }

  /* Nav mobile */
  .nav__links,
  .nav__cta {
    display: none;
  }

  .nav__hamburger {
    display: flex;
  }

  .nav__mobile-menu.is-visible {
    display: block;
  }

  .nav__mobile-menu.open {
    transform: translateY(0);
  }

  /* Hero mobile */
  .hero__layout {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  .hero__left,
  .hero__right {
    grid-column: 1;
  }

  .hero__name {
    font-size: var(--text-4xl);
    letter-spacing: -0.02em;
  }

  .hero__tagline {
    font-size: var(--text-2xl);
  }

  .hero__tagline-wrap {
    min-height: 2em;
  }

  .hero__desc {
    font-size: var(--text-base);
    max-width: 100%;
  }

  .hero__ctas {
    flex-direction: column;
    align-items: flex-start;
    width: 100%;
  }

  .hero__ctas .btn {
    width: 100%;
    justify-content: center;
    min-height: 52px;
    font-size: var(--text-base);
  }

  .hero__photo {
    max-width: 320px;
    margin: 0 auto;
  }

  /* About mobile */
  .about__grid {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  .about__photo-col {
    order: -1;
  }

  .about__photo {
    max-width: 280px;
    margin: 0 auto;
  }

  .about__stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-4);
    text-align: center;
  }

  .about__stat-number {
    font-size: var(--text-3xl);
  }

  /* Research interests mobile — 2 columns */
  .interests__grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-4);
  }

  .interest-card {
    padding: var(--space-4);
  }

  .interest-card__title {
    font-size: var(--text-base);
  }

  /* Projects filter — horizontal scroll, no wrap */
  .projects__filter {
    display: flex;
    flex-wrap: nowrap;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scroll-snap-type: x mandatory;
    padding-bottom: var(--space-2);
    gap: var(--space-2);
    scrollbar-width: none;
    -ms-overflow-style: none;
  }

  .projects__filter::-webkit-scrollbar {
    display: none;
  }

  .filter-btn {
    flex-shrink: 0;
    scroll-snap-align: start;
    min-height: 44px;
  }

  /* Projects mobile — 1 column */
  .projects__grid {
    grid-template-columns: 1fr;
  }

  /* Teaching mobile — 1 column */
  .teaching__grid {
    grid-template-columns: 1fr;
  }

  /* Repo grid — 1 column on mobile */
  .repo-grid {
    grid-template-columns: 1fr;
    gap: var(--space-4);
  }

  /* Skills mobile */
  .skills__categories {
    grid-template-columns: 1fr;
    gap: var(--space-6);
  }

  .skill-tag {
    font-size: var(--text-sm);
    padding: var(--space-2) var(--space-4);
    min-height: 36px;
    display: inline-flex;
    align-items: center;
  }

  /* Contact mobile — 1 column */
  .contact__grid {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  .contact-form__row {
    grid-template-columns: 1fr;
  }

  .contact__info-item {
    flex-direction: column;
    gap: var(--space-1);
  }

  .social-links {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-3);
    justify-content: center;
  }

  .social-link {
    min-width: 48px;
    min-height: 48px;
  }

  .contact-form input,
  .contact-form textarea,
  .contact-form select {
    font-size: 16px; /* 防止 iOS 自动缩放 */
    min-height: 48px;
  }

  .contact-form textarea {
    min-height: 120px;
  }

  /* Footer mobile */
  .footer__inner {
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: var(--space-3);
  }

  .footer__links {
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--space-3);
  }

  /* Timeline mobile */
  .timeline__list {
    padding-left: var(--space-6);
  }

  /* Back-to-top mobile */
  .back-to-top {
    bottom: var(--space-5);
    right: var(--space-5);
    width: 40px;
    height: 40px;
    font-size: var(--text-base);
  }

  /* Publication items mobile */
  .pub-item {
    padding: var(--space-4);
  }

  .pub-item__header {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-2);
  }

  .pub-tabs {
    gap: var(--space-1);
  }

  /* Pub tabs mobile */
  .pub-tab {
    min-height: 44px;
    font-size: var(--text-xs);
    padding: var(--space-2) var(--space-3);
  }

