/* ===================================================
   JEET PHYSICS — B.Sc Honours Study Portal
   Design System & Styles
=================================================== */

@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;500;600;700;800;900&family=Inter:wght@300;400;500;600&family=JetBrains+Mono:wght@400;500&display=swap');

/* ─── CSS Variables ─── */
:root {
  --bg-deep:        #020818;
  --bg-card:        rgba(8, 20, 50, 0.75);
  --bg-card-hover:  rgba(12, 28, 70, 0.90);
  --border:         rgba(82, 160, 255, 0.18);
  --border-glow:    rgba(82, 160, 255, 0.45);

  --blue-900:  #020818;
  --blue-800:  #051229;
  --blue-700:  #0a2044;
  --blue-600:  #0e3170;
  --blue-500:  #1a52b0;
  --blue-400:  #3b82f6;
  --blue-300:  #7db9ff;
  --blue-200:  #bfdbff;

  --gold-500:  #f59e0b;
  --gold-400:  #fbbf24;
  --gold-300:  #fde68a;

  --cyan-400:  #22d3ee;
  --cyan-300:  #67e8f9;
  --purple-400:#a78bfa;
  --green-400: #34d399;
  --red-400:   #f87171;
  --orange-400:#fb923c;
  --pink-400:  #f472b6;
  --teal-400:  #2dd4bf;

  --text-primary:   #e8f0ff;
  --text-secondary: #9ab3d8;
  --text-muted:     #5a7a9f;

  --font-head: 'Outfit', sans-serif;
  --font-body: 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;

  --shadow-card: 0 4px 32px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 40px rgba(59, 130, 246, 0.25);
  --shadow-gold:  0 0 30px rgba(245, 158, 11, 0.3);

  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
  background: var(--bg-deep);
  color: var(--text-primary);
  font-family: var(--font-body);
  line-height: 1.65;
  overflow-x: hidden;
  min-height: 100vh;
}

::selection { background: rgba(59, 130, 246, 0.4); color: #fff; }

::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--blue-900); }
::-webkit-scrollbar-thumb { background: var(--blue-600); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--blue-400); }

/* ─── Canvas Background ─── */
#starfield {
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
}

/* ─── Noise Overlay ─── */
body::after {
  content: '';
  position: fixed;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.03'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 1;
  opacity: 0.4;
}

/* ─── Layout Wrappers ─── */
.container {
  position: relative; z-index: 2;
  max-width: 1240px; margin: 0 auto; padding: 0 24px;
}

section { padding: 100px 0; }

/* ─── Typography ─── */
h1, h2, h3, h4, h5 { font-family: var(--font-head); line-height: 1.2; }

.gradient-text {
  background: linear-gradient(135deg, #7db9ff 0%, #ffffff 40%, #fbbf24 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}

.gradient-text-blue {
  background: linear-gradient(135deg, var(--blue-300), var(--cyan-300));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-label {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 0.78rem; font-weight: 600; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--gold-400);
  margin-bottom: 16px;
}
.section-label::before {
  content: ''; display: block;
  width: 20px; height: 2px; background: var(--gold-400);
  border-radius: 1px;
}

.section-title {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800; margin-bottom: 18px;
}

.section-subtitle {
  font-size: 1.05rem; color: var(--text-secondary);
  max-width: 600px; margin-bottom: 60px;
}

/* ─── Navbar ─── */
.navbar {
  position: fixed; top: 0; left: 0; right: 0;
  z-index: 1000;
  padding: 0 32px;
  height: 68px;
  display: flex; align-items: center; justify-content: space-between;
  background: rgba(2, 8, 24, 0.82);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  transition: var(--transition);
}

.navbar.scrolled {
  background: rgba(2, 8, 24, 0.96);
  border-bottom-color: var(--border-glow);
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.5);
}

.nav-brand {
  display: flex; align-items: center; gap: 10px;
  text-decoration: none;
}

.nav-logo-icon {
  width: 36px; height: 36px;
  background: linear-gradient(135deg, var(--blue-500), var(--cyan-400));
  border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem;
  box-shadow: 0 0 20px rgba(59, 130, 246, 0.5);
}

.nav-logo-text {
  font-family: var(--font-head); font-weight: 800; font-size: 1.2rem;
  letter-spacing: -0.01em;
}

.brand-jeet {
  font-family: 'Playfair Display', serif;
  font-style: italic;
  font-weight: 900;
  background: linear-gradient(135deg, #fff 0%, #bfdbff 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}

.brand-physics {
  font-family: 'Outfit', sans-serif;
  font-weight: 800;
  background: linear-gradient(135deg, var(--gold-400), #fb923c);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex; align-items: center; gap: 6px;
  list-style: none;
}

