/* ============================================
   Li Group - Modern Academic Website
   ============================================ */

/* --- CSS Variables (Light/Dark Theme) --- */
:root {
  --color-bg: #f8fbff;
  --color-bg-alt: #eef4fb;
  --color-bg-card: #ffffff;
  --color-text: #1a2332;
  --color-text-secondary: #445468;
  --color-text-muted: #7a8a9e;
  --color-accent: #2e86de;
  --color-accent-hover: #1b6dbf;
  --color-accent-light: #e0f0ff;
  --color-border: #d4e2f0;
  --color-shadow: rgba(10, 40, 80, 0.06);
  --color-hero-bg: #0c1a2e;
  --color-hero-text: #f0f6ff;
  --color-hero-sub: #8aa0bc;
  --color-tag-bg: #e8f1fb;
  --color-tag-text: #3a5a7c;
  --color-code-bg: #e8f1fb;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --transition: 0.25s ease;
  --max-width: 1140px;
  --nav-height: 64px;
}

[data-theme="dark"] {
  --color-bg: #0f172a;
  --color-bg-alt: #1e293b;
  --color-bg-card: #1e293b;
  --color-text: #e2e8f0;
  --color-text-secondary: #94a3b8;
  --color-text-muted: #64748b;
  --color-accent: #60a5fa;
  --color-accent-hover: #93bbfd;
  --color-accent-light: #1e3a5f;
  --color-border: #334155;
  --color-shadow: rgba(0, 0, 0, 0.3);
  --color-hero-bg: #020617;
  --color-hero-text: #f1f5f9;
  --color-hero-sub: #64748b;
  --color-tag-bg: #1e293b;
  --color-tag-text: #94a3b8;
  --color-code-bg: #1e293b;
}

/* --- Reset & Base --- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 20px);
}

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  transition: background var(--transition), color var(--transition);
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--color-accent-hover);
}

img {
  max-width: 100%;
  height: auto;
}

/* --- Typography --- */
h1, h2, h3, h4, h5 {
  color: var(--color-text);
  line-height: 1.3;
  font-weight: 700;
}

h1 { font-size: 2.5rem; margin-bottom: 1rem; }
h2 { font-size: 1.75rem; margin-bottom: 0.75rem; }
h3 { font-size: 1.35rem; margin-bottom: 0.5rem; }
h4 { font-size: 1.1rem; margin-bottom: 0.5rem; }

p {
  margin-bottom: 1rem;
  color: var(--color-text-secondary);
}

/* --- Layout --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 80px 0;
}

.section-alt {
  background: var(--color-bg-alt);
}

.section-title {
  text-align: center;
  margin-bottom: 3rem;
}

.section-title h2 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
}

.section-title p {
  color: var(--color-text-muted);
  font-size: 1.05rem;
}

/* --- Navigation --- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
  transition: background var(--transition), border-color var(--transition), box-shadow var(--transition);
}

.navbar.scrolled {
  box-shadow: 0 2px 20px var(--color-shadow);
}

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

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--color-text);
  text-decoration: none;
}

.nav-brand:hover {
  color: var(--color-accent);
}

.nav-brand .brand-icon {
  width: 36px;
  height: 36px;
  background: var(--color-accent);
  color: #fff;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
  list-style: none;
}

.nav-links a {
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: all var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-accent);
  background: var(--color-accent-light);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.theme-toggle {
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 8px;
  cursor: pointer;
  color: var(--color-text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
  width: 38px;
  height: 38px;
}

.theme-toggle:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

.theme-toggle svg {
  width: 18px;
  height: 18px;
}

.mobile-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  color: var(--color-text);
}

.mobile-toggle svg {
  width: 24px;
  height: 24px;
}

/* --- Nav Search --- */
.nav-search-btn {
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 8px;
  cursor: pointer;
  color: var(--color-text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
  width: 38px;
  height: 38px;
}

.nav-search-btn:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

.nav-search-btn svg {
  width: 18px;
  height: 18px;
}

.nav-search-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 1000;
  align-items: flex-start;
  justify-content: center;
  padding-top: 120px;
}

