:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --bg: #f4f6fb;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --border: #e5e7eb;
  --ok: #16a34a;
  --ok-bg: #e8f7ee;
  --bad: #dc2626;
  --bad-bg: #fdecec;
  --warn: #d97706;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Microsoft YaHei", "PingFang SC", "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
}

a { color: var(--primary); text-decoration: none; }

.navbar {
  background: var(--primary);
  color: #fff;
  padding: 0 24px;
  display: flex;
  align-items: center;
  gap: 24px;
  height: 60px;
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: 0 2px 8px rgba(0, 0, 0, .12);
}
.navbar .brand { font-size: 18px; font-weight: 700; letter-spacing: .5px; }
.navbar a { color: rgba(255, 255, 255, .9); }
.navbar a:hover, .navbar a.active { color: #fff; font-weight: 600; }
.navbar .spacer { flex: 1; }

.container { max-width: 1180px; margin: 0 auto; padding: 24px 16px 60px; }
.container.wide { max-width: 1400px; }

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px 22px;
  margin-bottom: 18px;
  box-shadow: 0 1px 3px rgba(16, 24, 40, .05);
}
.card h2 { margin: 0 0 14px; font-size: 18px; }
.card h3 { margin: 18px 0 10px; font-size: 15px; color: var(--muted); font-weight: 600; }

.grid-stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 14px; }
.stat {
  background: #f8fafc; border: 1px solid var(--border); border-radius: 10px;
  padding: 14px 16px; text-align: center;
}
.stat .num { font-size: 26px; font-weight: 700; color: var(--primary); }
.stat .lbl { font-size: 13px; color: var(--muted); }

table { width: 100%; border-collapse: collapse; font-size: 14px; }
th, td { padding: 10px 12px; border-bottom: 1px solid var(--border); text-align: left; }
th { background: #f8fafc; color: var(--muted); font-weight: 600; }
tbody tr:hover { background: #f9fafb; }

label.field { display: block; margin: 10px 0 6px; font-weight: 600; font-size: 14px; }
input[type=text], input[type=number], select {
  padding: 8px 10px; border: 1px solid var(--border); border-radius: 8px;
  font-size: 14px; width: 100%; max-width: 320px; background: #fff;
}
input:focus, select:focus { outline: 2px solid #bfdbfe; border-color: var(--primary); }

.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chip {
  border: 1px solid var(--border); border-radius: 999px; padding: 6px 14px;
  font-size: 13px; cursor: pointer; background: #fff; user-select: none;
}
.chip.on { background: var(--primary); color: #fff; border-color: var(--primary); }
.chip .c { color: var(--muted); font-size: 12px; margin-left: 4px; }
.chip.on .c { color: rgba(255, 255, 255, .85); }

.btn {
  display: inline-block; border: none; border-radius: 8px; cursor: pointer;
  padding: 10px 20px; font-size: 15px; font-weight: 600;
  background: var(--primary); color: #fff; transition: background .15s;
}
.btn:hover { background: var(--primary-dark); }
.btn.ghost { background: #fff; color: var(--primary); border: 1px solid var(--primary); }
.btn.ghost:hover { background: #eff6ff; }
.btn.warn { background: var(--warn); }
.btn:disabled { background: #9ca3af; cursor: not-allowed; }
.btn-row { display: flex; gap: 12px; flex-wrap: wrap; align-items: center; margin-top: 16px; }

.hint { color: var(--muted); font-size: 13px; }
.badge {
  display: inline-block; padding: 2px 10px; border-radius: 6px; font-size: 12px;
  background: #eef2ff; color: var(--primary); margin-right: 6px;
}
.badge.ok { background: var(--ok-bg); color: var(--ok); }
.badge.bad { background: var(--bad-bg); color: var(--bad); }
.badge.gray { background: #f3f4f6; color: var(--muted); }

/* ---------- 答题页 ---------- */
.paper-wrap { display: flex; gap: 18px; align-items: flex-start; }
.paper { flex: 1; min-width: 0; }

