/* ===== 基础变量 ===== */
:root{
  --bg:#f3f5fa;
  --surface:#ffffff;
  --surface-2:#f8f9fd;
  --ink:#161a2b;
  --ink-2:#3d4460;
  --muted:#6d7490;
  --line:#e6e9f3;
  --line-2:#eef0f8;
  --brand:#4356e8;
  --brand-2:#7a4dff;
  --brand-soft:#eef0ff;
  --ok:#0d9b63;
  --ok-soft:#e7f8f0;
  --bad:#dd474d;
  --bad-soft:#fdeeee;
  --warn:#c47a09;
  --warn-soft:#fdf5e4;
  --shadow:0 1px 2px rgba(20,30,70,.04), 0 8px 24px rgba(20,30,70,.05);
  --shadow-lg:0 24px 60px rgba(20,30,70,.16);
  --r-lg:18px;
  --r-md:12px;
  --r-sm:9px;

  /* 语义色：供深色模式整体覆盖 */
  --hover-line:#c3cbf0;
  --hover-line-2:#c9d0e8;
  --hover-bg:#fbfbff;
  --soft-bg:#f0f2ff;
  --track:#e8ebf5;
  --placeholder:#a6acc4;
  --faint:#9aa1ba;
  --code-bg:#f4f5fb;
  --code-ink:#424a6b;
  --ok-line:#c6ecdc;
  --bad-line:#f6cfd0;
  --warn-line:#f1e3c2;
  --inner-bg:rgba(255,255,255,.7);
  --inner-bg-2:rgba(255,255,255,.55);
  --tip-ink:#7a6023;
  --tag-topic-bg:#f4f1ff;
  --tag-topic-ink:#7050d8;
  --knob:#fff;
  --toast-bg:#1c2238;
  --toast-ink:#fff;

  /* 可调字号 */
  --stem-fs:16.5px;
  --opt-fs:14px;
  --fb-fs:13.5px;
}

*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  background:var(--bg);
  color:var(--ink);
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  font-size:14px;
  line-height:1.65;
  -webkit-font-smoothing:antialiased;
}
button{font-family:inherit;font-size:inherit;cursor:pointer}
input{font-family:inherit}
h1,h2,h3,h4,p{margin:0}

/* ===== 布局 ===== */
.app{display:flex;min-height:100vh}

.sidebar{
  width:272px;flex:0 0 272px;
  background:var(--surface);
  border-right:1px solid var(--line);
  height:100vh;position:sticky;top:0;
  overflow-y:auto;
  padding:22px 16px 18px;
  display:flex;flex-direction:column;gap:22px;
}
.sidebar::-webkit-scrollbar{width:6px}
.sidebar::-webkit-scrollbar-thumb{background:var(--track);border-radius:3px}

.main{flex:1;min-width:0;padding:0 26px 48px}

/* ===== 品牌 ===== */
.brand{display:flex;align-items:center;gap:11px;padding:2px 6px 0}
.logo{width:38px;height:38px;display:grid;place-items:center;border-radius:12px;background:linear-gradient(140deg,#eef0ff,#f6eeff)}
.brand-txt h1{font-size:15.5px;font-weight:700;letter-spacing:.2px}
.brand-txt p{font-size:11.5px;color:var(--muted);letter-spacing:.4px}

/* ===== 模式导航 ===== */
.mode-nav{display:flex;flex-direction:column;gap:3px}
.mode-item{
  display:flex;align-items:center;gap:10px;
  padding:9px 11px;border:0;border-radius:10px;background:transparent;
  color:var(--ink-2);text-align:left;width:100%;
  transition:background .16s,color .16s;
}
.mode-item:hover{background:var(--surface-2)}
.mode-item.on{background:var(--brand-soft);color:var(--brand);font-weight:600}
.mode-item .mi-ico{width:18px;display:grid;place-items:center;opacity:.9}
.mode-item .mi-txt{flex:1;font-size:13.5px}
.mode-item .mi-num{font-size:11.5px;color:var(--muted);font-variant-numeric:tabular-nums}
.mode-item.on .mi-num{color:var(--brand)}

/* ===== 侧栏区块 ===== */
.side-block{display:flex;flex-direction:column;gap:9px}
.side-hd{
  display:flex;align-items:center;justify-content:space-between;
  font-size:11px;font-weight:700;letter-spacing:1.2px;color:var(--faint);
  text-transform:uppercase;padding:0 6px;
}
.mini-link{
  border:0;background:none;color:var(--muted);font-size:11.5px;padding:0;
  letter-spacing:0;
}
.mini-link:hover{color:var(--brand)}

.cat-list{display:flex;flex-direction:column;gap:2px}
.cat-item{
  display:flex;align-items:center;gap:8px;border:0;background:none;
  padding:7px 9px;border-radius:9px;color:var(--ink-2);text-align:left;
  font-size:13px;transition:background .15s;
}
.cat-item:hover{background:var(--surface-2)}
.cat-item.on{background:var(--soft-bg);color:var(--brand);font-weight:600}
.cat-dot{width:7px;height:7px;border-radius:50%;flex:0 0 auto}
.cat-name{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.cat-num{font-size:11.5px;color:var(--muted);font-variant-numeric:tabular-nums}
.cat-item.on .cat-num{color:var(--brand)}

