/* ===== 低压电工练习系统 · 样式 ===== */
:root{
  --bg:#080d1a;
  --bg2:#0d1526;
  --panel:rgba(20,30,52,.72);
  --panel2:rgba(28,40,68,.6);
  --border:rgba(120,160,255,.16);
  --text:#e8eefc;
  --text-dim:#93a3c4;
  --primary:#38bdf8;
  --primary2:#8b5cf6;
  --accent:#22d3ee;
  --ok:#34d399;
  --err:#fb7185;
  --warn:#fbbf24;
  --shadow:0 18px 40px rgba(0,0,0,.45);
  --radius:16px;
  --menu-bg:#141d33;
  color-scheme:dark;
}
body[data-theme="light"]{
  color-scheme:light;
  --bg:#eef2f9;
  --bg2:#f7f9fd;
  --panel:rgba(255,255,255,.86);
  --panel2:rgba(255,255,255,.7);
  --border:rgba(30,60,120,.12);
  --text:#16233d;
  --text-dim:#46577a;
  --shadow:0 14px 30px rgba(40,70,140,.12);
  --menu-bg:#ffffff;
  /* 亮色下把主色/状态色调深，保证文字对比度（暗色版的亮蓝/亮绿在白底上看不清） */
  --primary:#0284c7;
  --primary2:#6d28d9;
  --accent:#0e7490;
  --ok:#047857;
  --err:#d9283c;
  --warn:#b45309;
}
body[data-theme="light"] .csel-menu{box-shadow:0 18px 38px rgba(30,60,120,.18)}

/* ===== 明亮模式对比度修正 ===== */
body[data-theme="light"] .bg-orbs span{opacity:.2}          /* 光斑在白底上会发灰，压淡 */
body[data-theme="light"] .tag{background:rgba(30,80,180,.09)}
body[data-theme="light"] .tag.idx{background:rgba(2,132,199,.13);color:#0369a1}
body[data-theme="light"] .tag.info{color:#46577a;opacity:1}
body[data-theme="light"] .tag.state{color:#46577a}
body[data-theme="light"] .tag.state.ok{background:rgba(4,120,87,.13);color:#047857}
body[data-theme="light"] .tag.state.err{background:rgba(217,40,60,.13);color:#c11a2b}
body[data-theme="light"] .qstem{color:#111c33;font-weight:600}
body[data-theme="light"] .opt{color:#1c2740}
body[data-theme="light"] .opt-key{background:rgba(30,80,180,.11);color:#33456b}
body[data-theme="light"] .act.favon,
body[data-theme="light"] .act.on{background:rgba(180,83,9,.12);color:#b45309;border-color:rgba(180,83,9,.35)}
body[data-theme="light"] .explain{
  background:linear-gradient(135deg,rgba(2,132,199,.09),rgba(109,40,217,.06));
  border-color:rgba(2,132,199,.28);color:#3f4f6d;
}
body[data-theme="light"] .explain b{color:#0e7490}
body[data-theme="light"] .keys,
body[data-theme="light"] .list-tags .t{background:rgba(30,80,180,.09);color:#46577a}
body[data-theme="light"] .sheet-cell{background:rgba(30,80,180,.08);color:#46577a}
body[data-theme="light"] .sheet-cell.done{background:rgba(2,132,199,.22);color:#111c33}
body[data-theme="light"] .score-ring::after{background:#fff}
body[data-theme="light"] .nav-item em{background:rgba(2,132,199,.16);color:#0369a1}
*{box-sizing:border-box;margin:0;padding:0}
body{
  font-family:"PingFang SC","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;
  background:var(--bg);color:var(--text);min-height:100vh;overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
}
button,input,select{font-family:inherit;outline:none}
kbd{background:var(--panel2);border:1px solid var(--border);border-radius:5px;padding:1px 6px;font-size:11px;color:var(--text-dim)}
.hidden{display:none !important}

/* 背景光斑 */
.bg-orbs{position:fixed;inset:0;z-index:0;overflow:hidden;pointer-events:none}
.bg-orbs span{position:absolute;border-radius:50%;filter:blur(90px);opacity:.55;animation:float 18s ease-in-out infinite}
.bg-orbs span:nth-child(1){width:520px;height:520px;background:#1d4ed8;top:-140px;left:-80px}
.bg-orbs span:nth-child(2){width:460px;height:460px;background:#7c3aed;bottom:-160px;right:8%;animation-delay:-6s}
.bg-orbs span:nth-child(3){width:380px;height:380px;background:#0891b2;top:38%;left:52%;animation-delay:-11s}
@keyframes float{0%,100%{transform:translate(0,0) scale(1)}50%{transform:translate(40px,-50px) scale(1.12)}}

