:root{
  --bg:#f4f6fb; --surface:#ffffff; --surface2:#f0f2f7; --warm:#e8d8d8;
  --text:#1f2733; --muted:#7a8699; --border:#e6e9f0;
  --primary:#4f6ef7; --primary-d:#3b56d6; --primary-soft:#eaf0ff;
  --ok:#1faa6b; --ok-soft:#e6f7ef; --bad:#e5484d; --bad-soft:#fdecec;
  --warn:#e8a33d; --gold:#f0b429;
  --radius:14px; --shadow:0 6px 22px rgba(31,39,51,.08);
}
body.dark{
  --bg:#11151c; --surface:#1a2029; --surface2:#222a35; --warm:#2d2626;
  --text:#e8edf5; --muted:#8a97a8; --border:#2b3441;
  --primary:#6d86ff; --primary-d:#5570f0; --primary-soft:#1e2740;
  --ok:#36c98a; --ok-soft:#133024; --bad:#ff6b70; --bad-soft:#3a1f22;
  --shadow:0 6px 22px rgba(0,0,0,.4);
}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent;}
html,body{margin:0;padding:0;}
/* 移动端：禁用双击缩放/下拉刷新，避免误触 */
html,body{overscroll-behavior-y:none;-webkit-text-size-adjust:100%;}
body{background:var(--bg);color:var(--text);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;line-height:1.6;touch-action:manipulation;}
/* 交互元素：去除 300ms 点击延迟，避免误选中文字 */
.btn,.tab,.opt,.mode,.qitem,.switch,.sheet .cell,tab,summary{cursor:pointer;-webkit-user-select:none;user-select:none;}
/* iOS 输入框聚焦会触发整体放大，统一 16px 规避 */
input,select,textarea{font-size:16px;}
.font-s{font-size:14px;} .font-m{font-size:15px;} .font-l{font-size:17px;}
#app{max-width:600px;margin:0 auto;min-height:100vh;display:flex;flex-direction:column;background:var(--bg);position:relative;}

/* 顶部栏 */
.topbar{position:sticky;top:0;z-index:20;background:var(--surface);border-bottom:1px solid var(--border);padding:10px 14px;box-shadow:0 1px 0 rgba(0,0,0,.02);}
.topbar-row{display:flex;align-items:center;justify-content:space-between;gap:10px;}
.brand{font-weight:800;font-size:1.15em;letter-spacing:.5px;}
.subject-select{background:var(--surface2);color:var(--text);border:1px solid var(--border);border-radius:10px;padding:6px 10px;font-size:.95em;font-weight:600;max-width:55%;}

/* 视图 */
.view{flex:1;padding:14px 14px 84px;overflow-y:auto;overscroll-behavior:contain;-webkit-overflow-scrolling:touch;}

/* 底部导航 */
.tabbar{position:fixed;bottom:0;left:50%;transform:translateX(-50%);width:100%;max-width:600px;z-index:30;
  display:flex;background:var(--surface);border-top:1px solid var(--border);padding:4px 0 env(safe-area-inset-bottom);}
.tab{flex:1;background:none;border:none;color:var(--muted);display:flex;flex-direction:column;align-items:center;gap:2px;padding:6px 0;font-size:.72em;cursor:pointer;transition:.15s;}
.tab .ic{font-size:1.5em;line-height:1;}
.tab.active{color:var(--primary);font-weight:700;}

/* 通用卡片 */
.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:14px;margin-bottom:12px;box-shadow:var(--shadow);}
.card h3{margin:0 0 10px;font-size:1.02em;}
.cont-card{border-left:4px solid var(--primary);background:linear-gradient(90deg,color-mix(in srgb,var(--primary) 10%,var(--surface)),var(--surface));}
.cont-card:active{transform:scale(.99);}
.row{display:flex;align-items:center;gap:10px;}
.between{justify-content:space-between;}
.muted{color:var(--muted);}
.small{font-size:.85em;}
.wrap{display:flex;flex-wrap:wrap;gap:8px;}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;background:var(--primary);color:#fff;border:none;border-radius:12px;padding:12px 16px;font-size:1em;font-weight:700;cursor:pointer;transition:.15s;width:100%;}
.btn:active{transform:scale(.98);}
.btn.ghost{background:var(--surface2);color:var(--text);border:1px solid var(--border);}
.btn.soft{background:var(--primary-soft);color:var(--primary-d);}
.btn.sm{padding:8px 12px;font-size:.9em;width:auto;border-radius:10px;}
.btn:disabled{opacity:.5;cursor:not-allowed;}
.tag{display:inline-block;background:var(--surface2);color:var(--muted);border-radius:999px;padding:3px 10px;font-size:.78em;}
.tag.ok{background:var(--ok-soft);color:var(--ok);font-weight:700;}

