:root {
  --bg: #f4f5f7;
  --bg-elev: #ffffff;
  --card: #ffffff;
  --text: #1b1f24;
  --text-2: #5b6472;
  --text-3: #8b939f;
  --line: #e6e9ee;
  --line-2: #eef1f5;
  --primary: #1765f0;
  --primary-weak: #e8f0ff;
  --success: #12a35a;
  --success-weak: #e6f7ee;
  --danger: #e0342b;
  --danger-weak: #fdeceb;
  --warn: #c77700;
  --warn-weak: #fff5e3;
  --shadow: 0 1px 2px rgba(16, 24, 40, .04), 0 6px 18px rgba(16, 24, 40, .06);
  --radius: 14px;
}

html[data-theme="dark"] {
  --bg: #101216;
  --bg-elev: #181b20;
  --card: #181b20;
  --text: #e9ecf1;
  --text-2: #a7afbb;
  --text-3: #78818f;
  --line: #272b33;
  --line-2: #20242b;
  --primary: #4d8dff;
  --primary-weak: #16233d;
  --success: #35c07b;
  --success-weak: #14271e;
  --danger: #ff6359;
  --danger-weak: #2c1a19;
  --warn: #e0a340;
  --warn-weak: #2a2213;
  --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 6px 18px rgba(0, 0, 0, .35);
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

html, body { margin: 0; padding: 0; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  font-size: 15px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: 860px; margin: 0 auto; padding: 0 14px 40px; }

/* ---------- 顶栏 ---------- */
.topbar {
  position: sticky; top: 0; z-index: 30;
  display: flex; align-items: center; gap: 10px;
  height: 54px; padding: 0 12px;
  background: color-mix(in srgb, var(--bg-elev) 88%, transparent);
  backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--line);
}
.topbar .tb-title { flex: 1; font-size: 16px; font-weight: 650; letter-spacing: .2px; text-align: center; }
.icon-btn {
  width: 36px; height: 36px; flex: none;
  display: grid; place-items: center;
  border: 1px solid var(--line); border-radius: 10px;
  background: var(--card); color: var(--text-2);
  font-size: 15px; cursor: pointer; padding: 0;
}
.icon-btn:hover { color: var(--text); border-color: var(--text-3); }
.icon-btn[hidden] { visibility: hidden; display: grid; }

/* ---------- 通用 ---------- */
.card {
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); box-shadow: var(--shadow);
  padding: 16px; margin-bottom: 14px;
}
.sec-title { font-size: 13px; font-weight: 700; color: var(--text-3); letter-spacing: .06em; margin: 22px 4px 10px; }
.muted { color: var(--text-3); }
.hint { font-size: 13px; color: var(--text-3); line-height: 1.7; }
a { color: var(--primary); text-decoration: none; }

/* ---------- 首页 ---------- */
.hero { padding: 22px 4px 16px; }
.hero h1 { margin: 0 0 6px; font-size: 22px; line-height: 1.35; letter-spacing: .2px; }
.hero .sub { color: var(--text-2); font-size: 13.5px; }
.hero .tags { margin-top: 12px; display: flex; flex-wrap: wrap; gap: 6px; }
.tag {
  font-size: 12px; padding: 3px 9px; border-radius: 999px;
  background: var(--primary-weak); color: var(--primary); font-weight: 600;
}

.mode-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
@media (max-width: 560px) { .mode-grid { grid-template-columns: 1fr 1fr; gap: 10px; } }

.mode-card {
  position: relative; overflow: hidden;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 15px 14px; cursor: pointer;
  display: flex; flex-direction: column; gap: 4px; min-height: 92px;
  text-align: left; color: inherit; font: inherit;
}
.mode-card:hover { border-color: var(--primary); }
.mode-card .mc-name { font-size: 15.5px; font-weight: 680; }
.mode-card .mc-desc { font-size: 12.5px; color: var(--text-3); line-height: 1.5; }
.mode-card .mc-count {
  margin-top: auto; font-size: 12px; font-weight: 650;
  color: var(--primary); font-variant-numeric: tabular-nums;
}
.mode-card .mc-ico { position: absolute; right: 12px; top: 12px; font-size: 18px; opacity: .5; }
.mode-card.primary { background: linear-gradient(135deg, var(--primary), #3f8bff); border-color: transparent; }
.mode-card.primary .mc-name, .mode-card.primary .mc-count { color: #fff; }
.mode-card.primary .mc-desc { color: rgba(255,255,255,.82); }
.mode-card.primary .mc-ico { opacity: .75; }

.stat-row { display: flex; gap: 10px; text-align: center; }
.stat { flex: 1; background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 11px 6px; }
.stat b { display: block; font-size: 19px; font-variant-numeric: tabular-nums; }
.stat span { font-size: 12px; color: var(--text-3); }