.layout{position:relative;z-index:1;display:flex;min-height:100vh}

/* 侧栏 */
.sidebar{
  width:236px;flex:0 0 236px;padding:22px 16px;
  background:linear-gradient(180deg,var(--panel),var(--panel2));
  border-right:1px solid var(--border);backdrop-filter:blur(14px);
  display:flex;flex-direction:column;gap:18px;position:sticky;top:0;height:100vh;
}
.brand{display:flex;align-items:center;gap:12px}
.brand-logo{
  width:44px;height:44px;border-radius:13px;display:grid;place-items:center;font-size:22px;
  background:linear-gradient(135deg,var(--primary),var(--primary2));
  box-shadow:0 8px 22px rgba(56,189,248,.35);
}
.brand-text{min-width:0;flex:1;display:flex;flex-direction:column;align-items:flex-start}
.brand-title{font-size:16px;font-weight:700;letter-spacing:.5px}
.brand-sub{font-size:11px;color:var(--text-dim);margin-top:2px}
/* 科目切换：标题位置直接做下拉，自带小三角 */
.brand .csel{width:auto}
.brand .csel-btn{
  width:auto;padding:1px 18px 1px 4px;margin-left:-4px;background:transparent;border:none;
  font-size:16px;font-weight:700;letter-spacing:.5px;border-radius:7px;line-height:1.3;
}
.brand .csel-btn:hover{background:rgba(56,189,248,.11);border:none}
.brand .csel-btn.on,.brand .csel-btn:focus{background:rgba(56,189,248,.14);border:none;box-shadow:none}
.brand .csel-arrow{right:2px;font-size:10px}

/* 题库未导入科目的顶部提示 */
.subject-empty{display:flex;align-items:flex-start;gap:10px;margin-bottom:16px;padding:11px 14px;border-radius:11px;
  background:rgba(255,176,32,.10);border:1px solid rgba(255,176,32,.3);
  font-size:12.5px;color:var(--text-dim);line-height:1.7}
.subject-empty .se-icon{font-size:15px;line-height:1.5}
.subject-empty b{color:var(--warn)}
.nav{display:flex;flex-direction:column;gap:6px;margin-top:6px}
.nav-item{
  display:flex;align-items:center;gap:10px;padding:11px 12px;border-radius:12px;cursor:pointer;
  background:transparent;border:1px solid transparent;color:var(--text-dim);font-size:13.5px;text-align:left;
  transition:.22s;
}
.nav-item i{font-style:normal;font-size:15px;width:20px;text-align:center}
.nav-item span{flex:1}
.nav-item em{font-style:normal;font-size:11px;padding:1px 7px;border-radius:20px;background:rgba(56,189,248,.18);color:var(--primary)}
.nav-item:hover{background:rgba(120,160,255,.1);color:var(--text);transform:translateX(3px)}
.nav-item.active{
  background:linear-gradient(90deg,rgba(56,189,248,.22),rgba(139,92,246,.16));
  border-color:rgba(56,189,248,.35);color:var(--text);box-shadow:0 6px 18px rgba(56,189,248,.12)
}
.side-progress{margin-top:auto;padding:14px;border-radius:14px;background:var(--panel2);border:1px solid var(--border);text-align:center}
.sp-title{font-size:12px;color:var(--text-dim);margin-bottom:10px}
.sp-ring{
  width:92px;height:92px;margin:0 auto;border-radius:50%;display:grid;place-items:center;
  background:conic-gradient(var(--primary) 0deg,var(--primary2) 0deg,rgba(140,160,220,.18) 0deg);
  position:relative;transition:background .6s;
}
.sp-ring::after{content:"";position:absolute;inset:7px;border-radius:50%;background:var(--bg2)}
.sp-ring span{position:relative;z-index:1;font-size:18px;font-weight:700}
.sp-info{font-size:11.5px;color:var(--text-dim);margin-top:10px}
.sp-info b{color:var(--primary)}