/* 首页统计 */
.hero{background:linear-gradient(135deg,var(--primary),var(--primary-d));color:#fff;border-radius:var(--radius);padding:16px;margin-bottom:12px;box-shadow:var(--shadow);}
.hero .lv{font-size:.85em;opacity:.92;}
.hero .xpbar{height:8px;background:rgba(255,255,255,.3);border-radius:999px;margin-top:8px;overflow:hidden;}
.hero .xpbar>i{display:block;height:100%;background:#fff;border-radius:999px;}
.stat-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-bottom:12px;}
.stat{background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:12px;text-align:center;box-shadow:var(--shadow);}
.stat b{display:block;font-size:1.5em;color:var(--primary);}
.stat span{font-size:.78em;color:var(--muted);}

.mode-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;}
.mode{border:1px solid var(--border);border-radius:12px;padding:14px;background:var(--surface);box-shadow:var(--shadow);cursor:pointer;transition:.15s;}
.mode:active{transform:scale(.98);}
.mode .em{font-size:1.6em;}
.mode .t{font-weight:700;margin-top:4px;}
.mode .d{font-size:.8em;color:var(--muted);}

/* 章节列表 */
.chapter{padding:14px;}

/* 题库检索 */
.search{display:flex;gap:8px;margin-bottom:10px;}
.search input{flex:1;background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:11px 14px;color:var(--text);font-size:1em;}
.qitem{padding:12px 14px;border-bottom:1px solid var(--border);cursor:pointer;}
.qitem:last-child{border-bottom:none;}
.qitem .q{display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;}
.qitem .meta{display:flex;gap:8px;margin-top:6px;align-items:center;}

/* 章节进度条（顺序刷题·选章） */
.ch-prog{display:flex;align-items:center;gap:8px;margin-top:8px;}
.ch-prog-bar{flex:1;height:6px;background:var(--surface2);border-radius:3px;overflow:hidden;display:flex;}
.ch-prog-bar i{display:block;height:100%;}
.ch-prog .pct{font-size:.8em;font-weight:700;color:var(--muted);min-width:38px;text-align:right;}