.nav-search-overlay.active {
  display: flex;
}

.nav-search-box {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
  width: 90%;
  max-width: 560px;
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.2);
}

.nav-search-box form {
  display: flex;
  gap: 8px;
}

.nav-search-box input {
  flex: 1;
  padding: 10px 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg);
  color: var(--color-text);
  font-size: 1rem;
  font-family: inherit;
  outline: none;
  transition: border-color var(--transition);
}

.nav-search-box input:focus {
  border-color: var(--color-accent);
}

.nav-search-box button[type="submit"] {
  padding: 10px 20px;
  background: var(--color-accent);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.9rem;
  font-family: inherit;
  transition: background var(--transition);
}

.nav-search-box button[type="submit"]:hover {
  background: var(--color-accent-hover);
}

/* --- Hero --- */
.hero {
  background: var(--color-bg-alt);
  color: var(--color-text);
  padding: 140px 0 100px;
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--color-border);
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(46, 134, 222, 0.08) 0%, transparent 70%);
  border-radius: 50%;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -10%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(46, 134, 222, 0.06) 0%, transparent 70%);
  border-radius: 50%;
}

.hero .container {
  position: relative;
  z-index: 1;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--color-accent-light);
  color: var(--color-accent);
  padding: 6px 16px;
  border-radius: 50px;
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 1.5rem;
  border: 1px solid var(--color-border);
}

.hero h1 {
  font-size: 3.25rem;
  color: var(--color-text);
  margin-bottom: 1rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  max-width: 700px;
}

.hero p {
  font-size: 1.2rem;
  color: var(--color-text-secondary);
  max-width: 600px;
  margin-bottom: 2rem;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition);
  border: none;
  text-decoration: none;
}

.btn-primary {
  background: var(--color-accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(46, 134, 222, 0.3);
}

.btn-outline {
  background: transparent;
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn-outline:hover {
  background: var(--color-bg-card);
  color: var(--color-accent);
  border-color: var(--color-accent);
}

/* --- Cards --- */
.card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: all var(--transition);
}

.card:hover {
  box-shadow: 0 8px 30px var(--color-shadow);
  transform: translateY(-2px);
}

.card-icon {
  width: 48px;
  height: 48px;
  background: var(--color-accent-light);
  color: var(--color-accent);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  font-size: 1.4rem;
}

.card h3 {
  margin-bottom: 0.5rem;
}

.card p {
  font-size: 0.95rem;
  color: var(--color-text-muted);
}

/* --- Grid Layouts --- */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

/* --- Research Areas Grid --- */
.research-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
}

.research-card .card-tag {
  display: inline-block;
  background: var(--color-tag-bg);
  color: var(--color-tag-text);
  padding: 4px 10px;
  border-radius: 4px;
  font-size: 0.8rem;
  font-weight: 500;
  margin-top: 12px;
}

/* --- People Section --- */
.people-section-title {
  font-size: 1.5rem;
  margin: 3rem 0 1.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 2px solid var(--color-accent);
  display: inline-block;
}

.people-section-title:first-of-type {
  margin-top: 0;
}

.pi-card {
  display: grid;
  grid-template-columns: 0.8fr 2.2fr;
  gap: 40px;
  align-items: start;
  margin-bottom: 3rem;
}

.pi-photo {
  width: 100%;
  aspect-ratio: 3/4;
  background: var(--color-bg-alt);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  font-size: 4rem;
  border: 1px solid var(--color-border);
  overflow: hidden;
}

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

.student-card .student-photo {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  object-fit: cover;
  margin-bottom: 12px;
  border: 2px solid var(--color-border);
}

/* Research card images */
.research-card .card-img {
  width: 100%;
  height: 180px;
  object-fit: cover;
  border-radius: var(--radius-sm);
  margin-bottom: 16px;
  background: var(--color-bg-alt);
}

/* Facility card images */
.facility-card .facility-img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: var(--radius-sm);
  margin-bottom: 16px;
  background: var(--color-bg-alt);
}

/* Nav brand logo */
.nav-brand img.brand-logo {
  width: 32px;
  height: 32px;
  border-radius: 4px;
}

