:root {
  --primary: #008751;
  --primary-dark: #006b40;
  --primary-light: #e8f5e9;
  --secondary: #f5c542;
  --accent: #1a237e;
  --bg: #f0f4f8;
  --surface: #ffffff;
  --text: #1e293b;
  --text-muted: #64748b;
  --text-light: #94a3b8;
  --border: #e2e8f0;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.06);
  --shadow-lg: 0 10px 40px rgba(0,0,0,.12);
  --font: 'Segoe UI', system-ui, -apple-system, sans-serif;
  --transition: .25s cubic-bezier(.4,0,.2,1);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; height: auto; display: block; }

/* ─── Global Portal Top Bar ─── */
.portal-topbar {
  background: var(--primary);
  color: #fff;
  padding: 0 1.5rem;
  height: 48px;
  display: flex;
  align-items: center;
  gap: .75rem;
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 8px rgba(0,0,0,.15);
}
.portal-topbar .brand {
  font-weight: 700;
  font-size: .95rem;
  display: flex;
  align-items: center;
  gap: .5rem;
  color: #fff;
  text-decoration: none;
}
.portal-topbar .brand:hover { text-decoration: none; }
.portal-topbar .brand .badge {
  font-size: .6rem;
  background: var(--secondary);
  color: var(--primary-dark);
  padding: .1rem .45rem;
  border-radius: 999px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: .03em;
}
.portal-topbar .breadcrumbs {
  display: flex;
  align-items: center;
  gap: .35rem;
  font-size: .78rem;
  opacity: .9;
  margin-left: auto;
}
.portal-topbar .breadcrumbs a {
  color: rgba(255,255,255,.8);
  text-decoration: none;
}
.portal-topbar .breadcrumbs a:hover { color: #fff; text-decoration: underline; }
.portal-topbar .breadcrumbs .sep {
  color: rgba(255,255,255,.4);
  font-size: .7rem;
}
.portal-topbar .breadcrumbs .current {
  color: var(--secondary);
  font-weight: 600;
}

/* ─── Dashboard Hero ─── */
.hero {
  position: relative;
  background: linear-gradient(135deg, var(--primary-dark) 0%, #00a86b 50%, var(--primary) 100%);
  color: #fff;
  padding: 4rem 2rem 5rem;
  text-align: center;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url('../assets/images/hero-school.jpg') center/cover no-repeat;
  opacity: .15;
  z-index: 0;
}
.hero > * { position: relative; z-index: 1; }
.hero h1 { font-size: clamp(1.8rem, 5vw, 2.8rem); font-weight: 800; margin-bottom: .5rem; }
.hero p { font-size: clamp(.9rem, 2vw, 1.1rem); opacity: .9; max-width: 600px; margin: 0 auto 1.5rem; }
.hero .stats {
  display: flex;
  justify-content: center;
  gap: 2rem;
  flex-wrap: wrap;
  margin-top: 1.5rem;
}
.hero .stat {
  text-align: center;
}
.hero .stat-num {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--secondary);
  line-height: 1;
}
.hero .stat-label {
  font-size: .75rem;
  opacity: .8;
  margin-top: .25rem;
}

/* ─── Class Tabs ─── */
.class-tabs {
  display: flex;
  justify-content: center;
  gap: .5rem;
  margin-top: -1.5rem;
  position: relative;
  z-index: 2;
  padding: 0 1rem;
}
.class-tabs button {
  padding: .65rem 1.5rem;
  border: none;
  border-radius: var(--radius) var(--radius) 0 0;
  background: rgba(255,255,255,.7);
  backdrop-filter: blur(8px);
  font-weight: 700;
  font-size: .85rem;
  color: var(--text-muted);
  cursor: pointer;
  transition: var(--transition);
  box-shadow: 0 -2px 8px rgba(0,0,0,.06);
}
.class-tabs button:hover { background: rgba(255,255,255,.9); color: var(--text); }
.class-tabs button.active {
  background: var(--surface);
  color: var(--primary);
  box-shadow: 0 -2px 12px rgba(0,0,0,.1);
}