/* 题目播放器 */
.player{position:fixed;inset:0;z-index:40;background:var(--bg);display:flex;flex-direction:column;max-width:600px;margin:0 auto;overscroll-behavior:contain;}
.player .phead{padding:12px 14px 0;border-bottom:1px solid var(--border);background:var(--surface);display:flex;flex-direction:column;gap:8px;}
.player .phead .phead-row{display:flex;align-items:center;justify-content:space-between;gap:8px;flex-wrap:wrap;}
.player .pbody{flex:1;overflow-y:auto;padding:16px 14px 130px;-webkit-overflow-scrolling:touch;touch-action:pan-y;}
.player .pfoot{position:fixed;bottom:0;left:50%;transform:translateX(-50%);width:100%;max-width:600px;background:var(--surface);border-top:1px solid var(--border);padding:12px 14px;padding-bottom:calc(12px + env(safe-area-inset-bottom));display:flex;gap:10px;z-index:41;}
.pbar{height:4px;background:var(--surface2);border-radius:2px;overflow:hidden;}
.pbar>i{display:block;height:100%;background:var(--primary);transition:width .25s;}
.swipe-hint{text-align:center;color:var(--muted);font-size:.74em;margin-top:20px;opacity:.7;}
.qstem{font-size:1.08em;font-weight:600;line-height:1.7;white-space:pre-wrap;-webkit-user-select:text;user-select:text;}
.qtype{display:flex;margin:2px 0 10px;}
.qtype .pill{font-size:.78em;padding:4px 12px;}
.pill-single{background:var(--primary-soft);color:var(--primary-d);}
.pill-multi{background:var(--ok-soft);color:var(--ok);}
.rv-hint{margin-top:10px;padding:9px 12px;background:var(--bad-soft);color:var(--bad);border-radius:10px;font-size:.9em;font-weight:600;}
.qimg{max-width:100%;border-radius:10px;margin:10px 0;border:1px solid var(--border);}
.opt{display:flex;gap:10px;align-items:flex-start;padding:14px;margin:10px 0;border:1.5px solid var(--border);border-radius:12px;background:var(--surface);cursor:pointer;transition:.12s;min-height:48px;}
.opt .k{flex:0 0 26px;height:26px;border-radius:50%;background:var(--surface2);display:flex;align-items:center;justify-content:center;font-weight:700;color:var(--muted);}
.opt .v{flex:1;}
.opt.sel{border-color:var(--primary);background:var(--primary-soft);}
.opt.correct{border-color:var(--ok);background:var(--ok-soft);}
.opt.correct .k{background:var(--ok);color:#fff;}
.opt.wrong{border-color:var(--bad);background:var(--bad-soft);}
.opt.wrong .k{background:var(--bad);color:#fff;}
.opt.dim{opacity:.55;}
.exp{margin-top:14px;padding:14px;background:var(--surface2);border-radius:12px;border-left:4px solid var(--primary);font-size:.95em;}
.exp h4{margin:0 0 6px;color:var(--primary-d);}
.exp b{color:var(--text);}
.ans-line{font-weight:800;margin:6px 0;}
.ans-line.ok{color:var(--ok);} .ans-line.bad{color:var(--bad);}
.q-actions{display:flex;gap:8px;margin-top:16px;flex-wrap:wrap;}
.chip{flex:1;min-width:84px;background:var(--surface2);color:var(--text);border:1px solid var(--border);border-radius:12px;padding:11px 10px;font-size:.92em;font-weight:700;cursor:pointer;transition:.15s;-webkit-user-select:none;user-select:none;display:inline-flex;align-items:center;justify-content:center;gap:4px;}
.chip:active{transform:scale(.97);}
.chip.on{background:var(--primary-soft);color:var(--primary-d);border-color:var(--primary);}

/* 答题卡 */
.sheet{display:grid;grid-template-columns:repeat(6,1fr);gap:8px;}
.sheet .cell{aspect-ratio:1;border-radius:10px;border:1px solid var(--border);display:flex;align-items:center;justify-content:center;font-weight:700;cursor:pointer;background:var(--surface);}
.sheet .cell.done{border-color:var(--primary);color:var(--primary-d);background:var(--primary-soft);}
.sheet .cell.wrong{border-color:var(--bad);color:var(--bad);background:var(--bad-soft);}
.sheet .cell.right{border-color:var(--ok);color:var(--ok);background:var(--ok-soft);}

/* 顺序刷题 · 章内题号导航（圆角正方形，与答题卡一致） */
.qnav-head{position:sticky;top:0;z-index:2;background:var(--surface);margin:-2px 0 6px;padding:2px 0 10px;border-bottom:1px solid var(--border);display:flex;align-items:center;gap:8px;}
.qnav-head .back{flex:0 0 auto;background:var(--surface2);border:1px solid var(--border);border-radius:10px;padding:7px 12px;font-weight:700;font-size:.92em;cursor:pointer;color:var(--text);-webkit-user-select:none;user-select:none;}
.qnav-head .back:active{transform:scale(.96);}
.qnav-head .ttl{flex:1;min-width:0;font-weight:800;font-size:1.02em;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;}
.qnav{display:grid;grid-template-columns:repeat(6,1fr);gap:10px;margin:14px 0;}
.qnav .qn{aspect-ratio:1;border-radius:12px;border:2px solid #2b313b;background:#fff;color:#222;
  display:flex;align-items:center;justify-content:center;font-weight:700;font-size:1em;
  cursor:pointer;transition:.12s;-webkit-user-select:none;user-select:none;line-height:1;padding:0;}
.qnav .qn:active{transform:scale(.92);}
.qnav .qn.correct{background:var(--ok);border-color:var(--ok);color:#fff;}
.qnav .qn.wrong{background:var(--bad);border-color:var(--bad);color:#fff;}
.qnav-legend{display:flex;gap:16px;justify-content:center;margin:2px 0 14px;font-size:.8em;color:var(--muted);flex-wrap:wrap;}
.qnav-legend span{display:flex;align-items:center;gap:5px;}
.qnav-legend .dot{width:13px;height:13px;border-radius:4px;display:inline-block;border:2px solid #2b313b;background:#fff;}
.qnav-legend .dot.ok{background:var(--ok);border-color:var(--ok);}
.qnav-legend .dot.bad{background:var(--bad);border-color:var(--bad);}