.pi-info h2 {
  margin-bottom: 0.25rem;
}

.pi-role {
  color: var(--color-accent);
  font-weight: 600;
  margin-bottom: 1rem;
  display: block;
}

.pi-links {
  display: flex;
  gap: 12px;
  margin-top: 1rem;
  flex-wrap: wrap;
}

.pi-links a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  transition: all var(--transition);
}

.pi-links a:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.student-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}

.student-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
  transition: all var(--transition);
}

.student-card:hover {
  box-shadow: 0 4px 16px var(--color-shadow);
}

.student-card h4 {
  margin-bottom: 4px;
}

.student-card .student-program {
  color: var(--color-accent);
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 8px;
}

.student-card .student-detail {
  color: var(--color-text-muted);
  font-size: 0.85rem;
  margin-bottom: 2px;
}

.student-card .student-email {
  font-size: 0.85rem;
  margin-top: 8px;
}

/* --- Publications --- */
.pub-controls {
  display: flex;
  gap: 12px;
  margin-bottom: 2rem;
  flex-wrap: wrap;
  align-items: center;
}

.pub-search {
  flex: 1;
  min-width: 200px;
  padding: 10px 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg-card);
  color: var(--color-text);
  font-size: 0.95rem;
  font-family: var(--font-sans);
  transition: border-color var(--transition);
}

.pub-search:focus {
  outline: none;
  border-color: var(--color-accent);
}

.pub-filter {
  padding: 10px 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg-card);
  color: var(--color-text);
  font-size: 0.9rem;
  font-family: var(--font-sans);
  cursor: pointer;
}

.pub-filter:focus {
  outline: none;
  border-color: var(--color-accent);
}

.pub-year-group {
  margin-bottom: 2.5rem;
}

.pub-year-heading {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--color-border);
  display: flex;
  align-items: center;
  gap: 12px;
}

.pub-year-heading .pub-count {
  background: var(--color-accent-light);
  color: var(--color-accent);
  padding: 2px 10px;
  border-radius: 50px;
  font-size: 0.8rem;
  font-weight: 600;
}

.pub-item {
  padding: 20px 0;
  border-bottom: 1px solid var(--color-border);
}

.pub-item:last-child {
  border-bottom: none;
}

.pub-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 6px;
  line-height: 1.5;
}

.pub-title a {
  color: var(--color-text);
}

.pub-title a:hover {
  color: var(--color-accent);
}

.pub-authors {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-bottom: 4px;
}

.pub-journal {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  font-style: italic;
}

.pub-links {
  display: flex;
  gap: 8px;
  margin-top: 8px;
  flex-wrap: wrap;
}

.pub-links a {
  font-size: 0.8rem;
  padding: 3px 10px;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  color: var(--color-text-secondary);
  transition: all var(--transition);
}

.pub-links a:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.pub-stats {
  display: flex;
  gap: 2rem;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}

.pub-stat {
  text-align: center;
}

.pub-stat-number {
  font-size: 2rem;
  font-weight: 800;
  color: var(--color-accent);
}

.pub-stat-label {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* --- Teaching --- */
.course-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 32px;
  margin-bottom: 24px;
  transition: all var(--transition);
}

.course-card:hover {
  box-shadow: 0 4px 20px var(--color-shadow);
}

.course-code {
  color: var(--color-accent);
  font-weight: 700;
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 6px;
}

.course-card h3 {
  margin-bottom: 0.5rem;
}

.course-prereq {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 1rem;
}

/* --- Facilities --- */
.facility-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: all var(--transition);
}

.facility-card:hover {
  box-shadow: 0 8px 24px var(--color-shadow);
  transform: translateY(-2px);
}

.facility-icon {
  width: 52px;
  height: 52px;
  background: var(--color-accent-light);
  color: var(--color-accent);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  font-size: 1.5rem;
}

/* --- Contact Form --- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
}

.contact-info-item {
  display: flex;
  gap: 16px;
  margin-bottom: 24px;
}

.contact-icon {
  width: 44px;
  height: 44px;
  min-width: 44px;
  background: var(--color-accent-light);
  color: var(--color-accent);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
}