.chips{display:flex;flex-wrap:wrap;gap:6px;padding:0 4px}
.chip{
  border:1px solid var(--line);background:var(--surface);
  color:var(--ink-2);font-size:12px;padding:4px 10px;border-radius:999px;
  transition:all .15s;
}
.chip:hover{border-color:var(--hover-line)}
.chip.on{background:var(--brand);border-color:var(--brand);color:#fff;font-weight:600}

/* 开关 */
.side-switch{gap:11px}
.switch-row{display:flex;align-items:center;gap:9px;cursor:pointer;padding:0 6px;font-size:12.5px;color:var(--ink-2)}
.switch-row input{display:none}
.switch-track{
  width:32px;height:18px;border-radius:999px;background:var(--track);position:relative;
  transition:background .18s;flex:0 0 auto;
}
.switch-dot{
  position:absolute;top:2px;left:2px;width:14px;height:14px;border-radius:50%;
  background:var(--knob);box-shadow:0 1px 3px rgba(0,0,0,.18);transition:transform .18s;
}
.switch-row input:checked + .switch-track{background:var(--brand)}
.switch-row input:checked + .switch-track .switch-dot{transform:translateX(14px)}

/* 侧栏快捷入口：手机访问 / 导出导入 */
.side-shortcuts{
  display:grid;grid-template-columns:1fr 1fr;gap:6px;margin-top:-7px;
}
.shortcut-btn{
  display:flex;align-items:center;justify-content:center;gap:4px;
  height:29px;padding:0 5px;border-radius:8px;
  border:1px solid var(--line);background:var(--surface-2);
  color:var(--ink-2);font-size:11.5px;font-weight:500;
  white-space:nowrap;transition:all .15s;
}
.shortcut-btn svg{opacity:.68;flex:0 0 auto}
.shortcut-btn:hover{border-color:var(--brand);color:var(--brand);background:var(--brand-soft)}
.shortcut-btn:hover svg{opacity:1}

/* 侧栏统计 */
.side-foot{
  margin-top:auto;border-top:1px solid var(--line-2);padding-top:14px;
  display:grid;grid-template-columns:1fr 1fr;gap:9px 6px;
}
.stat-cell{padding:2px 6px}
.stat-cell b{display:block;font-size:16px;font-weight:700;font-variant-numeric:tabular-nums}
.stat-cell span{font-size:11px;color:var(--muted)}

/* ===== 顶栏 ===== */
.topbar{
  position:sticky;top:0;z-index:20;
  display:flex;align-items:center;gap:14px;
  padding:20px 0 14px;
  background:linear-gradient(var(--bg) 76%,rgba(243,245,250,0));
}
.topbar-title h2{font-size:19px;font-weight:700;letter-spacing:.2px}
.topbar-title p{font-size:12px;color:var(--muted);margin-top:1px}
.top-actions{margin-left:auto;display:flex;align-items:center;gap:9px}

.search{position:relative;display:flex;align-items:center}
.search-ico{position:absolute;left:11px;color:var(--faint);pointer-events:none}
.search input{
  width:230px;height:36px;border-radius:10px;border:1px solid var(--line);
  background:var(--surface);padding:0 12px 0 33px;font-size:12.5px;color:var(--ink);
  outline:none;transition:border-color .15s,box-shadow .15s;
}
.search input::placeholder{color:var(--placeholder)}
.search input:focus{border-color:#b9c2f5;box-shadow:0 0 0 3px rgba(67,86,232,.1)}

.primary-btn{
  height:36px;padding:0 15px;border-radius:10px;border:0;
  background:linear-gradient(135deg,#4a5cf0,#6a4dff);color:#fff;
  font-size:12.5px;font-weight:600;letter-spacing:.2px;
  box-shadow:0 4px 14px rgba(80,86,232,.24);
  transition:transform .12s,box-shadow .16s;
}
.primary-btn:hover{transform:translateY(-1px);box-shadow:0 6px 18px rgba(80,86,232,.3)}
.primary-btn:active{transform:translateY(0)}
.primary-btn[disabled]{opacity:.5;cursor:not-allowed;transform:none;box-shadow:none}

.ghost-btn{
  height:36px;padding:0 13px;border-radius:10px;border:1px solid var(--line);
  background:var(--surface);color:var(--ink-2);font-size:12.5px;
  transition:border-color .15s,color .15s;
}
.ghost-btn:hover{border-color:var(--hover-line-2);color:var(--ink)}
.danger-btn{
  height:36px;padding:0 16px;border-radius:10px;border:0;
  background:var(--bad);color:#fff;font-size:12.5px;font-weight:600;
}
.danger-btn:hover{filter:brightness(1.06)}

.icon-btn{
  width:36px;height:36px;border-radius:10px;border:1px solid var(--line);
  background:var(--surface);color:var(--ink-2);display:grid;place-items:center;flex:0 0 auto;
}

/* ===== 进度条 ===== */
.progress-strip{padding:0 0 16px}
.progress-bar{height:5px;border-radius:99px;background:var(--track);overflow:hidden}
.progress-bar span{
  display:block;height:100%;width:0;border-radius:99px;
  background:linear-gradient(90deg,#4a5cf0,#8a4dff);
  transition:width .3s ease;
}
.progress-meta{
  display:flex;align-items:center;gap:7px;margin-top:7px;
  font-size:11.5px;color:var(--muted);font-variant-numeric:tabular-nums;
}
.dot-sep{opacity:.5}
.grow{flex:1}
.exam-timer{
  font-weight:700;color:var(--warn);background:var(--warn-soft);
  padding:2px 9px;border-radius:99px;letter-spacing:.5px;
}
.exam-timer.urgent{color:var(--bad);background:var(--bad-soft)}

