:root {
  --navy: #0b3d5c;
  --teal: #007f7b;
  --teal-light: #e4f5f3;
  --ink: #17252f;
  --muted: #5a6b75;
  --line: #d8e1e5;
  --surface: #ffffff;
  --ground: #f3f7f8;
  --good: #0b6e45;
  --good-bg: #e5f6ed;
  --bad: #a32323;
  --bad-bg: #fdeeee;
  --warn: #8b5a00;
  --warn-bg: #fff5dc;
  --shadow: 0 8px 24px rgba(11, 61, 92, .09);
  font-family: "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
}
* { box-sizing: border-box; }
html { background: var(--ground); }
body { margin: 0; min-width: 320px; color: var(--ink); background: var(--ground); font-size: 16px; line-height: 1.6; }
button, select { font: inherit; }
button { cursor: pointer; }
.skip-link { position: absolute; left: 1rem; top: -4rem; z-index: 10; padding: .7rem 1rem; color: #fff; background: var(--navy); border-radius: .5rem; }
.skip-link:focus { top: 1rem; }
.site-header { color: #fff; background: linear-gradient(135deg, #0b3d5c, #007f7b); }
.site-header__inner { width: min(100% - 2rem, 780px); margin: 0 auto; padding: 1.35rem 0 1.25rem; }
.site-header h1 { margin: 0; font-size: clamp(1.4rem, 5vw, 2rem); line-height: 1.2; }
.site-header p { margin: .2rem 0 0; font-size: .88rem; opacity: .9; }
.eyebrow { font-size: .78rem !important; letter-spacing: .06em; }
#app { width: min(100% - 1.25rem, 780px); margin: 0 auto; padding: 1rem 0 calc(5.8rem + env(safe-area-inset-bottom)); }
.card { margin-bottom: .9rem; padding: 1rem; background: var(--surface); border: 1px solid var(--line); border-radius: 1rem; box-shadow: var(--shadow); }
.card h2, .card h3 { margin: 0 0 .55rem; line-height: 1.35; }
.card h2 { font-size: 1.2rem; }
.card h3 { font-size: 1rem; }
.notice { border-left: .3rem solid var(--warn); background: var(--warn-bg); box-shadow: none; }
.notice p { margin: 0; color: #5e460e; font-size: .9rem; }
.stats { display: grid; grid-template-columns: repeat(2, 1fr); gap: .7rem; }
.stat { padding: .8rem; text-align: center; background: #f5fafb; border: 1px solid #dbecee; border-radius: .75rem; }
.stat b { display: block; color: var(--navy); font-size: 1.3rem; line-height: 1.1; }
.stat span { color: var(--muted); font-size: .78rem; }
.action-grid { display: grid; grid-template-columns: 1fr 1fr; gap: .7rem; }
.button { min-height: 46px; padding: .7rem .9rem; color: #fff; background: var(--navy); border: 1px solid var(--navy); border-radius: .75rem; font-weight: 700; text-align: center; }
.button:hover { filter: brightness(1.08); }
.button--teal { background: var(--teal); border-color: var(--teal); }
.button--light { color: var(--navy); background: #fff; border-color: #aebfc8; }
.button--danger { color: var(--bad); background: #fff; border-color: #e4b3b3; }
.button:disabled { cursor: not-allowed; opacity: .45; }
.wide { width: 100%; margin-top: .7rem; }
.toolbar { display: flex; align-items: center; justify-content: space-between; gap: .7rem; margin-bottom: .8rem; }
.toolbar .button { min-height: 40px; padding: .45rem .7rem; font-size: .88rem; }
.muted { color: var(--muted); font-size: .9rem; }
.progress { height: .55rem; overflow: hidden; background: #dce9ec; border-radius: 999px; }
.progress > span { display: block; height: 100%; background: var(--teal); border-radius: inherit; transition: width .2s ease; }
.tags { display: flex; flex-wrap: wrap; gap: .4rem; margin: .65rem 0; }
.tag { padding: .18rem .5rem; color: #155066; background: #eaf5f7; border-radius: 999px; font-size: .76rem; }
.question { font-size: 1.05rem; font-weight: 700; line-height: 1.7; }
.options { display: grid; gap: .65rem; margin-top: 1rem; }
.option { display: flex; align-items: flex-start; gap: .65rem; min-height: 52px; padding: .75rem; color: var(--ink); background: #fff; border: 2px solid #cbd9de; border-radius: .8rem; text-align: left; }
.option:hover, .option.is-selected { border-color: var(--teal); background: var(--teal-light); }
.option.is-correct { color: #064b30; background: var(--good-bg); border-color: var(--good); }
.option.is-wrong { color: #7b1717; background: var(--bad-bg); border-color: var(--bad); }
.option-letter { flex: 0 0 1.6rem; width: 1.6rem; height: 1.6rem; color: var(--navy); background: #e7f1f4; border-radius: 50%; font-weight: 700; text-align: center; }
.option.is-correct .option-letter { color: #fff; background: var(--good); }
.option.is-wrong .option-letter { color: #fff; background: var(--bad); }
.answer-box { margin-top: 1rem; padding: .85rem; border-radius: .75rem; }
.answer-box.good { background: var(--good-bg); border: 1px solid #a6dbbe; }
.answer-box.bad { background: var(--bad-bg); border: 1px solid #f1b8b8; }
.answer-box p { margin: .2rem 0; }
.filter-grid { display: grid; gap: .7rem; }
.field label { display: block; margin-bottom: .25rem; color: var(--muted); font-size: .85rem; font-weight: 700; }
.field select { width: 100%; min-height: 44px; padding: .55rem; background: #fff; border: 1px solid #9db0b9; border-radius: .6rem; }
.list { margin: 0; padding-left: 1.1rem; }
.list li { margin-bottom: .35rem; }
.weak { color: var(--bad); font-weight: 700; }
.empty { padding: 1.2rem; color: var(--muted); text-align: center; }
.bottom-bar { position: fixed; right: 0; bottom: 0; left: 0; z-index: 5; padding: .65rem max(.65rem, env(safe-area-inset-right)) calc(.65rem + env(safe-area-inset-bottom)) max(.65rem, env(safe-area-inset-left)); background: rgba(255,255,255,.96); border-top: 1px solid var(--line); box-shadow: 0 -8px 24px rgba(11, 61, 92, .08); }
.bottom-bar__inner { display: grid; grid-template-columns: 1fr 1.5fr; gap: .65rem; width: min(100%, 780px); margin: 0 auto; }
@media (min-width: 600px) { .stats { grid-template-columns: repeat(4, 1fr); } .filter-grid { grid-template-columns: repeat(3, 1fr); } .action-grid { grid-template-columns: repeat(3, 1fr); } }
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; } }