.contact-info-item h4 {
  margin-bottom: 2px;
}

.contact-info-item p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-bottom: 0;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.form-group label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text-secondary);
}

.form-group input,
.form-group textarea {
  padding: 12px 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg-card);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  transition: border-color var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-accent);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

/* --- Updates / News --- */
.update-item {
  display: flex;
  gap: 20px;
  padding: 24px 0;
  border-bottom: 1px solid var(--color-border);
}

.update-date {
  min-width: 90px;
  text-align: center;
}

.update-date .month {
  font-size: 0.8rem;
  color: var(--color-accent);
  font-weight: 600;
  text-transform: uppercase;
}

.update-date .day {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--color-text);
  line-height: 1.1;
}

.update-date .year {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.update-content h3 {
  margin-bottom: 0.25rem;
  font-size: 1.1rem;
}

.update-content p {
  font-size: 0.9rem;
}

/* --- Page Header --- */
.page-header {
  background: var(--color-bg-alt);
  color: var(--color-text);
  padding: 120px 0 60px;
  text-align: center;
  border-bottom: 1px solid var(--color-border);
}

.page-header h1 {
  color: var(--color-text);
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
}

.page-header p {
  color: var(--color-text-muted);
  font-size: 1.1rem;
}

/* --- Footer --- */
.footer {
  background: var(--color-hero-bg);
  color: var(--color-hero-sub);
  padding: 60px 0 30px;
  margin-top: 80px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer h4 {
  color: var(--color-hero-text);
  margin-bottom: 1rem;
  font-size: 1rem;
}

.footer p {
  color: var(--color-hero-sub);
  font-size: 0.9rem;
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: 8px;
}

.footer-links a {
  color: var(--color-hero-sub);
  font-size: 0.9rem;
  transition: color var(--transition);
}

.footer-links a:hover {
  color: #fff;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 24px;
  text-align: center;
  font-size: 0.85rem;
}


/* --- Scroll Reveal --- */
.scroll-reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.scroll-reveal.revealed {
  opacity: 1;
  transform: translateY(0);
}

/* --- Resource Page --- */
.resource-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
  transition: all var(--transition);
}

.resource-card:hover {
  box-shadow: 0 4px 16px var(--color-shadow);
}

/* --- Responsive --- */
@media (max-width: 1024px) {
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --nav-height: 56px;
  }

  .nav-links {
    display: none;
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--color-bg);
    flex-direction: column;
    padding: 16px;
    border-bottom: 1px solid var(--color-border);
    box-shadow: 0 8px 30px var(--color-shadow);
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    padding: 12px 16px;
    width: 100%;
  }

  .mobile-toggle {
    display: block;
  }

  .hero {
    padding: 100px 0 60px;
  }

  .hero .container {
    grid-template-columns: 1fr !important;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero p {
    font-size: 1rem;
  }

  .section {
    padding: 50px 0;
  }

  h1 { font-size: 1.75rem; }
  h2 { font-size: 1.35rem; }

  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
  }

  .pi-card {
    grid-template-columns: 1fr;
  }

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

  .form-row {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
  }

  .page-header {
    padding: 90px 0 40px;
  }

  .pub-controls {
    flex-direction: column;
  }

  .pub-search {
    min-width: 100%;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 1.65rem;
  }

  .hero-actions {
    flex-direction: column;
  }

  .btn {
    width: 100%;
    justify-content: center;
  }

  .student-grid {
    grid-template-columns: 1fr;
  }
}

/* --- Utility --- */
.text-center { text-align: center; }
.text-accent { color: var(--color-accent); }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }

/* --- Animations --- */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-in {
  opacity: 0;
  animation: fadeInUp 0.6s ease forwards;
}

.animate-in:nth-child(2) { animation-delay: 0.1s; }
.animate-in:nth-child(3) { animation-delay: 0.2s; }
.animate-in:nth-child(4) { animation-delay: 0.3s; }
.animate-in:nth-child(5) { animation-delay: 0.4s; }
.animate-in:nth-child(6) { animation-delay: 0.5s; }