:root {
  --green: #1f8a5b;
  --green-d: #166643;
  --bg: #f3f5f4;
  --card: #ffffff;
  --text: #1b1f1d;
  --sub: #6b7872;
  --line: #e2e8e4;
  --bad: #e2563f;
  --good: #1f8a5b;
  --warn: #e8a32a;
  --shadow: 0 4px 16px rgba(0, 0, 0, .08);
  --radius: 16px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14181a;
    --card: #1f2528;
    --text: #e9efec;
    --sub: #93a39b;
    --line: #2c3438;
    --shadow: 0 4px 16px rgba(0, 0, 0, .35);
  }
}
* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html, body { margin: 0; padding: 0; height: 100%; }
body {
  font-family: -apple-system, "Segoe UI", "Microsoft YaHei", "Hiragino Sans", "Noto Sans CJK SC", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
}
#app {
  max-width: 720px;
  margin: 0 auto;
  min-height: 100%;
  display: flex;
  flex-direction: column;
  padding-bottom: env(safe-area-inset-bottom);
}
.hidden { display: none !important; }

/* 顶部栏 */
.topbar {
  position: sticky; top: 0; z-index: 20;
  display: flex; align-items: center; gap: 10px;
  padding: 14px 16px calc(14px) 16px;
  padding-top: calc(14px + env(safe-area-inset-top));
  background: var(--green);
  color: #fff;
}
.topbar h1 { font-size: 19px; margin: 0; flex: 1; text-align: center; font-weight: 700; letter-spacing: 1px; }
.icon-btn {
  background: rgba(255,255,255,.18); border: none; color: #fff;
  width: 34px; height: 34px; border-radius: 50%; font-size: 22px; line-height: 1; cursor: pointer;
}
.book-btn {
  background: rgba(255,255,255,.2); border: 1px solid rgba(255,255,255,.4); color: #fff;
  padding: 6px 14px; border-radius: 20px; font-size: 14px; font-weight: 600; cursor: pointer;
}

.view { flex: 1; padding: 16px; animation: fade .18s ease; }
@keyframes fade { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

/* 主页统计 */
.stat-strip {
  display: flex; gap: 10px; margin-bottom: 16px;
}
.stat {
  flex: 1; background: var(--card); border-radius: var(--radius); padding: 12px;
  text-align: center; box-shadow: var(--shadow);
}
.stat b { display: block; font-size: 22px; color: var(--green); }
.stat span { font-size: 12px; color: var(--sub); }

/* 模式卡片 */
.mode-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.mode-card {
  background: var(--card); border: none; border-radius: var(--radius); padding: 18px 14px;
  text-align: left; cursor: pointer; box-shadow: var(--shadow);
  display: flex; flex-direction: column; gap: 4px; transition: transform .1s;
}
.mode-card:active { transform: scale(.97); }
.mode-ico { font-size: 28px; }
.mode-name { font-size: 16px; font-weight: 700; color: var(--text); }
.mode-sub { font-size: 12px; color: var(--sub); }

/* 筛选 */
.filter-box { margin-top: 18px; background: var(--card); border-radius: var(--radius); padding: 14px; box-shadow: var(--shadow); }
.filter-head { display: flex; justify-content: space-between; align-items: center; font-weight: 700; margin-bottom: 10px; }
.link-btn { background: none; border: none; color: var(--green); font-size: 14px; cursor: pointer; font-weight: 600; }
.seg { display: flex; background: var(--bg); border-radius: 10px; padding: 3px; margin-bottom: 12px; }
.seg-btn { flex: 1; border: none; background: none; padding: 7px; border-radius: 8px; font-size: 14px; color: var(--sub); cursor: pointer; font-weight: 600; }
.seg-btn.active { background: var(--card); color: var(--green); box-shadow: 0 1px 4px rgba(0,0,0,.1); }
.chip-list { display: flex; flex-wrap: wrap; gap: 8px; max-height: 230px; overflow-y: auto; }
.chip {
  border: 1px solid var(--line); background: var(--bg); color: var(--text);
  padding: 6px 12px; border-radius: 18px; font-size: 13px; cursor: pointer; white-space: nowrap;
}
.chip.active { background: var(--green); color: #fff; border-color: var(--green); }
.chip small { opacity: .7; margin-left: 4px; }
.filter-summary { margin-top: 10px; font-size: 13px; color: var(--sub); }
/* 朗读按钮 */
.speak-btn {
  background: var(--bg); border: 1px solid var(--line); border-radius: 50%;
  width: 30px; height: 30px; cursor: pointer; font-size: 15px; line-height: 1;
  display: inline-flex; align-items: center; justify-content: center;
  vertical-align: middle; margin-left: 8px; padding: 0; color: var(--text);
}
.speak-btn:active { background: var(--green); }
.fc-speak { width: 48px; height: 48px; font-size: 22px; margin: 16px 0 0; }