  /* Touch targets — minimum 44px for all interactive elements */
  .btn {
    min-height: 44px;
  }

  .nav__mobile-links li a {
    min-height: 44px;
    display: flex;
    align-items: center;
  }

  .repo-card__link {
    min-height: 44px;
    display: inline-flex;
    align-items: center;
  }
}


/* ============================================================
   20a. RESPONSIVE — EXTRA SMALL (<390px)
   ============================================================ */
@media (max-width: 390px) {
  :root {
    --container-padding: var(--space-3);
  }

  .section {
    padding-top: var(--space-10);
    padding-bottom: var(--space-10);
  }

  .section-title {
    font-size: var(--text-2xl);
  }

  /* Hero on 375px-class phones */
  .hero__name {
    font-size: 2rem;
  }

  .hero__tagline {
    font-size: 1.25rem;
  }

  .hero__eyebrow {
    font-size: 0.7rem;
  }

  .hero__badges {
    flex-direction: column;
    align-items: flex-start;
  }

  /* Interest cards — single column on very small screens */
  .interests__grid {
    grid-template-columns: 1fr;
  }
}


/* ============================================================
   20b. TOUCH FEEDBACK — hover: none (mobile/touch devices)
   ============================================================ */
@media (hover: none) {
  .btn:active {
    transform: scale(0.97);
    opacity: 0.9;
  }

  .project-card:active {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
  }

  .interest-card:active {
    transform: translateY(-2px);
  }

  .nav__mobile-links li a:active {
    color: var(--color-primary);
  }
}


/* ============================================================
   20c. iOS SAFARI FIXES
   ============================================================ */

/* Prevent iOS bounce-scroll issues on horizontal scroll containers */
.projects__filter {
  -webkit-overflow-scrolling: touch;
}

/* Fix position: sticky stacking context on iOS */
.nav {
  -webkit-transform: translateZ(0);
}

/* Fix 100vh including browser chrome on iOS — svh with vh fallback */
.hero {
  min-height: 100vh;
  min-height: 100svh;
}


/* ============================================================
   20. PRINT STYLES
   ============================================================ */
@media print {
  .nav,
  .hero__scroll,
  .back-to-top,
  .contact-form,
  .nav__hamburger,
  .nav__mobile-menu {
    display: none !important;
  }

  .section {
    padding-top: var(--space-8);
    padding-bottom: var(--space-8);
    page-break-inside: avoid;
  }

  body {
    font-size: 12pt;
    color: #000;
    background: #fff;
  }

  a {
    text-decoration: underline;
    color: var(--color-primary);
  }

  .contact {
    background: var(--color-surface-alt);
    color: var(--color-text);
  }

  .contact .section-title,
  .contact .section-label,
  .contact .section-subtitle {
    color: var(--color-text);
  }
}


/* ============================================================
   TASK 1 — Research Evolution Timeline
   Added below .about__stats in the About section
   ============================================================ */
.research-timeline {
  margin-top: var(--space-10);
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-border-light);
}

.research-timeline__header {
  margin-bottom: var(--space-6);
}

.research-timeline__label {
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 2.5px;
  text-transform: uppercase;
  color: var(--color-text-muted);
}

/* Horizontal track on desktop */
.research-timeline__track {
  display: flex;
  align-items: flex-start;
  gap: 0;
  position: relative;
}

/* Each phase node */
.rt-node {
  display: flex;
  flex-direction: column;
  align-items: center;
  flex: 1;
  position: relative;
}

/* Dot / icon circle */
.rt-node__dot {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  font-size: 1rem;
  flex-shrink: 0;
  transition: all var(--transition-base);
  z-index: 2;
  position: relative;
}

/* Connector line between nodes */
.rt-node__connector {
  position: absolute;
  top: 21px; /* center of dot (44/2 - 1) */
  left: 50%;
  width: 100%;
  height: 2px;
  background: linear-gradient(to right, var(--color-border) 0%, var(--color-border-light) 100%);
  z-index: 1;
}

