/* KIEMTRA — giao diện dùng chung (không phụ thuộc CDN: lớp học Wi-Fi yếu vẫn chạy) */
:root {
  --ink: #15232c;
  --ink-2: #4a5a64;
  --ink-3: #7d8b93;
  --line: #dfe3e1;
  --paper: #f5f3ee;
  --card: #ffffff;
  --accent: #0e6a69;
  --accent-2: #0a4f4e;
  --accent-soft: #e2f0ee;
  --rose: #b8456c;
  --rose-soft: #f8e7ed;
  --ok: #1f7a3d;
  --ok-soft: #e3f3e7;
  --warn: #a35d00;
  --warn-soft: #fdf0dc;
  --bad: #b3261e;
  --bad-soft: #fbe5e3;
  --shadow: 0 1px 2px rgba(20, 35, 44, .06), 0 4px 16px rgba(20, 35, 44, .06);
  --r: 12px;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 16px/1.5 var(--font); }
a { color: var(--accent); }
h1, h2, h3 { line-height: 1.25; margin: 0 0 .5em; letter-spacing: -.01em; }
h1 { font-size: 1.5rem; } h2 { font-size: 1.2rem; } h3 { font-size: 1.05rem; }
.muted { color: var(--ink-2); } .small { font-size: .875rem; } .tiny { font-size: .78rem; }
.mono { font-family: var(--mono); }
.hidden { display: none !important; }
.row { display: flex; gap: .75rem; align-items: center; flex-wrap: wrap; }
.row.between { justify-content: space-between; }
.stack > * + * { margin-top: .75rem; }
.grow { flex: 1 1 auto; }
.wrap { max-width: 1180px; margin: 0 auto; padding: 16px; }
.narrow { max-width: 560px; margin: 0 auto; padding: 16px; }

/* thanh trên cùng */
.topbar { background: var(--ink); color: #fff; }
.topbar .wrap { display: flex; align-items: center; gap: 12px; padding-top: 10px; padding-bottom: 10px; }
.brand { display: flex; align-items: center; gap: 10px; color: #fff; text-decoration: none; font-weight: 650; }
.brand img { width: 30px; height: 30px; border-radius: 6px; background: #fff; padding: 2px; }
.brand small { display: block; font-weight: 400; opacity: .7; font-size: .75rem; }
.topbar .spacer { flex: 1; }
.topbar .who { font-size: .85rem; opacity: .85; }

/* thẻ */
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--r); box-shadow: var(--shadow); padding: 18px; }
.card + .card { margin-top: 14px; }
.card h2 { margin-bottom: .75rem; }

/* nút */
.btn { appearance: none; border: 1px solid var(--line); background: #fff; color: var(--ink); border-radius: 10px; padding: .6em 1em; font: inherit; font-weight: 600; cursor: pointer; display: inline-flex; align-items: center; gap: .4em; text-decoration: none; min-height: 42px; }
.btn:hover { border-color: var(--ink-3); }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn.primary { background: var(--accent); color: #fff; border-color: var(--accent); }
.btn.primary:hover { background: var(--accent-2); }
.btn.rose { background: var(--rose); color: #fff; border-color: var(--rose); }
.btn.danger { color: var(--bad); border-color: #e9b9b5; }
.btn.danger.solid { background: var(--bad); color: #fff; border-color: var(--bad); }
.btn.ghost { background: transparent; border-color: transparent; }
.btn.sm { padding: .35em .7em; min-height: 32px; font-size: .875rem; border-radius: 8px; }
.btn.lg { padding: .85em 1.4em; font-size: 1.05rem; min-height: 52px; }
.btn.block { width: 100%; justify-content: center; }

/* nhập liệu */
label.f { display: block; font-weight: 600; font-size: .9rem; margin-bottom: .3rem; }
.f-help { font-size: .8rem; color: var(--ink-3); margin-top: .2rem; }
input[type=text], input[type=password], input[type=number], input[type=search], select, textarea {
  width: 100%; font: inherit; color: var(--ink); background: #fff; border: 1px solid #cfd6d3; border-radius: 10px; padding: .55em .7em; min-height: 42px;
}
textarea { min-height: 90px; resize: vertical; }
input:focus, select:focus, textarea:focus { outline: 2px solid var(--accent); outline-offset: 1px; border-color: var(--accent); }
.grid2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 12px; }
.grid3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 12px; }
.check { display: flex; gap: .55rem; align-items: flex-start; font-size: .95rem; }
.check input { width: 20px; height: 20px; margin-top: 2px; accent-color: var(--accent); flex: none; }

