/* =====================================================================
   AI GIỎI HƠN — Stylesheet (modern cosmic edition)
   - Dark base với starfield + nebula gradients
   - Glass-morphism cards
   - Mỗi hạng mục có gam màu riêng (theme-*)
   - Smooth animations, gradient buttons có glow
   ===================================================================== */
@import url('https://fonts.googleapis.com/css2?family=Fraunces:ital,wght@0,600;0,800;0,900;1,600;1,800&family=Plus+Jakarta+Sans:wght@400;500;600;700;800&display=swap');

:root {
  --bg-0: #060818;
  --bg-1: #0b1029;
  --bg-2: #141a3a;
  --ink: #e8ecff;
  --ink-mute: #9aa3c7;
  --line: rgba(255,255,255,0.10);
  --line-strong: rgba(255,255,255,0.22);
  --glass: rgba(255,255,255,0.04);
  --glass-strong: rgba(255,255,255,0.08);

  --accent-1: #7c6cff;
  --accent-2: #2fd9c9;
  --accent-3: #ff5e87;
  --glow: rgba(124,108,255,0.35);

  /* legacy aliases (giữ trang cũ không vỡ) */
  --cream: var(--bg-1);
  --paper: var(--glass);
  --forest: var(--accent-2);
  --coral: var(--accent-3);
  --gold: #ffc857;
  --rose: var(--accent-3);
  --muted: var(--ink-mute);
}

/* === Per-category themes === */
body.theme-kien-thuc       { --accent-1: #7c6cff; --accent-2: #4cc9f0; --accent-3: #b388ff; --glow: rgba(124,108,255,0.4); }
body.theme-dia-ly          { --accent-1: #00bfa6; --accent-2: #5eead4; --accent-3: #38bdf8; --glow: rgba(0,191,166,0.4); }
body.theme-van-hoa         { --accent-1: #f59e0b; --accent-2: #ef4444; --accent-3: #ec4899; --glow: rgba(245,158,11,0.4); }
body.theme-lich-su         { --accent-1: #ea580c; --accent-2: #f59e0b; --accent-3: #d97706; --glow: rgba(234,88,12,0.4); }
body.theme-do-vui          { --accent-1: #f43f5e; --accent-2: #fb923c; --accent-3: #facc15; --glow: rgba(244,63,94,0.4); }
body.theme-do-meo          { --accent-1: #a855f7; --accent-2: #6366f1; --accent-3: #ec4899; --glow: rgba(168,85,247,0.4); }
body.theme-tinh-nhanh      { --accent-1: #06b6d4; --accent-2: #3b82f6; --accent-3: #8b5cf6; --glow: rgba(6,182,212,0.4); }
body.theme-tinh-sieu-nhanh { --accent-1: #ef4444; --accent-2: #f43f5e; --accent-3: #f97316; --glow: rgba(239,68,68,0.5); }
body.theme-tinh-nham       { --accent-1: #10b981; --accent-2: #06b6d4; --accent-3: #14b8a6; --glow: rgba(16,185,129,0.4); }

* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }
body {
  font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, system-ui, sans-serif;
  background: var(--bg-0);
  color: var(--ink);
  line-height: 1.55;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  position: relative;
  overflow-x: hidden;
}

/* Starfield + nebula background */
body::before {
  content: ''; position: fixed; inset: 0; pointer-events: none; z-index: -2;
  background:
    radial-gradient(ellipse 80% 60% at 20% 10%, rgba(124,108,255,0.20) 0, transparent 50%),
    radial-gradient(ellipse 60% 50% at 80% 30%, rgba(47,217,201,0.15) 0, transparent 50%),
    radial-gradient(ellipse 70% 60% at 50% 90%, rgba(255,94,135,0.12) 0, transparent 50%),
    linear-gradient(180deg, var(--bg-0) 0%, var(--bg-1) 50%, var(--bg-0) 100%);
  animation: nebula-drift 30s ease-in-out infinite alternate;
}
body::after {
  content: ''; position: fixed; inset: 0; pointer-events: none; z-index: -1;
  background-image:
    radial-gradient(1px 1px at 20% 30%, white, transparent),
    radial-gradient(1px 1px at 60% 70%, white, transparent),
    radial-gradient(1px 1px at 50% 50%, rgba(255,255,255,0.6), transparent),
    radial-gradient(1px 1px at 80% 10%, white, transparent),
    radial-gradient(1px 1px at 90% 60%, rgba(255,255,255,0.6), transparent),
    radial-gradient(1px 1px at 33% 80%, white, transparent),
    radial-gradient(1px 1px at 15% 90%, rgba(255,255,255,0.7), transparent),
    radial-gradient(2px 2px at 70% 20%, white, transparent),
    radial-gradient(1px 1px at 25% 55%, rgba(255,255,255,0.5), transparent);
  opacity: 0.6;
  animation: twinkle 4s ease-in-out infinite alternate;
}
@keyframes nebula-drift { from { transform: translate(0,0); } to { transform: translate(-2%, 1%); } }
@keyframes twinkle { from { opacity: 0.4; } to { opacity: 0.8; } }

