/* ===========================
   CHE102 Course Website Styles
   Engineering Chemistry – AUMP
   =========================== */

/* ── Google Fonts ── */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=JetBrains+Mono:wght@400;600&display=swap');

/* ── CSS Custom Properties ── */
:root {
  --color-navy:      #0f2a4a;
  --color-navy-mid:  #1e3a5f;
  --color-navy-light:#2d5a8e;
  --color-teal:      #0d9488;
  --color-teal-light:#14b8a6;
  --color-amber:     #f59e0b;
  --color-orange:    #f97316;
  --color-red:       #ef4444;
  --color-green:     #22c55e;
  --color-white:     #ffffff;
  --color-gray-50:   #f8fafc;
  --color-gray-100:  #f1f5f9;
  --color-gray-200:  #e2e8f0;
  --color-gray-400:  #94a3b8;
  --color-gray-600:  #475569;
  --color-gray-800:  #1e293b;

  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;

  --shadow-sm:  0 1px 3px rgba(0,0,0,.1), 0 1px 2px rgba(0,0,0,.06);
  --shadow-md:  0 4px 6px rgba(0,0,0,.07), 0 2px 4px rgba(0,0,0,.06);
  --shadow-lg:  0 10px 15px rgba(0,0,0,.08), 0 4px 6px rgba(0,0,0,.05);
  --shadow-xl:  0 20px 25px rgba(0,0,0,.1),  0 10px 10px rgba(0,0,0,.04);

  --radius-sm:  .375rem;
  --radius-md:  .75rem;
  --radius-lg:  1.25rem;
  --radius-full: 9999px;

  --transition: .25s cubic-bezier(.4,0,.2,1);
}

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

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: var(--font-sans);
  color: var(--color-gray-800);
  background: var(--color-gray-50);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }
a   { color: inherit; text-decoration: none; }

/* ── Typography helpers ── */
.text-gradient {
  background: linear-gradient(135deg, var(--color-teal-light), var(--color-amber));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ── Layout ── */
.container {
  width: 100%;
  max-width: 1200px;
  margin-inline: auto;
  padding-inline: 1.5rem;
}

.section { padding-block: 5rem; }
.section-sm { padding-block: 3rem; }

/* ── Navbar ── */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  background: rgba(15,42,74,.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255,255,255,.08);
  transition: background var(--transition);
}

.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
  gap: 1rem;
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: .75rem;
  color: var(--color-white);
  font-weight: 700;
  font-size: 1.125rem;
  white-space: nowrap;
  flex-shrink: 0;
}

.navbar-brand .brand-badge {
  background: linear-gradient(135deg, var(--color-teal), var(--color-teal-light));
  color: white;
  font-size: .7rem;
  font-weight: 800;
  letter-spacing: .08em;
  padding: .25rem .55rem;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
}

.navbar-nav {
  display: flex;
  align-items: center;
  gap: .25rem;
  list-style: none;
}

.navbar-nav a {
  color: rgba(255,255,255,.82);
  font-size: .875rem;
  font-weight: 500;
  padding: .45rem .85rem;
  border-radius: var(--radius-sm);
  transition: color var(--transition), background var(--transition);
}

.navbar-nav a:hover,
.navbar-nav a.active {
  color: var(--color-white);
  background: rgba(255,255,255,.1);
}

.navbar-actions {
  display: flex;
  align-items: center;
  gap: .75rem;
  flex-shrink: 0;
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: .5rem;
  background: none;
  border: none;
}
.hamburger span {
  display: block;
  width: 22px; height: 2px;
  background: var(--color-white);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}
.hamburger.open span:nth-child(1) { transform: rotate(45deg) translate(5px,5px); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: rotate(-45deg) translate(5px,-5px); }

.mobile-menu {
  display: none;
  background: var(--color-navy);
  border-top: 1px solid rgba(255,255,255,.08);
  padding: 1rem 1.5rem;
}
.mobile-menu.open { display: block; }
.mobile-menu a {
  display: block;
  color: rgba(255,255,255,.82);
  padding: .65rem .75rem;
  border-radius: var(--radius-sm);
  font-size: .9rem;
  transition: color var(--transition), background var(--transition);
}
.mobile-menu a:hover { color: white; background: rgba(255,255,255,.08); }

