:root {
  --blue: #1565C0;
  --blue2: #1976D2;
  --blue3: #2196F3;
  --blue-light: #E3F2FD;
  --blue-bg: #EBF4FF;
  --green: #2E7D32;
  --green2: #388E3C;
  --green3: #4CAF50;
  --green-light: #E8F5E9;
  --yellow: #F9A825;
  --yellow2: #FFC107;
  --yellow-light: #FFF8E1;
  --dark: #0D1B2A;
  --dark2: #1A2740;
  --dark3: #243352;
  --text: #1A1A2E;
  --text2: #4A5568;
  --text3: #718096;
  --white: #FFFFFF;
  --bg: #F5F7FA;
  --bg2: #EEF2F7;
  --border: #E2E8F0;
  --shadow: 0 4px 20px rgba(21,101,192,0.12);
  --shadow2: 0 8px 40px rgba(21,101,192,0.2);
  --shadow3: 0 20px 60px rgba(0,0,0,0.15);
  --radius: 16px;
  --nav-h: 68px;
}

*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: 'Baloo 2', 'Noto Sans Devanagari', sans-serif;
  background: var(--bg);
  color: var(--text);
  overflow-x: hidden;
  line-height: 1.6;
}

/* ─── ACCESSIBILITY ──────────────────────────────────────────── */
.skip-link {
  position: absolute; top: -100%; left: 1rem;
  background: var(--yellow); color: var(--dark);
  padding: 0.6rem 1.2rem; border-radius: 0 0 8px 8px;
  font-weight: 700; font-size: 0.9rem; z-index: 9999;
  text-decoration: none; transition: top 0.2s;
}
.skip-link:focus { top: 0; }

:focus-visible {
  outline: 3px solid var(--yellow);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ─── NAV ────────────────────────────────────────────────────── */
.main-nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(13,27,42,0.97);
  border-bottom: 2px solid var(--yellow);
  padding: 0 2.5rem; display: flex; align-items: center;
  justify-content: space-between; height: var(--nav-h);
  box-shadow: 0 4px 24px rgba(0,0,0,0.4);
  backdrop-filter: blur(8px);
}
.nav-logo { display: flex; align-items: center; }
.nav-logo a { display: flex; align-items: center; gap: 0.6rem; text-decoration: none; }
.nav-logo img { height: 44px; width: auto; max-width: 180px; object-fit: contain; }

.nav-links { display: flex; gap: 0.25rem; align-items: center; }
.nav-links a {
  color: #A8B8CC; font-family: inherit; font-size: 0.88rem;
  font-weight: 600; padding: 0.45rem 0.9rem; border-radius: 7px;
  transition: color 0.2s, background 0.2s; text-decoration: none;
  letter-spacing: 0.01em;
}
.nav-links a:hover { color: #fff; background: rgba(255,255,255,0.08); }
.nav-links a.active,
.nav-links a[aria-current="page"] { color: var(--yellow); background: rgba(249,168,37,0.12); }

.nav-cta {
  background: linear-gradient(135deg, var(--yellow), #FFB300) !important;
  color: var(--dark) !important; border-radius: 8px !important;
  font-weight: 700 !important; margin-left: 0.4rem;
  box-shadow: 0 3px 10px rgba(249,168,37,0.35);
}
.nav-cta:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 18px rgba(249,168,37,0.5) !important;
  background: linear-gradient(135deg, #FFB300, var(--yellow)) !important;
}

/* Hamburger */
.hamburger {
  display: none; flex-direction: column; justify-content: center;
  gap: 5px; background: none; border: none; cursor: pointer;
  padding: 8px; border-radius: 6px; transition: background 0.2s;
}
.hamburger:hover { background: rgba(255,255,255,0.08); }
.hamburger span {
  display: block; width: 22px; height: 2px;
  background: #CBD5E0; border-radius: 2px;
  transition: transform 0.3s, opacity 0.3s;
}
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ─── HERO ───────────────────────────────────────────────────── */
.hero {
  padding-top: var(--nav-h);
  background: linear-gradient(160deg, var(--dark) 0%, var(--dark2) 50%, var(--dark3) 100%);
  position: relative; overflow: hidden; min-height: 520px;
  display: flex; align-items: center;
}
.hero-bg-pattern {
  position: absolute; inset: 0; opacity: 0.04;
  background-image:
    repeating-linear-gradient(0deg, transparent, transparent 40px, rgba(255,255,255,0.5) 40px, rgba(255,255,255,0.5) 41px),
    repeating-linear-gradient(90deg, transparent, transparent 40px, rgba(255,255,255,0.5) 40px, rgba(255,255,255,0.5) 41px);
}
.hero-glow {
  position: absolute; top: -100px; left: -100px; width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(21,101,192,0.3) 0%, transparent 70%);
  animation: slowPulse 4s ease-in-out infinite;
}
.hero-glow2 {
  position: absolute; bottom: -100px; right: -100px; width: 400px; height: 400px;
  background: radial-gradient(circle, rgba(46,125,50,0.2) 0%, transparent 70%);
  animation: slowPulse 4s ease-in-out infinite 2s;
}
@keyframes slowPulse { 0%, 100% { opacity: 0.6 } 50% { opacity: 1 } }