/* ─── Subject Grid ─── */
.subject-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
  padding: 2rem 1.5rem 3rem;
  max-width: 1200px;
  margin: 0 auto;
}
.subject-card {
  background: var(--surface);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
  border: 1px solid var(--border);
  display: flex;
  flex-direction: column;
}
.subject-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}
.subject-card .card-img {
  height: 160px;
  background: var(--primary-light);
  position: relative;
  overflow: hidden;
}
.subject-card .card-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform .4s ease;
}
.subject-card:hover .card-img img { transform: scale(1.05); }
.subject-card .card-img .overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(transparent 50%, rgba(0,0,0,.6));
}
.subject-card .card-body {
  padding: 1.25rem;
  flex: 1;
  display: flex;
  flex-direction: column;
}
.subject-card .card-body h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: .35rem;
}
.subject-card .card-body .class-badge {
  display: inline-block;
  font-size: .65rem;
  font-weight: 700;
  background: var(--primary-light);
  color: var(--primary);
  padding: .15rem .55rem;
  border-radius: 999px;
  margin-bottom: .5rem;
  text-transform: uppercase;
  letter-spacing: .03em;
}
.subject-card .card-body p {
  font-size: .82rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
  flex: 1;
}
.subject-card .card-links {
  display: flex;
  gap: .5rem;
  flex-wrap: wrap;
}
.subject-card .card-links a {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  padding: .4rem .85rem;
  border-radius: 999px;
  font-size: .75rem;
  font-weight: 600;
  transition: var(--transition);
  text-decoration: none;
}
.subject-card .card-links a.revision {
  background: var(--primary);
  color: #fff;
}
.subject-card .card-links a.revision:hover {
  background: var(--primary-dark);
  text-decoration: none;
}
.subject-card .card-links a.cbt {
  background: var(--secondary);
  color: var(--primary-dark);
}
.subject-card .card-links a.cbt:hover {
  background: #e6b03a;
  text-decoration: none;
}
.subject-card .card-links a.interactive {
  background: var(--accent);
  color: #fff;
}
.subject-card .card-links a.interactive:hover {
  background: #151b60;
  text-decoration: none;
}

/* ─── Subject Hub Page ─── */
.subject-hero {
  position: relative;
  background: linear-gradient(135deg, var(--primary-dark), var(--primary));
  color: #fff;
  padding: 3rem 2rem;
  text-align: center;
  overflow: hidden;
}
.subject-hero .img-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  opacity: .12;
  z-index: 0;
}
.subject-hero > * { position: relative; z-index: 1; }
.subject-hero h1 { font-size: clamp(1.5rem,4vw,2.2rem); font-weight: 800; margin-bottom: .3rem; }
.subject-hero p { font-size: .9rem; opacity: .85; max-width: 500px; margin: 0 auto; }
.subject-hub-links {
  max-width: 700px;
  margin: 2rem auto;
  padding: 0 1rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.subject-hub-links .hub-item {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  transition: var(--transition);
  display: flex;
  align-items: center;
  gap: 1rem;
  text-decoration: none;
  color: var(--text);
}
.subject-hub-links .hub-item:hover {
  transform: translateX(4px);
  box-shadow: var(--shadow-lg);
  text-decoration: none;
}
.subject-hub-links .hub-item .icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}
.subject-hub-links .hub-item .icon.revision { background: var(--primary-light); color: var(--primary); }
.subject-hub-links .hub-item .icon.cbt { background: #fef3c7; color: #d97706; }
.subject-hub-links .hub-item .icon.interactive { background: #e0e7ff; color: var(--accent); }
.subject-hub-links .hub-item .info h3 { font-size: .95rem; font-weight: 700; }
.subject-hub-links .hub-item .info p { font-size: .78rem; color: var(--text-muted); margin: 0; }

/* ─── Footer ─── */
.portal-footer {
  background: var(--primary-dark);
  color: rgba(255,255,255,.7);
  text-align: center;
  padding: 1.5rem;
  font-size: .78rem;
}
.portal-footer strong { color: var(--secondary); }

/* ─── 404 Page ─── */
.page-404 {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 70vh;
  padding: 2rem;
  text-align: center;
}
.page-404 h1 { font-size: 5rem; font-weight: 800; color: var(--primary); line-height: 1; }
.page-404 p { font-size: 1.1rem; color: var(--text-muted); margin: .5rem 0 1.5rem; }
.page-404 a {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  padding: .75rem 1.5rem;
  background: var(--primary);
  color: #fff;
  border-radius: 999px;
  font-weight: 600;
  font-size: .9rem;
  transition: var(--transition);
}
.page-404 a:hover { background: var(--primary-dark); text-decoration: none; }

/* ─── Utility ─── */
.container { max-width: 1200px; margin: 0 auto; }
.hidden { display: none !important; }

/* ─── Responsive ─── */
@media (max-width: 768px) {
  .subject-grid { grid-template-columns: 1fr; padding: 1rem; gap: 1rem; }
  .hero { padding: 2.5rem 1rem 4rem; }
  .class-tabs button { padding: .5rem 1rem; font-size: .78rem; }
  .portal-topbar { padding: 0 .75rem; }
  .portal-topbar .breadcrumbs { font-size: .7rem; }
  .subject-hub-links .hub-item { padding: 1rem; }
}