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5rem;
  padding: .625rem 1.5rem;
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: .9rem;
  font-weight: 600;
  cursor: pointer;
  border: 2px solid transparent;
  transition: all var(--transition);
  white-space: nowrap;
  line-height: 1;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-teal), var(--color-teal-light));
  color: white;
  box-shadow: 0 4px 14px rgba(13,148,136,.35);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(13,148,136,.45);
  filter: brightness(1.08);
}

.btn-secondary {
  background: transparent;
  color: var(--color-white);
  border-color: rgba(255,255,255,.4);
}
.btn-secondary:hover {
  background: rgba(255,255,255,.1);
  border-color: rgba(255,255,255,.7);
}

.btn-outline {
  background: transparent;
  color: var(--color-teal);
  border-color: var(--color-teal);
}
.btn-outline:hover {
  background: var(--color-teal);
  color: white;
}

.btn-sm { padding: .45rem 1rem; font-size: .8rem; }
.btn-lg { padding: .9rem 2rem; font-size: 1rem; border-radius: var(--radius-md); }
.btn-xl { padding: 1.1rem 2.5rem; font-size: 1.1rem; border-radius: var(--radius-md); }

/* ── Hero Section ── */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--color-navy) 0%, var(--color-navy-mid) 50%, #1a4a6b 100%);
  overflow: hidden;
  padding-top: 68px;
}

.hero-canvas {
  position: absolute;
  inset: 0;
  overflow: hidden;
}

.hero-particles {
  position: absolute;
  inset: 0;
}

/* Animated molecule dots */
.molecule-dot {
  position: absolute;
  border-radius: 50%;
  background: rgba(255,255,255,.06);
  animation: float linear infinite;
}

@keyframes float {
  0%   { transform: translateY(0) rotate(0deg); opacity: .5; }
  50%  { opacity: .15; }
  100% { transform: translateY(-100vh) rotate(360deg); opacity: 0; }
}

.hero-content {
  position: relative;
  z-index: 10;
  text-align: center;
  padding: 2rem 1.5rem;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  background: rgba(13,148,136,.25);
  border: 1px solid rgba(20,184,166,.4);
  color: var(--color-teal-light);
  padding: .45rem 1.1rem;
  border-radius: var(--radius-full);
  font-size: .8rem;
  font-weight: 600;
  letter-spacing: .08em;
  text-transform: uppercase;
  margin-bottom: 1.75rem;
}

.hero-title {
  font-size: clamp(2.25rem, 6vw, 4rem);
  font-weight: 800;
  color: var(--color-white);
  line-height: 1.15;
  margin-bottom: 1rem;
}

.hero-subtitle {
  font-size: clamp(1rem, 2.5vw, 1.35rem);
  color: rgba(255,255,255,.7);
  margin-bottom: .75rem;
  font-weight: 400;
}

.hero-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 1.5rem;
  color: rgba(255,255,255,.5);
  font-size: .85rem;
  margin-bottom: 2.5rem;
}

.hero-meta span {
  display: flex;
  align-items: center;
  gap: .35rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
}

/* Scroll indicator */
.scroll-indicator {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: .4rem;
  color: rgba(255,255,255,.4);
  font-size: .75rem;
  animation: bounce 2s ease-in-out infinite;
}
.scroll-indicator svg { width: 20px; height: 20px; }

@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50%       { transform: translateX(-50%) translateY(6px); }
}

/* ── Section Headers ── */
.section-header {
  text-align: center;
  margin-bottom: 3.5rem;
}

.section-label {
  display: inline-block;
  color: var(--color-teal);
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  margin-bottom: .75rem;
}

.section-title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 800;
  color: var(--color-navy);
  line-height: 1.2;
  margin-bottom: 1rem;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--color-gray-600);
  max-width: 600px;
  margin-inline: auto;
}

/* ── Cards ── */
.card {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  overflow: hidden;
  transition: transform var(--transition), box-shadow var(--transition);
}
.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
}

.card-body { padding: 1.75rem; }
.card-header-custom {
  background: linear-gradient(135deg, var(--color-navy), var(--color-navy-light));
  color: white;
  padding: 1.25rem 1.75rem;
}

/* ── Feature Grid ── */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.75rem;
}

.feature-card {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  padding: 2rem;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--color-gray-100);
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}
.feature-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--color-teal), var(--color-teal-light));
  opacity: 0;
  transition: opacity var(--transition);
}
.feature-card:hover::before { opacity: 1; }
.feature-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-xl);
}

.feature-icon {
  width: 52px; height: 52px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.25rem;
  font-size: 1.5rem;
}

.feature-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-navy);
  margin-bottom: .5rem;
}

