/* Digital Tower – Tiger Theme UI */
@import url('https://fonts.googleapis.com/css2?family=Be+Vietnam+Pro:wght@400;600;700;800&display=swap');

:root {
  --blue: #003DA5;
  --blue-dark: #00183a;
  --gold: #FFC72C;
  --gold-soft: rgba(255, 199, 44, 0.15);
  --black: #060a10;
  --surface: rgba(16, 24, 32, 0.85);
  --border: rgba(255, 199, 44, 0.2);
  --text: #eef2f7;
  --muted: #8a97a8;
  --red: #ff4757;
  --green: #2ed573;
  --radius: 20px;
  --shadow: 0 24px 80px rgba(0, 0, 0, 0.5);
}

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

html { scroll-behavior: smooth; }

body {
  min-height: 100vh;
  font-family: 'Be Vietnam Pro', system-ui, sans-serif;
  color: var(--text);
  background: var(--black);
  background-image:
    radial-gradient(ellipse 80% 50% at 20% -10%, rgba(255, 199, 44, 0.12), transparent),
    radial-gradient(ellipse 60% 40% at 90% 100%, rgba(0, 61, 165, 0.4), transparent),
    linear-gradient(180deg, #0a1018 0%, var(--black) 100%);
  line-height: 1.6;
}

a { color: var(--gold); text-decoration: none; transition: opacity 0.2s; }
a:hover { opacity: 0.85; }

.container { max-width: 920px; margin: 0 auto; padding: 24px 20px; }

/* ── Hero ── */
.hero {
  text-align: center;
  padding: 56px 20px 40px;
  animation: fadeUp 0.7s ease;
}

.hero-badge {
  display: inline-block;
  background: var(--gold-soft);
  border: 1px solid var(--border);
  color: var(--gold);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 2px;
  text-transform: uppercase;
  padding: 6px 16px;
  border-radius: 30px;
  margin-bottom: 20px;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 800;
  line-height: 1.15;
  background: linear-gradient(135deg, #fff 30%, var(--gold));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p { color: var(--muted); max-width: 480px; margin: 16px auto 0; font-size: 15px; }

/* ── Glass card ── */
.card {
  background: var(--surface);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  animation: fadeUp 0.6s ease backwards;
}

.card-header {
  background: linear-gradient(135deg, var(--blue) 0%, var(--blue-dark) 100%);
  padding: 24px 28px;
  border-bottom: 3px solid var(--gold);
}

.card-header h2 { font-size: 1.2rem; font-weight: 700; }
.card-body { padding: 28px; }

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: linear-gradient(135deg, var(--gold) 0%, #e6a800 100%);
  color: var(--blue-dark);
  border: none;
  font-family: inherit;
  font-weight: 800;
  font-size: 15px;
  padding: 15px 32px;
  border-radius: 50px;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s, filter 0.15s;
  box-shadow: 0 4px 20px rgba(255, 199, 44, 0.3);
}

.btn:hover { transform: translateY(-2px); filter: brightness(1.05); box-shadow: 0 8px 28px rgba(255, 199, 44, 0.4); }
.btn:active { transform: translateY(0); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; transform: none; }
.btn-block { width: 100%; }
.btn-outline {
  background: transparent;
  color: var(--gold);
  border: 2px solid var(--gold);
  box-shadow: none;
}
.btn-outline:hover { background: var(--gold-soft); }
.btn-sm { padding: 10px 20px; font-size: 13px; }
.btn-ghost { background: rgba(255,255,255,0.06); color: var(--text); box-shadow: none; border: 1px solid rgba(255,255,255,0.1); }

/* ── Forms ── */
.form-group { margin-bottom: 20px; }
.form-group label {
  display: block;
  font-size: 12px;
  font-weight: 600;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 8px;
}

.form-group input,
.form-group select {
  width: 100%;
  background: rgba(0, 0, 0, 0.35);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 12px;
  color: var(--text);
  padding: 14px 16px;
  font-family: inherit;
  font-size: 15px;
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group input:focus,
.form-group select:focus {
  border-color: var(--gold);
  box-shadow: 0 0 0 3px var(--gold-soft);
}