/* nhãn */
.badge { display: inline-flex; align-items: center; gap: .3em; border-radius: 999px; padding: .1em .6em; font-size: .78rem; font-weight: 650; background: #eef1f0; color: var(--ink-2); white-space: nowrap; }
.badge.ok { background: var(--ok-soft); color: var(--ok); }
.badge.warn { background: var(--warn-soft); color: var(--warn); }
.badge.bad { background: var(--bad-soft); color: var(--bad); }
.badge.acc { background: var(--accent-soft); color: var(--accent-2); }
.badge.rose { background: var(--rose-soft); color: var(--rose); }
.dot { width: 9px; height: 9px; border-radius: 50%; display: inline-block; background: var(--ink-3); }
.dot.ok { background: #2fa35a; } .dot.warn { background: #e09a1a; } .dot.bad { background: var(--bad); }

/* bảng */
.tbl-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--r); background: #fff; }
table.tbl { border-collapse: collapse; width: 100%; font-size: .9rem; }
.tbl th, .tbl td { padding: .55em .7em; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
.tbl th { background: #f8f9f8; font-weight: 650; color: var(--ink-2); font-size: .8rem; text-transform: uppercase; letter-spacing: .03em; position: sticky; top: 0; z-index: 1; }
.tbl tr:last-child td { border-bottom: 0; }
.tbl td.num, .tbl th.num { text-align: right; font-variant-numeric: tabular-nums; }
.tbl tr.alert td { background: #fff6f5; }
.tbl tr.locked td { background: #fdecea; }

/* tabs */
.tabs { display: flex; gap: 4px; border-bottom: 1px solid var(--line); margin-bottom: 16px; overflow-x: auto; }
.tabs button { appearance: none; border: 0; background: none; font: inherit; font-weight: 600; color: var(--ink-2); padding: .7em 1em; border-bottom: 3px solid transparent; cursor: pointer; white-space: nowrap; }
.tabs button.on { color: var(--accent-2); border-bottom-color: var(--accent); }

/* thông báo nổi */
#toast { position: fixed; left: 50%; bottom: 20px; transform: translateX(-50%); z-index: 1000; display: flex; flex-direction: column; gap: 8px; align-items: center; pointer-events: none; }
.toast { background: var(--ink); color: #fff; padding: .7em 1.1em; border-radius: 10px; box-shadow: var(--shadow); max-width: 92vw; font-size: .95rem; }
.toast.bad { background: var(--bad); } .toast.ok { background: var(--ok); }

/* hộp thoại */
.modal-bg { position: fixed; inset: 0; background: rgba(15, 25, 30, .55); z-index: 500; display: flex; align-items: flex-start; justify-content: center; padding: 4vh 12px; overflow-y: auto; }
.modal { background: #fff; border-radius: 14px; width: 100%; max-width: 760px; box-shadow: 0 20px 60px rgba(0,0,0,.25); }
.modal header { padding: 16px 18px; border-bottom: 1px solid var(--line); display: flex; align-items: center; gap: 10px; }
.modal header h2 { margin: 0; flex: 1; }
.modal .body { padding: 18px; }
.modal footer { padding: 14px 18px; border-top: 1px solid var(--line); display: flex; gap: 8px; justify-content: flex-end; flex-wrap: wrap; }

.kpi { display: grid; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr)); gap: 10px; }
.kpi > div { background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 10px 12px; }
.kpi b { display: block; font-size: 1.5rem; font-variant-numeric: tabular-nums; }
.kpi span { font-size: .78rem; color: var(--ink-2); text-transform: uppercase; letter-spacing: .03em; }

.empty { text-align: center; color: var(--ink-3); padding: 28px 10px; }
.callout { border-left: 4px solid var(--accent); background: var(--accent-soft); padding: 10px 14px; border-radius: 8px; font-size: .92rem; }
.callout.warn { border-color: var(--warn); background: var(--warn-soft); }
.callout.bad { border-color: var(--bad); background: var(--bad-soft); }

/* ===================== SINH VIÊN ===================== */
body.sv { background: #eef1ef; user-select: none; -webkit-user-select: none; -webkit-touch-callout: none; }
body.sv input, body.sv textarea { user-select: text; -webkit-user-select: text; }
.sv-head { background: var(--ink); color: #fff; padding: 10px 14px; display: flex; align-items: center; gap: 10px; position: sticky; top: 0; z-index: 20; }
.sv-head .t { flex: 1; min-width: 0; }
.sv-head .t b { display: block; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; font-size: .95rem; }
.sv-head .t span { font-size: .78rem; opacity: .75; }
.timer { font: 700 1.25rem/1 var(--mono); background: rgba(255,255,255,.12); padding: .35em .55em; border-radius: 8px; font-variant-numeric: tabular-nums; }
.timer.warn { background: #e09a1a; color: #1d1300; } .timer.bad { background: var(--bad); }
.vio { font-size: .8rem; background: rgba(255,255,255,.12); padding: .3em .55em; border-radius: 8px; white-space: nowrap; }
.vio.has { background: var(--bad); }
.progress { height: 4px; background: rgba(255,255,255,.15); }
.progress > i { display: block; height: 100%; background: #6fd0c6; width: 0; transition: width .3s; }