.feature-desc {
  font-size: .9rem;
  color: var(--color-gray-600);
  line-height: 1.65;
}

/* ── Lab Cards ── */
.lab-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
}

.lab-card {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--color-gray-100);
  overflow: hidden;
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
}
.lab-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-xl);
  border-color: var(--color-teal-light);
}

.lab-card-num {
  background: linear-gradient(135deg, var(--color-navy), var(--color-navy-light));
  color: rgba(255,255,255,.6);
  font-family: var(--font-mono);
  font-size: .75rem;
  font-weight: 600;
  padding: .85rem 1.25rem .5rem;
  letter-spacing: .08em;
}

.lab-card-body {
  padding: 1rem 1.25rem 1.25rem;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.lab-card-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-navy);
  margin-bottom: .75rem;
  line-height: 1.4;
}

.lab-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
  padding-top: .75rem;
  border-top: 1px solid var(--color-gray-100);
}

/* ── CO Badges ── */
.co-badge {
  display: inline-flex;
  align-items: center;
  font-size: .72rem;
  font-weight: 700;
  padding: .2rem .55rem;
  border-radius: var(--radius-full);
  letter-spacing: .05em;
  margin-right: .3rem;
  margin-bottom: .3rem;
}
.co1 { background: #e0f2fe; color: #0369a1; }
.co2 { background: #dcfce7; color: #15803d; }
.co3 { background: #fef3c7; color: #92400e; }
.co4 { background: #f3e8ff; color: #7c3aed; }
.co5 { background: #fce7f3; color: #be185d; }
.co6 { background: #ffedd5; color: #9a3412; }

/* ── Stats Row ── */
.stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1.5rem;
}

.stat-card {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  text-align: center;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--color-gray-100);
}

.stat-value {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--color-navy);
  line-height: 1;
  margin-bottom: .4rem;
}

.stat-label {
  font-size: .85rem;
  color: var(--color-gray-600);
  font-weight: 500;
}

/* ── Timeline ── */
.timeline {
  position: relative;
  padding-left: 2.5rem;
}
.timeline::before {
  content: '';
  position: absolute;
  left: .75rem;
  top: 0; bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, var(--color-teal), var(--color-teal-light));
}

.timeline-item {
  position: relative;
  margin-bottom: 1.75rem;
}
.timeline-item::before {
  content: '';
  position: absolute;
  left: -1.85rem;
  top: .35rem;
  width: 12px; height: 12px;
  border-radius: 50%;
  background: var(--color-teal);
  border: 2px solid white;
  box-shadow: 0 0 0 3px rgba(13,148,136,.2);
}

.timeline-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-navy);
  margin-bottom: .25rem;
}
.timeline-text {
  font-size: .9rem;
  color: var(--color-gray-600);
}

/* ── Table ── */
.table-wrap {
  overflow-x: auto;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

table {
  width: 100%;
  border-collapse: collapse;
  background: white;
}

thead th {
  background: var(--color-navy);
  color: white;
  padding: 1rem 1.25rem;
  font-size: .82rem;
  font-weight: 700;
  letter-spacing: .06em;
  text-align: left;
  text-transform: uppercase;
  white-space: nowrap;
}

tbody tr {
  border-bottom: 1px solid var(--color-gray-100);
  transition: background var(--transition);
}
tbody tr:hover { background: var(--color-gray-50); }
tbody td {
  padding: .9rem 1.25rem;
  font-size: .9rem;
  color: var(--color-gray-800);
  vertical-align: middle;
}
tbody tr:last-child { border-bottom: none; }

/* ── Tabs ── */
.tab-nav {
  display: flex;
  flex-wrap: wrap;
  gap: .35rem;
  border-bottom: 2px solid var(--color-gray-200);
  margin-bottom: 2rem;
}
.tab-btn {
  background: none;
  border: none;
  padding: .75rem 1.25rem;
  font-family: var(--font-sans);
  font-size: .875rem;
  font-weight: 600;
  color: var(--color-gray-600);
  cursor: pointer;
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  transition: all var(--transition);
}
.tab-btn:hover { color: var(--color-teal); background: rgba(13,148,136,.05); }
.tab-btn.active {
  color: var(--color-teal);
  border-bottom-color: var(--color-teal);
  background: rgba(13,148,136,.05);
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ── Alerts / Notices ── */
.alert {
  display: flex;
  align-items: flex-start;
  gap: .75rem;
  padding: 1rem 1.25rem;
  border-radius: var(--radius-md);
  font-size: .9rem;
  line-height: 1.5;
  margin-bottom: 1rem;
}
.alert-info    { background: #eff6ff; border-left: 4px solid #3b82f6; color: #1e40af; }
.alert-warning { background: #fffbeb; border-left: 4px solid #f59e0b; color: #92400e; }
.alert-success { background: #f0fdf4; border-left: 4px solid #22c55e; color: #166534; }
.alert-danger  { background: #fef2f2; border-left: 4px solid #ef4444; color: #991b1b; }