.icon-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 10px;
}

.icon-btn {
  aspect-ratio: 1;
  font-size: 2rem;
  background: rgba(0, 0, 0, 0.3);
  border: 2px solid transparent;
  border-radius: 14px;
  cursor: pointer;
  transition: all 0.2s;
}

.icon-btn:hover { transform: scale(1.08); border-color: rgba(255,199,44,0.4); }
.icon-btn.selected {
  border-color: var(--gold);
  background: var(--gold-soft);
  box-shadow: 0 0 20px rgba(255, 199, 44, 0.25);
}

/* ── Alerts ── */
.alert {
  padding: 14px 18px;
  border-radius: 12px;
  font-size: 14px;
  margin-bottom: 16px;
  animation: fadeUp 0.3s ease;
}
.alert-error { background: rgba(255,71,87,0.15); border: 1px solid var(--red); color: #ff8a95; }
.alert-success { background: rgba(46,213,115,0.12); border: 1px solid var(--green); color: #7dffb0; }
.alert-info { background: rgba(0,61,165,0.25); border: 1px solid var(--blue); color: #a8c4ff; }

/* ── Play header ── */
.play-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(6, 10, 16, 0.9);
  backdrop-filter: blur(16px);
  border-bottom: 2px solid var(--border);
  padding: 14px 0;
}

.play-header-inner {
  max-width: 920px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}

.player-chip {
  display: flex;
  align-items: center;
  gap: 12px;
}

.player-chip .avatar { font-size: 2rem; }
.player-chip .name { font-weight: 700; font-size: 15px; }
.player-chip .dept { font-size: 12px; color: var(--muted); }

.header-stats { display: flex; align-items: center; gap: 16px; }

.lives-bar { display: flex; gap: 5px; }
.life {
  width: 26px; height: 26px;
  border-radius: 50%;
  background: var(--red);
  display: flex; align-items: center; justify-content: center;
  font-size: 12px;
  transition: transform 0.3s;
}
.life.empty { background: rgba(255,255,255,0.08); opacity: 0.4; }

.score-pill {
  background: linear-gradient(135deg, var(--gold), #e6a800);
  color: var(--blue-dark);
  font-weight: 800;
  font-size: 13px;
  padding: 6px 14px;
  border-radius: 30px;
}

/* ── Door / question ── */
.door-topic {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--gold);
  opacity: 0.9;
}

.door-story { color: var(--muted); font-size: 14px; margin: 12px 0; }
.question-text {
  font-size: 1.15rem;
  font-weight: 600;
  line-height: 1.65;
  margin: 20px 0;
  padding: 20px;
  background: rgba(0, 61, 165, 0.15);
  border-left: 4px solid var(--gold);
  border-radius: 0 12px 12px 0;
}

.answer-row { display: flex; gap: 10px; margin-top: 8px; }
.answer-row input { flex: 1; }

.info-box, .prompt-box, .chat-box {
  background: rgba(0,0,0,0.3);
  border: 1px dashed rgba(255,255,255,0.12);
  border-radius: 12px;
  padding: 16px;
  margin: 12px 0;
  font-size: 14px;
}

.data-table { width: 100%; border-collapse: collapse; font-size: 14px; margin: 12px 0; }
.data-table th, .data-table td { border: 1px solid rgba(255,255,255,0.1); padding: 10px 12px; text-align: left; }
.data-table th { background: var(--blue-dark); color: var(--gold); }

/* ── Hints ── */
.hint-row { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 16px; }
.hint-btn {
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.12);
  color: var(--muted);
  padding: 8px 14px;
  border-radius: 10px;
  font-family: inherit;
  font-size: 12px;
  cursor: pointer;
  transition: all 0.2s;
}
.hint-btn:hover:not(:disabled) { border-color: var(--gold); color: var(--gold); }
.hint-btn:disabled { opacity: 0.5; }
.hint-box {
  margin-top: 12px;
  padding: 14px;
  background: var(--gold-soft);
  border-radius: 10px;
  font-size: 14px;
  display: none;
}
.hint-box.visible { display: block; animation: fadeUp 0.3s ease; }

