/* Rung Chuông Vàng — Trường THCS Kiến Hưng. Một bộ kiểu dùng chung cho mọi trang. */
@import url('https://fonts.googleapis.com/css2?family=Be+Vietnam+Pro:wght@400;500;600;700;800&display=swap');

:root {
  --navy: #12245b;
  --navy-2: #1c3480;
  --gold: #f2b705;
  --gold-2: #ffd34d;
  --gold-ink: #3a2a00;
  --bg: #f4f6fb;
  --card: #ffffff;
  --ink: #141a2e;
  --muted: #5d6680;
  --line: #e1e5ef;
  --good: #1f9d55;
  --good-bg: #e6f6ec;
  --bad: #d64545;
  --bad-bg: #fdecec;
  --warn: #c77800;
  --warn-bg: #fff4e0;
  --a: #e5484d;
  --b: #2f80ed;
  --c: #f2a900;
  --d: #27ae60;
  --radius: 16px;
  --shadow: 0 6px 24px rgba(18, 36, 91, 0.08);
  --font: 'Be Vietnam Pro', system-ui, 'Segoe UI', Roboto, sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme='light']) {
    --bg: #0d1330;
    --card: #161e44;
    --ink: #eef1fb;
    --muted: #a5aecb;
    --line: #2a3566;
    --good-bg: #123a27;
    --bad-bg: #3d1b22;
    --warn-bg: #3b2a0c;
    --shadow: 0 6px 24px rgba(0, 0, 0, 0.35);
  }
}
:root[data-theme='dark'] {
  --bg: #0d1330;
  --card: #161e44;
  --ink: #eef1fb;
  --muted: #a5aecb;
  --line: #2a3566;
  --good-bg: #123a27;
  --bad-bg: #3d1b22;
  --warn-bg: #3b2a0c;
  --shadow: 0 6px 24px rgba(0, 0, 0, 0.35);
}

* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.5 var(--font);
  -webkit-tap-highlight-color: transparent;
  min-height: 100dvh;
}
h1, h2, h3 { line-height: 1.25; margin: 0 0 8px; }
h1 { font-size: clamp(22px, 4vw, 30px); font-weight: 800; }
h2 { font-size: clamp(18px, 3vw, 22px); font-weight: 700; }
p { margin: 0 0 8px; }
.muted { color: var(--muted); }
.small { font-size: 13px; }
.hidden { display: none !important; }
a { color: var(--navy-2); }

/* Thanh tiêu đề */
.topbar {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 20px; background: var(--navy); color: #fff;
  position: sticky; top: 0; z-index: 20;
}
.topbar .brand { display: flex; align-items: center; gap: 10px; font-weight: 800; letter-spacing: .3px; }
.topbar .brand svg { width: 30px; height: 30px; }
.topbar .sp { flex: 1; }
.topbar .net { width: 10px; height: 10px; border-radius: 50%; background: #3ddc84; box-shadow: 0 0 0 3px rgba(61, 220, 132, .25); }
.topbar .net.mat { background: #ff6b6b; box-shadow: 0 0 0 3px rgba(255, 107, 107, .25); }
.topbar .sub { color: #c9d3f5; font-size: 14px; font-weight: 500; }

.wrap { max-width: 1180px; margin: 0 auto; padding: 20px 16px 48px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; box-shadow: var(--shadow); }
.grid { display: grid; gap: 16px; }
.g2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.g3 { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.row { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; }
.between { justify-content: space-between; }
.stack > * + * { margin-top: 12px; }

/* Nút */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 44px; padding: 10px 18px; border-radius: 12px; border: 1px solid var(--line);
  background: var(--card); color: var(--ink); font: 600 15px var(--font); cursor: pointer;
  transition: transform .06s ease, box-shadow .15s ease, background .15s ease;
}
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: .45; cursor: not-allowed; }
.btn.chinh { background: var(--gold); border-color: var(--gold); color: var(--gold-ink); box-shadow: 0 6px 16px rgba(242, 183, 5, .35); }
.btn.chinh:hover:not(:disabled) { background: var(--gold-2); }
.btn.xanh { background: var(--navy-2); border-color: var(--navy-2); color: #fff; }
.btn.do { color: var(--bad); border-color: color-mix(in srgb, var(--bad) 40%, var(--line)); }
.btn.to { min-height: 64px; font-size: 20px; padding: 14px 26px; border-radius: 16px; width: 100%; }
.btn.nho { min-height: 34px; padding: 6px 12px; font-size: 13px; border-radius: 10px; }

input, select, textarea {
  font: 16px var(--font); color: var(--ink); background: var(--card);
  border: 1.5px solid var(--line); border-radius: 12px; padding: 10px 12px; width: 100%;
}
input:focus, select:focus, textarea:focus { outline: none; border-color: var(--navy-2); box-shadow: 0 0 0 3px color-mix(in srgb, var(--navy-2) 20%, transparent); }
label { display: block; font-weight: 600; font-size: 14px; margin-bottom: 6px; }
label .muted { font-weight: 400; }

.pill { display: inline-flex; align-items: center; gap: 6px; padding: 4px 12px; border-radius: 999px; font-weight: 700; font-size: 13px; background: var(--line); color: var(--ink); }
.pill.san { background: var(--good-bg); color: var(--good); }
.pill.khan { background: var(--warn-bg); color: var(--warn); }
.pill.do { background: var(--bad-bg); color: var(--bad); }
.pill.vang { background: #fff3c4; color: #7a5600; }