.hero-inner {
  max-width: 1200px; margin: 0 auto; padding: 3rem 2rem;
  display: grid; grid-template-columns: 1fr 1fr; gap: 3rem;
  align-items: center; position: relative; z-index: 1; width: 100%;
}
.hero-badge {
  display: inline-flex; align-items: center; gap: 0.5rem;
  background: rgba(249,168,37,0.15); border: 1px solid rgba(249,168,37,0.4);
  padding: 0.4rem 1rem; border-radius: 50px; font-size: 0.8rem;
  color: var(--yellow); font-weight: 700; margin-bottom: 1.2rem;
  letter-spacing: 0.05em; text-transform: uppercase;
}
.hero h1 {
  font-size: clamp(2rem, 4vw, 3.2rem); font-weight: 800;
  color: white; line-height: 1.2; margin-bottom: 1rem;
}
.hero h1 .hl-blue { color: #64B5F6; }
.hero h1 .hl-green { color: #81C784; }
.hero h1 .hl-yellow { color: var(--yellow); }
.hero-sub { color: #A0AEC0; font-size: 1rem; line-height: 1.7; margin-bottom: 2rem; }
.hero-btns { display: flex; gap: 1rem; flex-wrap: wrap; }

/* Hero card */
.hero-3d-card {
  background: rgba(255,255,255,0.05); border: 1px solid rgba(255,255,255,0.1);
  border-radius: 20px; padding: 1.5rem; backdrop-filter: blur(10px);
  box-shadow: 0 20px 60px rgba(0,0,0,0.3), inset 0 1px 0 rgba(255,255,255,0.1);
  transform: perspective(800px) rotateY(-5deg); transition: transform 0.3s; min-width: 300px;
}
.hero-3d-card:hover { transform: perspective(800px) rotateY(0deg); }
.hc-title { font-size: 0.8rem; font-weight: 700; color: var(--yellow); letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 1rem; }
.hc-item {
  display: flex; align-items: center; gap: 0.8rem;
  padding: 0.7rem; border-radius: 10px; margin-bottom: 0.5rem;
  background: rgba(255,255,255,0.04); border: 1px solid rgba(255,255,255,0.06);
  transition: background 0.2s, transform 0.2s;
  text-decoration: none; color: inherit;
}
.hc-item:hover { background: rgba(255,255,255,0.08); transform: translateX(4px); }
.hc-icon { width: 36px; height: 36px; border-radius: 8px; display: flex; align-items: center; justify-content: center; font-size: 1.1rem; flex-shrink: 0; }
.hc-text h4 { font-size: 0.85rem; font-weight: 700; color: white; }
.hc-text p { font-size: 0.72rem; color: #A0AEC0; }
.hc-item.blue .hc-icon { background: rgba(21,101,192,0.3); }
.hc-item.green .hc-icon { background: rgba(46,125,50,0.3); }
.hc-item.yellow .hc-icon { background: rgba(249,168,37,0.3); }

/* ─── STATS BAR ──────────────────────────────────────────────── */
.stats-bar {
  background: var(--dark2); border-top: 2px solid var(--yellow); padding: 1.2rem 2rem;
}
.stats-inner { max-width: 1200px; margin: 0 auto; display: flex; justify-content: space-around; flex-wrap: wrap; gap: 1rem; }
.stat { text-align: center; }
.stat-num { font-size: 1.6rem; font-weight: 800; color: var(--yellow); }
.stat-label { font-size: 0.75rem; color: #A0AEC0; font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em; }

/* ─── BUTTONS ────────────────────────────────────────────────── */
.btn-primary {
  display: inline-block;
  background: linear-gradient(135deg, var(--blue), var(--blue3));
  color: white; border: none; padding: 0.85rem 1.8rem;
  font-family: inherit; font-size: 0.95rem; font-weight: 700;
  border-radius: 10px; cursor: pointer; text-decoration: none;
  box-shadow: 0 6px 20px rgba(21,101,192,0.4); transition: transform 0.3s, box-shadow 0.3s;
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 10px 30px rgba(21,101,192,0.5); color: white; }
.btn-primary:focus-visible { outline-color: white; }

.btn-secondary {
  display: inline-block;
  background: rgba(255,255,255,0.08); color: white;
  border: 1px solid rgba(255,255,255,0.2);
  padding: 0.85rem 1.8rem; font-family: inherit; font-size: 0.95rem;
  font-weight: 600; border-radius: 10px; cursor: pointer;
  transition: background 0.3s; text-decoration: none;
}
.btn-secondary:hover { background: rgba(255,255,255,0.15); color: white; }

