:root {
  --bg: #f4f5fb;
  --surface: #ffffff;
  --border: #e3e5ef;
  --text: #171a2b;
  --muted: #6b7089;
  --brand: #4338ca;
  --brand-soft: #eef0ff;
  --green: #128a5b;
  --green-soft: #e6f6ee;
  --red: #c62b45;
  --red-soft: #fdecef;
  --amber: #b26a00;
  --amber-soft: #fff4e0;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(16,20,45,.05), 0 8px 24px rgba(16,20,45,.06);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Inter, sans-serif;
  background: var(--bg); color: var(--text);
  font-size: 15px; line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--brand); }
h1, h2, h3 { margin: 0 0 .4em; line-height: 1.25; letter-spacing: -.01em; }
h1 { font-size: 22px; }
h2 { font-size: 18px; }
h3 { font-size: 15px; }
p { margin: 0 0 1em; }
.muted { color: var(--muted); }
.small { font-size: 13px; }
.tiny { font-size: 12px; }
.center { text-align: center; }
.row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.row.tight { gap: 6px; }
.spread { display: flex; gap: 10px; align-items: center; justify-content: space-between; flex-wrap: wrap; }
.grow { flex: 1; min-width: 0; }
.stack > * + * { margin-top: 14px; }
.hidden { display: none !important; }

.topbar {
  background: var(--surface); border-bottom: 1px solid var(--border);
  padding: 12px 18px; display: flex; align-items: center; justify-content: space-between;
  gap: 12px; flex-wrap: wrap; position: sticky; top: 0; z-index: 30;
}
.brand { display: flex; align-items: center; gap: 9px; font-weight: 650; letter-spacing: -.02em; }
.brand .dot { width: 22px; height: 22px; border-radius: 7px; background: var(--brand); color: #fff;
  display: grid; place-items: center; font-size: 12px; font-weight: 700; }

.wrap { max-width: 980px; margin: 0 auto; padding: 22px 18px 60px; }
.wrap.narrow { max-width: 520px; }
.wrap.wide { max-width: 1180px; }

.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px; box-shadow: var(--shadow); }
.card + .card { margin-top: 14px; }
.card-head { display: flex; justify-content: space-between; align-items: baseline; gap: 10px;
  flex-wrap: wrap; margin-bottom: 12px; }

label { display: block; font-size: 13px; font-weight: 600; margin-bottom: 5px; color: #3a3f57; }
input, select, textarea {
  width: 100%; padding: 10px 12px; font: inherit; color: var(--text);
  background: #fff; border: 1px solid var(--border); border-radius: 9px; outline: none;
}
input:focus, select:focus, textarea:focus { border-color: var(--brand); box-shadow: 0 0 0 3px var(--brand-soft); }
textarea { min-height: 90px; resize: vertical; }
.field + .field { margin-top: 12px; }
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.grid2 .field + .field { margin-top: 0; }
.check { display: flex; align-items: center; gap: 8px; font-size: 14px; font-weight: 500; }
.check input { width: auto; }

button, .btn {
  font: inherit; font-weight: 600; cursor: pointer; border-radius: 9px;
  padding: 10px 16px; border: 1px solid var(--brand); background: var(--brand); color: #fff;
  display: inline-flex; align-items: center; gap: 7px; text-decoration: none;
}
button:hover, .btn:hover { filter: brightness(1.07); }
button:disabled { opacity: .55; cursor: not-allowed; filter: none; }
.btn-ghost { background: #fff; color: var(--text); border-color: var(--border); }
.btn-danger { background: var(--red); border-color: var(--red); }
.btn-sm { padding: 6px 11px; font-size: 13px; }
.btn-block { width: 100%; justify-content: center; padding: 12px; }

.pill { display: inline-block; padding: 2px 9px; border-radius: 999px; font-size: 12px; font-weight: 650; }
.pill.grey { background: #eef0f5; color: var(--muted); }
.pill.green { background: var(--green-soft); color: var(--green); }
.pill.red { background: var(--red-soft); color: var(--red); }
.pill.amber { background: var(--amber-soft); color: var(--amber); }
.pill.brand { background: var(--brand-soft); color: var(--brand); }