/* ===== 工作区 ===== */
.workspace{
  display:grid;grid-template-columns:minmax(0,1fr) 286px;
  gap:20px;align-items:start;
}

/* ===== 题卡 ===== */
.stage{min-width:0}
.qcard{
  background:var(--surface);border:1px solid var(--line);border-radius:var(--r-lg);
  box-shadow:var(--shadow);padding:26px 28px 22px;
}

.qhead{display:flex;align-items:flex-start;gap:12px;margin-bottom:16px}
.tags{display:flex;flex-wrap:wrap;gap:6px;flex:1}
.tag{
  font-size:11px;line-height:1;padding:5px 9px;border-radius:6px;
  background:var(--surface-2);color:var(--muted);border:1px solid var(--line-2);
  letter-spacing:.2px;white-space:nowrap;
}
.tag.cat{background:var(--brand-soft);color:var(--brand);border-color:transparent;font-weight:600}
.tag.d1{background:var(--ok-soft);color:var(--ok);border-color:transparent}
.tag.d2{background:var(--warn-soft);color:var(--warn);border-color:transparent}
.tag.d3{background:var(--bad-soft);color:var(--bad);border-color:transparent}
.tag.topic{background:var(--tag-topic-bg);color:var(--tag-topic-ink);border-color:transparent}
.qno{font-size:11.5px;color:var(--placeholder);font-variant-numeric:tabular-nums;white-space:nowrap;padding-top:3px}

.stem{
  font-size:var(--stem-fs);font-weight:600;line-height:1.62;letter-spacing:.1px;
  color:var(--ink);margin-bottom:20px;word-break:break-word;
}
.stem code, .opt-txt code{
  font-family:"SFMono-Regular",Consolas,"Liberation Mono",monospace;
  background:var(--code-bg);border:1px solid var(--line-2);border-radius:5px;
  padding:1px 5px;font-size:.9em;color:var(--code-ink);
}

/* 上次作答记录提示（刷新/切换后回到已答过的题） */
.q-restored{
  display:inline-block;margin:-10px 0 14px;padding:5px 10px;border-radius:8px;
  border:1px dashed var(--line);background:var(--surface-2);
  font-size:11.5px;line-height:1.5;color:var(--muted);
}

/* 选项 */
.options{display:flex;flex-direction:column;gap:9px}
.opt{
  display:flex;align-items:flex-start;gap:12px;width:100%;text-align:left;
  padding:13px 15px;border-radius:var(--r-md);
  border:1.5px solid var(--line);background:var(--surface);
  color:var(--ink-2);font-size:var(--opt-fs);line-height:1.55;
  transition:border-color .14s,background .14s,transform .1s;
}
.opt:hover{border-color:var(--hover-line);background:var(--hover-bg)}
.opt:active{transform:scale(.997)}
.opt .key{
  flex:0 0 auto;width:24px;height:24px;border-radius:7px;
  display:grid;place-items:center;font-size:12px;font-weight:700;
  background:var(--surface-2);color:var(--muted);border:1px solid var(--line);
  transition:all .14s;font-variant-numeric:tabular-nums;
}
.opt .opt-txt{flex:1;padding-top:1px;word-break:break-word}
.opt.selected{border-color:var(--brand);background:var(--brand-soft)}
.opt.selected .key{background:var(--brand);border-color:var(--brand);color:#fff}
.opt.correct{border-color:var(--ok);background:var(--ok-soft)}
.opt.correct .key{background:var(--ok);border-color:var(--ok);color:#fff}
.opt.wrong{border-color:var(--bad);background:var(--bad-soft)}
.opt.wrong .key{background:var(--bad);border-color:var(--bad);color:#fff}
.opt.dim{opacity:.62}
.opt[disabled]{cursor:default}
.opt[disabled]:hover{border-color:var(--line);background:var(--surface)}
.opt.correct[disabled]:hover{border-color:var(--ok);background:var(--ok-soft)}
.opt.wrong[disabled]:hover{border-color:var(--bad);background:var(--bad-soft)}
.opt.selected[disabled]:hover{border-color:var(--brand);background:var(--brand-soft)}
.opt .mark{margin-left:auto;font-size:15px;font-weight:700;flex:0 0 auto;padding-top:1px}

/* 反馈 */
.feedback{margin-top:18px;border-radius:var(--r-md);overflow:hidden;border:1px solid transparent}
.feedback.ok{background:var(--ok-soft);border-color:var(--ok-line)}
.feedback.bad{background:var(--bad-soft);border-color:var(--bad-line)}
.fb-head{display:flex;align-items:center;gap:9px;padding:11px 15px;font-size:13.5px;font-weight:700}
.feedback.ok .fb-head{color:var(--ok)}
.feedback.bad .fb-head{color:var(--bad)}
.fb-badge{
  width:20px;height:20px;border-radius:50%;display:grid;place-items:center;
  color:#fff;font-size:12px;line-height:1;flex:0 0 auto;
}
.feedback.ok .fb-badge{background:var(--ok)}
.feedback.bad .fb-badge{background:var(--bad)}
.fb-right{margin-left:auto;font-weight:500;font-size:12px;color:var(--ink-2);opacity:.85}

