/* Sân khấu truyền hình kiểu Olympia: trường quay xanh đêm, đèn rọi, khung kính phát sáng,
   vàng sân khấu cho khoảnh khắc thắng. Hệ chọn qua ui-ux-pro-max (style: Retro-Futurism /
   broadcast) nhưng font đổi sang họ CÓ tiếng Việt (đo 07-10-2026: Russo One không có).
   4 đáp án mang màu + hình riêng (kiểu Kahoot) — không chỉ dựa vào màu (a11y). */
:root {
  --bg0: #040716;
  --bg1: #0A1238;
  --bg2: #111C52;
  --glass: rgba(18, 30, 86, .62);
  --glass-2: rgba(30, 48, 128, .55);
  --edge: #3D6BFF;
  --edge-soft: rgba(91, 132, 255, .35);
  --cyan: #22D3EE;
  --gold: #FFC83D;
  --gold-2: #FF9F1C;
  --hot: #FF3D6E;
  --ok: #2EE59D;
  --text: #F4F7FF;
  --muted: #9AAAE0;
  --faint: #5D6CA8;
  --a: #FF3D6E;   /* đáp án A · tam giác */
  --b: #3D6BFF;   /* đáp án B · thoi */
  --c: #FFB020;   /* đáp án C · tròn */
  --d: #20C997;   /* đáp án D · vuông */
  --display: "Barlow Condensed", "Be Vietnam Pro", sans-serif;
  --num: "Chakra Petch", "Be Vietnam Pro", monospace;
  --sans: "Be Vietnam Pro", system-ui, sans-serif;
  --ease: cubic-bezier(.22, 1, .36, 1);
}
* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; }
body {
  background: var(--bg0);
  color: var(--text);
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
  -webkit-tap-highlight-color: transparent;
}
button { font-family: inherit; color: inherit; cursor: pointer; touch-action: manipulation; }
::selection { background: var(--gold); color: var(--bg0); }

/* ── nền trường quay: đèn rọi + sàn lưới phối cảnh + bụi sáng ── */
.studio { position: absolute; inset: 0; overflow: hidden; pointer-events: none; z-index: 0;
  background:
    radial-gradient(60% 50% at 50% -10%, rgba(61,107,255,.55), transparent 70%),
    radial-gradient(40% 40% at 0% 100%, rgba(255,61,110,.18), transparent 70%),
    radial-gradient(40% 40% at 100% 100%, rgba(34,211,238,.18), transparent 70%),
    linear-gradient(180deg, var(--bg1) 0%, var(--bg0) 75%); }
.studio .beam { position: absolute; top: -20%; width: 34%; height: 140%; transform-origin: 50% 0;
  background: linear-gradient(180deg, rgba(140,170,255,.22), rgba(140,170,255,0) 75%);
  clip-path: polygon(46% 0, 54% 0, 100% 100%, 0 100%); filter: blur(6px); mix-blend-mode: screen; }
.studio .beam.l { left: 4%; animation: sweepL 9s ease-in-out infinite alternate; }
.studio .beam.r { right: 4%; animation: sweepR 11s ease-in-out infinite alternate; }
.studio .beam.c { left: 33%; opacity: .6; animation: sweepC 13s ease-in-out infinite alternate; }
@keyframes sweepL { from { transform: rotate(-24deg); } to { transform: rotate(10deg); } }
@keyframes sweepR { from { transform: rotate(22deg); } to { transform: rotate(-12deg); } }
@keyframes sweepC { from { transform: rotate(-8deg); } to { transform: rotate(8deg); } }
.studio .floor { position: absolute; left: -20%; right: -20%; bottom: -10%; height: 46%;
  background-image: linear-gradient(rgba(91,132,255,.28) 1px, transparent 1px), linear-gradient(90deg, rgba(91,132,255,.28) 1px, transparent 1px);
  background-size: 80px 80px; transform: perspective(600px) rotateX(62deg); transform-origin: 50% 100%;
  -webkit-mask-image: linear-gradient(180deg, transparent, #000 60%); mask-image: linear-gradient(180deg, transparent, #000 60%);
  animation: floor 6s linear infinite; }
@keyframes floor { to { background-position: 0 80px, 0 0; } }
.studio .dust { position: absolute; inset: 0; background-image:
  radial-gradient(1.5px 1.5px at 12% 22%, rgba(255,255,255,.7), transparent),
  radial-gradient(1px 1px at 72% 14%, rgba(255,255,255,.6), transparent),
  radial-gradient(1.5px 1.5px at 38% 64%, rgba(255,200,61,.6), transparent),
  radial-gradient(1px 1px at 86% 58%, rgba(34,211,238,.7), transparent),
  radial-gradient(1px 1px at 22% 82%, rgba(255,255,255,.5), transparent),
  radial-gradient(1.5px 1.5px at 58% 36%, rgba(255,255,255,.5), transparent);
  animation: drift 14s linear infinite alternate; }
@keyframes drift { to { transform: translateY(-30px); } }

/* ── khung kính góc vát (đặc trưng đồ hoạ truyền hình) ── */
.panel { position: relative; background: linear-gradient(180deg, var(--glass-2), var(--glass));
  border: 1px solid var(--edge-soft); backdrop-filter: blur(8px);
  clip-path: polygon(18px 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%, 0 18px);
  box-shadow: inset 0 1px 0 rgba(255,255,255,.12), 0 0 40px rgba(61,107,255,.18); }
.panel::before { content: ""; position: absolute; left: 18px; right: 0; top: 0; height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--edge) 40%, transparent); }