/* 版权 / 备案：常驻吸附在视口最底部，单行不换行
   left 起点 = 侧栏宽度 236px，既压不到侧栏，也不会在侧栏里撑出滚动条 */
.main-foot{
  position:fixed;left:236px;right:0;bottom:0;z-index:60;
  margin:0;padding:9px 26px;border-top:1px solid var(--border);
  background:var(--panel);
  -webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px);
  text-align:center;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
  font-size:12px;color:var(--text-dim);line-height:1.6;
}
.main-foot a{color:var(--text-dim);text-decoration:none;transition:color .2s}
.main-foot a:hover{color:var(--primary);text-decoration:underline;text-underline-offset:2px}
/* 版本号：贴在版权行右端的小徽标 */
.main-foot .ver{
  position:absolute;right:16px;top:50%;transform:translateY(-50%);
  padding:1px 8px;border:1px solid var(--border);border-radius:999px;
  font-size:11px;letter-spacing:.4px;color:var(--text-dim);
  background:rgba(255,255,255,.03);
}
@media (max-width:640px){.main-foot .ver{display:none}}
/* 专注模式下主区是垂直居中的，这行会打乱布局，临时隐去 */
body.focus .main-foot{display:none}

/* 主区 */
/* 底部给吸附版权行留出空间，否则最后一屏内容会被压住 */
.main{flex:1;padding:20px 26px 58px;min-width:0}
.topbar{display:flex;align-items:center;justify-content:space-between;margin-bottom:18px}
.top-title{font-size:20px;font-weight:700;letter-spacing:.5px}
.top-right{display:flex;align-items:center;gap:10px}
.chip{padding:6px 14px;border-radius:20px;background:var(--panel2);border:1px solid var(--border);font-size:12.5px;color:var(--text-dim)}
.icon-btn{width:36px;height:36px;border-radius:11px;border:1px solid var(--border);background:var(--panel2);color:var(--text);cursor:pointer;font-size:16px;transition:.2s}
.icon-btn:hover{transform:rotate(-18deg) scale(1.06)}

/* 初始化完成前不渲染任何页面，避免刷新时先闪默认的练习页 */
html:not(.app-ready) .view{display:none}
html:not(.app-ready) .layout{min-height:60vh}
.view{animation:fade .35s ease}
@keyframes fade{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:none}}

/* 工具条 */
.toolbar{display:flex;flex-wrap:wrap;gap:12px;padding:14px 16px;border-radius:var(--radius);
  background:var(--panel);border:1px solid var(--border);box-shadow:var(--shadow);margin-bottom:18px;backdrop-filter:blur(10px)}
.field{display:flex;flex-direction:column;gap:6px;min-width:132px}
.field.grow{flex:1;min-width:220px}
.field label{font-size:11.5px;color:var(--text-dim);letter-spacing:.4px}
.field select,.field input{
  padding:9px 11px;border-radius:10px;background:var(--panel2);border:1px solid var(--border);
  color:var(--text);font-size:13px;transition:.2s;
}
.field select:focus,.field input:focus{border-color:var(--primary);box-shadow:0 0 0 3px rgba(56,189,248,.15)}

/* 专练模式提示条（错题 / 收藏 / 不懂） */
.cbar{
  display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap;
  padding:11px 16px;border-radius:var(--radius);margin-bottom:14px;
  background:linear-gradient(135deg,rgba(56,189,248,.16),rgba(56,189,248,.05));
  border:1px solid rgba(56,189,248,.42);box-shadow:var(--shadow);backdrop-filter:blur(10px);
}
.cbar-l{display:flex;align-items:center;gap:9px;flex-wrap:wrap;font-size:13px}
.cbar-dot{width:8px;height:8px;border-radius:50%;background:var(--primary);box-shadow:0 0 0 4px rgba(56,189,248,.18);flex:none}
.cbar-txt{color:var(--text);letter-spacing:.3px}
.cbar-txt b{color:var(--primary);font-weight:600}
.cbar-dim{font-size:11.5px;color:var(--text-dim)}
.cbar-r{display:flex;align-items:center;gap:9px}
.cbar-r .btn{padding:7px 14px;font-size:12.5px}
body[data-theme="light"] .cbar{background:linear-gradient(135deg,rgba(2,132,199,.10),rgba(2,132,199,.03));border-color:rgba(2,132,199,.35)}
body[data-theme="light"] .cbar-txt b{color:#0369a1}
body[data-theme="light"] .cbar-dim{color:#5a6b8a}
/* 专注模式下工具条被隐藏，这条提示必须保留，否则用户出不了专练 */
/* 选择器要带上 .in-custom，否则专注模式下 .hidden 会被这条 !important 盖掉，
   未专练时也会冒出一条「正在专练 · 0 题」的空提示条 */
body.focus #view-practice.in-custom .cbar{display:flex !important}
body.focus .cbar-dim{display:none}
/* 专练中工具条的筛选条件不生效，直接锁住并可看出不能用 */
#view-practice.in-custom > .toolbar{opacity:.45;filter:saturate(.5);pointer-events:none;user-select:none}
body.focus #view-practice.in-custom > .toolbar{display:none !important}