.fb-body{padding:0 15px 15px;font-size:var(--fb-fs);color:var(--ink-2);line-height:1.75}
.fb-answer{
  display:inline-flex;align-items:center;gap:6px;
  background:var(--inner-bg);border-radius:7px;padding:4px 10px;
  font-size:12.5px;font-weight:700;margin-bottom:10px;color:var(--ink);
}
.fb-row{display:flex;gap:9px;margin-top:10px}
.fb-row .k{
  flex:0 0 auto;font-size:11px;font-weight:700;letter-spacing:.5px;
  color:#fff;border-radius:5px;padding:2px 7px;height:20px;line-height:16px;margin-top:2px;
}
.fb-row.exp .k{background:#6b7bd6}
.fb-row.tip .k{background:#b48a3a}
.fb-row .v{flex:1;color:var(--ink-2)}
.fb-row .v b{color:var(--ink);font-weight:700}
.fb-row.tip .v{color:var(--tip-ink)}
.fb-row.tip{background:var(--inner-bg-2);border-radius:8px;padding:8px 10px}

/* 考试/多选提示条 */
.exam-hint{
  margin-top:16px;padding:10px 14px;border-radius:var(--r-md);
  background:var(--surface-2);border:1px dashed var(--line);
  font-size:12.5px;color:var(--muted);line-height:1.6;
}

/* ===== 面试题（开放题） ===== */
.tag.open{background:var(--brand-soft);color:var(--brand)}
.ref-card{
  margin-top:18px;border:1px solid var(--line);border-radius:var(--r-md);
  background:var(--surface-2);padding:14px 16px 2px;
  animation:cardIn .22s ease;
}
.ref-hd{display:flex;align-items:center;gap:9px;flex-wrap:wrap}
.ref-badge{
  font-size:11px;font-weight:700;letter-spacing:.5px;color:#fff;
  background:linear-gradient(135deg,#4a5cf0,#6a4dff);border-radius:5px;padding:3px 8px;
}
.ref-sub{font-size:11.5px;color:var(--muted)}
.ref-list{
  list-style:none;counter-reset:ref;margin:12px 0 4px;padding:0;
}
.ref-list li{
  position:relative;counter-increment:ref;
  padding:5px 0 5px 26px;font-size:13.5px;line-height:1.72;color:var(--ink-2);
}
.ref-list li::before{
  content:counter(ref);position:absolute;left:0;top:8px;
  width:17px;height:17px;border-radius:50%;background:var(--brand-soft);color:var(--brand);
  font-size:10.5px;font-weight:700;display:grid;place-items:center;
  font-variant-numeric:tabular-nums;
}
.ref-list li b{color:var(--ink);font-weight:700}
.ref-ask{
  margin:10px 0 2px;padding:9px 12px;border-radius:8px;
  background:var(--warn-soft);border:1px solid var(--warn-line);
  font-size:12.5px;line-height:1.7;color:var(--tip-ink);
}
.ref-ask b{color:var(--warn);margin-right:6px}
.self-check{
  display:flex;align-items:center;gap:8px;flex-wrap:wrap;
  margin-top:12px;padding:12px 0 12px;border-top:1px dashed var(--line);
}
.self-check .sc-hint{font-size:12px;color:var(--muted);margin-right:auto}
.sc-btn{
  height:32px;padding:0 14px;border-radius:9px;border:1px solid var(--line);
  background:var(--surface);color:var(--ink-2);font-size:12.5px;
  transition:border-color .15s,color .15s,background .15s;
}
.sc-btn.ok:hover:not([disabled]){border-color:var(--ok-line);color:var(--ok);background:var(--ok-soft)}
.sc-btn.bad:hover:not([disabled]){border-color:var(--bad-line);color:var(--bad);background:var(--bad-soft)}
.sc-btn[disabled]{opacity:.45;cursor:default}

/* 底部操作 */
.qfoot{display:flex;align-items:center;gap:10px;margin-top:20px;padding-top:16px;border-top:1px dashed var(--line)}
.qfoot .left{display:flex;gap:8px}
.fav-btn{
  height:34px;padding:0 12px;border-radius:9px;border:1px solid var(--line);
  background:var(--surface);color:var(--muted);font-size:12.5px;display:flex;align-items:center;gap:6px;
}
.fav-btn:hover{border-color:var(--warn-line);color:var(--warn)}
.fav-btn.on{background:var(--warn-soft);border-color:var(--warn-line);color:var(--warn);font-weight:600}
.qnav{margin-left:auto;display:flex;gap:8px;align-items:center}
.nav-btn{
  height:34px;min-width:76px;padding:0 14px;border-radius:9px;
  border:1px solid var(--line);background:var(--surface);color:var(--ink-2);font-size:12.5px;
  transition:border-color .15s,color .15s;
}
.nav-btn:hover:not([disabled]):not(.main){border-color:var(--hover-line-2);color:var(--ink)}
.nav-btn[disabled]{opacity:.42;cursor:not-allowed}
.nav-btn.primary{
  background:linear-gradient(135deg,#4a5cf0,#6a4dff);border:0;color:#fff;font-weight:600;
  box-shadow:0 4px 12px rgba(80,86,232,.22);min-width:92px;
  /* 主按钮只过渡背景与阴影：过渡 color 会让文字在合成层里叠印出重影 */
  transition:box-shadow .18s ease,background-color .18s ease;
}
.nav-btn.primary:hover:not([disabled]){
  color:#fff;background:linear-gradient(135deg,#5566f6,#7558ff);
  box-shadow:0 6px 16px rgba(80,86,232,.3);
}
.nav-btn.primary:active:not([disabled]){transform:translateY(1px)}

