/* ---------- 主题 ---------- */
:root {
  --bg: #f6f3ec;
  --bg-veil: radial-gradient(1100px 520px at 50% -12%, #fffefb 0%, rgba(255, 254, 251, 0) 62%);
  --card: #fffefb;
  --ink: #26231e;
  --ink-soft: #4b453b;
  --muted: #8b8275;
  --line: #e9e3d7;
  --line-strong: #d5ccbb;
  --accent: #a8442f;
  --accent-ink: #fffdf9;
  --accent-soft: rgba(168, 68, 47, .07);
  --ok: #3d6f52;
  --ok-soft: rgba(61, 111, 82, .10);
  --bad: #b03a2e;
  --bad-soft: rgba(176, 58, 46, .09);
  --shadow: 0 1px 2px rgba(54, 44, 30, .04), 0 20px 44px -26px rgba(54, 44, 30, .30);
  --serif: "Noto Serif SC", "Source Han Serif SC", "Songti SC", "STSong", "SimSun", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", "Segoe UI", sans-serif;
  color-scheme: light;
}

[data-theme="dark"] {
  --bg: #161512;
  --bg-veil: radial-gradient(1100px 520px at 50% -12%, #221f19 0%, rgba(34, 31, 25, 0) 62%);
  --card: #201e19;
  --ink: #eae5d9;
  --ink-soft: #cfc7b8;
  --muted: #968d7e;
  --line: #322e27;
  --line-strong: #474237;
  --accent: #d98a72;
  --accent-ink: #1a1512;
  --accent-soft: rgba(217, 138, 114, .09);
  --ok: #7fb894;
  --ok-soft: rgba(127, 184, 148, .12);
  --bad: #e08a7c;
  --bad-soft: rgba(224, 138, 124, .12);
  --shadow: 0 1px 2px rgba(0, 0, 0, .5), 0 24px 48px -28px rgba(0, 0, 0, .8);
  color-scheme: dark;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

body {
  margin: 0;
  min-height: 100vh;
  background-color: var(--bg);
  background-image: var(--bg-veil);
  background-repeat: no-repeat;
  color: var(--ink);
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
  display: flex;
  flex-direction: column;
}

button { font: inherit; color: inherit; }
button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
::selection { background: var(--accent-soft); }

/* ---------- 顶栏 ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px max(20px, env(safe-area-inset-left)) 14px max(20px, env(safe-area-inset-right));
  background: color-mix(in srgb, var(--bg) 84%, transparent);
  -webkit-backdrop-filter: saturate(140%) blur(14px);
  backdrop-filter: saturate(140%) blur(14px);
}
body.is-scrolled .topbar { box-shadow: 0 1px 0 var(--line); }

.brand { display: flex; align-items: center; gap: 11px; min-width: 0; cursor: pointer; }
.seal {
  width: 34px; height: 34px; flex: none;
  display: grid; place-items: center;
  border-radius: 9px;
  background: var(--accent);
  color: var(--accent-ink);
  font-family: var(--serif);
  font-size: 19px;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .18), 0 4px 10px -6px rgba(168, 68, 47, .3);
}
.brand-text { min-width: 0; }
.brand-text h1 {
  margin: 0; font-size: 15px; font-weight: 600; letter-spacing: .015em;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.brand-text p { margin: 2px 0 0; font-size: 11.5px; color: var(--muted); letter-spacing: .02em; white-space: nowrap; }

.top-actions { display: flex; align-items: center; gap: 6px; }

.pill-btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 7px 12px 7px 14px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: transparent;
  color: var(--ink-soft);
  font-size: 12.5px;
  cursor: pointer;
  transition: background .16s ease, border-color .16s ease;
  white-space: nowrap;
}
.pill-btn:hover { background: var(--accent-soft); border-color: var(--muted); }
.badge {
  min-width: 18px; height: 18px; padding: 0 5px;
  display: inline-grid; place-items: center;
  border-radius: 9px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 11px;
  font-variant-numeric: tabular-nums;
}
.badge:empty, .badge[data-zero="1"] { display: none; }

.icon-btn {
  width: 36px; height: 36px;
  display: grid; place-items: center;
  border: 0; border-radius: 10px;
  background: transparent; color: var(--ink-soft);
  cursor: pointer;
}
.icon-btn:hover { background: var(--accent-soft); color: var(--ink); }
.icon-btn svg { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.i-sun { display: none; }
[data-theme="dark"] .i-sun { display: block; }
[data-theme="dark"] .i-moon { display: none; }

.progress-top { position: fixed; top: 0; left: 0; right: 0; height: 2px; z-index: 50; pointer-events: none; }
.progress-top i { display: block; height: 100%; width: 0; background: var(--accent); opacity: .55; transition: width .3s ease; }