/* ===== 自定义下拉框 ===== */
.csel{position:relative;width:100%}
/* 原生 select 仅作数据载体，视觉上完全隐藏 */
.csel-native{
  position:absolute;left:0;top:0;width:100%;height:100%;
  opacity:0;pointer-events:none;border:none;background:transparent;
}
.csel-btn{
  width:100%;display:flex;align-items:center;justify-content:space-between;gap:10px;
  padding:9px 32px 9px 12px;border-radius:10px;background:var(--panel2);
  border:1px solid var(--border);color:var(--text);font-size:13px;
  cursor:pointer;transition:.18s;text-align:left;line-height:1.35;
}
.csel-btn:hover{border-color:rgba(56,189,248,.45);background:var(--panel2)}
.csel-btn.on,.csel-btn:focus{
  border-color:var(--primary);box-shadow:0 0 0 3px rgba(56,189,248,.15);
}
.csel-val{flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.csel-arrow{
  position:absolute;right:11px;top:50%;transform:translateY(-50%);
  color:var(--text-dim);font-size:11px;line-height:1;transition:transform .2s;pointer-events:none;
}
.csel-btn.on .csel-arrow{transform:translateY(-50%) rotate(180deg);color:var(--primary)}

/* 浮层挂 body + fixed：不受父级 overflow / backdrop-filter 裁剪，也不会盖住输入框 */
.csel-menu{
  position:fixed;z-index:3000;display:none;max-height:290px;max-width:calc(100vw - 24px);overflow:auto;
  padding:6px;border-radius:12px;border:1px solid var(--border);
  background:var(--menu-bg);box-shadow:0 22px 48px rgba(0,0,0,.5);
  overscroll-behavior:contain;-webkit-overflow-scrolling:touch;   /* 内部滚动不带动页面、滚动更顺 */
  contain:paint;                                                  /* 菜单重绘不牵连整页，滚动更跟手 */
}
.csel-menu.open{display:block}
.csel-opt{
  padding:8px 11px;border-radius:8px;font-size:13px;color:var(--text-dim);
  cursor:pointer;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;transition:.12s;
}
.csel-opt:hover{background:rgba(56,189,248,.14);color:var(--text)}
.csel-opt.sel{color:var(--primary);background:rgba(56,189,248,.16);font-weight:600}
.csel-opt.sel::after{content:"✓";float:right;margin-left:10px}
.csel-menu::-webkit-scrollbar{width:6px}
.csel-menu::-webkit-scrollbar-thumb{background:rgba(120,160,255,.3);border-radius:3px}

.btn{padding:9px 18px;border-radius:11px;border:1px solid var(--border);cursor:pointer;font-size:13px;
  background:var(--panel2);color:var(--text);transition:.22s;font-weight:500}
.btn:hover{transform:translateY(-2px);box-shadow:0 10px 22px rgba(0,0,0,.28)}
.btn:disabled{opacity:.38;cursor:not-allowed}
.btn:disabled:hover{transform:none;box-shadow:none}
.btn.primary{background:linear-gradient(135deg,var(--primary),var(--primary2));border:none;color:#fff;box-shadow:0 8px 20px rgba(56,189,248,.3)}
.btn.ghost{background:transparent}
.btn.warn{background:linear-gradient(135deg,#fbbf24,#f59e0b);border:none;color:#3a2600}
.btn.danger{background:linear-gradient(135deg,#fb7185,#e11d48);border:none;color:#fff}
.btn.big{padding:12px 30px;font-size:15px}