/* 空状态 */
.empty{
  background:var(--surface);border:1px solid var(--line);border-radius:var(--r-lg);
  padding:64px 30px;text-align:center;box-shadow:var(--shadow);
}
.empty .em-ico{font-size:34px;opacity:.5;margin-bottom:12px}
.empty h3{font-size:15px;margin-bottom:6px}
.empty p{font-size:12.5px;color:var(--muted);margin-bottom:18px}

/* ===== 答题卡 ===== */
.sheet{
  background:var(--surface);border:1px solid var(--line);border-radius:var(--r-lg);
  box-shadow:var(--shadow);padding:16px;position:sticky;top:76px;
}
.sheet.collapsed .sheet-grid,.sheet.collapsed .sheet-legend,.sheet.collapsed .sheet-summary{display:none}
.sheet-hd{
  display:flex;align-items:center;justify-content:space-between;
  font-size:12.5px;font-weight:700;color:var(--ink-2);margin-bottom:12px;
}
.sheet-grid{
  display:grid;grid-template-columns:repeat(6,1fr);gap:6px;
  max-height:340px;overflow-y:auto;padding-right:2px;
}
.sheet-grid::-webkit-scrollbar{width:5px}
.sheet-grid::-webkit-scrollbar-thumb{background:var(--track);border-radius:3px}
.cell{
  aspect-ratio:1/1;border-radius:7px;border:1px solid var(--line);
  background:var(--surface-2);color:var(--muted);font-size:12px;
  display:grid;place-items:center;position:relative;
  font-variant-numeric:tabular-nums;transition:all .13s;
}
.cell:hover{border-color:var(--hover-line);color:var(--ink)}
.cell.done{background:var(--soft-bg);border-color:var(--brand-soft);color:var(--brand)}
.cell.ok{background:var(--ok-soft);border-color:var(--ok-line);color:var(--ok);font-weight:600}
.cell.bad{background:var(--bad-soft);border-color:var(--bad-line);color:var(--bad);font-weight:600}
.cell.cur{outline:2px solid var(--brand);outline-offset:1px;font-weight:700;border-color:var(--brand)}
.cell .fav-dot{
  position:absolute;top:2px;right:3px;width:5px;height:5px;border-radius:50%;
  background:#e0a72c;
}
.sheet-legend{
  display:flex;flex-wrap:wrap;gap:9px 12px;margin-top:13px;
  font-size:10.5px;color:var(--muted);
}
.sheet-legend span{display:flex;align-items:center;gap:5px}
.lg{width:8px;height:8px;border-radius:3px;display:inline-block}
.lg.cur{background:#dfe3ff;border:1px solid var(--brand)}
.lg.ok{background:var(--ok-soft);border:1px solid var(--ok-line)}
.lg.bad{background:var(--bad-soft);border:1px solid var(--bad-line)}
.lg.fav{background:#e0a72c;border-radius:50%}
.sheet-summary{
  margin-top:12px;padding-top:12px;border-top:1px solid var(--line-2);
  font-size:11.5px;color:var(--muted);line-height:1.7;
}
.sheet-summary b{color:var(--ink);font-weight:600}

/* ===== 弹窗 ===== */
.backdrop{
  position:fixed;inset:0;background:rgba(20,26,50,.4);backdrop-filter:blur(2px);
  opacity:0;pointer-events:none;transition:opacity .18s;z-index:60;
}
.backdrop.on{opacity:1;pointer-events:auto}
.modal-wrap{
  position:fixed;inset:0;display:grid;place-items:center;z-index:61;padding:20px;
  pointer-events:none;
}
.modal-wrap[hidden]{display:none}
.modal{
  width:min(520px,100%);background:var(--surface);border-radius:20px;
  box-shadow:var(--shadow-lg);padding:26px;pointer-events:auto;
  animation:modalIn .2s ease;max-height:86vh;overflow-y:auto;
}
@keyframes modalIn{from{opacity:0;transform:translateY(10px) scale(.98)}to{opacity:1;transform:none}}
.modal h3{font-size:18px;font-weight:700;margin-bottom:5px}
.modal .m-sub{font-size:12.5px;color:var(--muted);margin-bottom:18px}
.modal-actions{display:flex;gap:9px;justify-content:flex-end;margin-top:22px;flex-wrap:wrap}