/* =========================================================
   SCENERY THEO HẠNG MỤC — overlay phía sau, đè lên nebula
   Mỗi theme có một "thế giới" riêng cảm nhận được ngay
   ========================================================= */
.scenery {
  position: fixed; inset: 0; pointer-events: none; z-index: -1;
  opacity: 0.85;
  transition: opacity .6s;
}

/* --- KIẾN THỨC: thiên hà tri thức, vòng xoáy tím --- */
body.theme-kien-thuc .scenery {
  background:
    radial-gradient(circle at 50% 50%, rgba(124,108,255,0.35) 0, transparent 35%),
    conic-gradient(from 0deg at 50% 50%,
      rgba(124,108,255,0.15), rgba(76,201,240,0.12), rgba(179,136,255,0.15),
      rgba(124,108,255,0.15));
  animation: spin-slow 60s linear infinite;
  mix-blend-mode: screen;
}

/* --- ĐỊA LÝ: núi Himalaya silhouette + mây --- */
body.theme-dia-ly .scenery {
  background:
    radial-gradient(ellipse 60% 30% at 50% 30%, rgba(94,234,212,0.20) 0, transparent 60%),
    /* lớp núi xa */
    linear-gradient(to top, rgba(56,189,248,0.18) 0, transparent 35%),
    /* núi gần - polygon clip via svg data uri */
    url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1200 400' preserveAspectRatio='none'><polygon points='0,400 0,260 120,180 200,220 320,140 420,200 520,120 640,180 760,100 880,180 1000,140 1100,200 1200,160 1200,400' fill='%23000814' opacity='0.55'/><polygon points='0,400 0,300 100,260 220,300 340,240 460,290 580,220 700,280 820,230 940,290 1060,250 1200,290 1200,400' fill='%230b1029' opacity='0.85'/></svg>") no-repeat bottom / 100% 50%;
}

/* --- VĂN HÓA: mandala vàng đỏ ấm --- */
body.theme-van-hoa .scenery {
  background:
    radial-gradient(circle at 50% 50%, rgba(245,158,11,0.25) 0, transparent 25%),
    radial-gradient(circle at 50% 50%, rgba(239,68,68,0.15) 25%, transparent 45%),
    repeating-conic-gradient(from 0deg at 50% 50%,
      rgba(245,158,11,0.12) 0deg 15deg,
      transparent 15deg 30deg);
  animation: spin-slow 90s linear infinite reverse;
  mix-blend-mode: screen;
}

/* --- LỊCH SỬ: vortex thời gian, sepia + nâu vàng --- */
body.theme-lich-su .scenery {
  background:
    radial-gradient(ellipse 80% 60% at 50% 40%, rgba(234,88,12,0.22) 0, transparent 55%),
    radial-gradient(ellipse 50% 30% at 50% 60%, rgba(217,119,6,0.15) 0, transparent 60%),
    conic-gradient(from 90deg at 50% 50%,
      rgba(234,88,12,0.12), rgba(120,53,15,0.18), rgba(245,158,11,0.10),
      rgba(234,88,12,0.12));
  animation: spin-slow 45s linear infinite;
  mix-blend-mode: screen;
}