.big-code { font: 800 2.2rem/1 var(--mono); letter-spacing: .14em; text-align: center; }
.countdown { font: 800 3.4rem/1 var(--mono); text-align: center; font-variant-numeric: tabular-nums; color: var(--accent-2); }
.seat { display: inline-flex; flex-direction: column; align-items: center; justify-content: center; width: 74px; height: 74px; border-radius: 14px; background: var(--ink); color: #fff; font: 800 1.8rem/1 var(--mono); }
.seat small { font: 600 .6rem/1 var(--font); opacity: .7; margin-top: 4px; text-transform: uppercase; }
.rules li { margin: .3em 0; }
.checkitem { display: flex; gap: 10px; align-items: center; padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px; background: #fff; }
.checkitem .st { margin-left: auto; }

.q-card { background: #fff; border-radius: 14px; border: 1px solid var(--line); padding: 18px 16px; box-shadow: var(--shadow); }
.q-num { font-weight: 700; color: var(--accent-2); font-size: .85rem; text-transform: uppercase; letter-spacing: .04em; }
.q-stem { font-size: 1.08rem; margin: .4em 0 1em; white-space: pre-wrap; word-wrap: break-word; }
.q-img { display: block; max-width: 100%; max-height: 52vh; margin: 0 auto 1em; border-radius: 8px; border: 1px solid var(--line); pointer-events: none; }
.opt { display: flex; gap: 12px; align-items: flex-start; width: 100%; text-align: left; font: inherit; padding: 14px; margin: 0 0 10px; border: 2px solid var(--line); border-radius: 12px; background: #fff; cursor: pointer; color: var(--ink); }
.opt .k { flex: none; width: 32px; height: 32px; border-radius: 50%; border: 2px solid #b9c3bf; display: flex; align-items: center; justify-content: center; font-weight: 800; color: var(--ink-2); }
.opt.multi .k { border-radius: 8px; }
.opt.on { border-color: var(--accent); background: var(--accent-soft); }
.opt.on .k { background: var(--accent); border-color: var(--accent); color: #fff; }
.opt .tx { padding-top: 4px; white-space: pre-wrap; }
.q-nav { display: flex; gap: 10px; margin-top: 14px; }
.q-nav .btn { flex: 1; justify-content: center; }
.navgrid { display: grid; grid-template-columns: repeat(auto-fill, minmax(44px, 1fr)); gap: 6px; }
.navgrid button { height: 44px; border-radius: 9px; border: 1px solid var(--line); background: #fff; font: 700 .95rem var(--mono); cursor: pointer; position: relative; color: var(--ink); }
.navgrid button.ans { background: var(--accent); color: #fff; border-color: var(--accent); }
.navgrid button.cur { outline: 3px solid var(--rose); outline-offset: 1px; }
.navgrid button.flag::after { content: ""; position: absolute; top: 3px; right: 3px; width: 8px; height: 8px; border-radius: 50%; background: #f0a020; }
.saving { font-size: .78rem; color: var(--ink-3); }

.watermark { position: fixed; inset: 0; pointer-events: none; z-index: 15; overflow: hidden; opacity: .07; }
.watermark div { position: absolute; white-space: nowrap; font: 700 20px var(--mono); color: #000; transform: rotate(-24deg); }

.lock { position: fixed; inset: 0; z-index: 900; background: #7a1712; color: #fff; display: flex; align-items: center; justify-content: center; padding: 20px; text-align: center; }
.lock .box { max-width: 420px; width: 100%; }
.lock h1 { font-size: 1.6rem; }
.lock input { text-align: center; font: 700 1.6rem var(--mono); letter-spacing: .3em; }
.lock .seat { background: #fff; color: #7a1712; width: 96px; height: 96px; font-size: 2.4rem; }
.alertbar { position: fixed; left: 0; right: 0; top: 0; z-index: 800; background: var(--bad); color: #fff; padding: 12px 14px; font-weight: 600; text-align: center; box-shadow: 0 4px 14px rgba(0,0,0,.2); }
.result-score { font: 800 4rem/1 var(--mono); color: var(--accent-2); text-align: center; }
.rv-item { border: 1px solid var(--line); border-radius: 12px; padding: 14px; background: #fff; }
.rv-item + .rv-item { margin-top: 10px; }
.rv-opt { padding: 6px 10px; border-radius: 8px; margin: 4px 0; }
.rv-opt.key { background: var(--ok-soft); font-weight: 600; }
.rv-opt.wrong { background: var(--bad-soft); text-decoration: line-through; }
.expl { margin-top: 8px; padding: 10px 12px; background: #f6f8f7; border-radius: 8px; font-size: .92rem; }