.nav-links a {
  text-decoration: none; color: var(--text-secondary);
  font-size: 0.9rem; font-weight: 500;
  padding: 7px 14px; border-radius: var(--radius-sm);
  transition: var(--transition);
}

.nav-links a:hover {
  color: var(--text-primary);
  background: rgba(59, 130, 246, 0.12);
}

.nav-cta {
  background: linear-gradient(135deg, var(--blue-500), var(--blue-600)) !important;
  color: #fff !important;
  border-radius: var(--radius-sm) !important;
  padding: 8px 18px !important;
  box-shadow: 0 0 15px rgba(59, 130, 246, 0.35);
}

.nav-cta:hover {
  transform: translateY(-1px);
  box-shadow: 0 0 25px rgba(59, 130, 246, 0.55) !important;
}

.nav-hamburger {
  display: none; background: none; border: none;
  cursor: pointer; color: var(--text-primary);
  font-size: 1.4rem;
}

/* ─── Hero ─── */
.hero {
  min-height: 100vh;
  display: flex; align-items: center; justify-content: center;
  text-align: center;
  padding: 80px 24px 60px;
  position: relative; overflow: hidden;
}

.hero-bg-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(120px);
  pointer-events: none;
}
.hero-glow-1 {
  width: 700px; height: 700px; top: -200px; left: -200px;
  background: radial-gradient(circle, rgba(59,130,246,0.12), transparent 70%);
}
.hero-glow-2 {
  width: 600px; height: 600px; bottom: -150px; right: -150px;
  background: radial-gradient(circle, rgba(245,158,11,0.08), transparent 70%);
}
.hero-glow-3 {
  width: 500px; height: 500px; top: 50%; left: 50%; transform: translate(-50%,-50%);
  background: radial-gradient(circle, rgba(34,211,238,0.05), transparent 70%);
}

.hero-badge {
  display: inline-flex; align-items: center; gap: 8px;
  background: rgba(59, 130, 246, 0.12);
  border: 1px solid rgba(59, 130, 246, 0.3);
  border-radius: 100px; padding: 6px 18px;
  font-size: 0.82rem; font-weight: 500; color: var(--blue-300);
  margin-bottom: 28px;
  animation: fadeSlideUp 0.6s ease both;
}

.hero-badge span { color: var(--gold-400); }

.hero-title {
  font-size: clamp(2.8rem, 7vw, 5.5rem);
  font-weight: 900;
  line-height: 1.05;
  margin-bottom: 24px;
  animation: fadeSlideUp 0.7s 0.1s ease both;
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--text-secondary);
  max-width: 640px; margin: 0 auto 40px;
  animation: fadeSlideUp 0.7s 0.2s ease both;
}

.hero-actions {
  display: flex; align-items: center; justify-content: center;
  gap: 16px; flex-wrap: wrap;
  animation: fadeSlideUp 0.7s 0.3s ease both;
  margin-bottom: 64px;
}

.btn-primary {
  display: inline-flex; align-items: center; gap: 8px;
  background: linear-gradient(135deg, var(--blue-500), #1e40af);
  color: #fff; text-decoration: none;
  padding: 14px 32px; border-radius: var(--radius-md);
  font-weight: 600; font-size: 0.95rem;
  border: none; cursor: pointer;
  box-shadow: 0 0 30px rgba(59,130,246,0.4), inset 0 1px 0 rgba(255,255,255,0.1);
  transition: var(--transition);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 0 50px rgba(59,130,246,0.6), inset 0 1px 0 rgba(255,255,255,0.15);
}

.btn-secondary {
  display: inline-flex; align-items: center; gap: 8px;
  background: rgba(255,255,255,0.05);
  color: var(--text-primary); text-decoration: none;
  padding: 14px 32px; border-radius: var(--radius-md);
  font-weight: 600; font-size: 0.95rem;
  border: 1px solid var(--border);
  cursor: pointer; transition: var(--transition);
}

.btn-secondary:hover {
  background: rgba(255,255,255,0.08);
  border-color: var(--border-glow);
  transform: translateY(-3px);
}


}

.btn-secondary-cert:hover {
  background: linear-gradient(135deg, rgba(245,158,11,0.25), rgba(251,191,36,0.2));
  border-color: var(--gold-300);
  transform: translateY(-3px);
  box-shadow: 0 0 30px rgba(245,158,11,0.3);
}

.btn-secondary-cert i {
  font-size: 1.1rem;
}

/* Hero Stats */
.hero-stats {
  display: flex; justify-content: center; gap: 48px; flex-wrap: wrap;
  animation: fadeSlideUp 0.7s 0.4s ease both;
}

.stat-item { text-align: center; }
.stat-number {
  font-family: var(--font-head); font-size: 2.2rem; font-weight: 800;
  background: linear-gradient(135deg, var(--blue-300), var(--gold-400));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.stat-label { font-size: 0.82rem; color: var(--text-muted); margin-top: 2px; }
.stat-divider {
  width: 1px; background: var(--border); align-self: stretch;
}