/* Last node has no connector */
.rt-node:last-child .rt-node__connector {
  display: none;
}

/* Phase-specific colors */
.rt-node[data-phase="tourism"] .rt-node__dot {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-accent-light);
}

.rt-node[data-phase="ecology"] .rt-node__dot {
  border-color: var(--color-earth);
  color: var(--color-earth);
  background: var(--color-earth-light);
}

.rt-node[data-phase="gis"] .rt-node__dot {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-primary-light);
}

.rt-node[data-phase="geoai"] .rt-node__dot {
  border-color: var(--color-primary);
  color: #ffffff;
  background: var(--color-primary);
  box-shadow: 0 0 0 4px var(--color-primary-light);
}

/* Active node indicator */
.rt-node--active .rt-node__dot {
  transform: scale(1.1);
}

/* Content below dot */
.rt-node__content {
  text-align: center;
  margin-top: var(--space-3);
  padding: 0 var(--space-2);
}

.rt-node__period {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  font-weight: 600;
  color: var(--color-text-muted);
  letter-spacing: 0.5px;
  margin-bottom: var(--space-1);
}

.rt-node__title {
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  font-weight: 700;
  color: var(--color-text);
  line-height: 1.3;
  margin-bottom: var(--space-2);
}

.rt-node--active .rt-node__title {
  color: var(--color-primary);
}

/* Keyword tags inside each node */
.rt-node__tags {
  display: flex;
  flex-wrap: wrap;
  gap: 3px;
  justify-content: center;
}

.rt-node__tags span {
  font-family: var(--font-heading);
  font-size: 0.6rem;
  font-weight: 500;
  padding: 1px 6px;
  border-radius: var(--radius-full);
  background: var(--color-surface-alt);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border-light);
  white-space: nowrap;
}

/* Phase-specific tag accents */
.rt-node[data-phase="tourism"] .rt-node__tags span {
  background: var(--color-accent-light);
  color: var(--color-accent-dark);
  border-color: rgba(212,132,90,0.2);
}

.rt-node[data-phase="ecology"] .rt-node__tags span {
  background: var(--color-earth-light);
  color: var(--color-earth);
  border-color: rgba(123,158,135,0.2);
}

.rt-node[data-phase="gis"] .rt-node__tags span,
.rt-node[data-phase="geoai"] .rt-node__tags span {
  background: var(--color-primary-light);
  color: var(--color-primary);
  border-color: rgba(27,108,168,0.2);
}

/* Hover effect on nodes */
.rt-node:hover .rt-node__dot {
  transform: scale(1.15);
  box-shadow: 0 4px 12px rgba(0,0,0,0.12);
}

.rt-node--active:hover .rt-node__dot {
  transform: scale(1.2);
}

/* Responsive: vertical on mobile */
@media (max-width: 767px) {
  .research-timeline__track {
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
  }

  .rt-node {
    flex-direction: row;
    align-items: flex-start;
    width: 100%;
    padding-bottom: var(--space-6);
  }

  .rt-node__connector {
    position: absolute;
    top: 44px;
    left: 21px; /* center of dot */
    width: 2px;
    height: calc(100% - 22px);
    background: linear-gradient(to bottom, var(--color-border) 0%, var(--color-border-light) 100%);
  }

  .rt-node:last-child {
    padding-bottom: 0;
  }

  .rt-node__content {
    text-align: left;
    margin-top: 0;
    margin-left: var(--space-4);
    padding: 0;
  }

  .rt-node__tags {
    justify-content: flex-start;
  }
}

@media (max-width: 1024px) and (min-width: 768px) {
  .rt-node__title {
    font-size: 0.7rem;
  }

  .rt-node__period {
    font-size: 0.6rem;
  }
}


/* ============================================================
   TASK 2 — Hero Contour Canvas
   Canvas covers hero__bg and animates via JS
   ============================================================ */
.hero__bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 0;
}

.hero__contour-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  opacity: 0.35;
}