/* --- ĐỐ VUI: bong bóng confetti --- */
body.theme-do-vui .scenery {
  background:
    radial-gradient(circle 6px at 12% 20%, rgba(244,63,94,0.7), transparent 70%),
    radial-gradient(circle 5px at 80% 30%, rgba(251,146,60,0.7), transparent 70%),
    radial-gradient(circle 4px at 25% 70%, rgba(250,204,21,0.7), transparent 70%),
    radial-gradient(circle 6px at 75% 80%, rgba(244,63,94,0.6), transparent 70%),
    radial-gradient(circle 4px at 50% 15%, rgba(251,146,60,0.7), transparent 70%),
    radial-gradient(circle 5px at 45% 90%, rgba(250,204,21,0.6), transparent 70%),
    radial-gradient(circle 6px at 90% 60%, rgba(244,63,94,0.5), transparent 70%),
    radial-gradient(ellipse 80% 60% at 50% 50%, rgba(244,63,94,0.10) 0, transparent 60%);
  animation: float-up 14s linear infinite;
}

/* --- ĐỐ MẸO: sương mù tím bí ẩn --- */
body.theme-do-meo .scenery {
  background:
    radial-gradient(ellipse 60% 40% at 30% 40%, rgba(168,85,247,0.25) 0, transparent 60%),
    radial-gradient(ellipse 50% 50% at 70% 60%, rgba(99,102,241,0.22) 0, transparent 60%),
    radial-gradient(ellipse 80% 30% at 50% 80%, rgba(236,72,153,0.15) 0, transparent 60%);
  animation: fog-drift 25s ease-in-out infinite alternate;
  mix-blend-mode: screen;
}

/* --- TÍNH NHANH: tia chớp xanh điện --- */
body.theme-tinh-nhanh .scenery {
  background:
    linear-gradient(135deg, transparent 40%, rgba(6,182,212,0.18) 41%, rgba(6,182,212,0.18) 42%, transparent 43%),
    linear-gradient(135deg, transparent 60%, rgba(59,130,246,0.18) 61%, rgba(59,130,246,0.18) 62%, transparent 63%),
    linear-gradient(120deg, transparent 20%, rgba(139,92,246,0.15) 21%, rgba(139,92,246,0.15) 22%, transparent 23%),
    radial-gradient(ellipse 70% 50% at 50% 50%, rgba(6,182,212,0.15) 0, transparent 60%);
  animation: pulse-glow 2s ease-in-out infinite alternate;
  mix-blend-mode: screen;
}

/* --- TÍNH SIÊU NHANH: hyperspeed warp đỏ cam --- */
body.theme-tinh-sieu-nhanh .scenery {
  background:
    repeating-linear-gradient(90deg,
      transparent 0px, transparent 30px,
      rgba(239,68,68,0.10) 30px, rgba(239,68,68,0.10) 31px,
      transparent 31px, transparent 60px,
      rgba(249,115,22,0.12) 60px, rgba(249,115,22,0.12) 62px),
    radial-gradient(ellipse 70% 50% at 50% 50%, rgba(244,63,94,0.20) 0, transparent 55%);
  animation: warp 0.8s linear infinite;
  mix-blend-mode: screen;
}

/* --- TÍNH NHẨM: thiền — sóng xanh mint nhẹ --- */
body.theme-tinh-nham .scenery {
  background:
    radial-gradient(ellipse 100% 30% at 50% 25%, rgba(16,185,129,0.18) 0, transparent 70%),
    radial-gradient(ellipse 100% 30% at 50% 55%, rgba(6,182,212,0.15) 0, transparent 70%),
    radial-gradient(ellipse 100% 30% at 50% 85%, rgba(20,184,166,0.18) 0, transparent 70%);
  animation: wave-soft 18s ease-in-out infinite alternate;
  mix-blend-mode: screen;
}

@keyframes spin-slow { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }
@keyframes float-up { from { transform: translateY(20px); opacity: 0.4; } to { transform: translateY(-20px); opacity: 0.9; } }
@keyframes fog-drift { from { transform: translate(0,0) scale(1); } to { transform: translate(3%, -2%) scale(1.05); } }
@keyframes pulse-glow { from { opacity: 0.6; filter: brightness(0.9); } to { opacity: 1; filter: brightness(1.3); } }
@keyframes warp { from { background-position: 0 0; } to { background-position: 120px 0; } }
@keyframes wave-soft { from { transform: translateY(-8px); } to { transform: translateY(8px); } }