/* Hero Orbit */
.hero-orbit {
  position: absolute;
  border: 1px solid rgba(59, 130, 246, 0.12);
  border-radius: 50%;
  pointer-events: none;
  animation: spin linear infinite;
}
.orbit-1 { width: 800px; height: 800px; top:50%; left:50%; margin: -400px 0 0 -400px; animation-duration: 40s; }
.orbit-2 { width: 600px; height: 600px; top:50%; left:50%; margin: -300px 0 0 -300px; animation-duration: 25s; animation-direction: reverse; }
.orbit-dot {
  position: absolute; top: -4px; left: 50%;
  width: 8px; height: 8px; background: var(--blue-400);
  border-radius: 50%; transform: translateX(-50%);
  box-shadow: 0 0 10px var(--blue-400);
}

@keyframes spin { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }
@keyframes fadeSlideUp { from { opacity:0; transform:translateY(30px); } to { opacity:1; transform:translateY(0); } }

/* ─── Subjects Section ─── */
.subjects { background: linear-gradient(180deg, transparent, rgba(5,18,41,0.6) 30%, transparent); }

.semester-tabs {
  display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 40px;
}

.tab-btn {
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 8px 20px; border-radius: 100px;
  font-size: 0.85rem; font-weight: 500;
  cursor: pointer; transition: var(--transition);
}

.tab-btn:hover { border-color: var(--border-glow); color: var(--text-primary); }

.tab-btn.active {
  background: linear-gradient(135deg, var(--blue-500), #1e40af);
  border-color: transparent; color: #fff;
  box-shadow: 0 0 20px rgba(59,130,246,0.4);
}

.subjects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 24px;
}

.subject-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  cursor: pointer;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
  backdrop-filter: blur(12px);
}

.subject-card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: var(--card-accent, linear-gradient(90deg, var(--blue-400), var(--cyan-400)));
  border-radius: var(--radius-lg) var(--radius-lg) 0 0;
  opacity: 0; transition: var(--transition);
}

.subject-card::after {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(circle at 70% 30%, var(--card-glow, rgba(59,130,246,0.06)), transparent 60%);
  pointer-events: none; transition: var(--transition);
}

.subject-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-glow);
  background: var(--bg-card-hover);
  box-shadow: var(--shadow-card), var(--shadow-glow);
}

.subject-card:hover::before { opacity: 1; }
.subject-card:hover::after { opacity: 1.5; }

.card-header {
  display: flex; align-items: flex-start;
  justify-content: space-between; margin-bottom: 16px;
}

.card-icon {
  width: 52px; height: 52px;
  border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.5rem;
  background: var(--icon-bg, rgba(59,130,246,0.12));
  border: 1px solid var(--icon-border, rgba(59,130,246,0.2));
  flex-shrink: 0;
}

.card-meta { display: flex; flex-direction: column; align-items: flex-end; gap: 6px; }

.semester-tag {
  font-size: 0.72rem; font-weight: 600; letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 3px 10px; border-radius: 100px;
  background: rgba(245,158,11,0.12); color: var(--gold-400);
  border: 1px solid rgba(245,158,11,0.25);
}

.difficulty-tag {
  font-size: 0.72rem; font-weight: 500;
  padding: 3px 10px; border-radius: 100px;
  border: 1px solid;
}
.difficulty-tag.easy { background:rgba(52,211,153,0.1); color:var(--green-400); border-color:rgba(52,211,153,0.25); }
.difficulty-tag.medium { background:rgba(251,191,36,0.1); color:var(--gold-400); border-color:rgba(251,191,36,0.25); }
.difficulty-tag.hard { background:rgba(248,113,113,0.1); color:var(--red-400); border-color:rgba(248,113,113,0.25); }
.difficulty-tag.advanced { background:rgba(167,139,250,0.1); color:var(--purple-400); border-color:rgba(167,139,250,0.25); }

.card-title {
  font-family: var(--font-head); font-size: 1.2rem; font-weight: 700;
  margin-bottom: 8px;
}

.card-desc { font-size: 0.88rem; color: var(--text-secondary); line-height: 1.6; margin-bottom: 20px; }

.card-topics {
  display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 20px;
}

.topic-chip {
  font-size: 0.75rem; color: var(--text-muted);
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.07);
  padding: 3px 10px; border-radius: 100px;
  transition: var(--transition);
}
.topic-chip:hover { color: var(--text-secondary); border-color: var(--border); }

.card-footer {
  display: flex; align-items: center; justify-content: space-between;
  border-top: 1px solid var(--border);
  padding-top: 16px;
}

.card-progress { flex: 1; margin-right: 16px; }
.progress-label { font-size: 0.75rem; color: var(--text-muted); margin-bottom: 6px; display: flex; justify-content: space-between; }