/* 题目区 */
.qwrap{display:flex;flex-direction:column;gap:14px}
.qhead{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap}
.qmeta{display:flex;gap:8px;flex-wrap:wrap;align-items:center;cursor:default;user-select:none}
/* 信息标签：纯展示，不可点击，样式刻意做淡、无边框，避免与右侧按钮混淆 */
.tag{
  padding:3px 10px;border-radius:20px;font-size:11.5px;line-height:1.7;
  background:rgba(120,160,255,.09);color:var(--text-dim);border:none;
}
.tag.idx{background:rgba(56,189,248,.14);color:var(--primary);font-weight:600}
.tag.info{background:transparent;color:var(--text-dim);opacity:.85}
.tag.info::before{content:"· ";opacity:.5}
.tag.state{background:transparent;color:var(--text-dim)}
.tag.state.ok{background:rgba(52,211,153,.14);color:var(--ok)}
.tag.state.err{background:rgba(251,113,133,.14);color:var(--err)}
/* 题型徽标：单选蓝 / 判断紫，模考里要一眼分清单选题还是判断题 */
.tag.type{font-weight:600;letter-spacing:.4px;border:1px solid transparent;flex:none}
.tag.type.choice{background:rgba(56,189,248,.16);color:var(--primary);border-color:rgba(56,189,248,.35)}
.tag.type.judge{background:rgba(139,92,246,.18);color:var(--accent);border-color:rgba(139,92,246,.38)}
body[data-theme="light"] .tag.type.choice{background:rgba(2,132,199,.12);color:#0369a1;border-color:rgba(2,132,199,.32)}
body[data-theme="light"] .tag.type.judge{background:rgba(124,58,237,.12);color:#6d28d9;border-color:rgba(124,58,237,.3)}
.review-item .tag.type{margin-right:6px}
/* 答对后「已移出错题本」的一行小提示 */
.fb-tip{margin-left:10px;font-size:12px;font-weight:400;color:var(--ok);opacity:.9}
/* 可点击按钮组 */
.qacts{display:flex;gap:8px}
.qacts .act{cursor:pointer}
.act{padding:7px 13px;border-radius:10px;border:1px solid var(--border);background:var(--panel2);color:var(--text-dim);cursor:pointer;font-size:12.5px;transition:.2s;box-shadow:0 3px 10px rgba(0,0,0,.18)}
.act:hover{color:var(--text);border-color:var(--primary);transform:translateY(-1px)}
.act.on{background:rgba(251,191,36,.18);color:var(--warn);border-color:rgba(251,191,36,.4)}
.act.favon{background:rgba(251,191,36,.2);color:#fbbf24;border-color:rgba(251,191,36,.45)}
/* 列表里的小标签 */
.list-tags .t.ok{color:var(--ok)}

.progress-line{height:6px;border-radius:6px;background:var(--panel2);overflow:hidden;border:1px solid var(--border)}
.progress-fill{height:100%;width:0;border-radius:6px;
  background:linear-gradient(90deg,var(--primary),var(--primary2),var(--accent));
  background-size:200% 100%;animation:flow 3s linear infinite;transition:width .45s}
@keyframes flow{to{background-position:-200% 0}}

.qcard{padding:24px;border-radius:var(--radius);background:var(--panel);border:1px solid var(--border);
  box-shadow:var(--shadow);backdrop-filter:blur(10px)}
.qstem{font-size:17px;line-height:1.75;margin-bottom:18px;font-weight:500;word-break:break-word}
.qstem .no{color:var(--text-dim);font-weight:600;margin-right:4px;font-variant-numeric:tabular-nums}
.options{display:flex;flex-direction:column;gap:10px}
.opt{
  display:flex;gap:12px;align-items:flex-start;padding:13px 16px;border-radius:12px;cursor:pointer;
  background:var(--panel2);border:1px solid var(--border);transition:.2s;font-size:14.5px;line-height:1.6;
}
.opt:hover{border-color:var(--primary);transform:translateX(4px)}
.opt-key{
  flex:0 0 26px;height:26px;border-radius:8px;display:grid;place-items:center;font-size:12.5px;font-weight:700;
  background:rgba(120,160,255,.14);color:var(--text-dim)
}
.opt.correct{border-color:var(--ok);background:rgba(52,211,153,.14);box-shadow:0 0 0 1px rgba(52,211,153,.3) inset}
.opt.correct .opt-key{background:var(--ok);color:#04231a}
.opt.wrong{border-color:var(--err);background:rgba(251,113,133,.14)}
.opt.wrong .opt-key{background:var(--err);color:#3d0415}
.opt.disabled{cursor:default}
.opt.disabled:hover{transform:none}