.btn-outline {
  display: inline-block;
  background: white; color: var(--blue); border: 2px solid var(--blue);
  padding: 0.75rem 1.5rem; font-family: inherit; font-size: 0.9rem;
  font-weight: 700; border-radius: 10px; cursor: pointer;
  transition: background 0.2s, color 0.2s; text-decoration: none;
}
.btn-outline:hover { background: var(--blue-light); }

.btn-play {
  display: block; width: 100%; padding: 0.8rem;
  background: linear-gradient(135deg, var(--blue), var(--blue3));
  border: none; border-radius: 10px; color: white;
  font-family: inherit; font-size: 0.95rem; font-weight: 700;
  cursor: pointer; transition: transform 0.3s, box-shadow 0.3s;
  text-align: center; text-decoration: none;
}
.btn-play:hover { transform: scale(1.02); box-shadow: 0 8px 20px rgba(21,101,192,0.4); color: white; }

/* ─── SECTION ────────────────────────────────────────────────── */
.section { padding: 4rem 2rem; max-width: 1200px; margin: 0 auto; }
.section-header { text-align: center; margin-bottom: 3rem; }
.section-tag {
  display: inline-block; font-size: 0.72rem; font-weight: 700;
  padding: 0.3rem 1rem; border-radius: 50px;
  background: var(--blue-light); color: var(--blue); border: 1px solid rgba(21,101,192,0.2);
  text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 0.8rem;
}
.section-tag.green { background: var(--green-light); color: var(--green); border-color: rgba(46,125,50,0.2); }
.section-tag.yellow { background: var(--yellow-light); color: #E65100; border-color: rgba(249,168,37,0.3); }
.section-header h2 { font-size: clamp(1.6rem, 3vw, 2.4rem); font-weight: 800; color: var(--dark); margin-bottom: 0.5rem; }
.section-header p { color: var(--text2); font-size: 0.95rem; }

.section-light { padding: 5rem 2rem; background: var(--bg2); }
.section-inner { max-width: 1200px; margin: 0 auto; }

/* ─── CATEGORY CARDS ─────────────────────────────────────────── */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 360px));
  gap: 1.5rem;
  justify-content: center;
}
.cat-card {
  background: white; border-radius: 18px; overflow: hidden;
  box-shadow: 0 2px 16px rgba(21,101,192,0.08);
  border: 1px solid var(--border);
  transition: transform 0.25s, box-shadow 0.25s;
}
.cat-card:hover { transform: translateY(-6px); box-shadow: 0 12px 36px rgba(21,101,192,0.16); }
.cat-card-link { display: flex; flex-direction: column; height: 100%; text-decoration: none; color: inherit; }
.cat-card-link:focus-visible { outline: 3px solid var(--yellow); outline-offset: 2px; border-radius: 18px; }
.cat-card-top { height: 5px; }
.cat-card.web .cat-card-top { background: linear-gradient(90deg, var(--blue), var(--blue3)); }
.cat-card.quiz .cat-card-top { background: linear-gradient(90deg, var(--yellow), #FF8F00); }
.cat-card.office .cat-card-top { background: linear-gradient(90deg, var(--green), var(--green3)); }
.cat-body { padding: 1.5rem; flex: 1; display: flex; flex-direction: column; }
.cat-icon-wrap { display: flex; align-items: center; gap: 0.875rem; margin-bottom: 0.875rem; }
.cat-icon {
  width: 52px; height: 52px; border-radius: 14px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.6rem; flex-shrink: 0;
}
.cat-card.web .cat-icon { background: #EBF4FF; }
.cat-card.quiz .cat-icon { background: #FFF8E1; }
.cat-card.office .cat-icon { background: #E8F5E9; }
.cat-name { font-size: 1.1rem; font-weight: 800; color: var(--dark); line-height: 1.3; }
.cat-name-hi { font-size: 0.8rem; color: var(--text3); font-weight: 500; margin-top: 2px; }
.cat-desc { color: var(--text2); font-size: 0.85rem; line-height: 1.65; margin-bottom: 1rem; margin-top: 0.5rem; flex: 1; }
.sub-tags { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-bottom: 1.25rem; }
.sub-tag { font-size: 0.75rem; padding: 0.25rem 0.75rem; border-radius: 50px; font-weight: 600; }
.cat-card.web .sub-tag { background: #EBF4FF; color: var(--blue); }
.cat-card.quiz .sub-tag { background: #FFF8E1; color: #E65100; }
.cat-card.office .sub-tag { background: #E8F5E9; color: var(--green); }
.cat-footer {
  display: flex; align-items: center; justify-content: space-between;
  padding-top: 0.875rem; border-top: 1px solid var(--border);
}
.cat-count { font-size: 0.8rem; color: var(--text3); font-weight: 600; }
.cat-btn {
  padding: 0.45rem 1.1rem; border-radius: 8px;
  font-size: 0.82rem; font-weight: 700;
  transition: transform 0.15s, box-shadow 0.15s;
}
.cat-card.web .cat-btn { background: var(--blue); color: white; }
.cat-card.quiz .cat-btn { background: var(--yellow); color: var(--dark); }
.cat-card.office .cat-btn { background: var(--green); color: white; }
.cat-card:hover .cat-btn { transform: translateX(4px); }

