:root {
  --bg: #f6f5f2; --card: #ffffff; --text: #1c1c1c; --muted: #6b6b6b;
  --primary: #1a5fb4; --primary-weak: #e7effa;
  --ok: #2ec27e; --ok-weak: #e3f6ee; --bad: #e01b24; --bad-weak: #fbe5e6;
  --warn: #e5a50a; --border: #e0ddd6; --mark: #f8e45c;
  --shadow: 0 1px 3px rgba(0,0,0,.08);
}
[data-theme="dark"] {
  --bg: #17191c; --card: #22252a; --text: #e6e6e6; --muted: #9a9a9a;
  --primary: #62a0ea; --primary-weak: #1d2b3d;
  --ok: #57e389; --ok-weak: #17301f; --bad: #ff7b63; --bad-weak: #3a1d1a;
  --warn: #f8e45c; --border: #35393f; --mark: #7a6a1e;
  --shadow: 0 1px 3px rgba(0,0,0,.4);
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body { background: var(--bg); color: var(--text); font: 16px/1.7 -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif; }
a { color: var(--primary); text-decoration: none; }
button { font: inherit; cursor: pointer; }

header.site { display: flex; align-items: center; gap: 16px; padding: 10px 20px; background: var(--card); border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 50; }
header.site h1 { font-size: 18px; margin: 0; white-space: nowrap; }
#nav { display: flex; gap: 4px; align-items: center; margin-left: auto; }
#nav a { padding: 6px 12px; border-radius: 8px; color: var(--text); }
#nav a.active, #nav a:hover { background: var(--primary-weak); color: var(--primary); }
.theme-btn { background: none; border: 1px solid var(--border); border-radius: 8px; padding: 4px 10px; color: var(--text); }

.wrap { max-width: 1000px; margin: 0 auto; padding: 20px 16px 60px; }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 18px 20px; margin-bottom: 16px; box-shadow: var(--shadow); }
.card h2 { margin: 0 0 12px; font-size: 17px; }
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.muted { color: var(--muted); font-size: 14px; }
.big { font-size: 30px; font-weight: 700; }
.btn { display: inline-block; border: none; border-radius: 10px; padding: 10px 20px; background: var(--primary); color: #fff; }
.btn.secondary { background: var(--primary-weak); color: var(--primary); }
.btn.danger { background: var(--bad); }
.btn.ghost { background: none; border: 1px solid var(--border); color: var(--text); }
.btn:disabled { opacity: .45; cursor: not-allowed; }
.btn-group { display: flex; flex-wrap: wrap; gap: 10px; margin: 0 0 4px; }
@media (max-width: 760px) {
  .btn-group { flex-direction: column; }
  .btn-group .btn { width: 100%; text-align: center; box-sizing: border-box; }
}
.tag { display: inline-block; padding: 1px 8px; border-radius: 6px; font-size: 12px; background: var(--primary-weak); color: var(--primary); margin-right: 6px; }
.tag.warn { background: var(--bad-weak); color: var(--bad); }
select, input[type=file] { font: inherit; padding: 6px 10px; border-radius: 8px; border: 1px solid var(--border); background: var(--card); color: var(--text); }
label.chk { margin-right: 14px; white-space: nowrap; }

/* ---------- 题目渲染 ---------- */
.q-stem { margin: 6px 0 14px; }
.q-no { font-weight: 700; margin-right: 6px; }
.opt { display: flex; gap: 10px; align-items: flex-start; padding: 10px 12px; border: 1px solid var(--border); border-radius: 10px; margin-bottom: 8px; cursor: pointer; }
.opt:hover { border-color: var(--primary); }
.opt.sel { border-color: var(--primary); background: var(--primary-weak); }
.opt.right { border-color: var(--ok); background: var(--ok-weak); }
.opt.wrong { border-color: var(--bad); background: var(--bad-weak); }
.opt .k { font-weight: 700; min-width: 20px; }
.analysis { border-left: 3px solid var(--primary); background: var(--primary-weak); padding: 10px 14px; border-radius: 0 10px 10px 0; margin-top: 12px; font-size: 15px; }
.analysis .verdict { font-weight: 700; }
.analysis .verdict.ok { color: var(--ok); }
.analysis .verdict.bad { color: var(--bad); }
.law { margin-top: 6px; font-size: 13px; color: var(--muted); }

/* ---------- 考试页 ---------- */
.exam-top { display: flex; align-items: center; gap: 14px; padding: 8px 16px; background: var(--card); border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 60; }
.timer { font-size: 22px; font-weight: 700; font-variant-numeric: tabular-nums; }
.timer.warn30 { color: var(--warn); } .timer.warn10 { color: var(--bad); }
.timer.warn5 { color: var(--bad); animation: blink 1s infinite; }
@keyframes blink { 50% { opacity: .35; } }
.exam-body { display: grid; grid-template-columns: 1fr 260px; gap: 16px; max-width: 1100px; margin: 16px auto; padding: 0 16px 40px; }
.sheet { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 14px; align-self: start; position: sticky; top: 64px; max-height: calc(100vh - 90px); overflow: auto; }
.sheet-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 6px; margin-top: 8px; }
.cell { border: 1px solid var(--border); border-radius: 6px; text-align: center; padding: 3px 0; font-size: 13px; cursor: pointer; background: var(--card); color: var(--text); }
.cell.answered { background: var(--primary); color: #fff; border-color: var(--primary); }
.cell.marked { outline: 2px solid var(--warn); }
.cell.cur { outline: 2px solid var(--text); }
.cell.blinkme { animation: blink 1s infinite; }
.sec-label { font-size: 12px; color: var(--muted); margin-top: 10px; }

/* ---------- 统计 ---------- */
canvas.chart { width: 100%; max-width: 460px; }
table.list { width: 100%; border-collapse: collapse; font-size: 15px; }
table.list th, table.list td { padding: 8px 10px; border-bottom: 1px solid var(--border); text-align: left; }
.bar-row { display: flex; align-items: center; gap: 10px; margin: 6px 0; }
.bar-row .lab { width: 160px; font-size: 14px; }
.bar-track { flex: 1; height: 14px; background: var(--border); border-radius: 7px; overflow: hidden; }
.bar-fill { height: 100%; background: var(--primary); border-radius: 7px; }
.heat { display: grid; grid-template-columns: repeat(auto-fill, 14px); gap: 3px; }
.heat i { width: 14px; height: 14px; border-radius: 3px; background: var(--border); }
.heat i.l1 { background: #9ec5e8; } .heat i.l2 { background: #5c9fd8; } .heat i.l3 { background: var(--primary); }

footer.site { text-align: center; padding: 24px; color: var(--muted); font-size: 12px; }

/* ---------- 移动端 ---------- */
@media (max-width: 760px) {
  .grid2 { grid-template-columns: 1fr; }
  .exam-body { grid-template-columns: 1fr; }
  .sheet { position: fixed; top: auto; bottom: 0; left: 0; right: 0; max-height: 45vh; border-radius: 16px 16px 0 0; transform: translateY(calc(100% - 44px)); transition: transform .25s; z-index: 70; }
  .sheet.open { transform: none; }
  .sheet .drawer-handle { display: block; text-align: center; cursor: pointer; font-size: 14px; color: var(--primary); padding-bottom: 6px; }
  .exam-top { flex-wrap: wrap; gap: 8px; }
  .timer { font-size: 18px; }
}
@media (min-width: 761px) { .sheet .drawer-handle { display: none; } }