/* 手机访问面板 */
.dev-list{display:flex;flex-direction:column;gap:7px;margin:4px 0 0}
.dev-addr{
  display:flex;align-items:center;justify-content:space-between;gap:10px;
  padding:10px 12px;border:1px solid var(--line);border-radius:10px;
  background:var(--surface-2);color:var(--ink);
  font-family:ui-monospace,SFMono-Regular,Consolas,"Courier New",monospace;
  font-size:13px;letter-spacing:.2px;text-align:left;
  transition:all .15s;
}
.dev-addr:hover{border-color:var(--brand);background:var(--brand-soft)}
.dev-addr i{font-style:normal;font-size:11px;color:var(--muted);font-family:inherit;flex:0 0 auto}
.dev-addr:hover i{color:var(--brand)}
.dev-hint{
  margin-top:12px;padding:10px 12px;border-radius:10px;
  background:var(--warn-soft);color:var(--tip-ink);font-size:12px;line-height:1.7;
}
.dev-hint b{color:var(--warn)}
.dev-steps{margin:14px 0 0;padding-left:17px;font-size:12.5px;color:var(--ink-2);line-height:1.85}
.dev-steps li::marker{color:var(--brand);font-weight:700}
.dev-steps code{
  font-family:ui-monospace,SFMono-Regular,Consolas,monospace;
  background:var(--surface-2);border:1px solid var(--line-2);
  padding:1px 5px;border-radius:5px;font-size:11.5px;color:var(--ink);
}
.dev-note{
  margin-top:9px;padding:9px 12px;border-radius:10px;
  background:var(--surface-2);border:1px dashed var(--line);
  color:var(--muted);font-size:11.5px;line-height:1.7;
}
.dev-note b{color:var(--ink-2)}

/* 导入进度摘要 */
.msum{display:flex;flex-direction:column;gap:0;margin:2px 0 0;font-size:13px}
.msum div{
  display:flex;align-items:baseline;justify-content:space-between;gap:12px;
  padding:9px 0;border-bottom:1px solid var(--line-2);
}
.msum div:last-child{border-bottom:0}
.msum span{color:var(--muted);font-size:12.5px}
.msum b{font-weight:700;font-variant-numeric:tabular-nums;color:var(--ink)}
.msum b em{font-style:normal;font-weight:500;font-size:11.5px;color:var(--ok);margin-left:5px}
.msum b em.zero{color:var(--muted)}

.score-hero{display:flex;align-items:center;gap:20px;margin:6px 0 18px}
.ring{
  --p:0;--rc:#4a5cf0;
  width:104px;height:104px;border-radius:50%;flex:0 0 auto;
  background:conic-gradient(var(--rc) calc(var(--p)*1%),var(--track) 0);
  display:grid;place-items:center;position:relative;
}
.ring.good{--rc:#0d9b63}
.ring.mid{--rc:#d3891a}
.ring.low{--rc:#dd474d}
.ring::after{content:"";position:absolute;inset:9px;background:var(--surface);border-radius:50%}
.ring-txt{position:relative;z-index:1;text-align:center;line-height:1.15}
.ring-txt b{font-size:26px;font-weight:800;letter-spacing:-.5px}
.ring.good .ring-txt b{color:var(--ok)}
.ring.mid .ring-txt b{color:var(--warn)}
.ring.low .ring-txt b{color:var(--bad)}
.ring-txt span{display:block;font-size:10.5px;color:var(--muted);letter-spacing:1px}
.score-meta{flex:1}
.score-meta .sm-row{display:flex;justify-content:space-between;font-size:12.5px;color:var(--muted);padding:4px 0}
.score-meta .sm-row b{color:var(--ink);font-weight:700}
.bars{display:flex;flex-direction:column;gap:9px;margin-top:4px}
.bar-row{font-size:12px}
.bar-row .bl{display:flex;justify-content:space-between;color:var(--muted);margin-bottom:4px}
.bar-row .bt{height:5px;border-radius:99px;background:var(--track);overflow:hidden}
.bar-row .bf{height:100%;border-radius:99px;background:linear-gradient(90deg,#4a5cf0,#8a4dff)}

/* ===== 提示 ===== */
.kbd-hint{
  display:flex;align-items:center;justify-content:flex-start;gap:4px;flex-wrap:wrap;
  margin:18px 0 0 4px;font-size:11px;color:var(--faint);user-select:none;
}
.kbd-hint kbd{
  font-family:inherit;font-size:10.5px;line-height:1;
  padding:3px 6px;border-radius:5px;background:var(--surface);color:var(--muted);
  border:1px solid var(--line);box-shadow:0 1px 0 var(--line);
}
.kbd-hint i{font-style:normal;margin:0 5px;opacity:.5}

.toast{
  position:fixed;left:50%;bottom:34px;transform:translate(-50%,14px);
  background:var(--toast-bg);color:var(--toast-ink);font-size:12.5px;padding:9px 16px;border-radius:10px;
  opacity:0;pointer-events:none;transition:all .22s;z-index:80;
  box-shadow:0 10px 30px rgba(10,16,40,.28);
}
.toast.on{opacity:1;transform:translate(-50%,0)}