/* ── Login Form ── */
.login-wrap {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--color-navy) 0%, var(--color-navy-mid) 60%, #1a4a6b 100%);
  padding: 2rem 1.5rem;
}

.login-card {
  background: white;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  width: 100%;
  max-width: 440px;
  overflow: hidden;
}

.login-header {
  background: linear-gradient(135deg, var(--color-navy), var(--color-navy-light));
  color: white;
  padding: 2.25rem;
  text-align: center;
}

.login-body { padding: 2.25rem; }

.form-group { margin-bottom: 1.25rem; }

.form-label {
  display: block;
  font-size: .85rem;
  font-weight: 600;
  color: var(--color-gray-800);
  margin-bottom: .45rem;
}

.form-input {
  width: 100%;
  padding: .75rem 1rem;
  border: 2px solid var(--color-gray-200);
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: .9rem;
  color: var(--color-gray-800);
  background: var(--color-gray-50);
  transition: border-color var(--transition), box-shadow var(--transition);
  outline: none;
}
.form-input:focus {
  border-color: var(--color-teal);
  box-shadow: 0 0 0 3px rgba(13,148,136,.15);
  background: white;
}

/* ── Breadcrumb ── */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: .5rem;
  flex-wrap: wrap;
  font-size: .85rem;
  color: var(--color-gray-600);
  margin-bottom: 1.75rem;
}
.breadcrumb a { color: var(--color-teal); }
.breadcrumb a:hover { text-decoration: underline; }
.breadcrumb-sep { color: var(--color-gray-400); }

/* ── Page Header ── */
.page-header {
  background: linear-gradient(135deg, var(--color-navy) 0%, var(--color-navy-mid) 100%);
  color: white;
  padding: 6rem 0 3rem;
  margin-top: 68px;
}
.page-header-title {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 800;
  margin-bottom: .5rem;
}
.page-header-sub {
  color: rgba(255,255,255,.7);
  font-size: 1rem;
}

/* ── Sidebar Layout ── */
.page-layout {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 2rem;
  align-items: start;
}

.sidebar {
  position: sticky;
  top: 88px;
  background: var(--color-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  overflow: hidden;
}
.sidebar-header {
  background: var(--color-navy);
  color: white;
  padding: 1rem 1.25rem;
  font-size: .8rem;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
}
.sidebar-nav a {
  display: flex;
  align-items: center;
  gap: .6rem;
  padding: .75rem 1.25rem;
  color: var(--color-gray-700, #374151);
  font-size: .875rem;
  border-bottom: 1px solid var(--color-gray-100);
  transition: all var(--transition);
}
.sidebar-nav a:hover,
.sidebar-nav a.active {
  background: rgba(13,148,136,.08);
  color: var(--color-teal);
  padding-left: 1.5rem;
}

/* ── Semester Banner ── */
.semester-banner {
  background: linear-gradient(135deg, #064e3b 0%, #065f46 50%, #047857 100%);
  color: white;
  border-radius: var(--radius-lg);
  padding: 1.5rem 2rem;
  margin-bottom: 2rem;
  display: flex;
  align-items: center;
  gap: 1.25rem;
  flex-wrap: wrap;
}
.semester-banner-icon { font-size: 2.5rem; }
.semester-banner-text h2 { font-size: 1.2rem; font-weight: 700; }
.semester-banner-text p { font-size: .875rem; opacity: .8; margin-top: .2rem; }
.semester-live-badge {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  background: rgba(255,255,255,.2);
  border: 1px solid rgba(255,255,255,.3);
  color: white;
  padding: .35rem .85rem;
  border-radius: var(--radius-full);
  font-size: .75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .08em;
  margin-left: auto;
}
.live-dot {
  width: 8px; height: 8px;
  background: #4ade80;
  border-radius: 50%;
  animation: pulse 1.5s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: .4; }
}

/* ── Archive Cards ── */
.archive-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
}

.archive-card {
  background: white;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--color-gray-100);
  overflow: hidden;
  transition: all var(--transition);
}
.archive-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
}