/* ===================== GIẢNG VIÊN ===================== */
.q-row { display: grid; grid-template-columns: 34px 1fr auto; gap: 10px; padding: 12px; border-bottom: 1px solid var(--line); align-items: start; }
.q-row:last-child { border-bottom: 0; }
.q-row .stem { white-space: pre-wrap; }
.q-row .opts { font-size: .85rem; color: var(--ink-2); margin-top: 4px; }
.q-row .opts .key { color: var(--ok); font-weight: 700; }
.opt-edit { display: grid; grid-template-columns: 38px 1fr 40px; gap: 8px; align-items: center; margin-bottom: 8px; }
.opt-edit .kk { display: flex; align-items: center; justify-content: center; }
.opt-edit .kk input { width: 22px; height: 22px; accent-color: var(--ok); }
.thumb { max-width: 220px; max-height: 140px; border-radius: 8px; border: 1px solid var(--line); display: block; }

.mon-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(190px, 1fr)); gap: 10px; align-items: start; align-content: start; }
.tile { background: #fff; border: 1px solid var(--line); border-radius: 12px; padding: 10px 12px; cursor: pointer; position: relative; }
.tile .s { position: absolute; top: 10px; right: 10px; }
.tile .nm { font-weight: 650; font-size: .92rem; padding-right: 22px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.tile .seatn { font: 800 1.1rem var(--mono); color: var(--accent-2); }
.tile.vio { border-color: #f0b3ad; background: #fff7f6; }
.tile.locked { border: 2px solid var(--bad); background: var(--bad-soft); animation: pulse 1.4s infinite; }
.tile.done { background: #f3f8f4; border-color: #cfe6d6; }
.tile.offline { opacity: .7; border-style: dashed; }
@keyframes pulse { 50% { box-shadow: 0 0 0 4px rgba(179, 38, 30, .25); } }
.feed { max-height: 420px; overflow-y: auto; font-size: .86rem; }
.feed div { padding: 6px 4px; border-bottom: 1px dashed var(--line); }
.feed .cnt { color: var(--bad); font-weight: 650; }

.proj { position: fixed; inset: 0; z-index: 400; background: #0e1b22; color: #fff; display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 4vw; align-items: center; padding: 4vh 5vw; }
.proj .qr { background: #fff; border-radius: 18px; padding: 2.4vh; justify-self: center; }
.proj .qr img, .proj .qr canvas { display: block; width: min(38vw, 70vh); height: auto; image-rendering: pixelated; }
.proj .ttl { font-size: clamp(18px, 2.6vw, 40px); font-weight: 700; }
.proj .code { font: 800 clamp(40px, 7vw, 120px)/1 var(--mono); letter-spacing: .12em; color: #7fe0d4; margin: 2vh 0; }
.proj .url { font: 600 clamp(14px, 1.6vw, 26px) var(--mono); opacity: .85; }
.proj .cd { font: 800 clamp(48px, 9vw, 150px)/1 var(--mono); margin-top: 3vh; font-variant-numeric: tabular-nums; }
.proj .cnt { font-size: clamp(16px, 2vw, 32px); opacity: .9; margin-top: 1.5vh; }
.proj .close { position: absolute; top: 14px; right: 14px; }
@media (max-width: 760px) { .proj { grid-template-columns: 1fr; text-align: center; } .proj .qr img, .proj .qr canvas { width: 70vw; } }

.bar { height: 8px; background: #edf0ee; border-radius: 6px; overflow: hidden; min-width: 60px; }
.bar > i { display: block; height: 100%; background: var(--accent); }
.bar.ok > i { background: #2fa35a; } .bar.bad > i { background: var(--bad); } .bar.warn > i { background: #e09a1a; }
.hist { display: flex; align-items: flex-end; gap: 6px; height: 150px; padding: 8px 4px 0; border-bottom: 1px solid var(--line); }
.hist div { flex: 1; background: var(--accent); border-radius: 5px 5px 0 0; position: relative; min-height: 2px; }
.hist div span { position: absolute; top: -18px; left: 0; right: 0; text-align: center; font-size: .75rem; color: var(--ink-2); }
.hist-x { display: flex; gap: 6px; padding: 4px; font-size: .72rem; color: var(--ink-3); }
.hist-x span { flex: 1; text-align: center; }

@media print {
  .topbar, .tabs, .btn, .noprint { display: none !important; }
  body { background: #fff; }
  .card { box-shadow: none; border: 0; padding: 0; }
}
@media (max-width: 600px) {
  .wrap { padding: 12px; }
  .card { padding: 14px; }
  .q-row { grid-template-columns: 26px 1fr; }
  .q-row > :last-child { grid-column: 1 / -1; }
}
.lock input::placeholder { letter-spacing: normal; font: 600 1rem var(--font); }