:root{
  --bg:#f5f6fb; --card:#ffffff; --ink:#1f2430; --muted:#6b7280; --line:#e7e9f0;
  --primary:#4c6fff; --primary-soft:#eaefff; --green:#16a34a; --green-soft:#e7f6ec;
  --red:#e5484d; --red-soft:#fdecec; --amber:#f59e0b; --amber-soft:#fef3e2;
  --purple:#7a5cff; --purple-soft:#efeaff;
  --radius:16px; --shadow:0 1px 2px rgba(20,30,60,.04),0 8px 24px rgba(20,30,60,.06);
}
*{box-sizing:border-box}
body{margin:0;font-family:-apple-system,"Segoe UI","Microsoft YaHei",system-ui,sans-serif;
  background:var(--bg);color:var(--ink);-webkit-font-smoothing:antialiased;overscroll-behavior-y:none}
button,input{touch-action:manipulation}
button:disabled{opacity:.45;cursor:not-allowed}
.app{display:flex;min-height:100vh}
.sidebar{width:220px;background:#fff;border-right:1px solid var(--line);padding:20px 14px;
  position:sticky;top:0;height:100vh;display:flex;flex-direction:column;gap:3px;overflow:auto}
.brand{display:flex;align-items:center;gap:10px;padding:6px 10px 14px}
.brand .logo{width:34px;height:34px;border-radius:9px;background:linear-gradient(135deg,#4c6fff,#7a5cff);
  display:grid;place-items:center;color:#fff;font-weight:800;font-size:15px}
.brand b{font-size:16px}.brand span{font-size:11px;color:var(--muted);display:block;font-weight:500}
.navlabel{font-size:11px;color:#9aa1b1;padding:12px 12px 4px;letter-spacing:.04em}
.nav{display:flex;align-items:center;gap:10px;padding:9px 12px;border-radius:10px;cursor:pointer;
  color:#4b5162;font-size:14px;font-weight:500;border:0;background:none;width:100%;text-align:left}
.nav:hover{background:#f3f4f9}
.nav.active{background:var(--primary-soft);color:var(--primary);font-weight:600}
.nav .ic{width:18px;text-align:center}
.side-foot{margin-top:auto;border-top:1px solid var(--line);padding-top:12px}
.pill{display:flex;align-items:center;justify-content:space-between;background:#f3f4f9;border-radius:10px;
  padding:9px 12px;font-size:12.5px;color:#4b5162}
.main{flex:1;min-width:0}
.topbar{display:flex;align-items:center;justify-content:space-between;padding:18px 30px;
  border-bottom:1px solid var(--line);background:rgba(255,255,255,.7);backdrop-filter:blur(6px);position:sticky;top:0;z-index:5}
.topbar h1{font-size:19px;margin:0}.topbar .sub{font-size:12px;color:var(--muted);margin-top:2px}
.streak{display:flex;align-items:center;gap:8px;background:var(--amber-soft);color:#b45309;padding:8px 14px;border-radius:999px;font-size:13px;font-weight:600}
.wrap{padding:26px 30px;max-width:1040px}
.screen{display:none}.screen.on{display:block}
.grid{display:grid;gap:16px}
.stat{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:18px;box-shadow:var(--shadow)}
.stat .k{font-size:12px;color:var(--muted);display:flex;align-items:center;gap:6px}
.stat .v{font-size:25px;font-weight:750;margin-top:6px}.stat .v small{font-size:14px;color:var(--muted);font-weight:600}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}
.btn{border:0;border-radius:11px;padding:12px 20px;font-size:15px;font-weight:650;cursor:pointer;font-family:inherit}
.btn.primary{background:var(--primary);color:#fff}.btn.ghost{background:#fff;border:1px solid var(--line);color:var(--ink)}
.btn.green{background:var(--green);color:#fff}.btn.red{background:var(--red);color:#fff}
.btn.danger{background:var(--red-soft);color:var(--red);border:1px solid #f3c6c6}
.bar{height:9px;border-radius:999px;background:#eef0f6;overflow:hidden}
.bar>i{display:block;height:100%;background:linear-gradient(90deg,#4c6fff,#7a5cff);border-radius:999px}
.ring{--p:0;width:118px;height:118px;border-radius:50%;background:conic-gradient(var(--primary) calc(var(--p)*1%),#eef0f6 0);display:grid;place-items:center}
.ring .in{width:88px;height:88px;background:#fff;border-radius:50%;display:grid;place-items:center;text-align:center}