.wrap { max-width: 760px; margin: 0 auto; padding: 24px 18px 60px; position: relative; z-index: 1; }

/* ===== Header ===== */
.site-header {
  display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center;
  gap: 12px;
  padding: 14px 18px;
  background: rgba(11,16,41,0.7);
  backdrop-filter: blur(14px) saturate(140%);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 100;
}
.site-header .logo {
  font-family: 'Fraunces', serif; font-weight: 900; font-size: 22px;
  letter-spacing: -0.02em; text-decoration: none;
  background: linear-gradient(135deg, var(--accent-2), var(--accent-1));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.site-header .logo span {
  background: linear-gradient(135deg, var(--accent-3), var(--accent-1));
  -webkit-background-clip: text; background-clip: text; color: transparent;
  font-style: italic;
}
.site-header nav { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; }
.site-header nav a {
  color: var(--ink); text-decoration: none; font-weight: 600; font-size: 13.5px;
  padding: 7px 13px; border-radius: 999px;
  transition: all .2s; border: 1px solid transparent;
}
.site-header nav a:hover {
  background: var(--glass-strong);
  border-color: var(--line);
  color: var(--accent-2);
}
.site-header nav a.active,
.site-header nav a.admin {
  background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
  color: white; border-color: transparent;
  box-shadow: 0 0 18px var(--glow);
}

/* ===== Typography ===== */
h1, h2, h3, h4 {
  font-family: 'Fraunces', serif; letter-spacing: -0.02em; color: var(--ink);
}
h1 { font-size: clamp(34px, 7vw, 56px); font-weight: 900; line-height: 1.05; }
h1 em {
  font-style: italic;
  background: linear-gradient(135deg, var(--accent-2), var(--accent-1), var(--accent-3));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
h2 { font-size: 24px; font-weight: 800; margin-bottom: 12px; }
h3 { font-size: 18px; font-weight: 700; }
p { color: var(--ink); }
.muted { color: var(--ink-mute); }

/* ===== Card (glass) ===== */
.card {
  background: var(--glass);
  border: 1px solid var(--line);
  border-radius: 22px;
  padding: 26px 22px;
  backdrop-filter: blur(20px) saturate(140%);
  -webkit-backdrop-filter: blur(20px) saturate(140%);
  margin-bottom: 18px;
  position: relative;
  overflow: hidden;
  box-shadow: 0 8px 32px rgba(0,0,0,0.3), inset 0 1px 0 rgba(255,255,255,0.08);
}
.card::before {
  content: ''; position: absolute; inset: 0; pointer-events: none;
  background: radial-gradient(circle at 0% 0%, var(--glow) 0, transparent 60%);
  opacity: 0.4; mix-blend-mode: screen;
}
.card > * { position: relative; }

/* ===== Forms ===== */
.form-group { margin-bottom: 14px; }
.form-group label {
  display: block; font-size: 11px; font-weight: 700;
  text-transform: uppercase; letter-spacing: 0.12em;
  color: var(--ink-mute); margin-bottom: 8px;
}
.form-group input, .form-group textarea, .form-group select {
  width: 100%; padding: 13px 15px;
  background: rgba(255,255,255,0.06);
  border: 1px solid var(--line); border-radius: 12px;
  font-family: inherit; font-size: 15px; color: var(--ink);
  transition: all .2s;
}
.form-group input::placeholder, .form-group textarea::placeholder { color: var(--ink-mute); }
.form-group input:focus, .form-group textarea:focus, .form-group select:focus {
  outline: none;
  border-color: var(--accent-1);
  background: rgba(255,255,255,0.10);
  box-shadow: 0 0 0 3px var(--glow);
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  border: none; cursor: pointer; text-decoration: none;
  padding: 14px 26px; border-radius: 14px;
  font-family: 'Plus Jakarta Sans', sans-serif; font-weight: 700; font-size: 15px;
  background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
  color: white;
  box-shadow: 0 4px 18px var(--glow), inset 0 1px 0 rgba(255,255,255,0.25);
  transition: transform .15s, box-shadow .2s, filter .2s;
  position: relative; overflow: hidden;
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 8px 28px var(--glow), inset 0 1px 0 rgba(255,255,255,0.3); filter: brightness(1.1); }
.btn:active { transform: translateY(0); }
.btn.block { display: flex; width: 100%; }
.btn.secondary {
  background: var(--glass-strong); color: var(--ink);
  border: 1px solid var(--line-strong); box-shadow: none;
}
.btn.secondary:hover { background: rgba(255,255,255,0.12); }
.btn.gold {
  background: linear-gradient(135deg, #ffc857, #f59e0b);
  color: #0b1029;
  box-shadow: 0 4px 18px rgba(255,200,87,0.35);
}
.btn.forest { background: linear-gradient(135deg, var(--accent-2), var(--accent-1)); }
.btn.danger {
  background: linear-gradient(135deg, var(--accent-3), #ef4444);
  box-shadow: 0 4px 18px rgba(239,68,68,0.4);
}
.btn.huge { padding: 18px 32px; font-size: 18px; border-radius: 16px; }