/* 无内容时彻底不占位，避免留下空白块 */
.feedback:empty,.explain:empty{display:none !important}
.feedback{margin-top:16px;font-size:14px;font-weight:600;display:flex;align-items:center;gap:8px}
.feedback.ok{color:var(--ok)}
.feedback.err{color:var(--err)}
.feedback.reveal{color:var(--warn)}
.explain{
  margin-top:12px;padding:14px 16px;border-radius:12px;font-size:13.5px;line-height:1.8;
  background:linear-gradient(135deg,rgba(56,189,248,.1),rgba(139,92,246,.08));
  border:1px solid rgba(56,189,248,.2);color:var(--text-dim);
}
.explain b{color:var(--accent)}

/* 上一题 / 快捷键提示 / 下一题 */
.qfoot{display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap}
.keys{font-size:11.5px;color:var(--text-dim)}

/* ===== 危险操作确认弹窗 ===== */
.modal-mask{
  position:fixed;inset:0;z-index:4000;display:none;align-items:center;justify-content:center;
  background:rgba(8,14,28,.62);backdrop-filter:blur(6px);animation:fade .2s ease;
}
.modal-mask.show{display:flex}
.modal{
  width:min(420px,92vw);padding:26px 26px 22px;border-radius:20px;text-align:center;
  background:var(--panel);border:1px solid var(--border);box-shadow:0 26px 60px rgba(0,0,0,.5);
  animation:pop .25s cubic-bezier(.2,1.3,.4,1);
}
@keyframes pop{from{opacity:0;transform:scale(.9) translateY(12px)}to{opacity:1;transform:none}}
.modal-icon{font-size:34px;line-height:1;margin-bottom:12px}
.modal-title{font-size:17px;font-weight:700;margin-bottom:10px}
.modal-desc{font-size:13px;color:var(--text-dim);line-height:1.8}
.modal-desc b{color:var(--err);font-size:15px}
.modal-check{
  display:flex;align-items:center;gap:9px;justify-content:center;margin:18px 0 4px;padding:11px 12px;
  border-radius:12px;background:var(--panel2);border:1px solid var(--border);font-size:12.5px;color:var(--text-dim);cursor:pointer;
}
.modal-check input{width:16px;height:16px;accent-color:var(--err);cursor:pointer}
.modal-check label{cursor:pointer;user-select:none;line-height:1.6;text-align:left}
.modal-actions{display:flex;gap:12px;margin-top:18px}
.modal-actions .btn{flex:1;justify-content:center}
.btn.danger{
  background:linear-gradient(135deg,#fb7185,#e11d48);color:#fff;border-color:transparent;
  box-shadow:0 8px 20px rgba(225,29,72,.3);
}
.btn.danger:disabled{opacity:.4;cursor:not-allowed;box-shadow:none;filter:grayscale(.4)}
body[data-theme="light"] .modal{box-shadow:0 26px 60px rgba(30,60,120,.25)}
body[data-theme="light"] .modal-mask{background:rgba(180,200,235,.5)}

/* ===== 撤销条 ===== */
.undo-bar{
  /* 顶部还要给 toast 留位置，两者错开避免叠在一起 */
  position:fixed;top:74px;left:50%;z-index:3800;
  display:flex;align-items:center;gap:14px;padding:11px 16px;border-radius:14px;overflow:hidden;
  background:var(--panel);border:1px solid var(--border);box-shadow:var(--shadow);
  font-size:13px;color:var(--text);
  transform:translate(-50%,-140%);visibility:hidden;pointer-events:none;
  transition:transform .32s cubic-bezier(.2,1.1,.4,1),visibility .32s;
}
.undo-bar.show{transform:translate(-50%,0);visibility:visible;pointer-events:auto}
.u-txt{color:var(--text-dim)}
.u-btn{
  padding:5px 13px;border-radius:9px;border:1px solid rgba(56,189,248,.4);cursor:pointer;
  background:rgba(56,189,248,.16);color:var(--primary);font-size:12.5px;font-weight:600;
}
.u-btn:hover{background:rgba(56,189,248,.28)}
.u-close{cursor:pointer;color:var(--text-dim);font-size:13px;opacity:.7}
.u-close:hover{opacity:1}
.u-line{position:absolute;left:0;bottom:0;height:2px;width:100%;background:linear-gradient(90deg,var(--primary),var(--primary2));transform-origin:left}
.undo-bar.show .u-line{animation:undobar 8s linear forwards}
@keyframes undobar{from{transform:scaleX(1)}to{transform:scaleX(0)}}