.progress-bar {
  height: 4px; background: rgba(255,255,255,0.07);
  border-radius: 2px; overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: var(--card-accent, linear-gradient(90deg, var(--blue-400), var(--cyan-400)));
  border-radius: 2px;
  transition: width 1.5s cubic-bezier(0.4, 0, 0.2, 1);
  width: 0;
}

.card-arrow {
  width: 34px; height: 34px; border-radius: 50%;
  background: rgba(255,255,255,0.06);
  border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.9rem; transition: var(--transition); flex-shrink: 0;
  color: var(--text-secondary);
}
.subject-card:hover .card-arrow {
  background: var(--blue-500);
  border-color: transparent; color: #fff;
  transform: rotate(45deg);
}

/* ─── Formulae Section ─── */
.formulae { background: linear-gradient(180deg, transparent, rgba(10,32,68,0.3) 50%, transparent); }

.formulae-search-wrapper {
  position: relative; max-width: 540px; margin-bottom: 40px;
}

.formulae-search {
  width: 100%;
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 14px 20px 14px 48px;
  color: var(--text-primary);
  font-family: var(--font-body); font-size: 0.95rem;
  transition: var(--transition); outline: none;
}
.formulae-search:focus {
  border-color: var(--blue-400);
  background: rgba(255,255,255,0.08);
  box-shadow: 0 0 0 3px rgba(59,130,246,0.15);
}
.formulae-search::placeholder { color: var(--text-muted); }

.search-icon {
  position: absolute; left: 16px; top: 50%; transform: translateY(-50%);
  color: var(--text-muted); font-size: 1rem;
}

.formulae-categories {
  display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 32px;
}

.formulae-cat-btn {
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 7px 18px; border-radius: 100px;
  font-size: 0.82rem; font-weight: 500;
  cursor: pointer; transition: var(--transition);
}
.formulae-cat-btn.active, .formulae-cat-btn:hover {
  background: rgba(59,130,246,0.15);
  border-color: rgba(59,130,246,0.4);
  color: var(--blue-300);
}

.formulae-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}

.formulae-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 22px;
  backdrop-filter: blur(10px);
  transition: var(--transition);
}

.formulae-card:hover {
  border-color: var(--border-glow);
  transform: translateY(-3px);
  box-shadow: var(--shadow-card);
}

.formulae-card-header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 14px;
}
.formulae-subject {
  font-size: 0.72rem; font-weight: 600; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--blue-300);
}
.formulae-copy-btn {
  background: none; border: none; cursor: pointer;
  color: var(--text-muted); font-size: 0.85rem; transition: var(--transition);
  padding: 4px 8px; border-radius: 6px;
}
.formulae-copy-btn:hover { color: var(--blue-300); background: rgba(59,130,246,0.1); }

.formulae-name {
  font-family: var(--font-head); font-size: 0.95rem; font-weight: 600;
  margin-bottom: 12px;
}

.formulae-math {
  background: rgba(0,0,0,0.35);
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: var(--radius-sm);
  padding: 16px;
  text-align: center;
  margin-bottom: 10px;
  font-family: var(--font-mono);
  min-height: 60px;
  display: flex; align-items: center; justify-content: center;
  overflow-x: auto;
}

.formulae-desc { font-size: 0.8rem; color: var(--text-muted); }

/* ─── Resources ─── */
.resources { }

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

.resource-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 24px;
  text-decoration: none; color: inherit;
  transition: var(--transition);
  backdrop-filter: blur(10px);
  display: block;
}
.resource-card:hover {
  border-color: var(--border-glow);
  transform: translateY(-4px);
  box-shadow: var(--shadow-card);
}

.resource-icon {
  width: 48px; height: 48px; border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.4rem; margin-bottom: 16px;
}

.resource-type {
  font-size: 0.72rem; font-weight: 600; letter-spacing: 0.1em;
  text-transform: uppercase; margin-bottom: 8px;
}

.resource-name {
  font-family: var(--font-head); font-size: 1.05rem; font-weight: 700;
  margin-bottom: 8px;
}

.resource-desc { font-size: 0.83rem; color: var(--text-secondary); line-height: 1.55; margin-bottom: 16px; }

.resource-link-text {
  display: flex; align-items: center; gap: 6px;
  font-size: 0.82rem; font-weight: 600;
  transition: gap 0.2s;
}
.resource-card:hover .resource-link-text { gap: 10px; }

/* ─── Study Tips ─── */
.study-tips {
  background: linear-gradient(180deg, transparent, rgba(5,18,41,0.5) 40%, transparent);
}

.tips-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px;
}

.tip-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 24px;
  backdrop-filter: blur(10px);
  transition: var(--transition);
}

.tip-card:hover {
  border-color: var(--border-glow);
  transform: translateY(-3px);
}