/* 设置开关 */
.settings-row { margin: 18px 0 2px; }
.set-item { display: flex; align-items: center; justify-content: center; gap: 10px; font-size: 13px; color: var(--sub); }
.toggle { width: 42px; height: 24px; border-radius: 12px; background: var(--line); border: none; position: relative; cursor: pointer; transition: background .2s; padding: 0; }
.toggle.on { background: var(--green); }
.toggle .knob { position: absolute; top: 3px; left: 3px; width: 18px; height: 18px; border-radius: 50%; background: #fff; transition: left .2s; }
.toggle.on .knob { left: 21px; }

.device-foot { text-align: center; font-size: 12px; color: var(--sub); margin: 18px 0 4px; }
.device-foot a { color: var(--bad); text-decoration: none; }

/* 进度条 */
.progress-line { height: 6px; background: var(--line); border-radius: 3px; overflow: hidden; margin-bottom: 6px; }
.progress-fill { height: 100%; width: 0; background: var(--green); transition: width .25s; }
.counter { text-align: center; font-size: 13px; color: var(--sub); margin-bottom: 14px; }

/* 闪卡 */
.flash-wrap { perspective: 1400px; margin: 6px 0 22px; }
.flash-card {
  position: relative; width: 100%; min-height: 340px; cursor: pointer;
  transform-style: preserve-3d; transition: transform .5s;
}
.flash-card.flipped { transform: rotateY(180deg); }
.flash-face {
  position: absolute; inset: 0; backface-visibility: hidden; -webkit-backface-visibility: hidden;
  background: var(--card); border-radius: 20px; box-shadow: var(--shadow);
  padding: 24px; display: flex; flex-direction: column;
}
.flash-front { align-items: center; justify-content: center; text-align: center; }
.fc-word { font-size: 44px; font-weight: 800; letter-spacing: 2px; }
.fc-reading { font-size: 20px; color: var(--sub); margin-top: 10px; }
.fc-hint { position: absolute; bottom: 18px; font-size: 12px; color: var(--sub); }
.flash-back { transform: rotateY(180deg); overflow-y: auto; gap: 10px; }

.bk-word { font-size: 24px; font-weight: 800; }
.bk-reading { font-size: 15px; color: var(--sub); margin-bottom: 4px; }
.bk-cat { display: inline-block; align-self: flex-start; background: var(--green); color:#fff; font-size: 12px; padding: 2px 10px; border-radius: 12px; }
.bk-section { font-size: 14px; }
.bk-label { font-size: 12px; font-weight: 700; color: var(--green); display: block; margin-bottom: 2px; }
.bk-def { font-size: 15px; }
.tag-row { display: flex; flex-wrap: wrap; gap: 6px; }
.mini-tag { background: var(--bg); border: 1px solid var(--line); border-radius: 12px; padding: 2px 9px; font-size: 12px; }
.mini-tag.tag-link { border-color: var(--green); color: var(--green); cursor: pointer; font-weight: 600; }
.mini-tag.tag-link:active { background: var(--green); color: #fff; }

.flash-actions, .quiz-q { margin-top: auto; }
.flash-actions { display: flex; gap: 12px; }
.big-btn {
  flex: 1; border: none; border-radius: 14px; padding: 16px; font-size: 16px; font-weight: 700;
  color: #fff; cursor: pointer;
}
.big-btn.good { background: var(--good); }
.big-btn.bad { background: var(--bad); }
.big-btn.wide { width: 100%; margin-top: 16px; }
.big-btn:active { filter: brightness(.93); }

/* 测验 */
.quiz-q { font-size: 14px; color: var(--sub); margin-bottom: 6px; }
.quiz-prompt-main { font-size: 30px; font-weight: 800; color: var(--text); margin: 4px 0 18px; }
.quiz-prompt-main.small { font-size: 17px; font-weight: 600; line-height: 1.5; }
.quiz-options { display: flex; flex-direction: column; gap: 10px; }
.opt {
  text-align: left; background: var(--card); border: 2px solid var(--line); border-radius: 14px;
  padding: 14px 16px; font-size: 15px; cursor: pointer; color: var(--text); transition: .12s;
}
.opt:active { transform: scale(.99); }
.opt.correct { border-color: var(--good); background: rgba(31,138,91,.12); }
.opt.wrong { border-color: var(--bad); background: rgba(226,86,63,.12); }
.opt.disabled { pointer-events: none; }
.blank { color: var(--green); font-weight: 700; letter-spacing: 1px; margin: 0 1px; }