/* ─── QUIZ CARDS ─────────────────────────────────────────────── */
.quiz-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 1.2rem; }
.quiz-card {
  background: white; border: 1px solid var(--border); border-radius: 16px;
  box-shadow: var(--shadow); overflow: hidden; transition: transform 0.3s, box-shadow 0.3s, border-color 0.3s;
}
.quiz-card:hover { transform: translateY(-4px); box-shadow: var(--shadow2); border-color: var(--blue3); }
.quiz-card-link { display: block; padding: 1.5rem; text-decoration: none; color: inherit; }
.quiz-card-link:focus-visible { outline: 3px solid var(--yellow); outline-offset: 2px; border-radius: 16px; }
.quiz-diff {
  display: inline-flex; align-items: center; gap: 0.3rem;
  font-size: 0.72rem; font-weight: 700; padding: 0.25rem 0.7rem;
  border-radius: 50px; margin-bottom: 0.8rem; text-transform: uppercase; letter-spacing: 0.05em;
}
.quiz-diff.easy { background: #E8F5E9; color: #2E7D32; }
.quiz-diff.medium { background: #FFF8E1; color: #E65100; }
.quiz-diff.hard { background: #FFEBEE; color: #C62828; }
.quiz-card h3 { font-size: 1rem; font-weight: 700; color: var(--dark); margin-bottom: 0.3rem; }
.quiz-card p { font-size: 0.82rem; color: var(--text2); margin-bottom: 1rem; line-height: 1.5; }
.quiz-meta { display: flex; gap: 1rem; font-size: 0.78rem; color: var(--text3); font-weight: 600; }

/* ─── NOTES GRID ─────────────────────────────────────────────── */
.notes-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 1.5rem; margin-top: 2rem; }
.notes-card {
  background: white; border: 1px solid var(--border); border-radius: 16px;
  overflow: hidden; box-shadow: var(--shadow);
  transition: transform 0.3s, box-shadow 0.3s;
}
.notes-card:hover { transform: translateY(-6px); box-shadow: var(--shadow2); }
.notes-card-link { display: block; text-decoration: none; color: inherit; }
.notes-card-link:focus-visible { outline: 3px solid var(--yellow); outline-offset: 2px; border-radius: 16px; }
.notes-card-h { font-size: 0.95rem; font-weight: 700; color: var(--dark); margin-bottom: 0.4rem; line-height: 1.4; }

.notes-thumb {
  height: 160px; display: flex; align-items: center; justify-content: center; font-size: 3rem;
}
.notes-thumb.php { background: linear-gradient(135deg, #3949AB, #7E57C2); color: white; }
.notes-thumb.node-js, .notes-thumb.node { background: linear-gradient(135deg, #1B5E20, #43A047); color: white; }
.notes-thumb.ms-excel, .notes-thumb.excel { background: linear-gradient(135deg, #0277BD, #039BE5); color: white; }
.notes-thumb.javascript, .notes-thumb.js { background: linear-gradient(135deg, #FBC02D, #F9A825); color: white; }
.notes-thumb.html, .notes-thumb.css { background: linear-gradient(135deg, #E64A19, #F4511E); color: white; }
.notes-thumb.quiz { background: linear-gradient(135deg, #BF360C, #EF6C00); color: white; }
.notes-thumb.general { background: linear-gradient(135deg, var(--blue), var(--blue3)); color: white; }

.notes-body { padding: 1.3rem; }
.notes-tag {
  display: inline-block; font-size: 0.7rem; font-weight: 700;
  padding: 0.2rem 0.7rem; border-radius: 50px;
  background: var(--blue-light); color: var(--blue);
  margin-bottom: 0.6rem; text-transform: uppercase; letter-spacing: 0.05em;
}
.notes-tag.green { background: var(--green-light); color: var(--green); }
.notes-tag.orange { background: #FFF3E0; color: #E65100; }
.notes-body h3 { font-size: 0.95rem; font-weight: 700; color: var(--dark); margin-bottom: 0.4rem; line-height: 1.4; }
.notes-body p { font-size: 0.82rem; color: var(--text2); line-height: 1.5; }
.notes-footer {
  display: flex; align-items: center; justify-content: space-between;
  margin-top: 0.8rem; padding-top: 0.7rem; border-top: 1px solid var(--border);
  font-size: 0.75rem; color: var(--text3);
}

/* ─── PAGE HEADER ────────────────────────────────────────────── */
.page-header {
  padding-top: var(--nav-h);
  background: linear-gradient(135deg, var(--dark) 0%, var(--dark2) 100%); color: white;
}
.page-header-inner { max-width: 1200px; margin: 0 auto; padding: 2.5rem 2rem; }
.page-header h1 { font-size: clamp(1.6rem, 3vw, 2rem); font-weight: 800; margin-bottom: 0.4rem; }
.page-header p { color: #A0AEC0; font-size: 0.9rem; }