/* Respect reduced motion — canvas animation handled in JS */
@media (prefers-reduced-motion: reduce) {
  .hero__contour-canvas {
    display: none;
  }
}


/* ============================================================
   TASK 3 — Project Card: Left Accent Bar + Category Badge
   ============================================================ */

/* Left 4px accent bar via pseudo-element */
.project-card {
  position: relative;
  overflow: visible; /* allow badge to overflow */
  padding-left: calc(var(--space-6) + 4px); /* make room for bar */
}

.project-card::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  border-radius: var(--radius-sm) 0 0 var(--radius-sm);
  background: var(--color-border);
  transition: width var(--transition-base), background var(--transition-base), border-radius var(--transition-base);
}

/* Category-specific bar colors via data-primary-category */
.project-card[data-primary-category="ecology"]::before {
  background: var(--color-earth);
}

.project-card[data-primary-category="geoai"]::before {
  background: var(--color-primary);
}

.project-card[data-primary-category="gis"]::before {
  background: var(--color-accent);
}

.project-card[data-primary-category="mobility"]::before {
  background: var(--color-accent);
}

/* Hover: bar expands into subtle full gradient background */
.project-card:hover::before {
  width: 100%;
  border-radius: var(--radius-xl);
  opacity: 0.06;
}

.project-card[data-primary-category="ecology"]:hover::before {
  background: linear-gradient(135deg, var(--color-earth) 0%, transparent 60%);
  opacity: 1;
}

.project-card[data-primary-category="geoai"]:hover::before {
  background: linear-gradient(135deg, var(--color-primary) 0%, transparent 60%);
  opacity: 1;
}

.project-card[data-primary-category="gis"]:hover::before,
.project-card[data-primary-category="mobility"]:hover::before {
  background: linear-gradient(135deg, var(--color-accent) 0%, transparent 60%);
  opacity: 1;
}

/* Category badge — top right corner */
.project-card__cat-badge {
  position: absolute;
  top: var(--space-4);
  right: var(--space-4);
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px var(--space-3);
  border-radius: var(--radius-full);
  font-family: var(--font-heading);
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  white-space: nowrap;
  z-index: 2;
  pointer-events: none;
}

.project-card__cat-badge--ecology {
  background: var(--color-earth-light);
  color: var(--color-earth);
  border: 1px solid rgba(123,158,135,0.3);
}

.project-card__cat-badge--geoai {
  background: var(--color-primary-light);
  color: var(--color-primary);
  border: 1px solid rgba(27,108,168,0.3);
}

.project-card__cat-badge--gis {
  background: var(--color-accent-light);
  color: var(--color-accent-dark);
  border: 1px solid rgba(212,132,90,0.3);
}

.project-card__cat-badge--mobility {
  background: var(--color-accent-light);
  color: var(--color-accent-dark);
  border: 1px solid rgba(212,132,90,0.3);
}


/* ============================================================
   TASK 4 — Skills Three-Tier Pill Badge System
   ============================================================ */
.skills__tier {
  margin-bottom: var(--space-10);
}

.skills__tier:last-child {
  margin-bottom: 0;
}

.skills__tier-header {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--color-border-light);
}

.skills__tier-header i {
  color: var(--color-primary);
  font-size: var(--text-base);
  width: 20px;
  text-align: center;
}

.skills__tier--2 .skills__tier-header i {
  color: var(--color-earth);
}

.skills__tier--3 .skills__tier-header i {
  color: var(--color-text-muted);
}

.skills__tier-label {
  font-family: var(--font-heading);
  font-size: var(--text-sm);
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: 0.5px;
}

.skills__tier-desc {
  font-family: var(--font-heading);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-left: auto;
  font-weight: 500;
}

.skills__pills {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  align-items: center;
}

/* Base pill styles */
.skill-pill {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  border-radius: var(--radius-full);
  font-family: var(--font-heading);
  font-weight: 600;
  white-space: nowrap;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
  cursor: default;
}

.skill-pill:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

/* TIER 1: Large, fully filled pills */
.skill-pill--t1 {
  font-size: var(--text-sm);
  padding: var(--space-2) var(--space-5);
}