.archive-card-header {
  background: linear-gradient(135deg, var(--color-gray-800), var(--color-gray-600));
  color: white;
  padding: 1.25rem;
}

/* ── Footer ── */
.footer {
  background: var(--color-navy);
  color: rgba(255,255,255,.7);
  padding: 4rem 0 2rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 2.5rem;
  margin-bottom: 3rem;
}

.footer-title {
  color: white;
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 1.25rem;
}

.footer-links { list-style: none; }
.footer-links li + li { margin-top: .55rem; }
.footer-links a {
  color: rgba(255,255,255,.6);
  font-size: .875rem;
  transition: color var(--transition);
}
.footer-links a:hover { color: var(--color-teal-light); }

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.08);
  padding-top: 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: .82rem;
}

/* ── Protected Content Overlay ── */
.protected-overlay {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 4rem 2rem;
  background: var(--color-gray-50);
  border-radius: var(--radius-lg);
  border: 2px dashed var(--color-gray-200);
  min-height: 400px;
}

.lock-icon {
  width: 72px; height: 72px;
  background: linear-gradient(135deg, var(--color-navy), var(--color-navy-light));
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.5rem;
  font-size: 2rem;
}

/* ── Accordion ── */
.accordion-item {
  background: white;
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-md);
  overflow: hidden;
  margin-bottom: .75rem;
}
.accordion-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.1rem 1.5rem;
  cursor: pointer;
  font-weight: 600;
  color: var(--color-navy);
  transition: background var(--transition);
}
.accordion-header:hover { background: var(--color-gray-50); }
.accordion-header svg {
  flex-shrink: 0;
  transition: transform var(--transition);
}
.accordion-item.open .accordion-header svg { transform: rotate(180deg); }
.accordion-body {
  display: none;
  padding: 0 1.5rem 1.25rem;
  font-size: .9rem;
  color: var(--color-gray-600);
  line-height: 1.7;
}
.accordion-item.open .accordion-body { display: block; }

/* ── Progress Bar ── */
.progress-bar-wrap {
  background: var(--color-gray-200);
  border-radius: var(--radius-full);
  height: 8px;
  overflow: hidden;
  margin-top: .35rem;
}
.progress-bar-fill {
  height: 100%;
  border-radius: var(--radius-full);
  background: linear-gradient(90deg, var(--color-teal), var(--color-teal-light));
  transition: width 1s ease;
}

/* ── Responsive ── */
@media (max-width: 1024px) {
  .page-layout {
    grid-template-columns: 1fr;
  }
  .sidebar {
    position: static;
    display: none; /* hidden on mobile; toggled via JS */
  }
  .sidebar.show { display: block; }
}

@media (max-width: 768px) {
  .navbar-nav { display: none; }
  .hamburger { display: flex; }

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

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

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }

  .semester-banner { flex-direction: column; align-items: flex-start; }
  .semester-live-badge { margin-left: 0; }
}

@media (max-width: 480px) {
  .section { padding-block: 3.5rem; }
  .stats-row { grid-template-columns: 1fr 1fr; }
  .lab-grid { grid-template-columns: 1fr; }
}

/* ── Utilities ── */
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; }
.mt-1 { margin-top: .25rem; }
.mt-2 { margin-top: .5rem; }
.mt-3 { margin-top: .75rem; }
.mt-4 { margin-top: 1rem; }
.mb-1 { margin-bottom: .25rem; }
.mb-2 { margin-bottom: .5rem; }
.mb-3 { margin-bottom: .75rem; }
.mb-4 { margin-bottom: 1rem; }
.mb-6 { margin-bottom: 1.5rem; }
.mb-8 { margin-bottom: 2rem; }
.gap-1 { gap: .25rem; }
.flex   { display: flex; }
.items-center { align-items: center; }
.flex-wrap { flex-wrap: wrap; }
.justify-between { justify-content: space-between; }
.text-center { text-align: center; }
.text-sm    { font-size: .875rem; }
.text-xs    { font-size: .75rem; }
.text-gray  { color: var(--color-gray-600); }
.text-teal  { color: var(--color-teal); }
.text-navy  { color: var(--color-navy); }
.font-bold  { font-weight: 700; }
.font-semibold { font-weight: 600; }
.rounded-full { border-radius: var(--radius-full); }
.bg-gray    { background: var(--color-gray-100); }
.w-full     { width: 100%; }
.block      { display: block; }
.hidden     { display: none; }