/* ─── BREADCRUMB ─────────────────────────────────────────────── */
.breadcrumb {
  display: flex; align-items: center; gap: 0.5rem; flex-wrap: wrap;
  font-size: 0.82rem; color: #A0AEC0; margin-bottom: 1rem;
}
.breadcrumb a { color: var(--yellow); font-weight: 600; text-decoration: none; }
.breadcrumb a:hover { text-decoration: underline; }
.breadcrumb span[aria-current="page"] { color: white; font-weight: 500; }
.breadcrumb span[aria-hidden] { color: #718096; }

/* ─── FILTER BAR ─────────────────────────────────────────────── */
.filter-bar {
  background: white; border-bottom: 1px solid var(--border);
  padding: 0.8rem 2rem; display: flex; gap: 0.5rem; flex-wrap: wrap;
  overflow-x: auto; -webkit-overflow-scrolling: touch;
}
.filter-btn {
  padding: 0.5rem 1.3rem; border-radius: 50px; border: 1px solid var(--border);
  background: var(--bg); color: var(--text2);
  font-family: inherit; font-size: 0.85rem; font-weight: 600;
  transition: background 0.2s, border-color 0.2s, color 0.2s;
  white-space: nowrap; text-decoration: none; cursor: pointer;
}
.filter-btn.active, .filter-btn[aria-current="true"] { background: var(--blue); color: white; border-color: var(--blue); }
.filter-btn:hover:not(.active):not([aria-current="true"]) { border-color: var(--blue3); color: var(--blue3); }

/* ─── TUTORIAL CARDS ─────────────────────────────────────────── */
.tutorial-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem; padding: 2rem; max-width: 1200px; margin: 1rem auto 0;
}
.tut-card {
  background: white; border: 1px solid var(--border); border-radius: 12px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
  transition: border-color 0.3s, box-shadow 0.3s, transform 0.3s;
}
.tut-card:hover { border-color: var(--blue3); box-shadow: var(--shadow); transform: translateX(4px); }
.tut-card-link { display: flex; gap: 0.9rem; padding: 1.2rem; text-decoration: none; color: inherit; }
.tut-card-link:focus-visible { outline: 3px solid var(--yellow); outline-offset: 2px; border-radius: 12px; }
.tut-card-h { font-size: 0.9rem; font-weight: 700; color: var(--dark); margin-bottom: 0.25rem; }
.tut-num {
  width: 38px; height: 38px; border-radius: 10px; flex-shrink: 0;
  display: flex; align-items: center; justify-content: center;
  font-size: 0.8rem; font-weight: 800;
}
.tut-num.blue { background: var(--blue-light); color: var(--blue); }
.tut-num.green { background: var(--green-light); color: var(--green); }
.tut-info h2,
.tut-info h4 { font-size: 0.9rem; font-weight: 700; color: var(--dark); margin-bottom: 0.25rem; }
.tut-info p { font-size: 0.78rem; color: var(--text2); line-height: 1.5; }
.tut-meta { font-size: 0.72rem; color: var(--text3); margin-top: 0.4rem; font-weight: 600; }

/* ─── QUIZ PLAY ──────────────────────────────────────────────── */
.quiz-play-wrap {
  min-height: 100vh; padding: calc(var(--nav-h) + 2rem) 1rem 2rem;
  background: var(--bg); display: flex; flex-direction: column; align-items: center;
}
.quiz-topbar { width: 100%; max-width: 680px; display: flex; align-items: center; gap: 1rem; margin-bottom: 1.5rem; }
.quiz-progress-wrap { flex: 1; }
.qp-label { font-size: 0.78rem; color: var(--text2); font-weight: 600; display: flex; justify-content: space-between; margin-bottom: 0.4rem; }
.qp-bar { height: 10px; background: var(--border); border-radius: 50px; overflow: hidden; }
.qp-fill { height: 100%; border-radius: 50px; background: linear-gradient(90deg, var(--blue), var(--green3)); transition: width 0.5s ease; }
.quiz-timer {
  width: 52px; height: 52px; border-radius: 50%; border: 3px solid var(--blue);
  display: flex; align-items: center; justify-content: center;
  font-size: 1rem; font-weight: 800; color: var(--blue); flex-shrink: 0;
  transition: border-color 0.3s, color 0.3s; background: white; box-shadow: var(--shadow);
}
.quiz-timer.urgent { border-color: #C62828; color: #C62828; animation: blink 0.5s infinite; }
@keyframes blink { 0%, 100% { opacity: 1 } 50% { opacity: 0.4 } }
.q-card {
  width: 100%; max-width: 680px; background: white;
  border: 1px solid var(--border); border-radius: 20px;
  padding: 2rem; box-shadow: var(--shadow2);
}
.q-num { font-size: 0.8rem; color: var(--text3); font-weight: 700; margin-bottom: 0.8rem; text-transform: uppercase; letter-spacing: 0.05em; }
.q-text { font-size: 1.1rem; font-weight: 700; color: var(--dark); line-height: 1.6; margin-bottom: 1.8rem; }
.options { display: flex; flex-direction: column; gap: 0.7rem; }
.option {
  padding: 0.9rem 1.2rem; border-radius: 12px;
  border: 2px solid var(--border); background: var(--bg);
  cursor: pointer; transition: border-color 0.2s, background 0.2s;
  display: flex; align-items: center; gap: 0.9rem;
  font-family: inherit; font-size: 0.9rem; color: var(--text); text-align: left; font-weight: 500;
}
.option:hover { border-color: var(--blue3); background: var(--blue-light); }
.option.selected { border-color: var(--blue); background: var(--blue-light); }
.option.correct { border-color: var(--green3); background: var(--green-light); color: var(--green); font-weight: 700; }
.option.wrong { border-color: #EF5350; background: #FFEBEE; color: #C62828; font-weight: 700; }
.opt-label {
  width: 32px; height: 32px; border-radius: 50%; background: white;
  border: 2px solid var(--border); display: flex; align-items: center; justify-content: center;
  font-weight: 800; font-size: 0.8rem; flex-shrink: 0; color: var(--text2);
}
.option.correct .opt-label { border-color: var(--green3); color: var(--green); }
.option.wrong .opt-label { border-color: #EF5350; color: #C62828; }
.quiz-nav { width: 100%; max-width: 680px; margin-top: 1.2rem; display: flex; justify-content: flex-end; }