/* Số liệu */
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr)); gap: 12px; }
.stat { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 12px 14px; }
.stat b { display: block; font-size: 26px; font-weight: 800; }
.stat span { color: var(--muted); font-size: 13px; }

/* Đáp án A/B/C/D */
.dapan { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.da {
  position: relative; display: flex; align-items: center; gap: 12px; text-align: left;
  min-height: 76px; padding: 14px 16px; border-radius: 18px; border: 2.5px solid transparent;
  color: #fff; font: 700 18px var(--font); cursor: pointer; box-shadow: 0 6px 0 rgba(0, 0, 0, .18);
  transition: transform .06s, box-shadow .06s, opacity .2s, filter .2s;
}
.da:active:not(:disabled) { transform: translateY(4px); box-shadow: 0 2px 0 rgba(0, 0, 0, .18); }
.da .l { flex: none; width: 40px; height: 40px; border-radius: 50%; background: rgba(255, 255, 255, .25); display: grid; place-items: center; font-size: 20px; }
.da .t { font-weight: 600; font-size: 16px; line-height: 1.3; }
.da.A { background: var(--a); } .da.B { background: var(--b); } .da.C { background: var(--c); color: #2e2000; } .da.D { background: var(--d); }
.da.C .l { background: rgba(0, 0, 0, .12); }
.da:disabled { cursor: default; }
.dapan.khoa .da:not(.chon) { opacity: .45; filter: saturate(.6); }
.da.chon { border-color: #fff; outline: 4px solid var(--navy); outline-offset: 2px; }
.da.chon::after { content: '✓'; position: absolute; right: 14px; top: 10px; font-size: 22px; }
.da.dung { outline: 5px solid var(--good); outline-offset: 2px; opacity: 1 !important; filter: none !important; }
.da.sai-chon { outline: 5px solid var(--bad); outline-offset: 2px; }

/* Đồng hồ */
.timebar { height: 10px; border-radius: 999px; background: var(--line); overflow: hidden; }
.timebar i { display: block; height: 100%; background: linear-gradient(90deg, var(--gold), #ff8a00); transition: width .2s linear; }
.timebar.gap i { background: linear-gradient(90deg, #ff6b6b, var(--bad)); }

/* Lưới ghế */
.seats { display: grid; grid-template-columns: repeat(auto-fill, minmax(46px, 1fr)); gap: 6px; }
.seat { aspect-ratio: 1; border-radius: 10px; display: grid; place-items: center; font: 700 13px var(--font); background: var(--line); color: var(--muted); border: 0; cursor: default; }
.seat.d { background: color-mix(in srgb, var(--navy-2) 18%, var(--card)); color: var(--navy-2); }
.seat.s { background: var(--good); color: #fff; }
.seat.k { background: color-mix(in srgb, var(--warn) 25%, var(--card)); color: var(--warn); }
.seat.x { background: var(--bad); color: #fff; }
.seat.v { background: transparent; border: 1.5px dashed var(--line); }
button.seat { cursor: pointer; }

/* Bảng */
.bang { overflow: auto; max-height: 60vh; border: 1px solid var(--line); border-radius: 12px; }
table { border-collapse: collapse; width: 100%; font-size: 14px; }
th, td { padding: 8px 10px; border-bottom: 1px solid var(--line); text-align: left; white-space: nowrap; }
th { position: sticky; top: 0; background: var(--card); color: var(--muted); font-size: 12px; text-transform: uppercase; letter-spacing: .3px; z-index: 1; }
td.D { color: var(--good); font-weight: 800; text-align: center; }
td.S { color: var(--bad); text-align: center; }
td.K { color: var(--muted); text-align: center; }

/* Tab */
.tabs { display: flex; gap: 6px; overflow-x: auto; padding-bottom: 4px; }
.tabs button { flex: none; border: 1px solid var(--line); background: var(--card); color: var(--ink); padding: 8px 14px; border-radius: 999px; font: 600 14px var(--font); cursor: pointer; }
.tabs button.on { background: var(--navy); color: #fff; border-color: var(--navy); }

.banner { border-radius: 14px; padding: 12px 16px; font-weight: 600; }
.banner.vang { background: #fff3c4; color: #5c4200; border: 1px solid #f2d36b; }
.banner.xanh { background: var(--good-bg); color: var(--good); }
.banner.do { background: var(--bad-bg); color: var(--bad); }

#toasts { position: fixed; left: 50%; bottom: 24px; transform: translateX(-50%); display: grid; gap: 8px; z-index: 100; width: min(92vw, 420px); }
.toast { background: var(--navy); color: #fff; padding: 12px 16px; border-radius: 12px; box-shadow: var(--shadow); font-weight: 600; transition: opacity .5s, transform .5s; }
.toast.loi { background: var(--bad); }
.toast.an { opacity: 0; transform: translateY(8px); }

.bell { display: inline-block; transform-origin: 50% 8%; }
.bell.rung { animation: rung 1.2s ease-in-out infinite; }
@keyframes rung { 0%, 100% { transform: rotate(0); } 15% { transform: rotate(14deg); } 30% { transform: rotate(-12deg); } 45% { transform: rotate(8deg); } 60% { transform: rotate(-5deg); } 75% { transform: rotate(2deg); } }

@media (max-width: 520px) {
  .wrap { padding: 14px 12px 40px; }
  .card { padding: 14px; border-radius: 14px; }
  .da { min-height: 70px; padding: 12px; gap: 10px; }
  .da .l { width: 34px; height: 34px; font-size: 18px; }
  .da .t { font-size: 15px; }
  .topbar { padding: 10px 14px; }
}