/* ===== 响应式 ===== */
.only-mobile{display:none}

@media (max-width:1180px){
  .workspace{grid-template-columns:minmax(0,1fr)}
  /* 悬浮答题卡会盖住底部内容，给主区域留出安全区 */
  .main{padding-bottom:104px}
  .sheet{position:fixed;top:auto;right:16px;bottom:16px;width:286px;z-index:50;
    box-shadow:0 18px 50px rgba(20,30,70,.18);max-height:70vh;overflow-y:auto}
  .sheet-hd{cursor:pointer}
}
@media (max-width:900px){
  .sidebar{position:fixed;left:0;top:0;z-index:55;transform:translateX(-100%);
    transition:transform .22s ease;box-shadow:0 0 40px rgba(10,16,40,.16)}
  .sidebar.open{transform:none}
  .main{padding:0 16px calc(108px + env(safe-area-inset-bottom,0px))}
  .only-mobile{display:grid}
  .search input{width:150px}
  .topbar-title p{display:none}
  .primary-btn,.ghost-btn{padding:0 11px;font-size:12px}
  #resetBtn{display:none}
}
@media (max-width:620px){
  .qcard{padding:20px 16px 18px;border-radius:14px}
  .stem{font-size:calc(var(--stem-fs) - 1px)}
  .opt{padding:11px 12px;font-size:calc(var(--opt-fs) - .5px)}
  /* 搜索框在窄屏改为点击放大镜后从顶栏下方展开，避免顶栏被挤爆 */
  .top-actions .search{
    position:absolute;left:0;right:0;top:100%;
    padding:0 0 12px;background:var(--bg);
    opacity:0;pointer-events:none;transform:translateY(-8px);
    transition:opacity .16s ease,transform .16s ease;z-index:6;
  }
  .topbar.searching .top-actions .search{opacity:1;pointer-events:auto;transform:none}
  .top-actions .search input{width:100%}
  .topbar-title{min-width:0}
  .topbar-title h2{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
  .qfoot{flex-wrap:wrap}
  .qnav{width:100%;margin-left:0}
  .nav-btn{flex:1;min-width:0}
  .sheet{right:10px;bottom:calc(10px + env(safe-area-inset-bottom,0px));left:10px;width:auto;max-height:56vh;border-radius:16px}
  .sheet-grid{grid-template-columns:repeat(8,1fr)}
}

/* ===== 云同步 ===== */
.cloud-dot{
  width:6px;height:6px;border-radius:50%;background:var(--placeholder);
  margin-left:1px;flex:0 0 auto;transition:background .2s;
}
.cloud-dot.ok{background:var(--ok);box-shadow:0 0 0 3px rgba(13,155,99,.14)}
.cloud-dot.err{background:var(--bad);box-shadow:0 0 0 3px rgba(221,71,77,.14)}
.cloud-dot.busy{background:var(--brand);animation:cloudPulse 1s ease-in-out infinite}
@keyframes cloudPulse{0%,100%{opacity:1}50%{opacity:.2}}

.cloud-input{
  display:block;width:100%;margin-top:10px;height:38px;padding:0 12px;
  border:1px solid var(--line);border-radius:var(--r-sm);
  background:var(--surface-2);color:var(--ink);font-size:12.5px;
  outline:none;transition:border-color .15s,background .15s;
}
.cloud-input:focus{border-color:var(--brand);background:var(--surface)}
.cloud-input::placeholder{color:var(--placeholder)}

.cloud-steps{margin:16px 0 4px;display:flex;flex-direction:column;gap:11px}
.cstep{display:flex;gap:9px;font-size:12.5px;color:var(--ink-2);line-height:1.7}
.cstep i{
  flex:0 0 auto;width:18px;height:18px;margin-top:2px;border-radius:50%;
  background:var(--brand-soft);color:var(--brand);
  font-style:normal;font-size:10.5px;font-weight:700;
  display:grid;place-items:center;
}
.cstep a{color:var(--brand);text-decoration:none;border-bottom:1px solid rgba(67,86,232,.3)}
.cstep code{
  background:var(--surface-2);border:1px solid var(--line);
  border-radius:4px;padding:1px 4px;font-size:11.5px;
}
.cstep b{color:var(--ink)}

.modal-foot{margin-top:14px;padding-top:12px;border-top:1px solid var(--line-2);display:flex;justify-content:center}
.danger-text{color:var(--bad)}
.danger-text:hover{color:var(--bad);background:var(--bad-soft)}

/* 同步后端选择 */
.prov-pick{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin:14px 0 2px}
.prov-btn{
  display:flex;flex-direction:column;align-items:flex-start;gap:1px;
  padding:9px 12px;border-radius:10px;border:1px solid var(--line);
  background:var(--surface-2);color:var(--ink-2);font-size:13px;font-weight:600;
  text-align:left;transition:all .15s;
}
.prov-btn em{font-style:normal;font-size:11px;font-weight:400;color:var(--muted)}
.prov-btn:hover{border-color:var(--brand);color:var(--brand)}
.prov-btn.active{border-color:var(--brand);background:var(--brand-soft);color:var(--brand)}
.prov-btn.active em{color:var(--brand);opacity:.85}

/* ===== 深色主题 ===== */
html[data-theme="dark"]{
  color-scheme:dark;
  --bg:#11131b;
  --surface:#191c26;
  --surface-2:#212533;
  --ink:#e7eaf4;
  --ink-2:#c1c7da;
  --muted:#8d95ae;
  --line:#2b3040;
  --line-2:#242837;
  --brand:#7b8bff;
  --brand-2:#a983ff;
  --brand-soft:#252b4d;
  --ok:#3ecf8e;
  --ok-soft:#12312a;
  --bad:#ff7379;
  --bad-soft:#3a1f24;
  --warn:#dfa93f;
  --warn-soft:#382d18;
  --shadow:0 1px 2px rgba(0,0,0,.5), 0 8px 24px rgba(0,0,0,.38);
  --shadow-lg:0 24px 60px rgba(0,0,0,.6);