.chip{display:inline-flex;align-items:center;gap:6px;background:#f3f4f9;border-radius:8px;padding:6px 11px;font-size:13px;color:#4b5162;border:1px solid var(--line)}
.tag{font-size:11px;padding:2px 8px;border-radius:6px;font-weight:600;white-space:nowrap}
.tag.word{background:var(--primary-soft);color:var(--primary)}
.tag.phrase{background:var(--purple-soft);color:#5b43c9}
.tag.pos{background:var(--amber-soft);color:#b45309}
.speak{width:34px;height:34px;border-radius:50%;background:var(--primary-soft);color:var(--primary);border:0;font-size:15px;cursor:pointer;display:inline-grid;place-items:center;vertical-align:middle}
.small{font-size:12px;color:var(--muted)}
.session{max-width:640px;margin:0 auto}
.session .pgs{display:flex;align-items:center;gap:12px;margin-bottom:10px}
.passbar{display:flex;gap:8px;margin-bottom:18px}
.passbar .p{flex:1;text-align:center;font-size:12px;font-weight:600;color:#9aa1b1;padding:7px;border-radius:9px;background:#eef0f6}
.passbar .p.on{background:var(--primary);color:#fff}.passbar .p.done{background:var(--green-soft);color:var(--green)}
.wordbig{font-size:48px;font-weight:800;letter-spacing:.01em}
.ipa{color:var(--muted);font-size:17px;margin-top:6px}
.input{width:100%;border:2px solid var(--line);border-radius:12px;padding:15px 16px;font-size:20px;font-family:inherit;text-align:center;letter-spacing:.02em}
.blank{display:inline-block;min-width:110px;border-bottom:3px solid var(--primary);margin:0 4px}
.rowlist{display:flex;align-items:center;justify-content:space-between;padding:13px 16px;border-bottom:1px solid var(--line);gap:12px}
.rowlist:last-child{border-bottom:0}
.tabs{display:inline-flex;background:#eef0f6;border-radius:11px;padding:4px;gap:4px;margin-bottom:18px}
.tabs button{border:0;background:none;padding:8px 16px;border-radius:8px;font-size:14px;font-weight:600;color:#6b7280;cursor:pointer;font-family:inherit}
.tabs button.on{background:#fff;color:var(--ink);box-shadow:var(--shadow)}
.cal{display:grid;grid-template-columns:repeat(7,1fr);gap:7px}
.cal .d{aspect-ratio:1;border-radius:8px;background:#eef0f6;display:grid;place-items:center;font-size:12px;color:#9aa1b1}
.cal .d.on{background:var(--primary);color:#fff;font-weight:700}.cal .d.mid{background:#c9d4ff;color:#33409a}
.spark{display:flex;align-items:flex-end;gap:8px;height:120px}
.spark i{flex:1;background:linear-gradient(180deg,#7a5cff,#4c6fff);border-radius:6px 6px 0 0}
.note{background:var(--primary-soft);border:1px solid #d5deff;color:#33409a;border-radius:12px;padding:12px 14px;font-size:13px}
.setrow{display:flex;align-items:center;justify-content:space-between;padding:16px 4px;border-bottom:1px solid var(--line)}
.tg{width:44px;height:26px;border-radius:999px;background:var(--primary);position:relative}
.tg::after{content:"";position:absolute;width:20px;height:20px;background:#fff;border-radius:50%;top:3px;right:3px}
.tg.off{background:#cfd4e2}.tg.off::after{right:auto;left:3px}
.wchip{display:inline-block;background:#f3f4f9;border:1px solid var(--line);border-radius:7px;padding:5px 9px;font-size:13px;margin:3px}
.lg{position:relative;display:inline-block;margin-top:6px;max-width:100%}
.lg-cells{display:flex;gap:8px;justify-content:center;flex-wrap:wrap}
.lg-cell{width:38px;height:50px;border:2px solid var(--line);border-radius:10px;display:grid;place-items:center;font-size:24px;font-weight:700;background:#fff}
.lg-cell.filled{border-color:#c9d4ff}
.lg-cell.active{border-color:var(--primary);box-shadow:0 0 0 3px var(--primary-soft)}
.lg-gap{width:14px}
.lg-input{position:absolute;inset:0;opacity:0;width:100%;height:100%;cursor:text;font-size:16px;border:0}

/* ---- v1.4 mobile-first components ---- */
.stat-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px}