/* ===== Alerts ===== */
.alert {
  padding: 12px 16px; border-radius: 12px; margin-bottom: 14px;
  font-size: 14px; font-weight: 500;
  background: var(--glass-strong); border: 1px solid var(--line-strong);
}
.alert.error   { background: rgba(239,68,68,0.12); border-color: rgba(239,68,68,0.35); color: #fca5a5; }
.alert.success { background: rgba(16,185,129,0.12); border-color: rgba(16,185,129,0.35); color: #6ee7b7; }
.alert.info    { background: rgba(255,200,87,0.12); border-color: rgba(255,200,87,0.35); color: #fcd34d; }

/* ===== Stats ===== */
.stats-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; margin: 18px 0; }
.stat-box {
  border: 1px solid var(--line);
  background: rgba(255,255,255,0.04);
  border-radius: 16px; padding: 16px;
  transition: all .2s;
  position: relative; overflow: hidden;
}
.stat-box:hover { border-color: var(--line-strong); transform: translateY(-2px); background: rgba(255,255,255,0.07); }
.stat-box .num {
  font-family: 'Fraunces', serif; font-weight: 800; font-size: 30px;
  background: linear-gradient(135deg, var(--accent-2), var(--accent-1));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.stat-box .lbl {
  font-size: 11px; color: var(--ink-mute);
  text-transform: uppercase; letter-spacing: 0.1em; font-weight: 700; margin-top: 4px;
}

/* ===== Category card ===== */
.cat-card {
  display: flex; flex-direction: column; gap: 6px;
  padding: 18px; border-radius: 16px;
  border: 1px solid var(--line);
  background: var(--glass);
  text-decoration: none; color: var(--ink);
  transition: all .2s; position: relative; overflow: hidden;
}
.cat-card::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(135deg, var(--cat-color, var(--accent-1)) 0%, transparent 60%);
  opacity: 0.15; transition: opacity .2s;
}
.cat-card:hover { transform: translateY(-3px); border-color: var(--cat-color, var(--accent-1)); }
.cat-card:hover::before { opacity: 0.3; }
.cat-card .cat-icon { font-size: 28px; }
.cat-card .cat-name { font-family: 'Fraunces', serif; font-weight: 800; font-size: 18px; position: relative; }
.cat-card .cat-desc { color: var(--ink-mute); font-size: 13px; position: relative; }

.cat-card.c-kien-thuc       { --cat-color: #7c6cff; }
.cat-card.c-dia-ly          { --cat-color: #00bfa6; }
.cat-card.c-van-hoa         { --cat-color: #f59e0b; }
.cat-card.c-lich-su         { --cat-color: #ea580c; }
.cat-card.c-do-vui          { --cat-color: #f43f5e; }
.cat-card.c-do-meo          { --cat-color: #a855f7; }
.cat-card.c-tinh-nhanh      { --cat-color: #06b6d4; }
.cat-card.c-tinh-sieu-nhanh { --cat-color: #ef4444; }
.cat-card.c-tinh-nham       { --cat-color: #10b981; }