.tip-number {
  font-family: var(--font-head); font-size: 2.5rem; font-weight: 900;
  opacity: 0.08; line-height: 1; margin-bottom: 12px;
  background: linear-gradient(135deg, var(--blue-400), var(--cyan-400));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.tip-title {
  font-family: var(--font-head); font-size: 1rem; font-weight: 700;
  margin-bottom: 8px;
}
.tip-desc { font-size: 0.85rem; color: var(--text-secondary); line-height: 1.6; }

/* ─── PYQ Section ─── */
.pyq-section {
  background: linear-gradient(180deg, rgba(22,211,238,0.05) 0%, transparent 40%, rgba(59,130,246,0.05) 100%);
}

.pyq-filters {
  display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 40px;
}

.pyq-filter-btn {
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 8px 20px; border-radius: 100px;
  font-size: 0.85rem; font-weight: 500;
  cursor: pointer; transition: var(--transition);
}

.pyq-filter-btn:hover {
  border-color: var(--border-glow);
  color: var(--text-primary);
}

.pyq-filter-btn.active {
  background: linear-gradient(135deg, var(--cyan-400), var(--blue-400));
  border-color: transparent; color: var(--bg-deep);
  box-shadow: 0 0 20px rgba(34,211,238,0.4);
  font-weight: 600;
}

.pyq-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
}

.pyq-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 24px;
  backdrop-filter: blur(10px);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.pyq-card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, var(--cyan-400), var(--blue-400));
  opacity: 0; transition: var(--transition);
}

.pyq-card:hover {
  border-color: var(--border-glow);
  transform: translateY(-4px);
  box-shadow: var(--shadow-card), 0 0 30px rgba(34,211,238,0.2);
}

.pyq-card:hover::before { opacity: 1; }

.pyq-exam-badge {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 0.72rem; font-weight: 600; letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 4px 12px; border-radius: 100px;
  background: rgba(34,211,238,0.12); color: var(--cyan-300);
  border: 1px solid rgba(34,211,238,0.25);
  margin-bottom: 12px;
}

.pyq-year {
  font-size: 0.8rem; color: var(--text-muted); margin-bottom: 8px;
}

.pyq-title {
  font-family: var(--font-head); font-size: 1.1rem; font-weight: 700;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.pyq-subject {
  font-size: 0.82rem; color: var(--text-secondary);
  margin-bottom: 14px;
  display: flex; align-items: center; gap: 6px;
}

.pyq-footer {
  display: flex; align-items: center; justify-content: space-between;
  border-top: 1px solid var(--border);
  padding-top: 16px;
  margin-top: 14px;
}

.pyq-difficulty {
  font-size: 0.75rem; font-weight: 600;
  padding: 3px 10px; border-radius: 100px;
  border: 1px solid;
}
.pyq-difficulty.easy { background:rgba(52,211,153,0.1); color:var(--green-400); border-color:rgba(52,211,153,0.25); }
.pyq-difficulty.medium { background:rgba(251,191,36,0.1); color:var(--gold-400); border-color:rgba(251,191,36,0.25); }
.pyq-difficulty.hard { background:rgba(248,113,113,0.1); color:var(--red-400); border-color:rgba(248,113,113,0.25); }

.pyq-view-btn {
  display: inline-flex; align-items: center; gap: 5px;
  background: none; border: none;
  color: var(--blue-300); font-size: 0.82rem; font-weight: 600;
  cursor: pointer; transition: var(--transition);
  padding: 4px 8px;
}
.pyq-view-btn:hover { color: var(--blue-400); gap: 8px; }

/* ─── PYQ Access Container ─── */
.pyq-access-container {
  display: flex; align-items: center; justify-content: center;
  padding: 40px 24px;
  min-height: 200px;
}

.btn-primary-large {
  display: inline-flex; align-items: center; gap: 12px;
  background: linear-gradient(135deg, var(--blue-500), #1e40af);
  color: #fff; text-decoration: none;
  padding: 18px 48px; border-radius: var(--radius-md);
  font-weight: 700; font-size: 1.1rem;
  border: none; cursor: pointer;
  box-shadow: 0 0 40px rgba(59,130,246,0.5), inset 0 1px 0 rgba(255,255,255,0.1);
  transition: var(--transition);
}

.btn-primary-large:hover {
  transform: translateY(-4px);
  box-shadow: 0 0 60px rgba(59,130,246,0.7), inset 0 1px 0 rgba(255,255,255,0.15);
}

.btn-primary-large i {
  font-size: 1.3rem;
}

/* ─── Timeline ─── */
.syllabus-timeline { }
.timeline-wrapper { position: relative; }
.timeline-line {
  position: absolute; left: 24px; top: 0; bottom: 0;
  width: 2px;
  background: linear-gradient(180deg, var(--blue-500), var(--cyan-400), var(--gold-500));
  border-radius: 1px;
}