/* modal */
.modal{position:fixed;inset:0;z-index:50;background:rgba(0,0,0,.45);display:flex;align-items:center;justify-content:center;padding:18px;padding-bottom:calc(18px + env(safe-area-inset-bottom));}
.modal-box{background:var(--surface);border-radius:16px;max-width:560px;width:100%;max-height:86vh;overflow-y:auto;padding:18px;box-shadow:var(--shadow);-webkit-overflow-scrolling:touch;}
.modal-box h3{margin-top:0;}

/* 设置 */
.set-row{display:flex;align-items:center;justify-content:space-between;padding:12px 0;border-bottom:1px solid var(--border);}
.switch{width:48px;height:28px;border-radius:999px;background:var(--surface2);position:relative;cursor:pointer;transition:.2s;border:1px solid var(--border);}
.switch.on{background:var(--primary);}
.switch i{position:absolute;top:2px;left:2px;width:22px;height:22px;border-radius:50%;background:#fff;transition:.2s;box-shadow:0 1px 3px rgba(0,0,0,.2);}
.switch.on i{left:22px;}
input[type=range]{width:140px;}

/* 成就 / 徽章 */
.badge-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;}
.badge{background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:12px 8px;text-align:center;box-shadow:var(--shadow);}
.badge.locked{opacity:.45;filter:grayscale(1);}
.badge .em{font-size:1.8em;}
.badge .nm{font-weight:700;font-size:.85em;margin-top:4px;}
.badge .ds{font-size:.72em;color:var(--muted);}
canvas{max-width:100%;}

/* 历史成绩 */
.exam-item{padding:12px 14px;border-bottom:1px solid var(--border);}
.exam-item:last-child{border-bottom:none;}
.score-big{font-size:1.3em;font-weight:800;}

/* 刷题热度图 */
.heatmap{display:flex;justify-content:center;margin-top:10px;overflow-x:auto;-webkit-overflow-scrolling:touch;padding-bottom:4px;scrollbar-width:thin;}
.heatmap::-webkit-scrollbar{height:6px;}
.heatmap::-webkit-scrollbar-thumb{background:var(--border);border-radius:3px;}
.heatmap::-webkit-scrollbar-track{background:transparent;}
.hm-svg{display:block;max-width:100%;}
.hm-svg rect{transition:transform .12s,filter .12s;transform-box:fill-box;transform-origin:center;}
.hm-svg rect:hover{transform:scale(1.12);filter:brightness(.95);}
.hm-foot{display:flex;align-items:center;justify-content:space-between;gap:8px;margin-top:8px;font-size:.72em;color:var(--muted);}
.hm-legend{display:flex;align-items:center;gap:6px;color:var(--muted);}
.hm-legend i{width:13px;height:13px;border-radius:3px;display:inline-block;}
.toast{position:fixed;bottom:90px;left:50%;transform:translateX(-50%);z-index:90;background:rgba(31,39,51,.92);color:#fff;padding:10px 18px;border-radius:999px;font-size:.9em;box-shadow:var(--shadow);}

.hidden{display:none!important;}
.empty{text-align:center;color:var(--muted);padding:40px 10px;}
.section-title{font-weight:800;margin:6px 2px 10px;font-size:1.05em;}
.pill{font-size:.75em;background:var(--primary-soft);color:var(--primary-d);border-radius:999px;padding:2px 9px;font-weight:700;}
.pill-correct{background:var(--ok-soft);color:var(--ok);}
.pill-wrong{background:var(--bad-soft);color:var(--bad);}