/* ---------- 练习 ---------- */
.qhead { display: flex; align-items: center; gap: 8px; margin-bottom: 12px; flex-wrap: wrap; }
.badge {
  font-size: 12px; font-weight: 700; padding: 3px 9px; border-radius: 7px;
  background: var(--primary-weak); color: var(--primary);
}
.badge.ok { background: var(--success-weak); color: var(--success); }
.badge.no { background: var(--danger-weak); color: var(--danger); }
.badge.mute { background: var(--line-2); color: var(--text-3); }
.spacer { flex: 1; }
.counter { font-size: 13px; color: var(--text-3); font-variant-numeric: tabular-nums; }

.stem { font-size: 16.5px; line-height: 1.72; font-weight: 520; margin: 2px 0 16px; word-break: break-word; }

.opts { display: flex; flex-direction: column; gap: 9px; }
.opt {
  display: flex; align-items: flex-start; gap: 10px;
  padding: 12px 13px; border: 1.5px solid var(--line); border-radius: 11px;
  background: var(--card); color: var(--text);
  font: inherit; text-align: left; line-height: 1.6;
  cursor: pointer; transition: border-color .12s, background .12s;
}
.opt:hover { border-color: var(--primary); }
.opt .k {
  flex: none; width: 24px; height: 24px; border-radius: 50%;
  display: grid; place-items: center; font-size: 13px; font-weight: 700;
  background: var(--line-2); color: var(--text-2); margin-top: 1px;
}
.opt .v { flex: 1; word-break: break-word; }
.opt.locked { cursor: default; }
.opt.correct { border-color: var(--success); background: var(--success-weak); }
.opt.correct .k { background: var(--success); color: #fff; }
.opt.wrong { border-color: var(--danger); background: var(--danger-weak); }
.opt.wrong .k { background: var(--danger); color: #fff; }
.opt.chosen { border-color: var(--primary); background: var(--primary-weak); }
.opt.chosen .k { background: var(--primary); color: #fff; }
.opt .mk { flex: none; font-size: 13px; font-weight: 700; margin-top: 2px; }
.opt.correct .mk { color: var(--success); }
.opt.wrong .mk { color: var(--danger); }

.analysis {
  margin-top: 14px; border-radius: 12px; overflow: hidden;
  border: 1px solid var(--line); background: var(--bg-elev);
}
.analysis .a-hd {
  display: flex; align-items: center; gap: 8px;
  padding: 10px 13px; font-size: 13.5px; font-weight: 700;
  border-bottom: 1px solid var(--line-2); background: var(--line-2);
}
.analysis .a-hd .res { font-size: 12.5px; font-weight: 700; }
.analysis .a-hd .res.ok { color: var(--success); }
.analysis .a-hd .res.no { color: var(--danger); }
.analysis .a-bd { padding: 12px 13px; font-size: 14.5px; line-height: 1.78; color: var(--text); }
.analysis .a-bd .ans-line { margin-bottom: 8px; font-size: 13.5px; color: var(--text-2); }
.analysis .a-bd .ans-line b { color: var(--text); }

.bottom-bar {
  position: sticky; bottom: 0; z-index: 20;
  display: flex; gap: 10px; align-items: center;
  padding: 10px 0 14px; margin-top: 16px;
  background: linear-gradient(to top, var(--bg) 65%, transparent);
}
@media (max-width: 560px) {
  .bottom-bar {
    position: fixed; left: 0; right: 0; bottom: 0;
    padding: 9px 14px calc(9px + env(safe-area-inset-bottom));
    background: color-mix(in srgb, var(--bg-elev) 94%, transparent);
    backdrop-filter: blur(12px); border-top: 1px solid var(--line);
    margin: 0;
  }
}

.btn {
  flex: 1; height: 44px; border-radius: 11px; border: 1px solid var(--line);
  background: var(--card); color: var(--text); font: inherit; font-weight: 620;
  cursor: pointer; display: grid; place-items: center;
}
.btn:hover { border-color: var(--text-3); }
.btn.primary { background: var(--primary); border-color: var(--primary); color: #fff; }
.btn.primary:hover { filter: brightness(1.06); }
.btn[disabled] { opacity: .45; cursor: not-allowed; }
.btn.sm { flex: none; height: 38px; padding: 0 14px; font-size: 13.5px; }

/* ---------- 答题卡 ---------- */
.sheet-mask {
  position: fixed; inset: 0; z-index: 60; background: rgba(8, 12, 20, .45);
  display: flex; align-items: flex-end; justify-content: center;
}
.sheet {
  width: 100%; max-width: 860px; max-height: 76vh; overflow: auto;
  background: var(--card); border-radius: 18px 18px 0 0; padding: 16px 16px 24px;
}
.sheet h3 { margin: 0 0 12px; font-size: 15px; }
.sheet-legend { display: flex; gap: 14px; font-size: 12.5px; color: var(--text-3); margin-bottom: 12px; flex-wrap: wrap; }
.sheet-legend i { display: inline-block; width: 10px; height: 10px; border-radius: 3px; margin-right: 5px; vertical-align: 1px; }
.grid-num { display: grid; grid-template-columns: repeat(auto-fill, minmax(42px, 1fr)); gap: 8px; }
.gn {
  height: 40px; border-radius: 9px; border: 1.5px solid var(--line);
  background: var(--card); color: var(--text-2); font: inherit; font-size: 13.5px;
  font-variant-numeric: tabular-nums; cursor: pointer;
}
.gn.ok { border-color: var(--success); background: var(--success-weak); color: var(--success); font-weight: 700; }
.gn.no { border-color: var(--danger); background: var(--danger-weak); color: var(--danger); font-weight: 700; }
.gn.cur { outline: 2px solid var(--primary); outline-offset: 1px; }
.gn.done { border-color: var(--primary); color: var(--primary); font-weight: 700; }