.dashboard-grid,.stats-grid{display:grid;grid-template-columns:minmax(0,1.45fr) minmax(280px,.8fr);gap:16px;margin-top:16px}
.today-card,.review-card,.stats-panel,.settings-card{padding:20px}
.today-card>.btn,.review-card>.btn{width:100%;margin-top:14px}
.review-card p,.mode-card p,.section-head p,.done-card p,.settings-card p{color:var(--muted);font-size:13px;line-height:1.6;margin:6px 0}
.section-head{display:flex;align-items:flex-start;justify-content:space-between;gap:12px;margin-bottom:14px}
.section-head>b,.section-head b{font-size:16px}
.install-banner{display:flex;align-items:center;gap:12px;background:#fff7db;border:1px solid #f5d76e;border-radius:13px;padding:12px 14px;margin-bottom:16px;font-size:13px;color:#7c5700}
.install-banner span{flex:1}.install-banner button{border:0;background:none;color:#7c5700;font-weight:700}
.mode-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}
.mode-card{padding:18px;display:grid;grid-template-columns:auto 1fr;gap:10px;align-items:start}
.mode-card>.btn{grid-column:1/-1;width:100%}.mode-icon{font-size:26px}
.challenge-picker{padding:20px;margin-top:16px}
.group-card-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;margin-bottom:16px;max-height:48vh;overflow:auto}
.select-card{display:flex;align-items:center;gap:10px;padding:12px;border:1px solid var(--line);border-radius:11px;background:#fff;cursor:pointer}
.select-card input{width:20px;height:20px}.select-card span{display:flex;flex-direction:column;gap:3px}.select-card small{color:var(--muted)}
.question-card{padding:28px;text-align:center}.question-meta{display:flex;align-items:center;justify-content:center;gap:8px;margin-bottom:16px}
.meaning-prompt{font-size:clamp(22px,5vw,30px);font-weight:800;line-height:1.55;margin:16px 0}
.cloze-prompt{font-size:clamp(18px,4vw,23px);font-weight:650;line-height:1.75;margin:16px 0}
.question-hint{font-size:13px;color:var(--muted);margin:8px 0 18px}
.answer-input{font-size:20px;min-height:56px}.feedback{margin-top:14px;min-height:20px}.feedback .ok{color:var(--green);font-weight:750}.feedback .bad{color:var(--red);font-weight:750}
.answer-detail{border-top:1px dashed var(--line);margin-top:14px;padding-top:14px;display:grid;gap:7px;line-height:1.5}
.test-session>.btn{width:100%;margin-top:10px}.done-card,.empty-state{padding:38px;text-align:center;max-width:640px;margin:0 auto}.done-card>b{font-size:20px}.done-emoji{font-size:42px;margin-bottom:8px}
.flash-card{display:block;width:100%;padding:34px 24px;text-align:center;font-family:inherit;color:inherit;cursor:pointer}
.flash-back{margin-top:20px}.divider{border-top:1px dashed var(--line);margin-bottom:20px}.flash-meaning{font-size:clamp(18px,4vw,28px);font-weight:750;line-height:1.5}
.example{font-size:clamp(15px,2.8vw,20px);line-height:1.7;margin-top:14px;color:#555d70}.example small{display:block;color:var(--muted);margin-top:6px;font-size:clamp(14px,2.5vw,17px)}
.fp-pos{display:inline-block;font-size:15px;background:var(--amber-soft);color:#b45309;padding:3px 10px;border-radius:7px;font-weight:600;vertical-align:middle}
.update-banner{display:flex;align-items:center;justify-content:center;gap:12px;background:#33409a;color:#fff;font-size:14px;padding:10px 16px;text-align:center;z-index:500}
.update-banner button{background:#fff;color:#33409a;border:0;border-radius:8px;padding:6px 14px;font-weight:700;font-size:13px;cursor:pointer}
.flash-hint{margin-top:20px}.flash-actions{display:grid;grid-template-columns:1fr 1fr 1fr;gap:10px;margin-top:16px}.flash-session>#pause{width:100%;margin-top:10px}
.fp-pos{display:inline-block;font-size:15px;background:var(--amber-soft);color:#b45309;padding:3px 10px;border-radius:7px;font-weight:600;vertical-align:middle}
.settings-layout{display:grid;gap:16px;max-width:760px}.settings-card h2{font-size:17px;margin:0 0 8px}.settings-card .setrow small{display:block;color:var(--muted);margin-top:4px;line-height:1.45}