.qbar {
  position: sticky; top: 60px; z-index: 40; background: #fff;
  border: 1px solid var(--border); border-radius: 12px; padding: 12px 18px;
  display: flex; align-items: center; gap: 16px; flex-wrap: wrap; margin-bottom: 16px;
  box-shadow: 0 1px 3px rgba(16, 24, 40, .06);
}
.qbar .timer { font-size: 22px; font-weight: 700; font-variant-numeric: tabular-nums; color: var(--bad); }
.qbar .timer.safe { color: var(--ok); }

.question {
  background: #fff; border: 1px solid var(--border); border-radius: 12px;
  padding: 16px 20px; margin-bottom: 14px;
}
.question .qhead { font-size: 13px; color: var(--muted); margin-bottom: 6px; }
.question .qstem { font-size: 16px; font-weight: 600; margin-bottom: 12px; white-space: pre-wrap; }
.question.correct { border-left: 5px solid var(--ok); }
.question.wrong { border-left: 5px solid var(--bad); }

.opt {
  display: block; border: 1px solid var(--border); border-radius: 8px;
  padding: 9px 14px; margin: 7px 0; cursor: pointer; background: #fff; font-size: 15px;
}
.opt:hover { background: #f8fafc; }
.opt input { margin-right: 10px; transform: translateY(2px); }
.opt.picked { border-color: var(--primary); background: #eff6ff; }
.opt.right { border-color: var(--ok); background: var(--ok-bg); }
.opt.wrong { border-color: var(--bad); background: var(--bad-bg); }

.qfeedback { margin-top: 10px; font-size: 14px; }
.qfeedback .ok { color: var(--ok); font-weight: 600; }
.qfeedback .bad { color: var(--bad); font-weight: 600; }

.sheet {
  width: 220px; flex: 0 0 220px; background: #fff; border: 1px solid var(--border);
  border-radius: 12px; padding: 14px; position: sticky; top: 132px;
}
.sheet h4 { margin: 0 0 10px; font-size: 14px; }
.sheet .cells { display: grid; grid-template-columns: repeat(5, 1fr); gap: 6px; }
.sheet .cell {
  height: 32px; line-height: 32px; text-align: center; border: 1px solid var(--border);
  border-radius: 6px; font-size: 13px; cursor: pointer; background: #fff;
}
.sheet .cell.done { background: var(--primary); color: #fff; border-color: var(--primary); }
.sheet .cell.right { background: var(--ok); color: #fff; border-color: var(--ok); }
.sheet .cell.wrong { background: var(--bad); color: #fff; border-color: var(--bad); }
.sheet .legend { font-size: 12px; color: var(--muted); margin-top: 10px; }

/* ---------- 结果页 ---------- */
.score-hero {
  display: flex; gap: 28px; align-items: center; flex-wrap: wrap;
  background: linear-gradient(120deg, #2563eb, #1e40af); color: #fff;
  border-radius: 14px; padding: 24px 28px; margin-bottom: 18px;
}
.score-hero .big { font-size: 46px; font-weight: 800; line-height: 1.1; }
.score-hero .item { font-size: 14px; opacity: .95; }
.score-hero .num { font-size: 22px; font-weight: 700; }

.result-q { border: 1px solid var(--border); border-radius: 12px; padding: 14px 18px; margin-bottom: 12px; background: #fff; }
.result-q.ok { border-left: 5px solid var(--ok); }
.result-q.no { border-left: 5px solid var(--bad); }
.result-q .stem { font-weight: 600; white-space: pre-wrap; margin: 6px 0 10px; }
.res-line { font-size: 14px; margin-top: 8px; }
.res-line b.ok { color: var(--ok); }
.res-line b.bad { color: var(--bad); }
.mono { font-family: Consolas, monospace; letter-spacing: 2px; font-weight: 700; }

@media (max-width: 900px) {
  .paper-wrap { flex-direction: column-reverse; }
  .sheet { width: 100%; flex: none; position: static; }
  .sheet .cells { grid-template-columns: repeat(10, 1fr); }
  .navbar { padding: 0 14px; gap: 14px; }
  .navbar .brand { font-size: 15px; }
}