  --hover-line:#3b4a86;
  --hover-line-2:#39405a;
  --hover-bg:#1f2431;
  --soft-bg:#252b4d;
  --track:#282e3d;
  --placeholder:#6e7793;
  --faint:#7b839d;
  --code-bg:#252a3a;
  --code-ink:#cfd7ee;
  --ok-line:rgba(62,207,142,.3);
  --bad-line:rgba(255,115,121,.3);
  --warn-line:rgba(223,169,63,.32);
  --inner-bg:rgba(255,255,255,.06);
  --inner-bg-2:rgba(255,255,255,.045);
  --tip-ink:#d9bd80;
  --tag-topic-bg:#2a2447;
  --tag-topic-ink:#b79cff;
  --knob:#e7eaf4;
  --toast-bg:#e7eaf4;
  --toast-ink:#171a24;
}
html[data-theme="dark"] .logo{background:linear-gradient(140deg,#252b4d,#2d2450)}
html[data-theme="dark"] .opt.selected .key,
html[data-theme="dark"] .opt.correct .key,
html[data-theme="dark"] .opt.wrong .key{color:#12141c}
html[data-theme="dark"] .chip.on{color:#12141c}

/* ===== 字号档位 ===== */
html[data-fs="s"]{--stem-fs:15px;--opt-fs:13px;--fb-fs:12.5px}
html[data-fs="l"]{--stem-fs:18px;--opt-fs:15px;--fb-fs:14.5px}
html[data-fs="xl"]{--stem-fs:19.5px;--opt-fs:16px;--fb-fs:15.5px}

/* ===== 外观面板 ===== */
.seg-label{margin:16px 0 7px;font-size:12px;font-weight:600;color:var(--muted);letter-spacing:.3px}
.seg{display:grid;grid-template-columns:repeat(3,1fr);gap:7px}
.seg.four{grid-template-columns:repeat(4,1fr)}
.seg-btn{
  padding:9px 6px;border-radius:9px;border:1px solid var(--line);
  background:var(--surface-2);color:var(--ink-2);
  font-size:12.5px;font-weight:500;transition:all .14s;
}
.seg-btn:hover{border-color:var(--brand);color:var(--brand)}
.seg-btn.on{border-color:var(--brand);background:var(--brand-soft);color:var(--brand);font-weight:600}
.seg-demo{
  margin-top:15px;padding:12px 14px;border-radius:10px;
  border:1px dashed var(--line);background:var(--surface-2);
  font-size:var(--stem-fs);line-height:1.6;color:var(--ink);
}

/* ===== 新版本提示条 ===== */
.update-bar{
  position:fixed;left:50%;transform:translateX(-50%);
  bottom:calc(72px + env(safe-area-inset-bottom,0px));
  z-index:90;display:flex;align-items:center;gap:9px;
  max-width:calc(100vw - 24px);
  background:var(--toast-bg);color:var(--toast-ink);
  padding:8px 8px 8px 15px;border-radius:12px;
  font-size:12.5px;font-weight:500;
  box-shadow:0 12px 34px rgba(0,0,0,.24);
  animation:barIn .22s ease;
}
.update-bar[hidden]{display:none}
.update-bar > span{white-space:nowrap;flex:0 0 auto}
.update-go{
  border:0;border-radius:8px;padding:6px 11px;white-space:nowrap;flex:0 0 auto;
  font-size:12px;font-weight:600;background:var(--brand);color:#fff;
}
.update-go:hover{filter:brightness(1.08)}
.update-x{
  border:0;background:transparent;color:inherit;opacity:.55;flex:0 0 auto;
  font-size:16px;line-height:1;padding:2px 6px;
}
.update-x:hover{opacity:1}
@keyframes barIn{from{opacity:0;transform:translate(-50%,8px)}to{opacity:1;transform:translate(-50%,0)}}
html[data-theme="dark"] .update-go{color:#12141c}

/* ===== 移动端侧栏关闭 / 搜索展开 ===== */
/* 侧栏右上角关闭按钮，仅窄屏出现 */
.side-close{
  display:none;
  margin-left:auto;flex:0 0 auto;
  width:30px;height:30px;border-radius:9px;
  border:1px solid var(--line);background:var(--surface-2);color:var(--ink-2);
  place-items:center;transition:all .15s;
}
.side-close:hover{border-color:var(--bad-line);color:var(--bad);background:var(--bad-soft)}
.side-close svg{pointer-events:none}

/* 侧栏遮罩：点空白处关闭 */
.side-scrim{
  position:fixed;inset:0;z-index:54;
  background:rgba(20,26,50,.42);backdrop-filter:blur(2px);
  opacity:0;pointer-events:none;transition:opacity .2s;
}
.side-scrim.on{opacity:1;pointer-events:auto}

/* 搜索开关：只在最窄档出现 */
.search-toggle{display:none}

@media (max-width:900px){
  .side-close{display:grid}
  .sidebar{padding-top:calc(22px + env(safe-area-inset-top,0px))}
  html.side-open,body.side-open{overflow:hidden}
  html.side-open{overscroll-behavior:contain}
}
@media (max-width:620px){
  .search-toggle{display:grid}
  .search-toggle.on{border-color:var(--brand);color:var(--brand);background:var(--brand-soft)}
}
html[data-theme="dark"] .side-scrim{background:rgba(0,0,0,.55)}