/* ===== Tables ===== */
table { width: 100%; border-collapse: collapse; }
th, td { padding: 12px 10px; text-align: left; border-bottom: 1px solid var(--line); color: var(--ink); font-size: 14px; }
th { font-weight: 700; color: var(--ink-mute); font-size: 11px; text-transform: uppercase; letter-spacing: 0.1em; }
tr:hover td { background: rgba(255,255,255,0.03); }

/* ===== Quiz ===== */
.quiz-timer {
  font-family: 'Fraunces', serif; font-weight: 800;
  font-size: 48px; text-align: center;
  background: linear-gradient(135deg, var(--accent-2), var(--accent-1));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.quiz-question { font-family: 'Fraunces', serif; font-weight: 700; font-size: 22px; line-height: 1.3; margin: 20px 0; }
.quiz-options { display: flex; flex-direction: column; gap: 10px; }
.quiz-option {
  background: var(--glass-strong); border: 1px solid var(--line);
  border-radius: 14px; padding: 14px 18px; cursor: pointer;
  font-size: 15px; color: var(--ink);
  transition: all .15s; text-align: left;
  display: flex; align-items: center; gap: 12px;
}
.quiz-option .letter {
  flex-shrink: 0; width: 32px; height: 32px; border-radius: 8px;
  background: rgba(255,255,255,0.06); display: flex; align-items: center; justify-content: center;
  font-weight: 800; font-family: 'Fraunces', serif;
}
.quiz-option:hover { border-color: var(--accent-1); background: rgba(255,255,255,0.08); transform: translateX(4px); }
.quiz-option.selected { border-color: var(--accent-1); background: rgba(124,108,255,0.18); }
.quiz-option.correct { border-color: #10b981; background: rgba(16,185,129,0.18); }
.quiz-option.wrong { border-color: #ef4444; background: rgba(239,68,68,0.18); }

/* ===== Helpers ===== */
.text-center { text-align: center; }
.text-right { text-align: right; }
.mt-1 { margin-top: 8px; } .mt-2 { margin-top: 16px; } .mt-3 { margin-top: 24px; } .mt-4 { margin-top: 32px; }
.mb-1 { margin-bottom: 8px; } .mb-2 { margin-bottom: 16px; }
.link { color: var(--accent-2); text-decoration: none; font-weight: 600; border-bottom: 1px dashed currentColor; }
.link:hover { color: var(--accent-1); }
.badge-pill {
  display: inline-block; padding: 4px 10px; border-radius: 999px;
  background: var(--glass-strong); border: 1px solid var(--line);
  font-size: 12px; font-weight: 600;
}
.divider { height: 1px; background: var(--line); margin: 16px 0; }
hr { border: none; height: 1px; background: var(--line); margin: 16px 0; }

/* Tabs */
.tabs { display: flex; gap: 6px; margin-bottom: 16px; flex-wrap: wrap; }
.tabs a {
  padding: 8px 14px; border-radius: 999px;
  background: var(--glass-strong); border: 1px solid var(--line);
  color: var(--ink); text-decoration: none; font-weight: 600; font-size: 13px;
  transition: all .15s;
}
.tabs a:hover { border-color: var(--accent-1); }
.tabs a.active {
  background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
  border-color: transparent; color: white;
  box-shadow: 0 0 18px var(--glow);
}

.hero-glow {
  background: linear-gradient(135deg, var(--accent-2), var(--accent-1), var(--accent-3));
  background-size: 200% 200%;
  -webkit-background-clip: text; background-clip: text; color: transparent;
  animation: gradient-shift 6s ease-in-out infinite;
}
@keyframes gradient-shift {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

.site-footer {
  margin-top: 40px; padding: 24px 18px;
  text-align: center; color: var(--ink-mute); font-size: 13px;
  border-top: 1px solid var(--line);
}
.site-footer a { color: var(--ink-mute); }

/* ===== Layout helpers for existing pages ===== */
.cats {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px;
}
.cat-card .icon { font-size: 28px; }
.cat-card .name { font-family: 'Fraunces', serif; font-weight: 800; font-size: 17px; position: relative; }
.cat-card .desc { color: var(--ink-mute); font-size: 13px; position: relative; }
.cat-card.mix { --cat-color: #ffc857; }

.row { display: flex; flex-wrap: wrap; gap: 10px; }
.btn.small { padding: 10px 16px; font-size: 13.5px; border-radius: 12px; }