/* ── Puzzle ── */
.puzzle-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
  max-width: 260px;
  margin: 24px auto;
}

.puzzle-piece {
  aspect-ratio: 1;
  background: linear-gradient(145deg, var(--blue), var(--blue-dark));
  border: 2px solid rgba(255,199,44,0.3);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 18px;
  opacity: 0.2;
  transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.puzzle-piece.collected {
  opacity: 1;
  border-color: var(--gold);
  box-shadow: 0 0 16px rgba(255,199,44,0.3);
  animation: popIn 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.pair-code {
  font-size: clamp(1.8rem, 5vw, 2.5rem);
  font-weight: 800;
  color: var(--gold);
  letter-spacing: 6px;
  text-shadow: 0 0 30px rgba(255,199,44,0.4);
  margin: 20px 0;
}

/* ── Popup ── */
.overlay {
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.75);
  backdrop-filter: blur(8px);
  display: flex; align-items: center; justify-content: center;
  z-index: 200; padding: 20px;
  opacity: 0; pointer-events: none;
  transition: opacity 0.3s;
}
.overlay.show { opacity: 1; pointer-events: auto; }

.popup {
  background: var(--surface);
  border: 2px solid var(--gold);
  border-radius: var(--radius);
  padding: 36px 32px;
  max-width: 400px;
  width: 100%;
  text-align: center;
  transform: scale(0.9);
  transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}
.overlay.show .popup { transform: scale(1); }

.popup-icon { font-size: 3.5rem; margin-bottom: 12px; }
.popup h3 { color: var(--gold); font-size: 1.3rem; margin-bottom: 10px; }
.popup p { color: var(--muted); line-height: 1.7; }

/* ── Leaderboard ── */
.lb-table { width: 100%; border-collapse: collapse; font-size: 14px; }
.lb-table th { text-align: left; padding: 12px; color: var(--gold); font-size: 11px; text-transform: uppercase; letter-spacing: 1px; border-bottom: 1px solid var(--border); }
.lb-table td { padding: 12px; border-bottom: 1px solid rgba(255,255,255,0.05); }
.lb-table tr.top1 td { color: var(--gold); font-weight: 700; }
.lb-table tr:hover td { background: rgba(255,199,44,0.04); }

/* ── Layout helpers ── */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.text-center { text-align: center; }
.hidden { display: none !important; }
.mt-16 { margin-top: 16px; }
.mt-24 { margin-top: 24px; }
.gap-12 { gap: 12px; display: flex; flex-wrap: wrap; justify-content: center; }

footer {
  text-align: center;
  color: rgba(255,255,255,0.25);
  font-size: 12px;
  padding: 32px;
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes popIn {
  0% { transform: scale(0) rotate(-10deg); }
  70% { transform: scale(1.12) rotate(2deg); }
  100% { transform: scale(1) rotate(0); }
}

@media (max-width: 640px) {
  .icon-grid { grid-template-columns: repeat(4, 1fr); }
  .grid-2 { grid-template-columns: 1fr; }
  .answer-row { flex-direction: column; }
}

/* Trắc nghiệm */
.choice-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 16px;
}

.choice-btn {
  background: rgba(0, 61, 165, 0.2);
  border: 2px solid rgba(255, 199, 44, 0.25);
  color: var(--text);
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  padding: 16px 14px;
  border-radius: 14px;
  cursor: pointer;
  transition: all 0.2s;
  text-align: left;
}

.choice-btn:hover {
  border-color: var(--gold);
  background: var(--gold-soft);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(255, 199, 44, 0.15);
}

.choice-btn:active { transform: translateY(0); }

@media (max-width: 480px) {
  .choice-grid { grid-template-columns: 1fr; }
}