/* ===== 专注模式（只留题目） ===== */
.focus-exit{display:none}
body.focus .sidebar,
body.focus .topbar,
body.focus .keys,
body.focus #btnFocus,                              /* 专注时退出只保留右上角浮动条 */
body.focus #view-practice > .toolbar{display:none !important}   /* 筛选/搜索工具条彻底不占位 */
body.focus .qwrap{gap:16px}
body.focus .main{padding:0;display:flex;flex-direction:column;min-height:100vh}
body.focus #view-practice{max-width:920px;width:100%;margin:auto;padding:40px 22px}   /* 内容少时垂直居中，内容长时正常滚动 */
body.focus .bg-orbs span{opacity:.22}
body.focus .qstem{font-size:19px;line-height:1.85}
body.focus .opt{padding:15px 17px;font-size:15.5px}
body.focus .qfoot{margin-top:2px}                  /* 保持全宽：上一题靠左、下一题靠右 */
body.focus .focus-exit{
  display:flex;align-items:center;gap:9px;position:fixed;top:18px;right:22px;z-index:2500;cursor:pointer;
  padding:8px 14px;border-radius:22px;font-size:12.5px;color:var(--text-dim);
  background:var(--panel);border:1px solid var(--border);box-shadow:var(--shadow);backdrop-filter:blur(10px);
  opacity:.5;transition:.25s;
}
body.focus .focus-exit:hover{opacity:1;color:var(--text);transform:translateY(-2px)}
.focus-exit b{color:var(--text);font-weight:600}
.fe-dot{width:7px;height:7px;border-radius:50%;background:var(--ok);box-shadow:0 0 0 4px rgba(52,211,153,.18)}
body[data-theme="light"] .focus-exit{background:rgba(255,255,255,.92)}

/* 面板 */
.panel{padding:22px;border-radius:var(--radius);background:var(--panel);border:1px solid var(--border);
  box-shadow:var(--shadow);margin-bottom:18px;backdrop-filter:blur(10px)}
.panel-title{font-size:15px;font-weight:700;margin-bottom:16px;display:flex;align-items:center;gap:8px}
.panel-title::before{content:"";width:4px;height:16px;border-radius:3px;background:linear-gradient(180deg,var(--primary),var(--primary2))}
.setup-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:14px}
/* 未完成考试的提醒条 */
.setup-resume{display:flex;align-items:center;gap:12px;flex-wrap:wrap;
  margin-bottom:16px;padding:11px 14px;border-radius:11px;
  background:rgba(255,176,32,.10);border:1px solid rgba(255,176,32,.35)}
.setup-resume .sr-dot{flex:none;width:8px;height:8px;border-radius:50%;background:var(--warn);
  box-shadow:0 0 0 4px rgba(255,176,32,.16)}
.setup-resume .sr-txt{flex:1;min-width:180px;font-size:13px;color:var(--text)}
.setup-resume .sr-txt b{color:var(--warn)}
.setup-resume .sr-btns{display:flex;gap:8px}
.setup-tip{margin-top:14px;font-size:12.5px;color:var(--text-dim);line-height:1.7;text-align:center}
/* 开始考试按钮居中，说明文字也居中 */
.setup-actions{margin-top:22px;display:flex;justify-content:center;align-items:center;gap:14px;flex-wrap:wrap}
#btnStartExam{min-width:180px}