.notice { padding: 11px 13px; border-radius: 9px; font-size: 14px; margin-bottom: 12px; }
.notice.error { background: var(--red-soft); color: var(--red); }
.notice.ok { background: var(--green-soft); color: var(--green); }
.notice.info { background: var(--brand-soft); color: var(--brand); }
.notice.warn { background: var(--amber-soft); color: var(--amber); }

table { width: 100%; border-collapse: collapse; font-size: 14px; }
th, td { text-align: left; padding: 9px 10px; border-bottom: 1px solid var(--border); }
th { font-size: 12px; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); font-weight: 650; }
tbody tr:hover { background: #fafbff; }
.table-scroll { overflow-x: auto; }

.code-box { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 26px;
  font-weight: 700; letter-spacing: .16em; background: var(--brand-soft); color: var(--brand);
  padding: 12px 16px; border-radius: 10px; text-align: center; }

.stat-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); gap: 10px; }
.stat { background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: 12px 14px; }
.stat .n { font-size: 22px; font-weight: 700; letter-spacing: -.02em; }
.stat .l { font-size: 12px; color: var(--muted); }

.tabs { display: flex; gap: 4px; border-bottom: 1px solid var(--border); margin-bottom: 16px; flex-wrap: wrap; }
.tabs button { background: none; border: none; color: var(--muted); padding: 9px 13px;
  border-bottom: 2px solid transparent; border-radius: 0; }
.tabs button.active { color: var(--brand); border-bottom-color: var(--brand); }

/* ---------- candidate sign-in ---------- */
.candidate-bg {
  background:
    radial-gradient(900px 420px at 12% -8%, #e5e8ff 0%, rgba(229,232,255,0) 62%),
    radial-gradient(760px 420px at 92% 4%, #e2f5ee 0%, rgba(226,245,238,0) 58%),
    var(--bg);
  background-attachment: fixed;
}

.hero { display: grid; place-items: center; padding: 40px 0; }
.hero-card {
  background: var(--surface); border: 1px solid var(--border); border-radius: 16px;
  padding: 30px 26px; box-shadow: var(--shadow); text-align: center; width: 100%; max-width: 420px;
}
.hero-card p { margin-bottom: 20px; }

.code-input {
  text-align: center; text-transform: uppercase; font-weight: 700;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 26px; letter-spacing: .28em; padding: 14px 12px; margin-bottom: 14px;
}
.code-input::placeholder { color: #c3c7dd; letter-spacing: .28em; }

.step-dots { display: flex; gap: 6px; justify-content: center; margin-bottom: 14px; }
.step-dots i { width: 22px; height: 4px; border-radius: 2px; background: var(--border); display: block; }
.step-dots i.on { background: var(--brand); }
.step-dots i.done { background: #a9b0e8; }

.track-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(215px, 1fr));
  gap: 12px; max-width: 760px; margin: 0 auto;
}
.track-card {
  display: flex; flex-direction: column; align-items: flex-start; gap: 3px;
  text-align: left; background: var(--surface); color: var(--text);
  border: 1px solid var(--border); border-radius: 14px; padding: 18px;
  box-shadow: var(--shadow); font-weight: 400; transition: transform .12s ease, border-color .12s ease;
}
.track-card:hover { filter: none; border-color: var(--brand); transform: translateY(-2px); }
.track-icon { font-size: 26px; line-height: 1.1; margin-bottom: 4px; }
.track-label { font-size: 16px; font-weight: 650; letter-spacing: -.01em; }
.track-desc { font-size: 13px; color: var(--muted); line-height: 1.4; }
.track-meta { font-size: 12px; color: var(--brand); font-weight: 650; margin-top: 8px; }

.detail-layout {
  display: grid; grid-template-columns: 1fr 290px; gap: 14px;
  max-width: 840px; margin: 0 auto; align-items: start;
}
.detail-layout .card + .card { margin-top: 0; }
.summary-card { position: sticky; top: 76px; }
.summary-head { display: flex; gap: 11px; align-items: center; padding-bottom: 12px;
  border-bottom: 1px solid var(--border); margin-bottom: 10px; }
.summary-icon { font-size: 28px; }
.summary-row { display: flex; justify-content: space-between; gap: 10px; padding: 5px 0; font-size: 14px; color: var(--muted); }
.summary-row strong { color: var(--text); text-align: right; }