.ad-slot {
  margin: 18px 0;
  padding: 22px 18px;
  text-align: center;
  border: 1px dashed var(--line-strong);
  border-radius: 18px;
  background: rgba(255,200,87,0.04);
  color: var(--ink-mute);
  font-size: 13px;
}

/* Notification bell badge */
.notif-bell {
  position: relative; display: inline-flex;
  padding: 6px 10px; border-radius: 999px;
  background: var(--glass-strong); border: 1px solid var(--line);
  font-size: 16px; text-decoration: none;
}
.notif-bell .count {
  position: absolute; top: -4px; right: -4px;
  background: linear-gradient(135deg, var(--accent-3), #ef4444);
  color: white; font-size: 10px; font-weight: 700;
  min-width: 18px; height: 18px; border-radius: 999px;
  display: flex; align-items: center; justify-content: center; padding: 0 4px;
  box-shadow: 0 0 8px rgba(239,68,68,0.5);
}

/* =========================================================
   LEGACY CLASS COMPAT — pages already using these
   ========================================================= */

/* Pills (play.php settings) */
.pill-group { display: inline-flex; gap: 6px; flex-wrap: wrap; }
.pill {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 44px; padding: 8px 14px;
  border-radius: 999px; cursor: pointer;
  background: var(--glass-strong); border: 1px solid var(--line);
  color: var(--ink); font-weight: 700; font-size: 14px;
  transition: all .15s; user-select: none;
}
.pill:hover { border-color: var(--accent-1); }
.pill.active {
  background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
  color: white; border-color: transparent;
  box-shadow: 0 0 14px var(--glow);
}
.lbl-text {
  font-size: 11px; font-weight: 700; color: var(--ink-mute);
  text-transform: uppercase; letter-spacing: 0.12em;
  align-self: center; margin-right: 6px;
}

/* Quiz (game.php) */
.topbar {
  display: flex; justify-content: space-between; align-items: center;
  gap: 12px; margin-bottom: 14px; flex-wrap: wrap;
}
.qnum {
  font-family: 'Fraunces', serif; font-weight: 800; font-size: 14px;
  color: var(--ink-mute);
}
.time {
  font-family: 'Fraunces', serif; font-weight: 900; font-size: 36px;
  background: linear-gradient(135deg, var(--accent-2), var(--accent-1));
  -webkit-background-clip: text; background-clip: text; color: transparent;
  min-width: 70px; text-align: right;
}
.qcat {
  display: inline-block; padding: 4px 10px; border-radius: 999px;
  background: var(--glass-strong); border: 1px solid var(--line);
  font-size: 12px; font-weight: 600; color: var(--ink-mute);
  margin-bottom: 12px;
}
.qcard {
  background: var(--glass); border: 1px solid var(--line);
  border-radius: 22px; padding: 26px 22px;
  backdrop-filter: blur(20px) saturate(140%);
  -webkit-backdrop-filter: blur(20px) saturate(140%);
  box-shadow: 0 12px 40px rgba(0,0,0,0.4), inset 0 1px 0 rgba(255,255,255,0.08);
  position: relative; overflow: hidden;
}
.qcard::before {
  content: ''; position: absolute; inset: 0; pointer-events: none;
  background: radial-gradient(circle at 50% 0%, var(--glow) 0, transparent 60%);
  opacity: 0.5;
}
.qcard > * { position: relative; }
.qtext {
  font-family: 'Fraunces', serif; font-weight: 700;
  font-size: clamp(20px, 4.5vw, 26px);
  line-height: 1.3; margin: 8px 0 22px;
}
.options { display: flex; flex-direction: column; gap: 10px; }
.opt {
  background: var(--glass-strong); border: 1px solid var(--line);
  border-radius: 14px; padding: 14px 18px; cursor: pointer;
  font-size: 15px; color: var(--ink);
  transition: all .15s; text-align: left;
  display: flex; align-items: center; gap: 12px;
  font-family: inherit;
}
.opt::before {
  content: attr(data-letter); flex-shrink: 0;
  width: 32px; height: 32px; border-radius: 10px;
  background: rgba(255,255,255,0.08);
  display: flex; align-items: center; justify-content: center;
  font-family: 'Fraunces', serif; font-weight: 800;
  color: var(--accent-2);
}
.opt:hover { border-color: var(--accent-1); background: rgba(255,255,255,0.08); transform: translateX(4px); }
.opt.selected { border-color: var(--accent-1); background: rgba(124,108,255,0.18); box-shadow: 0 0 16px var(--glow); }
.opt.correct { border-color: #10b981; background: rgba(16,185,129,0.18); }
.opt.correct::before { background: #10b981; color: white; }
.opt.wrong { border-color: #ef4444; background: rgba(239,68,68,0.18); }
.opt.wrong::before { background: #ef4444; color: white; }
.opt:disabled { cursor: default; }