/* 浏览 */
.search { width: 100%; padding: 12px 14px; border-radius: 12px; border: 1px solid var(--line); background: var(--card); color: var(--text); font-size: 15px; margin-bottom: 12px; }
.browse-count { font-size: 13px; color: var(--sub); margin-bottom: 8px; }
.browse-list { display: flex; flex-direction: column; gap: 8px; }
.row {
  background: var(--card); border-radius: 12px; padding: 12px 14px; cursor: pointer;
  box-shadow: var(--shadow); display: flex; align-items: center; gap: 10px;
}
.row .rw { font-size: 17px; font-weight: 700; }
.row .rr { font-size: 13px; color: var(--sub); }
.row .rstate { margin-left: auto; font-size: 11px; padding: 2px 8px; border-radius: 10px; }
.rstate.known { background: rgba(31,138,91,.15); color: var(--good); }
.rstate.due { background: rgba(232,163,42,.18); color: var(--warn); }

/* 弹层 */
.sheet { position: fixed; inset: 0; z-index: 50; display: flex; align-items: flex-end; justify-content: center; }
.sheet-bg { position: absolute; inset: 0; background: rgba(0,0,0,.45); animation: fade .2s; }
.sheet-body {
  position: relative; width: 100%; max-width: 720px; max-height: 86vh; overflow-y: auto;
  background: var(--card); border-radius: 22px 22px 0 0; padding: 22px 20px calc(28px + env(safe-area-inset-bottom));
  animation: slideup .26s ease;
}
@keyframes slideup { from { transform: translateY(100%); } to { transform: none; } }
.sheet-body .bk-word { font-size: 30px; }
.detail-close { position: absolute; right: 16px; top: 14px; font-size: 26px; color: var(--sub); background: none; border: none; cursor: pointer; }

.result-body { text-align: center; }
.result-body h2 { margin: 6px 0; }
.result-ring { font-size: 46px; font-weight: 800; color: var(--green); }
.result-stats { display: flex; gap: 12px; margin: 18px 0; }
.result-stats .stat b { font-size: 20px; }

/* 激活码门禁 */
.gate {
  position: fixed; inset: 0; z-index: 100;
  display: flex; align-items: center; justify-content: center; padding: 22px;
  background: linear-gradient(160deg, var(--green), #0e4f33);
}
.gate-card {
  width: 100%; max-width: 380px; background: var(--card); border-radius: 22px;
  padding: 30px 24px 24px; text-align: center; box-shadow: 0 14px 40px rgba(0,0,0,.3);
}
.gate-logo { font-size: 46px; }
.gate-card h2 { margin: 6px 0 2px; letter-spacing: 2px; }
.gate-tip { color: var(--sub); font-size: 14px; margin: 0 0 18px; }
.gate-input {
  width: 100%; padding: 14px; border-radius: 12px; border: 2px solid var(--line);
  background: var(--bg); color: var(--text); font-size: 18px; text-align: center;
  letter-spacing: 3px; text-transform: uppercase; font-weight: 700;
}
.gate-input:focus { outline: none; border-color: var(--green); }
.gate-input2 { margin-top: 10px; letter-spacing: normal; text-transform: none; font-size: 16px; font-weight: 500; }
.gate-err { color: var(--bad); font-size: 13px; min-height: 18px; margin: 8px 0; }
.gate-foot { color: var(--sub); font-size: 12px; line-height: 1.6; margin: 14px 0 0; }

/* 报错/反馈 */
.fb-report { display: inline-flex; align-items: center; gap: 4px; margin-top: 10px;
  background: none; border: 1px solid var(--line); color: var(--sub);
  font-size: 12px; padding: 5px 12px; border-radius: 16px; cursor: pointer; align-self: flex-start; }
.fb-report:active { background: var(--bg); }
.fb-word { font-size: 18px; font-weight: 700; margin: 4px 0 12px; }
.fb-label { font-size: 12px; color: var(--sub); margin: 12px 0 6px; }
.fb-msg { width: 100%; border: 1px solid var(--line); border-radius: 10px; padding: 10px;
  font-size: 15px; background: var(--bg); color: var(--text); resize: vertical; font-family: inherit; }
.fb-msg:focus { outline: none; border-color: var(--green); }

/* 错题本 */
.wrong-top { margin-bottom: 12px; }
.wrong-count { font-size: 14px; color: var(--sub); margin-bottom: 10px; }
.wrong-bar { display: flex; align-items: center; gap: 14px; }
.wrong-bar .big-btn { flex: 1; padding: 13px; }
.rm-btn { margin-left: auto; background: none; border: none; color: var(--sub);
  font-size: 18px; cursor: pointer; padding: 4px 8px; border-radius: 8px; }
.rm-btn:active { background: var(--bg); color: var(--bad); }

.empty { text-align: center; color: var(--sub); padding: 50px 20px; }
.loading { text-align: center; color: var(--sub); padding: 40px; }

@media (min-width: 560px) {
  .flash-card { min-height: 380px; }
}