/* ---------- 首页 ---------- */
main { flex: 1; width: 100%; }

.home {
  max-width: 1040px;
  margin: 0 auto;
  padding: 40px 24px 70px;
}

.hero { text-align: center; padding: 8px 0 34px; }
.hero-kicker {
  margin: 0 0 10px;
  font-size: 11.5px;
  letter-spacing: .22em;
  color: var(--muted);
  text-transform: uppercase;
}
.hero h2 {
  margin: 0;
  font-family: var(--serif);
  font-size: 34px;
  font-weight: 600;
  letter-spacing: .06em;
}
.hero-sub { margin: 12px 0 0; font-size: 13.5px; color: var(--muted); letter-spacing: .02em; }
.hero-actions { display: flex; justify-content: center; gap: 10px; margin-top: 24px; flex-wrap: wrap; }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 11px 22px;
  border-radius: 999px;
  border: 1px solid transparent;
  font-size: 14px;
  letter-spacing: .02em;
  cursor: pointer;
  transition: transform .14s ease, background .16s ease, border-color .16s ease, box-shadow .16s ease;
  -webkit-tap-highlight-color: transparent;
}
.btn:active { transform: translateY(1px); }
.btn.primary { background: var(--accent); color: var(--accent-ink); box-shadow: 0 8px 18px -12px rgba(168, 68, 47, .45); }
.btn.primary:hover { filter: brightness(1.04); }
.btn.ghost { background: transparent; border-color: var(--line-strong); color: var(--ink-soft); }
.btn.ghost:hover { border-color: var(--muted); background: var(--accent-soft); }
.btn:disabled { opacity: .45; cursor: default; }
.btn.small { padding: 8px 16px; font-size: 13px; }

.period-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.period-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 18px 18px 15px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--card);
  box-shadow: 0 1px 2px rgba(54, 44, 30, .03);
  cursor: pointer;
  text-align: left;
  transition: transform .16s ease, box-shadow .16s ease, border-color .16s ease;
}
.period-card:hover {
  transform: translateY(-2px);
  border-color: var(--line-strong);
  box-shadow: var(--shadow);
}
.pc-top { display: flex; align-items: baseline; justify-content: space-between; gap: 8px; }
.pc-label { font-family: var(--serif); font-size: 19px; font-weight: 600; letter-spacing: .03em; }
.pc-tag { font-size: 11px; color: var(--muted); letter-spacing: .04em; }
.pc-meta { font-size: 12px; color: var(--muted); font-variant-numeric: tabular-nums; }
.pc-bar { height: 3px; border-radius: 2px; background: var(--line); overflow: hidden; }
.pc-bar i { display: block; height: 100%; width: 0; background: var(--accent); border-radius: 2px; transition: width .3s ease; }
.pc-state { font-size: 11.5px; color: var(--muted); }
.pc-state.done { color: var(--accent); }

.home-note {
  margin: 30px 0 0;
  text-align: center;
  font-size: 12px;
  line-height: 1.9;
  color: var(--muted);
}

/* ---------- 练习页 ---------- */
.practice {
  max-width: 820px;
  margin: 0 auto;
  padding: 22px 24px 60px;
}

.practice-head { display: flex; align-items: center; gap: 12px; margin-bottom: 16px; }
.back-btn {
  width: 34px; height: 34px; flex: none;
  display: grid; place-items: center;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: transparent;
  color: var(--ink-soft);
  font-size: 17px;
  cursor: pointer;
}
.back-btn:hover { background: var(--accent-soft); }
.practice-title { min-width: 0; flex: 1; display: flex; flex-direction: column; }
.practice-title b { font-size: 15px; font-weight: 600; letter-spacing: .02em; }
.practice-title span { font-size: 11.5px; color: var(--muted); margin-top: 2px; }
.practice-count { font-size: 12.5px; color: var(--muted); font-variant-numeric: tabular-nums; }

.seg-tabs {
  display: inline-flex;
  gap: 2px;
  padding: 3px;
  border-radius: 10px;
  background: var(--line);
}
.seg-tabs button {
  padding: 7px 16px;
  border: 0;
  border-radius: 8px;
  background: transparent;
  color: var(--muted);
  font-size: 13px;
  cursor: pointer;
  transition: background .16s ease, color .16s ease;
}
.seg-tabs button.is-on { background: var(--card); color: var(--ink); box-shadow: 0 1px 2px rgba(0, 0, 0, .06); }

.bar { height: 2px; margin: 14px 0 18px; background: var(--line); border-radius: 2px; overflow: hidden; }
.bar i { display: block; height: 100%; width: 0; background: var(--accent); opacity: .65; transition: width .3s ease; }

.qcard {
  padding: 30px 34px 26px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--card);
  box-shadow: var(--shadow);
}

.qhead { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; }
.tag {
  display: inline-block;
  padding: 3px 9px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 11px;
  letter-spacing: .04em;
}
.qno { font-size: 11.5px; color: var(--muted); font-variant-numeric: tabular-nums; }