/* ===== 新增组件（借鉴四六级备考台）===== */
.inp{background:var(--surface2);border:1px solid var(--border);border-radius:10px;padding:7px 10px;font-size:.95em;color:var(--text);}
.cols2{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-bottom:12px;}
.cols2 .card{margin-bottom:0;}
.cd-num{font-size:2.4em;font-weight:800;color:var(--primary);line-height:1.1;margin-top:8px;}
.cd-num span{font-size:.38em;margin-left:4px;color:var(--muted);font-weight:700;}
.ring{display:flex;align-items:center;gap:14px;margin-top:10px;}
.ring-c{display:flex;flex-direction:column;align-items:center;line-height:1.1;}
.ring-c b{font-size:1.7em;color:var(--primary);}
.ring-c span{font-size:.8em;color:var(--muted);}
.banner{background:#fff7e6;color:#7a5b16;border:1px solid #f3d9a0;border-radius:12px;padding:10px 12px;margin:10px 14px 0;font-size:.85em;display:flex;gap:8px;align-items:flex-start;line-height:1.5;}
.banner.hidden{display:none;}
.banner-x{margin-left:auto;background:none;border:none;color:inherit;font-size:1.1em;cursor:pointer;flex:0 0 auto;line-height:1;padding:0 2px;}
.tab{position:relative;}
.tab-dot{position:absolute;top:2px;right:calc(50% - 18px);min-width:16px;height:16px;padding:0 4px;border-radius:8px;background:var(--bad);color:#fff;font-size:10px;font-weight:800;display:none;align-items:center;justify-content:center;line-height:1;z-index:2;}
.card{animation:fadeUp .22s ease;}
@keyframes fadeUp{from{opacity:0;transform:translateY(8px);}to{opacity:1;transform:none;}}

/* ===== 云端账号同步 ===== */
.account-btn{margin-left:auto;background:var(--surface2);border:1px solid var(--border);border-radius:999px;padding:5px 12px;font-size:.82em;color:var(--text);cursor:pointer;white-space:nowrap;}
.account-btn:hover{border-color:var(--primary);}
.account-btn.is-guest{background:var(--primary);color:#fff;border-color:var(--primary);font-weight:700;}
.account-btn.is-guest:hover{filter:brightness(1.06);}
.account-card{border:1.5px solid var(--primary);background:var(--surface);box-shadow:0 2px 10px rgba(79,110,247,.12);}
.account-card .ac-row{display:flex;align-items:center;justify-content:space-between;gap:12px;}
.account-card .ac-meta{min-width:0;}

/* ===== 强制登录门禁 ===== */
.auth-gate{position:fixed;inset:0;z-index:9999;display:flex;align-items:center;justify-content:center;
  background:linear-gradient(160deg,#eef1ff,#f7f8ff);padding:20px;}
body.gated{overflow:hidden;}
.auth-card{width:100%;max-width:360px;background:var(--surface);border:1px solid var(--border);
  border-radius:18px;padding:26px 22px;box-shadow:0 14px 44px rgba(79,110,247,.20);}
.auth-brand{font-size:22px;font-weight:800;color:var(--primary);}
.auth-sub{margin:6px 0 18px;color:#6b7280;font-size:13px;line-height:1.5;}
.auth-card .am-tabs{display:flex;gap:8px;margin-bottom:14px;}
.auth-card .am-tabs .btn{flex:1;width:auto;}
.auth-card .inp{margin-bottom:12px;}
.auth-card #gMsg.min-h{min-height:18px;color:#e2562a;margin:2px 0 10px;font-size:12px;}
.auth-card .tiny{text-align:center;margin-top:12px;font-size:11px;color:#9ca3af;}
.auth-gate .g-tab.active{background:var(--primary);color:#fff;border-color:var(--primary);}

.account-card .ac-title{font-weight:700;margin-bottom:4px;color:var(--primary);}
.account-card .ac-avatar{font-size:1.7em;line-height:1;}
.account-card .ac-name{font-weight:700;}
.account-card.logged{border-color:var(--ok);box-shadow:0 2px 10px rgba(46,160,67,.1);}
.am-card{padding:18px 16px;}
.am-card h3{font-size:1.1em;}
.am-tabs{display:flex;gap:8px;margin-bottom:12px;}
.inp.block{width:100%;margin:8px 0;box-sizing:border-box;}
.btn.block{width:100%;margin-top:10px;}
.am-card .muted{margin:4px 0;}