/* ─── RESULT CARD ────────────────────────────────────────────── */
.result-card {
  width: 100%; max-width: 480px; background: white;
  border: 1px solid var(--border); border-radius: 24px; padding: 2.5rem 2rem;
  text-align: center; box-shadow: var(--shadow2);
  animation: popIn 0.5s cubic-bezier(0.34,1.56,0.64,1);
}
@keyframes popIn { from { opacity: 0; transform: scale(0.8) } to { opacity: 1; transform: scale(1) } }
.result-emoji { font-size: 4rem; margin-bottom: 1rem; }
.result-score { font-size: 3rem; font-weight: 800; color: var(--blue); margin-bottom: 0.4rem; }
.result-label { color: var(--text2); margin-bottom: 2rem; font-size: 0.95rem; }
.result-btns { display: flex; gap: 0.8rem; justify-content: center; flex-wrap: wrap; }

/* ─── NOTES DETAIL ───────────────────────────────────────────── */
.notes-detail-wrap { max-width: 800px; margin: 0 auto; padding: calc(var(--nav-h) + 2rem) 2rem 5rem; }
.notes-detail-wrap .breadcrumb { margin-bottom: 1rem; }
.back-btn {
  display: inline-flex; align-items: center; gap: 0.4rem;
  background: white; border: 1px solid var(--border); color: var(--text2);
  padding: 0.45rem 1rem; border-radius: 8px; font-family: inherit;
  font-size: 0.82rem; font-weight: 600; cursor: pointer;
  transition: border-color 0.2s, color 0.2s; margin-bottom: 1.5rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.05); text-decoration: none;
}
.back-btn:hover { border-color: var(--blue3); color: var(--blue); }
.notes-detail-thumb {
  height: 200px; border-radius: 20px; margin-bottom: 0;
  display: flex; align-items: center; justify-content: center; font-size: 5rem;
  border-radius: 20px 20px 0 0;
}
article.notes-article {
  background: white; border-radius: 20px; box-shadow: 0 4px 32px rgba(21,101,192,0.09);
  border: 1px solid var(--border); overflow: hidden;
}
.notes-detail-header {
  padding: 2rem 2.5rem 1.5rem;
  border-bottom: 2px solid var(--border);
}
.notes-detail-header h1 { font-size: clamp(1.45rem, 3vw, 2rem); font-weight: 800; color: var(--dark); line-height: 1.3; margin: 0.6rem 0 1rem; }
.notes-meta {
  display: flex; gap: 1.2rem; flex-wrap: wrap; font-size: 0.8rem;
  color: var(--text3); font-weight: 600;
}
.notes-meta span { display: flex; align-items: center; gap: 0.3rem; }
.notes-content {
  padding: 2rem 2.5rem; line-height: 2; color: #374151; font-size: 1rem;
}
.notes-content h2 {
  font-size: 1.25rem; font-weight: 800; color: var(--dark);
  margin: 2.5rem 0 1rem; padding: 0.75rem 1.2rem;
  background: var(--blue-bg); border-left: 4px solid var(--blue);
  border-radius: 0 10px 10px 0;
}
.notes-content h3 {
  font-size: 1.05rem; font-weight: 700; color: var(--dark2);
  margin: 2rem 0 0.6rem; padding-left: 0.9rem;
  border-left: 3px solid var(--yellow);
}
.notes-content p { margin-bottom: 1.1rem; }
.notes-content ul, .notes-content ol { padding-left: 1.5rem; margin-bottom: 1.1rem; }
.notes-content li { margin-bottom: 0.4rem; }
.notes-content strong { color: var(--dark); font-weight: 700; }
.notes-content a { color: var(--blue); text-decoration: underline; text-underline-offset: 3px; }
.notes-content blockquote {
  border-left: 4px solid var(--yellow); background: var(--yellow-light);
  padding: 1rem 1.2rem; margin: 1.5rem 0; border-radius: 0 10px 10px 0;
  font-style: italic; color: var(--text2);
}
.code-block {
  background: #1E2A3A; border-radius: 12px; padding: 1.5rem; margin: 1.5rem 0;
  font-family: 'Courier New', monospace; font-size: 0.85rem;
  color: #E2E8F0; overflow-x: auto; line-height: 1.7;
  border: 1px solid rgba(255,255,255,0.08); tab-size: 2;
}
.code-block .kw { color: #79A8D2; }
.code-block .str { color: #A8D591; }
.code-block .fn { color: #F0B27A; }
.code-block .cm { color: #718096; font-style: italic; }
.quiz-cta-box {
  margin: 0 2.5rem 2.5rem;
  padding: 1.8rem 2rem;
  background: linear-gradient(135deg, var(--blue-bg) 0%, #dbeeff 100%);
  border: 2px solid rgba(21,101,192,0.18); border-radius: 16px;
  display: flex; align-items: center; gap: 1.5rem; flex-wrap: wrap;
}
.quiz-cta-box-icon { font-size: 2.5rem; flex-shrink: 0; }
.quiz-cta-box-text { flex: 1; min-width: 200px; }
.quiz-cta-box h2 { font-size: 1.1rem; font-weight: 800; color: var(--dark); margin-bottom: 0.3rem; }
.quiz-cta-box p { font-size: 0.87rem; color: var(--text2); margin-bottom: 0; }