.timeline-item {
  display: flex; gap: 32px; margin-bottom: 40px;
  position: relative;
}

.timeline-dot {
  width: 50px; height: 50px; border-radius: 50%;
  background: var(--bg-deep); border: 2px solid var(--blue-400);
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-head); font-weight: 800; font-size: 0.85rem;
  color: var(--blue-300); flex-shrink: 0;
  box-shadow: 0 0 20px rgba(59,130,246,0.3);
  z-index: 1;
}

.timeline-content {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  flex: 1;
  backdrop-filter: blur(10px);
}

.timeline-semester {
  font-size: 0.75rem; font-weight: 600; color: var(--gold-400);
  text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 8px;
}

.timeline-subjects {
  display: flex; flex-wrap: wrap; gap: 8px;
}

.timeline-subject-tag {
  font-size: 0.82rem; color: var(--text-secondary);
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--border);
  padding: 4px 12px; border-radius: 100px;
  transition: var(--transition);
}
.timeline-subject-tag:hover {
  color: var(--blue-300);
  border-color: rgba(59,130,246,0.4);
}

/* ─── Subject Modal ─── */
.modal-overlay {
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.7);
  backdrop-filter: blur(10px);
  z-index: 2000;
  display: flex; align-items: center; justify-content: center;
  padding: 24px;
  opacity: 0; visibility: hidden; transition: var(--transition);
}
.modal-overlay.open { opacity: 1; visibility: visible; }

.modal {
  background: var(--blue-800);
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-xl);
  max-width: 680px; width: 100%;
  max-height: 85vh; overflow-y: auto;
  box-shadow: 0 20px 80px rgba(0,0,0,0.7);
  transform: scale(0.9) translateY(20px);
  transition: var(--transition);
}
.modal-overlay.open .modal { transform: scale(1) translateY(0); }

.modal-header {
  padding: 28px 28px 20px;
  border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: 16px;
}

.modal-icon {
  width: 56px; height: 56px; border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.8rem; flex-shrink: 0;
}

.modal-title { font-family: var(--font-head); font-size: 1.5rem; font-weight: 800; margin-bottom: 4px; }
.modal-semester { font-size: 0.82rem; color: var(--text-muted); }

.modal-close {
  margin-left: auto;
  background: rgba(255,255,255,0.07); border: 1px solid var(--border);
  width: 36px; height: 36px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  cursor: pointer; color: var(--text-secondary);
  font-size: 1rem; transition: var(--transition); flex-shrink: 0;
}
.modal-close:hover { background: rgba(248,113,113,0.15); border-color: rgba(248,113,113,0.4); color: var(--red-400); }

.modal-body { padding: 24px 28px 28px; }

.modal-section-title {
  font-family: var(--font-head); font-size: 0.95rem; font-weight: 700;
  color: var(--text-secondary); text-transform: uppercase;
  letter-spacing: 0.08em; margin-bottom: 14px; margin-top: 24px;
}
.modal-section-title:first-child { margin-top: 0; }

.modal-topics-list {
  display: grid; grid-template-columns: 1fr 1fr; gap: 8px; list-style: none;
}
.modal-topics-list li {
  font-size: 0.88rem; color: var(--text-secondary);
  display: flex; align-items: center; gap: 8px;
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--border);
  padding: 8px 12px; border-radius: var(--radius-sm);
}
.modal-topics-list li::before { content: '→'; color: var(--blue-400); font-weight: 700; }

.modal-textbooks { display: flex; flex-direction: column; gap: 10px; }
.modal-textbook {
  display: flex; align-items: center; gap: 12px;
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 12px 16px;
}
.modal-textbook-icon { font-size: 1.2rem; }
.modal-textbook-info { flex: 1; }
.modal-textbook-title { font-size: 0.88rem; font-weight: 600; margin-bottom: 2px; }
.modal-textbook-author { font-size: 0.78rem; color: var(--text-muted); }

.modal-key-formulae { display: flex; flex-direction: column; gap: 10px; }
.modal-formula-item {
  background: rgba(0,0,0,0.3);
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: var(--radius-sm); padding: 12px 16px;
  font-family: var(--font-mono); font-size: 0.85rem;
  text-align: center; color: var(--blue-200);
}

/* ─── Footer ─── */
footer {
  background: rgba(2, 8, 24, 0.95);
  border-top: 1px solid var(--border);
  padding: 60px 0 32px;
  position: relative; z-index: 2;
}

.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 48px;
  margin-bottom: 48px;
}

.footer-brand p {
  font-size: 0.88rem; color: var(--text-muted); line-height: 1.65;
  margin-top: 14px; max-width: 300px;
}

.footer-col-title {
  font-family: var(--font-head); font-size: 0.9rem; font-weight: 700;
  margin-bottom: 18px; color: var(--text-primary);
}