.mine-layout{display:grid;gap:26px;max-width:760px}
.mine-h{font-size:17px;margin:0 0 14px}
.learn-cta{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:16px 0 18px}
.learn-cta .btn{padding:15px 18px;font-size:16px}
@media (max-width:720px){.learn-cta{grid-template-columns:1fr}}
.compact-input{width:92px!important;padding:9px!important;font-size:16px!important}.switch-input{appearance:none;width:48px;height:28px;border-radius:999px;background:#cfd4e2;position:relative;transition:.2s;flex:none}
.switch-input:after{content:"";position:absolute;width:22px;height:22px;border-radius:50%;background:#fff;left:3px;top:3px;box-shadow:0 1px 4px #0002;transition:.2s}.switch-input:checked{background:var(--primary)}.switch-input:checked:after{transform:translateX(20px)}
.file-btn{position:relative;overflow:hidden}.file-btn input{position:absolute;inset:0;opacity:0}.danger-row b{color:var(--red)}.app-info{font-size:13px}
.version-card{display:flex;align-items:center;gap:14px;padding:14px;margin:12px 0;background:var(--primary-soft);border:1px solid #dbe2ff;border-radius:13px}.version-card>span:last-child{display:flex;flex-direction:column;gap:4px}.version-card small{color:var(--muted)}.version-badge{display:grid;place-items:center;min-width:76px;padding:10px 12px;border-radius:10px;background:var(--primary);color:#fff;font-size:17px;font-weight:800;letter-spacing:.3px}
.audio-unlock{position:fixed;right:18px;bottom:84px;z-index:1000;box-shadow:0 8px 28px #1f25502e}
.calendar-grid{display:grid;grid-template-columns:repeat(7,1fr);gap:7px}.calendar-day{aspect-ratio:1;border-radius:8px;background:#eef0f6;display:grid;place-items:center;font-size:11px;color:#9aa1b1}.calendar-day.on{background:var(--primary);color:#fff;font-weight:700}
.trend-chart{height:170px;display:flex;align-items:flex-end;gap:7px;padding-top:12px}.trend-col{height:100%;flex:1;display:flex;flex-direction:column;justify-content:flex-end;align-items:center;gap:5px}.trend-col i{display:block;width:100%;min-height:4px;background:linear-gradient(180deg,#7a5cff,#4c6fff);border-radius:5px 5px 2px 2px}.trend-col span{font-size:10px;color:var(--muted)}
.mobile-sticky{width:100%}

/* ---- 全屏模式: 隐藏 chrome, 内容纵向撑满, 按钮沉底 ---- */
body.fullscreen .sidebar, body.fullscreen .topbar { display: none !important; }
body.fullscreen .main { padding: 0 !important; }
body.fullscreen .wrap { padding: 0; max-width: none; margin: 0; height: 100dvh; display: flex; flex-direction: column; }
body.fullscreen .screen.on { display: flex; flex-direction: column; flex: 1; min-height: 0; }
body.fullscreen .screen.on .page-root { flex: 1; display: flex; flex-direction: column; min-height: 0; }
body.fullscreen .session { flex: 1; display: flex; flex-direction: column; min-height: 0; max-width: 720px; width: 100%; margin: 0 auto; padding: 12px 16px 0; }
body.fullscreen .test-session { padding-bottom: 8px; }
body.fullscreen .pgs { flex: none; padding: 8px 0; }
body.fullscreen .flash-card { flex: 1; display: flex; flex-direction: column; justify-content: center; align-items: center; padding: 24px 20px; overflow-y: auto; min-height: 0; }
body.fullscreen .wordbig { font-size: clamp(42px, 8vw, 72px) !important; }
body.fullscreen .wordbig + .ipa { font-size: clamp(16px, 3vw, 22px); }
body.fullscreen .flash-actions { flex: none; padding: 12px 0 20px; margin-top: 0; }
body.fullscreen .flash-session > #pause { flex: none; padding-bottom: 12px; }
body.fullscreen .question-card { flex: 1; display: flex; flex-direction: column; justify-content: center; overflow-y: auto; }
body.fullscreen .test-session > .btn { flex: none; }
.fs-btn { width: 34px; height: 34px; border-radius: 50%; background: var(--primary-soft); color: var(--primary); border: 0; font-size: 16px; cursor: pointer; display: inline-grid; place-items: center; line-height: 1; }