/* TIER 2: Medium, outlined pills */
.skill-pill--t2 {
  font-size: var(--text-sm);
  padding: var(--space-2) var(--space-4);
  background: var(--color-surface);
}

/* TIER 3: Small, dashed border pills */
.skill-pill--t3 {
  font-size: var(--text-xs);
  padding: var(--space-1) var(--space-3);
  background: var(--color-surface-alt);
  opacity: 0.85;
}

/* Category color variants */

/* GIS — Primary blue */
.skill-pill--t1.skill-pill--gis {
  background: var(--color-primary);
  color: #ffffff;
  border: 2px solid var(--color-primary);
}

.skill-pill--t2.skill-pill--gis {
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.skill-pill--t3.skill-pill--gis {
  color: var(--color-primary);
  border: 2px dashed rgba(27,108,168,0.5);
}

/* Code — Earth green */
.skill-pill--t1.skill-pill--code {
  background: var(--color-earth);
  color: #ffffff;
  border: 2px solid var(--color-earth);
}

.skill-pill--t2.skill-pill--code {
  color: var(--color-earth);
  border: 2px solid var(--color-earth);
}

.skill-pill--t3.skill-pill--code {
  color: var(--color-earth);
  border: 2px dashed rgba(123,158,135,0.5);
}

/* Method / Accent — Terracotta orange */
.skill-pill--t1.skill-pill--method {
  background: var(--color-accent);
  color: #ffffff;
  border: 2px solid var(--color-accent);
}

.skill-pill--t2.skill-pill--method {
  color: var(--color-accent-dark);
  border: 2px solid var(--color-accent);
}

.skill-pill--t3.skill-pill--method {
  color: var(--color-accent-dark);
  border: 2px dashed rgba(212,132,90,0.5);
}

/* Language pills */
.skill-pill--lang {
  border: 2px solid var(--color-border);
  color: var(--color-text-secondary);
}

.skill-pill--lang i {
  color: var(--color-earth);
}

/* Mobile adjustments */
@media (max-width: 767px) {
  .skills__tier-desc {
    display: none;
  }

  .skill-pill--t1 {
    font-size: var(--text-xs);
    padding: var(--space-2) var(--space-4);
  }
}


/* ============================================================
   TASK 5 — Section Wave Transitions
   ============================================================ */
.section-wave {
  position: relative;
  line-height: 0;
  overflow: hidden;
}

.section-wave svg {
  display: block;
  width: 100%;
}

/* Hero → About wave: sits at bottom of hero */
.section-wave--hero-to-about {
  position: absolute;
  bottom: -1px;
  left: 0;
  right: 0;
  z-index: 2;
  pointer-events: none;
}

.hero {
  /* ensure hero has position relative for the wave child */
  position: relative;
}

/* GitHub/Open Source → Contact wave */
.section-wave--to-contact {
  background: var(--color-bg); /* matches the preceding section */
  margin-bottom: -2px;
}

.section-wave--to-contact svg path {
  /* fill matches the contact section gradient start */
  fill: var(--color-primary);
}

/* Subtle angle/clip on About section bottom edge */
.about {
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 40px), 50% 100%, 0 calc(100% - 40px));
  padding-bottom: calc(var(--space-24) + 40px);
}

/* Compensate for clip-path on tablet */
@media (max-width: 1024px) {
  .about {
    clip-path: polygon(0 0, 100% 0, 100% calc(100% - 28px), 50% 100%, 0 calc(100% - 28px));
    padding-bottom: calc(var(--space-16) + 28px);
  }
}

/* Remove clip-path on mobile to avoid overflow issues */
@media (max-width: 767px) {
  .about {
    clip-path: none;
    padding-bottom: var(--space-12);
  }
}

/* Respect reduced motion for wave SVG animation (none here, static only) */
@media (prefers-reduced-motion: reduce) {
  .section-wave {
    display: none;
  }
  .about {
    clip-path: none;
    padding-bottom: var(--space-24);
  }
}