/* ─── QUIZ LIST PAGE ─────────────────────────────────────────── */
.quiz-list-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem; padding: 0 2rem 4rem; max-width: 1200px; margin: 2rem auto 0;
}
.ql-card {
  background: white; border: 1px solid var(--border); border-radius: 20px;
  overflow: hidden; box-shadow: var(--shadow);
  transition: transform 0.3s, box-shadow 0.3s;
  display: flex; flex-direction: column;
}
.ql-card:hover { transform: translateY(-6px); box-shadow: var(--shadow2); }
.ql-top { height: 6px; flex-shrink: 0; }
.ql-card:nth-child(4n+1) .ql-top { background: linear-gradient(90deg, var(--blue), var(--blue3)); }
.ql-card:nth-child(4n+2) .ql-top { background: linear-gradient(90deg, var(--green), var(--green3)); }
.ql-card:nth-child(4n+3) .ql-top { background: linear-gradient(90deg, var(--yellow), #FF8F00); }
.ql-card:nth-child(4n) .ql-top { background: linear-gradient(90deg, #7B1FA2, #AB47BC); }
.ql-body { padding: 1.8rem; display: flex; flex-direction: column; flex: 1; }
.ql-icon { font-size: 2.5rem; margin-bottom: 1rem; }
.ql-title { font-size: 1.15rem; font-weight: 800; color: var(--dark); margin-bottom: 0.4rem; }
.ql-desc { font-size: 0.85rem; color: var(--text2); line-height: 1.6; margin-bottom: 1.2rem; flex: 1; }
.ql-stats { display: flex; gap: 1.5rem; margin-bottom: 1.5rem; padding: 1rem; background: var(--bg); border-radius: 10px; }
.ql-stat { text-align: center; flex: 1; }
.ql-stat-val { font-size: 1.2rem; font-weight: 800; color: var(--blue); }
.ql-stat-key { font-size: 0.7rem; color: var(--text3); font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em; }

/* ─── FOOTER ─────────────────────────────────────────────────── */
footer {
  background: #0A1628;
  border-top: 3px solid var(--yellow);
}
.footer-inner {
  max-width: 1100px; margin: 0 auto;
  padding: 3rem 2rem 1.5rem;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 2.5rem;
}
.footer-brand {}
.footer-name {
  font-size: 1.4rem; font-weight: 800; color: #fff;
  font-family: 'Baloo 2', sans-serif;
  margin-bottom: 0.75rem;
}
.footer-name span { color: var(--yellow); }
.footer-tagline {
  color: #64748B; font-size: 0.875rem;
  line-height: 1.75; margin: 0;
}
.footer-col {
  display: flex; flex-direction: column; gap: 0.5rem;
}
.footer-col-title {
  color: #fff; font-size: 0.75rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: 0.1em;
  margin-bottom: 0.5rem;
}
.footer-col a {
  color: #64748B !important; font-size: 0.875rem;
  text-decoration: none !important; font-weight: 400;
  transition: color 0.15s;
}
.footer-col a:hover { color: var(--yellow) !important; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.07);
  padding-top: 1.25rem;
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 0.5rem;
}
.footer-bottom p { color: #3D4F6A; font-size: 0.8rem; margin: 0; }