.footer-links { list-style: none; display: flex; flex-direction: column; gap: 10px; }
.footer-links a {
  text-decoration: none; color: var(--text-muted); font-size: 0.86rem;
  transition: var(--transition);
}
.footer-links a:hover { color: var(--blue-300); }

.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 24px;
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 12px;
}

.footer-copy { font-size: 0.82rem; color: var(--text-muted); }
.footer-copy span { color: var(--gold-400); }

.footer-socials { display: flex; gap: 10px; }
.footer-social-btn {
  width: 36px; height: 36px; border-radius: 50%;
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  color: var(--text-muted); font-size: 0.9rem;
  text-decoration: none; transition: var(--transition);
}
.footer-social-btn:hover {
  color: var(--blue-300);
  border-color: rgba(59,130,246,0.4);
  background: rgba(59,130,246,0.1);
}

/* ─── Back to Top ─── */
#backToTop {
  position: fixed; bottom: 28px; right: 28px;
  width: 44px; height: 44px; border-radius: 50%;
  background: linear-gradient(135deg, var(--blue-500), var(--blue-600));
  border: none; cursor: pointer; color: #fff; font-size: 1rem;
  display: flex; align-items: center; justify-content: center;
  box-shadow: 0 4px 20px rgba(59,130,246,0.45);
  transition: var(--transition); z-index: 500;
  opacity: 0; transform: translateY(20px);
}
#backToTop.visible { opacity: 1; transform: translateY(0); }
#backToTop:hover { transform: translateY(-3px); box-shadow: 0 8px 30px rgba(59,130,246,0.6); }

/* ─── Scroll Animations ─── */
.reveal {
  opacity: 0; transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ─── Responsive ─── */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-hamburger { display: flex; }

  .nav-links.open {
    display: flex; flex-direction: column;
    position: fixed; top: 68px; left: 0; right: 0;
    background: rgba(2,8,24,0.97);
    border-bottom: 1px solid var(--border);
    padding: 20px 24px 24px;
    gap: 4px;
  }
  .nav-links.open a { display: block; }

  .hero-orbit { display: none; }
  .hero-stats { gap: 24px; }
  .stat-divider { display: none; }

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

  .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
  .footer-brand { grid-column: 1 / -1; }

  .modal-topics-list { grid-template-columns: 1fr; }

  section { padding: 72px 0; }

  .timeline-line { left: 20px; }
  .timeline-dot { width: 42px; height: 42px; font-size: 0.78rem; }
}

@media (max-width: 480px) {
  .footer-grid { grid-template-columns: 1fr; }
  .hero-actions { flex-direction: column; align-items: center; }
  .hero-actions > * { width: 100%; max-width: 280px; justify-content: center; }
}

/* ─── KaTeX overrides ─── */
.katex { font-size: 1.1em !important; }
.formula-math .katex-display { margin: 0; }
.formula-math .katex-display > .katex { white-space: normal; }

/* ─── Announcement Banner ─── */
.banner {
  background: linear-gradient(90deg, var(--blue-700), var(--blue-600), var(--blue-700));
  border-bottom: 1px solid rgba(59,130,246,0.3);
  padding: 10px 24px;
  text-align: center;
  font-size: 0.85rem; color: var(--blue-200);
  position: sticky; top: 0; z-index: 999;
  display: flex; align-items: center; justify-content: center; gap: 10px;
}

.banner-badge {
  background: var(--gold-500); color: #000;
  font-size: 0.7rem; font-weight: 700; letter-spacing: 0.08em;
  text-transform: uppercase; padding: 2px 8px; border-radius: 4px;
}

.banner-close {
  margin-left: auto; background: none; border: none; cursor: pointer;
  color: var(--blue-300); font-size: 1rem; opacity: 0.7;
  transition: opacity 0.2s;
}
.banner-close:hover { opacity: 1; }

/* ─── CHATBOT STYLES ─── */
.chatbot-toggle {
  position: fixed; bottom: 24px; right: 24px; z-index: 999;
  width: 56px; height: 56px; border-radius: 50%;
  background: linear-gradient(135deg, var(--blue-500), #1e40af);
  border: none; cursor: pointer; color: #fff;
  font-size: 1.4rem; display: flex; align-items: center; justify-content: center;
  box-shadow: 0 0 30px rgba(59,130,246,0.4), inset 0 1px 0 rgba(255,255,255,0.1);
  transition: var(--transition);
}
.chatbot-toggle:hover {
  transform: translateY(-3px);
  box-shadow: 0 0 50px rgba(59,130,246,0.6), inset 0 1px 0 rgba(255,255,255,0.15);
}