/* Leaderboard */
.lb-tabs { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 14px; }
.lb-tabs a {
  padding: 8px 14px; border-radius: 999px;
  background: var(--glass-strong); border: 1px solid var(--line);
  color: var(--ink); text-decoration: none; font-weight: 600; font-size: 13px;
  transition: all .15s;
}
.lb-tabs a:hover { border-color: var(--accent-1); }
.lb-tabs a.active {
  background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
  color: white; border-color: transparent;
  box-shadow: 0 0 14px var(--glow);
}
.lb { width: 100%; border-collapse: collapse; }
.lb th, .lb td {
  padding: 12px 10px; text-align: left;
  border-bottom: 1px solid var(--line);
  color: var(--ink); font-size: 14px;
}
.lb th { font-weight: 700; color: var(--ink-mute); font-size: 11px; text-transform: uppercase; letter-spacing: 0.1em; }
.lb tr:hover td { background: rgba(255,255,255,0.04); }
.lb .rank-1 { color: #facc15; font-weight: 800; }
.lb .rank-2 { color: #cbd5e1; font-weight: 800; }
.lb .rank-3 { color: #fdba74; font-weight: 800; }

/* Badges */
.badges-row { display: flex; flex-wrap: wrap; gap: 10px; }
.badge-chip {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 8px 14px; border-radius: 999px;
  background: var(--glass-strong); border: 1px solid var(--line);
  font-size: 13px; font-weight: 600;
  transition: all .15s;
}
.badge-chip:hover { border-color: var(--accent-1); transform: translateY(-2px); }
.badge-chip.common   { color: var(--ink-mute); }
.badge-chip.rare     { color: #93c5fd; border-color: rgba(147,197,253,0.3); }
.badge-chip.epic     { color: #c4b5fd; border-color: rgba(196,181,253,0.4); box-shadow: 0 0 12px rgba(196,181,253,0.2); }
.badge-chip.legendary { color: #fcd34d; border-color: rgba(252,211,77,0.5); box-shadow: 0 0 16px rgba(252,211,77,0.3); }

/* Notifications */
.notif-item {
  padding: 14px 16px; border-radius: 14px; margin-bottom: 10px;
  background: var(--glass-strong); border: 1px solid var(--line);
  transition: all .15s;
}
.notif-item:hover { border-color: var(--accent-1); }
.notif-item.unread {
  background: rgba(124,108,255,0.10);
  border-color: rgba(124,108,255,0.35);
  border-left: 3px solid var(--accent-1);
}

/* Progress bar */
.progress-track {
  height: 8px; background: var(--glass-strong);
  border-radius: 999px; overflow: hidden;
  border: 1px solid var(--line);
}
.progress-fill {
  height: 100%; border-radius: 999px;
  background: linear-gradient(90deg, var(--accent-2), var(--accent-1), var(--accent-3));
  background-size: 200% 100%;
  animation: gradient-shift 4s ease-in-out infinite;
  box-shadow: 0 0 14px var(--glow);
}

/* Stat mini */
.stat-mini {
  display: inline-flex; align-items: baseline; gap: 6px;
  padding: 6px 12px; border-radius: 999px;
  background: var(--glass-strong); border: 1px solid var(--line);
  font-size: 13px; font-weight: 600;
}
.stat-mini b { font-family: 'Fraunces', serif; font-weight: 800; color: var(--accent-2); }

/* Misc modifiers */
.flat { background: transparent !important; border: none !important; box-shadow: none !important; padding: 0 !important; }
.fade { opacity: 0.6; }
.dark { background: rgba(0,0,0,0.3); }