/* ─── EMPTY STATE ────────────────────────────────────────────── */
.empty-state { padding: 5rem 1rem; }
.empty-state h2 { font-size: 1.2rem; color: var(--text3); margin-bottom: 0.5rem; }
.empty-state p { color: var(--text3); margin-bottom: 1.5rem; }

/* ─── PAGINATION ─────────────────────────────────────────────── */
.pagination-wrap { display: flex; align-items: center; gap: 0.5rem; justify-content: center; margin-top: 3rem; }
.page-link-custom {
  display: flex !important; align-items: center !important; justify-content: center !important;
  width: 38px; height: 38px; border-radius: 8px;
  background: white; border: 1px solid var(--border);
  color: var(--text2); font-weight: 700; text-decoration: none !important;
  transition: border-color 0.2s, color 0.2s, background 0.2s; font-size: 0.9rem;
}
.page-link-custom:hover { border-color: var(--blue3); color: var(--blue3); background: var(--blue-light); }
.pagination-wrap .page-link-custom.active {
  background: var(--blue) !important; color: white !important;
  border-color: var(--blue) !important; box-shadow: 0 4px 10px rgba(21,101,192,0.3);
}
.page-link-custom.disabled { opacity: 0.5; cursor: not-allowed; pointer-events: none; }
.page-arrow { font-size: 1.1rem; }

/* ─── UTILITIES ──────────────────────────────────────────────── */
.text-center { text-align: center; }
.mt-2 { margin-top: 2rem; }
.mt-3 { margin-top: 3rem; }
.mt-1-5 { margin-top: 1.5rem; }
.mb-2-5 { margin-bottom: 2.5rem; }
.mb-0-5 { margin-bottom: 0.5rem; }
.flex-center { display: flex; justify-content: center; }
.d-inline-block { display: inline-block; }
.fs-4 { font-size: 4rem; margin-bottom: 1rem; }
.no-underline { text-decoration: none !important; color: inherit; }
.hidden { display: none !important; }
.pagination-container { margin-top: 2rem; }

/* ─── RESPONSIVE ─────────────────────────────────────────────── */
@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; text-align: center; gap: 2rem; }
  .hero-btns { justify-content: center; }
  .hero-right { display: flex; justify-content: center; }
  .hero-3d-card { transform: none; width: 100%; max-width: 400px; min-width: unset; }
}

@media (max-width: 768px) {
  .main-nav { padding: 0 1rem; }
  .nav-logo img { max-width: 140px; }
  .hamburger { display: flex; }
  .nav-links {
    position: fixed; top: var(--nav-h); left: 0; right: 0; bottom: 0;
    background: var(--dark); flex-direction: column; gap: 0;
    padding: 1.5rem 1.5rem 2rem; overflow-y: auto;
    transform: translateX(100%); transition: transform 0.3s ease;
    border-top: 1px solid rgba(255,255,255,0.08); z-index: 999;
  }
  .nav-links.open { transform: translateX(0); }
  .nav-links a {
    font-size: 1.1rem; padding: 1rem 0.5rem;
    border-bottom: 1px solid rgba(255,255,255,0.06); border-radius: 0; width: 100%;
  }
  .nav-links a:last-child { border-bottom: none; margin-top: 1rem; border-radius: 8px; text-align: center; }

  .hero-inner { padding: 2rem 1.5rem; }
  .section { padding: 3rem 1rem; }
  .section-light { padding: 3rem 1rem; }
  .cat-grid, .notes-grid { grid-template-columns: 1fr; }
  .filter-bar { padding: 0.8rem 1rem; }
  .quiz-list-grid { padding: 0 1rem 2rem; }
  .tutorial-grid { padding: 1rem; }
  .notes-detail-wrap { padding: calc(var(--nav-h) + 1rem) 1rem 3rem; }
  .notes-detail-header { padding: 1.5rem 1.2rem 1.2rem; }
  .notes-content { padding: 1.5rem 1.2rem; }
  .quiz-cta-box { margin: 0 1.2rem 1.5rem; padding: 1.2rem; }
  .notes-detail-header h1 { font-size: 1.35rem; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 2rem; }
  .footer-brand { grid-column: 1 / -1; }
  .footer-inner { padding: 2.5rem 1.5rem 1.5rem; }
  .footer-bottom { flex-direction: column; text-align: center; }
}

@media (max-width: 480px) {
  .hero h1 { font-size: 1.8rem; }
  .stats-inner { gap: 0.5rem; }
  .stat-num { font-size: 1.3rem; }
  .hero-btns { flex-direction: column; align-items: stretch; }
  .hero-btns a { text-align: center; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
  html { scroll-behavior: auto; }
}