.chatbot-container {
  position: fixed; bottom: 100px; right: 24px; z-index: 999;
  width: 380px; height: 600px; max-height: 80vh;
  background: var(--blue-800);
  border: 1px solid var(--border-glow);
  border-radius: var(--radius-lg);
  display: flex; flex-direction: column;
  box-shadow: 0 20px 80px rgba(0,0,0,0.7);
  transform: scale(0.9) translateY(20px);
  transition: var(--transition);
  opacity: 0; visibility: hidden;
}

.chatbot-container.open {
  opacity: 1; visibility: visible;
  transform: scale(1) translateY(0);
}

.chatbot-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 20px; border-bottom: 1px solid var(--border);
  background: linear-gradient(135deg, rgba(59,130,246,0.1), rgba(34,211,238,0.05));
}

.chatbot-title {
  display: flex; align-items: center; gap: 10px;
  font-family: var(--font-head); font-weight: 700; font-size: 1rem;
  color: var(--blue-300);
}

.chatbot-title i { font-size: 1.2rem; }

.chatbot-close {
  background: none; border: none; cursor: pointer;
  color: var(--text-muted); font-size: 1rem;
  width: 32px; height: 32px; border-radius: 6px;
  transition: var(--transition);
}
.chatbot-close:hover {
  background: rgba(248,113,113,0.15);
  color: var(--red-400);
}

.chatbot-messages {
  flex: 1; overflow-y: auto; padding: 16px;
  display: flex; flex-direction: column; gap: 12px;
}

.chatbot-message {
  display: flex; gap: 10px; animation: fadeSlideUp 0.3s ease;
}

.chatbot-message.user-message {
  justify-content: flex-end;
}

.chatbot-message.bot-message {
  justify-content: flex-start;
}

.message-content {
  max-width: 80%; padding: 12px 14px; border-radius: var(--radius-md);
  font-size: 0.9rem; line-height: 1.5;
}

.user-message .message-content {
  background: linear-gradient(135deg, var(--blue-500), #1e40af);
  color: #fff;
}

.bot-message .message-content {
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--border);
  color: var(--text-primary);
}

.bot-message .message-content p {
  margin: 0; margin-bottom: 8px;
}

.bot-message .message-content p:last-child {
  margin-bottom: 0;
}

.bot-message .message-content ul {
  margin: 8px 0; padding-left: 20px;
  list-style: none;
}

.bot-message .message-content ul li {
  position: relative; padding-left: 6px;
  margin-bottom: 4px;
}

.bot-message .message-content ul li::before {
  content: '→'; color: var(--blue-300); font-weight: 600;
  position: absolute; left: -16px;
}

.chatbot-input-wrapper {
  display: flex; gap: 10px; padding: 12px 16px;
  border-top: 1px solid var(--border);
  background: rgba(255,255,255,0.02);
}

.chatbot-input {
  flex: 1; background: rgba(255,255,255,0.05);
  border: 1px solid var(--border); color: var(--text-primary);
  padding: 10px 14px; border-radius: var(--radius-md);
  font-size: 0.9rem; font-family: var(--font-body);
  outline: none; transition: var(--transition);
}

.chatbot-input:focus {
  border-color: var(--blue-400);
  background: rgba(255,255,255,0.08);
  box-shadow: 0 0 0 3px rgba(59,130,246,0.15);
}

.chatbot-input::placeholder { color: var(--text-muted); }

.chatbot-send {
  width: 40px; height: 40px; border-radius: var(--radius-md);
  background: linear-gradient(135deg, var(--blue-500), #1e40af);
  border: none; cursor: pointer; color: #fff;
  display: flex; align-items: center; justify-content: center;
  transition: var(--transition);
  font-size: 1rem;
}

.chatbot-send:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 20px rgba(59,130,246,0.4);
}

.chatbot-send:active { transform: scale(0.95); }

.chatbot-typing {
  display: flex; align-items: center; gap: 4px;
}

.typing-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--blue-300); animation: typingBounce 1.4s infinite;
}

.typing-dot:nth-child(2) { animation-delay: 0.2s; }
.typing-dot:nth-child(3) { animation-delay: 0.4s; }

@keyframes typingBounce {
  0%, 60%, 100% { transform: translateY(0); opacity: 0.7; }
  30% { transform: translateY(-10px); opacity: 1; }
}

/* Scrollbar for chat messages */
.chatbot-messages::-webkit-scrollbar { width: 4px; }
.chatbot-messages::-webkit-scrollbar-track { background: transparent; }
.chatbot-messages::-webkit-scrollbar-thumb { background: rgba(59,130,246,0.3); border-radius: 2px; }
.chatbot-messages::-webkit-scrollbar-thumb:hover { background: rgba(59,130,246,0.5); }

/* Responsive chatbot */
@media (max-width: 480px) {
  .chatbot-container {
    width: calc(100% - 32px);
    height: 500px;
    bottom: 80px;
  }
}