.fs-btn:hover { background: #dce5ff; }
@media (min-width: 901px) {
  body.fullscreen .flash-session { flex-direction: column; }
}
@media (max-width: 900px) {
  body.fullscreen .session { max-width: 100%; padding: 10px 12px 0; }
  body.fullscreen .flash-card { padding: 20px 14px; }
  body.fullscreen .flash-actions { padding: 12px 0 calc(8px + env(safe-area-inset-bottom)); }
}

/* ---- 触屏/平板 响应式(iPad 竖屏、手机) ---- */
@media (max-width: 900px) {
  .app { flex-direction: column; }
  .sidebar {
    position: fixed; left: 0; right: 0; bottom: 0; top: auto;
    width: 100%; height: auto; display:grid;grid-template-columns:repeat(4,minmax(0,1fr));overflow:hidden;
    border-right: 0; border-top: 1px solid var(--line);
    padding: 6px 4px calc(6px + env(safe-area-inset-bottom)); gap: 1px; z-index: 30;
    box-shadow: 0 -2px 12px rgba(20,30,60,.06);
  }
  .brand, .navlabel, .side-foot { display: none; }
  .nav { flex-direction: column; gap: 3px; font-size: 10px; padding: 6px 1px; min-width:0;text-align:center;white-space:nowrap;justify-content:center; }
  .nav .ic { width: auto; font-size: 19px; }
  .main { padding-bottom: calc(76px + env(safe-area-inset-bottom)); }
  .topbar { padding: calc(12px + env(safe-area-inset-top)) 16px 12px; position:sticky; }
  .wrap { padding: 16px; max-width:none; }
  .btn { padding: 15px 18px; font-size: 16px; }        /* 触屏更大 */
  .session { max-width: 100%; }
  .lg-cell { width: 34px; height: 46px; font-size: 22px; }
  .mode-grid,.dashboard-grid,.stats-grid{grid-template-columns:1fr}
  .group-card-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .stat-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .question-card{padding:24px 16px}.wordbig{font-size:clamp(36px,12vw,48px)}
  .mobile-sticky{position:sticky;bottom:calc(72px + env(safe-area-inset-bottom));z-index:10;box-shadow:0 8px 28px #1f243033}
  .rowlist{align-items:flex-start;flex-direction:column}.install-banner{align-items:flex-start;flex-wrap:wrap}
}
/* stat/组卡在窄屏两列 */
@media (max-width: 720px) {
  .grid[style*="repeat(4"] { grid-template-columns: repeat(2, 1fr) !important; }
  .grid[style*="1.6fr"], .grid[style*="1.2fr"] { grid-template-columns: 1fr !important; }
  .wordbig { font-size: 40px !important; }
  .streak{font-size:11px;padding:7px 10px}.topbar .sub{display:none}
  .flash-actions{grid-template-columns:1fr 1fr}.flash-actions #known{grid-column:1/-1;grid-row:1}.flash-actions #prev{grid-row:2}.flash-actions #unknown{grid-row:2}
  .section-head{flex-direction:column}.group-card-grid{grid-template-columns:1fr 1fr}
  .setrow{gap:12px}.settings-card{padding:16px}
}

@media (max-width:380px){.nav{font-size:9px}.nav .ic{font-size:17px}.group-card-grid{grid-template-columns:1fr}.stat .v{font-size:21px}}
@media (prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}

/* ---- 选组页: 左列表 + 右预览 ---- */
.pickwrap{display:flex;gap:18px;align-items:flex-start}
.grouplist{width:300px;flex:none;max-height:calc(100vh - 170px);overflow:auto;display:flex;flex-direction:column;gap:8px;padding-right:4px}
.grouprow{text-align:left;border:1px solid var(--line);background:#fff;border-radius:12px;padding:12px 14px;cursor:pointer;font-family:inherit}
.grouprow:hover{border-color:#c9d4ff}
.grouprow.active{border:2px solid var(--primary);background:var(--primary-soft)}
.gr-top{display:flex;justify-content:space-between;align-items:center}
.preview{flex:1;min-width:0;padding:22px;position:sticky;top:20px}
@media (max-width:900px){
  .pickwrap{flex-direction:column}
  .grouplist{width:100%;max-height:40vh;flex-direction:row;flex-wrap:nowrap;overflow-x:auto;padding-bottom:6px}
  .grouprow{min-width:150px;flex:none}
  .preview{position:static;width:100%}
}