.kicker { display: inline-flex; align-items: center; gap: 10px; font-family: var(--display); font-weight: 700; font-style: italic;
  text-transform: uppercase; letter-spacing: .08em; color: var(--cyan); }
.kicker::before { content: ""; width: 10px; height: 10px; background: var(--gold); transform: rotate(45deg); box-shadow: 0 0 12px var(--gold); }

/* chữ tô gradient chỉ vẽ trong HỘP DÒNG — chữ hoa có dấu tiếng Việt (Ỉ, Ẩ, Ộ…) cao vượt hộp khi line-height
   sát, dấu hỏi bị cắt thành giống dấu sắc. Đệm trên + kéo margin ngược để hộp ôm trọn dấu mà bố cục không xê dịch. */
.gold-text, .grad { display: inline-block; padding: .22em .06em .26em; margin: -.22em -.06em -.26em; }
.gold-text { background: linear-gradient(180deg, #FFF3C4 0%, var(--gold) 45%, var(--gold-2) 100%); -webkit-background-clip: text; background-clip: text; color: transparent;
  filter: drop-shadow(0 4px 18px rgba(255,159,28,.45)); }

/* nút: khối vát, nền xanh điện / vàng */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 10px; height: 56px; padding: 0 30px; border: 0;
  font-family: var(--display); font-weight: 800; font-style: italic; font-size: 22px; letter-spacing: .06em; text-transform: uppercase; text-decoration: none;
  color: #fff; background: linear-gradient(180deg, #5B84FF, var(--edge)); box-shadow: 0 0 24px rgba(61,107,255,.55), inset 0 1px 0 rgba(255,255,255,.35);
  clip-path: polygon(14px 0, 100% 0, calc(100% - 14px) 100%, 0 100%); transition: transform .15s var(--ease), filter .2s; }
.btn:active:not(:disabled) { transform: scale(.97); }
.btn:hover:not(:disabled) { filter: brightness(1.15); }
.btn.gold { color: #2A1600; background: linear-gradient(180deg, #FFE08A, var(--gold) 45%, var(--gold-2)); box-shadow: 0 0 28px rgba(255,200,61,.55), inset 0 1px 0 rgba(255,255,255,.6); }
.btn.hot { background: linear-gradient(180deg, #FF6D90, var(--hot)); box-shadow: 0 0 24px rgba(255,61,110,.5); }
.btn.ghost { background: rgba(255,255,255,.06); box-shadow: inset 0 0 0 1px var(--edge-soft); }
.btn:disabled { opacity: .4; cursor: default; filter: grayscale(.4); }

/* hình đáp án */
.shape { width: 26px; height: 26px; flex: none; }

/* đĩa tháp: bóng kính */
.disc { margin: 2px auto 0; border-radius: 6px; height: 14px;
  background-image: linear-gradient(180deg, rgba(255,255,255,.55), rgba(255,255,255,0) 45%, rgba(0,0,0,.25));
  box-shadow: 0 0 10px currentColor, inset 0 -1px 0 rgba(0,0,0,.3); }

@keyframes rise { from { opacity: 0; transform: translateY(24px); } to { opacity: 1; transform: none; } }
.rise { animation: rise .5s var(--ease) both; }
@keyframes pop { 0% { transform: scale(.7); opacity: 0; } 60% { transform: scale(1.06); opacity: 1; } 100% { transform: scale(1); } }
.pop { animation: pop .45s var(--ease) both; }
@keyframes shake { 0%,100%{transform:translateX(0)} 20%{transform:translateX(-8px)} 40%{transform:translateX(8px)} 60%{transform:translateX(-5px)} 80%{transform:translateX(5px)} }
.shake { animation: shake .4s; }
/* tia sáng quét ngang khi lật bài / thắng */
@keyframes shine { from { transform: translateX(-120%) skewX(-20deg); } to { transform: translateX(220%) skewX(-20deg); } }
.shine { position: relative; overflow: hidden; }
.shine::after { content: ""; position: absolute; top: 0; bottom: 0; left: 0; width: 40%; background: linear-gradient(90deg, transparent, rgba(255,255,255,.55), transparent);
  animation: shine 1.1s var(--ease) .1s both; pointer-events: none; }
@keyframes slam { 0% { opacity: 0; transform: scale(1.5); filter: blur(10px); } 60% { opacity: 1; transform: scale(.97); filter: none; } 100% { transform: scale(1); } }
.slam { animation: slam .65s var(--ease) both; }
.hidden { display: none !important; }

@media (prefers-reduced-motion: reduce) {
  .studio .beam, .studio .floor, .studio .dust { animation: none !important; }
  .rise, .pop, .slam, .shine::after { animation: none !important; }
}

/* avatar đội: tròn, viền màu đội phát sáng */
.av { position: relative; display: inline-grid; place-items: center; flex: none; border-radius: 50%; overflow: hidden;
  background: radial-gradient(circle at 35% 30%, color-mix(in srgb, var(--ac) 70%, #fff), var(--ac)); box-shadow: 0 0 0 2px var(--ac), 0 0 14px color-mix(in srgb, var(--ac) 70%, transparent); }
.av img { width: 100%; height: 100%; object-fit: cover; display: block; }
.av b { font-family: var(--display); font-weight: 900; font-style: italic; color: #fff; text-shadow: 0 1px 3px rgba(0,0,0,.4); }