.qtext {
  margin: 0 0 18px;
  font-family: var(--serif);
  font-size: 18.5px;
  line-height: 1.85;
  font-weight: 500;
  letter-spacing: .01em;
  white-space: pre-wrap;
}
.qtext .poem { display: block; margin-top: 6px; color: var(--ink-soft); font-size: 17px; line-height: 1.9; }

.opts { display: grid; gap: 9px; }
.opt {
  display: flex;
  align-items: flex-start;
  gap: 11px;
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: transparent;
  color: var(--ink);
  font-family: var(--serif);
  font-size: 16px;
  line-height: 1.6;
  text-align: left;
  cursor: pointer;
  transition: border-color .14s ease, background .14s ease, transform .1s ease;
}
.opt:hover { border-color: var(--line-strong); background: var(--accent-soft); }
.opt .letter {
  flex: none;
  width: 22px; height: 22px; margin-top: 1px;
  display: grid; place-items: center;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  font-family: var(--sans);
  font-size: 11.5px;
  color: var(--muted);
  transition: all .14s ease;
}
.opt.is-picked { border-color: var(--accent); background: var(--accent-soft); }
.opt.is-picked .letter { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.opt.is-right { border-color: var(--ok); background: var(--ok-soft); }
.opt.is-right .letter { background: var(--ok); border-color: var(--ok); color: #fff; }
.opt.is-wrong { border-color: var(--bad); background: var(--bad-soft); }
.opt.is-wrong .letter { background: var(--bad); border-color: var(--bad); color: #fff; }
.opts.locked .opt { cursor: default; }
.opts.locked .opt:hover { background: transparent; border-color: var(--line); }
.opts.locked .opt.is-picked:hover, .opts.locked .opt.is-right:hover { background: var(--ok-soft); }
.opts.locked .opt.is-picked { background: var(--accent-soft); }

.qactions { display: flex; align-items: center; gap: 12px; margin-top: 18px; }
.qactions .hint { font-size: 12px; color: var(--muted); }

.explain {
  margin-top: 20px;
  padding-top: 18px;
  border-top: 1px dashed var(--line);
}
.explain h3, .answer h3 {
  margin: 0 0 8px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .08em;
  color: var(--muted);
}
.explain p, .answer p {
  margin: 0 0 .55em;
  font-size: 14.5px;
  line-height: 1.95;
  color: var(--ink-soft);
  white-space: pre-wrap;
}
.explain p:last-child, .answer p:last-child { margin-bottom: 0; }
.verdict { font-size: 13.5px; font-weight: 600; margin-bottom: 10px; }
.verdict.ok { color: var(--ok); }
.verdict.bad { color: var(--bad); }

.answer {
  margin-top: 20px;
  padding: 20px 22px;
  border-left: 2px solid var(--accent);
  border-radius: 0 12px 12px 0;
  background: color-mix(in srgb, var(--accent) 5%, transparent);
}
.answer .block + .block { margin-top: 18px; }

.selfgrade { margin-top: 18px; display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.selfgrade .label { font-size: 12.5px; color: var(--muted); margin-right: 4px; }
.self-btn {
  padding: 8px 14px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: transparent;
  font-size: 13px;
  color: var(--ink-soft);
  cursor: pointer;
}
.self-btn:hover { background: var(--accent-soft); }
.self-btn.is-on { border-color: var(--accent); background: var(--accent-soft); color: var(--accent); }

.qnav { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-top: 18px; }
.qnav-dots { font-size: 12px; color: var(--muted); font-variant-numeric: tabular-nums; letter-spacing: .04em; }

.foot {
  padding: 24px 20px 30px;
  text-align: center;
  font-size: 11.5px;
  color: var(--muted);
}

/* ---------- 移动端 ---------- */
@media (max-width: 860px) {
  .period-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 640px) {
  .topbar { padding-top: 11px; padding-bottom: 11px; }
  .brand-text p { display: none; }
  .brand-text h1 { font-size: 14px; }
  .pill-btn { padding: 7px 10px; font-size: 12px; }
  .home { padding: 24px 15px 50px; }
  .hero { padding-bottom: 24px; }
  .hero h2 { font-size: 27px; }
  .hero-sub { font-size: 12.5px; }
  .period-grid { grid-template-columns: 1fr; gap: 9px; }
  .period-card { padding: 15px 16px 13px; }
  .pc-label { font-size: 17px; }
  .practice { padding: 16px 14px 40px; }
  .qcard { padding: 22px 18px 20px; border-radius: 14px; }
  .qtext { font-size: 17px; }
  .opt { font-size: 15px; padding: 11px 12px; }
  .qnav { margin-top: 14px; }
  .qnav .btn { padding: 10px 16px; font-size: 13.5px; }
  .qnav-dots { display: none; }
  .answer { padding: 16px 16px; }
  .foot { font-size: 11px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .001ms !important; transition-duration: .001ms !important; }
}
.done-line { margin: -6px 0 2px; font-size: 14px; line-height: 1.9; color: var(--muted); }
.muted { color: var(--muted); }