/* ---------- 结果 ---------- */
.score-ring { display: grid; place-items: center; padding: 8px 0 4px; }
.score-ring .num { font-size: 44px; font-weight: 750; font-variant-numeric: tabular-nums; line-height: 1; }
.score-ring .num.ok { color: var(--success); }
.score-ring .num.no { color: var(--danger); }
.score-ring .lbl { font-size: 13px; color: var(--text-3); margin-top: 6px; }
.kv { display: flex; justify-content: space-between; padding: 9px 2px; border-bottom: 1px solid var(--line-2); font-size: 14px; }
.kv:last-child { border-bottom: 0; }
.kv span { color: var(--text-2); }

/* ---------- 简答 ---------- */
.qa-card .qa-q { font-weight: 640; font-size: 15.5px; margin-bottom: 10px; }
.qa-card .qa-a {
  border-left: 3px solid var(--primary); background: var(--bg-elev);
  padding: 10px 12px; border-radius: 0 10px 10px 0;
  font-size: 14.5px; line-height: 1.8; white-space: pre-wrap;
}
.qa-toggle { margin-top: 10px; }

.qa-input {
  width: 100%; min-height: 96px; resize: vertical;
  border: 1.5px solid var(--line); border-radius: 11px;
  background: var(--bg-elev); color: var(--text);
  font: inherit; font-size: 14.5px; line-height: 1.75;
  padding: 11px 12px; outline: none;
}
.qa-input:focus { border-color: var(--primary); }
.qa-input::placeholder { color: var(--text-3); }

.qa-bar {
  display: flex; align-items: center; gap: 8px;
  margin-top: 10px; flex-wrap: wrap;
}
.qa-saved { font-size: 12.5px; color: var(--text-3); }
.qa-a-hd {
  font-size: 12.5px; font-weight: 700; color: var(--text-3);
  letter-spacing: .04em; margin-bottom: 6px;
}
.qa-card .qa-a .qa-a-hd { margin-top: 0; }
.qa-mine {
  border-left: 3px solid var(--text-3); background: var(--bg-elev);
  padding: 10px 12px; border-radius: 0 10px 10px 0; margin-bottom: 10px;
  font-size: 14.5px; line-height: 1.8; white-space: pre-wrap;
}
.qa-mine .qa-a-hd { color: var(--text-3); }
.qa-a .qa-a-hd { color: var(--primary); }
.btn.ok { background: var(--success-weak); border-color: var(--success); color: var(--success); font-weight: 700; }

/* ---------- 排行榜 ---------- */
.rank-card { padding: 6px 4px; overflow-x: auto; }
table.rank { width: 100%; border-collapse: collapse; font-size: 14px; }
table.rank th {
  text-align: left; font-size: 12.5px; font-weight: 700; color: var(--text-3);
  padding: 9px 10px; border-bottom: 1px solid var(--line); white-space: nowrap;
}
table.rank td {
  padding: 10px; border-bottom: 1px solid var(--line-2);
  font-variant-numeric: tabular-nums;
}
table.rank tr:last-child td { border-bottom: 0; }
table.rank tr.me td { background: var(--primary-weak); font-weight: 700; }
table.rank td.rk { width: 68px; white-space: nowrap; font-weight: 700; }
table.rank td.nk { word-break: break-word; }
table.rank td.sc { width: 64px; font-weight: 700; color: var(--primary); }
table.rank td.tm, table.rank td.at { width: 92px; color: var(--text-2); white-space: nowrap; }
table.rank td.empty { text-align: center; color: var(--text-3); padding: 26px 10px; }
@media (max-width: 560px) {
  table.rank { font-size: 13px; }
  table.rank td.at, table.rank th:nth-child(5) { display: none; }
}

/* ---------- 底部 ---------- */
.foot {
  max-width: 860px; margin: 32px auto 0; padding: 18px 14px 26px;
  text-align: center; font-size: 12.5px; color: var(--text-3); line-height: 1.9;
  border-top: 1px solid var(--line);
}
.foot a { color: var(--text-3); }
.foot a:hover { color: var(--text-2); }

.loading { text-align: center; padding: 60px 0; color: var(--text-3); }
.toast {
  position: fixed; left: 50%; bottom: 84px; transform: translateX(-50%);
  background: rgba(20, 24, 32, .92); color: #fff; font-size: 13.5px;
  padding: 9px 16px; border-radius: 999px; z-index: 90; pointer-events: none;
  opacity: 0; transition: opacity .2s;
}
.toast.show { opacity: 1; }