/* ---------- exam ---------- */
.exam-bar { position: sticky; top: 0; z-index: 40; background: var(--surface);
  border-bottom: 1px solid var(--border); padding: 10px 16px; }
.timer { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-weight: 700;
  font-size: 19px; padding: 5px 12px; border-radius: 8px; background: var(--brand-soft); color: var(--brand); }
.timer.warn { background: var(--amber-soft); color: var(--amber); }
.timer.danger { background: var(--red-soft); color: var(--red); animation: pulse 1s infinite; }
@keyframes pulse { 50% { opacity: .55; } }

.exam-layout { display: grid; grid-template-columns: 1fr 250px; gap: 16px;
  max-width: 1120px; margin: 0 auto; padding: 16px; align-items: start; }
.opt { display: flex; gap: 11px; align-items: flex-start; padding: 12px 14px; border: 1px solid var(--border);
  border-radius: 10px; cursor: pointer; background: #fff; margin-bottom: 9px; }
.opt:hover { border-color: #c3c7dd; }
.opt.sel { border-color: var(--brand); background: var(--brand-soft); }
.opt input { width: auto; margin-top: 3px; }
.opt .letter { font-weight: 700; color: var(--muted); min-width: 18px; }
.opt.sel .letter { color: var(--brand); }

.palette { display: grid; grid-template-columns: repeat(5, 1fr); gap: 7px; }
.palette button { padding: 0; height: 36px; border-radius: 8px; font-size: 13px; font-weight: 650;
  background: #fff; color: var(--text); border: 1px solid var(--border); justify-content: center; }
.palette button.answered { background: var(--green); border-color: var(--green); color: #fff; }
.palette button.review { background: var(--amber); border-color: var(--amber); color: #fff; }
.palette button.current { outline: 3px solid var(--brand); outline-offset: 1px; }
.legend { display: flex; flex-direction: column; gap: 5px; margin-top: 12px; font-size: 12px; color: var(--muted); }
.legend span::before { content: ''; display: inline-block; width: 10px; height: 10px;
  border-radius: 3px; margin-right: 7px; vertical-align: -1px; }
.legend .g::before { background: var(--green); }
.legend .a::before { background: var(--amber); }
.legend .n::before { background: #fff; border: 1px solid var(--border); }

.sheet-q { border: 1px solid var(--border); border-radius: 10px; padding: 14px; margin-bottom: 10px; background: #fff; }
.sheet-q.correct { border-left: 4px solid var(--green); }
.sheet-q.wrong { border-left: 4px solid var(--red); }
.sheet-q.skipped { border-left: 4px solid #c9cddd; }
.sheet-opt { padding: 6px 10px; border-radius: 7px; font-size: 14px; }
.sheet-opt.is-correct { background: var(--green-soft); color: var(--green); font-weight: 600; }
.sheet-opt.is-picked { background: var(--red-soft); color: var(--red); font-weight: 600; }

.modal-back { position: fixed; inset: 0; background: rgba(16,20,45,.5); display: grid;
  place-items: center; z-index: 60; padding: 16px; }
.modal { background: #fff; border-radius: 14px; padding: 22px; max-width: 480px; width: 100%;
  box-shadow: 0 20px 50px rgba(16,20,45,.25); max-height: 90vh; overflow: auto; }
.modal.lg { max-width: 780px; }

@media (max-width: 760px) {
  .exam-layout { grid-template-columns: 1fr; padding: 12px; }
  /* The question stays on top; the palette is a compact scroller underneath,
     otherwise 50+ buttons push the actual question off a phone screen. */
  .palette { grid-template-columns: repeat(8, 1fr); max-height: 150px; overflow-y: auto; }
  .palette button { height: 32px; }
  .exam-bar { padding: 8px 12px; }
  .exam-bar strong { display: block; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 14px; }
  .timer { font-size: 17px; padding: 4px 9px; }
  .grid2 { grid-template-columns: 1fr; }
  .detail-layout { grid-template-columns: 1fr; }
  .summary-card { position: static; order: -1; }
  .track-grid { grid-template-columns: 1fr; }
  .track-card { flex-direction: row; flex-wrap: wrap; align-items: center; padding: 14px; }
  .track-icon { margin: 0 4px 0 0; font-size: 22px; }
  .track-label { flex: 1; }
  .track-desc { flex-basis: 100%; }
  .track-meta { margin-top: 4px; }
  .code-input { font-size: 22px; }
  h1 { font-size: 19px; }
}