:root {
  --primary: #4f8cff;
  --primary-dark: #3a6fd8;
  --bg: #f5f8ff;
  --card: #ffffff;
  --text: #2b2f3a;
  --muted: #7a8299;
  --ok: #34a853;
  --err: #ea4335;
  --radius: 16px;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 18px;
  line-height: 1.6;
}
.container { max-width: 720px; margin: 0 auto; padding: 24px 16px; }
.card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: 0 2px 12px rgba(79, 140, 255, 0.12);
  margin-bottom: 20px;
}
h1 { font-size: 28px; }
h2 { font-size: 22px; }
input, select {
  font-size: 18px;
  padding: 10px 14px;
  border: 2px solid #d9e2f5;
  border-radius: 10px;
  width: 100%;
  margin: 6px 0 14px;
  font-family: inherit;
}
input:focus, select:focus { outline: none; border-color: var(--primary); }
button {
  font-size: 19px;
  padding: 12px 28px;
  border: none;
  border-radius: 12px;
  background: var(--primary);
  color: #fff;
  cursor: pointer;
  font-family: inherit;
}
button:hover { background: var(--primary-dark); }
button.secondary { background: #e8eefc; color: var(--primary-dark); }
button:disabled { opacity: 0.55; cursor: not-allowed; }
.msg { padding: 10px 14px; border-radius: 10px; margin: 8px 0; }
.msg.err { background: #fdecea; color: var(--err); }
.msg.ok { background: #e6f4ea; color: var(--ok); }
.muted { color: var(--muted); font-size: 15px; }
.nav { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; margin-bottom: 20px; }
.nav a { text-decoration: none; color: var(--primary-dark); font-weight: 600; }
.big-question { font-size: 34px; text-align: center; margin: 24px 0; }
.big-question input { width: 140px; text-align: center; font-size: 28px; }
.answer-options { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; margin: 20px 0; }
.answer-options button { min-width: 90px; }
.stat-row { display: flex; gap: 16px; flex-wrap: wrap; margin: 14px 0; }
.stat { background: #eef3ff; border-radius: 12px; padding: 12px 20px; min-width: 120px; }
.stat .num { font-size: 28px; font-weight: 700; color: var(--primary-dark); }
table.records { width: 100%; border-collapse: collapse; font-size: 16px; }
table.records th, table.records td { padding: 8px 10px; border-bottom: 1px solid #e8eefc; text-align: left; }
table.records td.correct { color: var(--ok); font-weight: 600; }
table.records td.wrong { color: var(--err); font-weight: 600; }