/* 考试 */
.exam-top{display:flex;align-items:center;gap:18px;margin-bottom:16px;flex-wrap:wrap}
.timer{font-size:26px;font-weight:800;letter-spacing:1px;
  background:linear-gradient(135deg,var(--primary),var(--primary2));-webkit-background-clip:text;background-clip:text;color:transparent;
  min-width:110px}
.timer.danger{background:linear-gradient(135deg,#fb7185,#e11d48);-webkit-background-clip:text;background-clip:text}
.exam-progress{flex:1;min-width:200px;display:flex;flex-direction:column;gap:6px}
.exam-stat{font-size:12px;color:var(--text-dim)}
.exam-stat b{color:var(--primary)}
.exam-body{display:grid;grid-template-columns:1fr 260px;gap:18px}
@media(max-width:1100px){.exam-body{grid-template-columns:1fr}}
.exam-foot{margin-top:18px;justify-content:center}
.sheet{padding:16px;border-radius:var(--radius);background:var(--panel2);border:1px solid var(--border);align-self:start}
.sheet-title{display:flex;justify-content:space-between;gap:8px;flex-wrap:wrap;
  font-size:13px;font-weight:600;margin-bottom:12px;color:var(--text-dim)}
.sheet-title em{font-style:normal;font-size:11px;font-weight:500;opacity:.85;font-variant-numeric:tabular-nums}
.sheet-grid{display:grid;grid-template-columns:repeat(6,1fr);gap:7px}
.sheet-cell{
  aspect-ratio:1;border-radius:8px;display:grid;place-items:center;font-size:12px;cursor:pointer;
  background:rgba(120,160,255,.1);border:1px solid var(--border);color:var(--text-dim);transition:.15s
}
.sheet-cell:hover{transform:scale(1.1);border-color:var(--primary)}
.sheet-cell.done{background:rgba(56,189,248,.28);color:var(--text)}
.sheet-cell.mark{background:rgba(251,191,36,.32);color:var(--warn);border-color:rgba(251,191,36,.5)}
.sheet-cell.cur{box-shadow:0 0 0 2px var(--primary)}
/* 判断题部分：答题卡上换一种底色，单选题与判断题一眼分开 */
.sheet-cell.judge{background:rgba(167,139,250,.13);border-color:rgba(167,139,250,.32)}
.sheet-cell.judge.done{background:rgba(167,139,250,.4);color:#ede9fe}
.sheet-cell.judge.mark{background:rgba(251,191,36,.32);color:var(--warn);border-color:rgba(251,191,36,.5)}
.legend{display:flex;gap:12px;margin-top:12px;font-size:11px;color:var(--text-dim);flex-wrap:wrap}
.legend span{display:flex;align-items:center;gap:5px}
.dot{width:9px;height:9px;border-radius:3px;display:inline-block}
.dot.done{background:var(--primary)}
.dot.mark{background:var(--warn)}
.dot.none{background:rgba(120,160,255,.2)}
.dot.judge{background:#a78bfa}

/* 成绩 */
.score-card{display:flex;gap:28px;align-items:center;flex-wrap:wrap}
.score-ring{
  width:150px;height:150px;border-radius:50%;display:grid;place-items:center;position:relative;
  background:conic-gradient(var(--ok) 0deg,rgba(140,160,220,.18) 0deg);transition:background 1s
}
.score-ring::after{content:"";position:absolute;inset:12px;border-radius:50%;background:var(--bg2)}
.score-ring span{position:relative;z-index:1;font-size:38px;font-weight:800;
  background:linear-gradient(135deg,var(--primary),var(--primary2));-webkit-background-clip:text;background-clip:text;color:transparent}
.score-info{flex:1;min-width:240px}
.score-verdict{font-size:22px;font-weight:700;margin-bottom:8px}
.score-detail{font-size:13px;color:var(--text-dim);line-height:1.9}
.score-btns{display:flex;gap:10px;margin-top:14px;flex-wrap:wrap}
.review-list{margin-top:20px;display:flex;flex-direction:column;gap:12px}
.review-item{padding:16px 18px;border-radius:12px;background:var(--panel2);border:1px solid var(--border);border-left:4px solid var(--err)}
.review-item.right{border-left-color:var(--ok)}
.review-item .rt{font-size:14.5px;line-height:1.7;margin-bottom:8px}
.review-item .ra{font-size:13px;color:var(--text-dim)}
.review-item .ra b{color:var(--ok)}
.review-item .re{margin-top:8px;font-size:13px;color:var(--text-dim);line-height:1.75}

/* 列表 */
.list-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:16px;flex-wrap:wrap;gap:12px}
.list-head div{display:flex;gap:10px}
.list-count{font-size:13px;color:var(--text-dim);font-variant-numeric:tabular-nums}
.list-count b{color:var(--text);font-size:15px;font-weight:700}
.list{display:flex;flex-direction:column;gap:10px}
.list-item{
  padding:14px 16px;border-radius:12px;background:var(--panel);border:1px solid var(--border);
  display:flex;gap:14px;align-items:flex-start;transition:.2s;backdrop-filter:blur(8px)
}
.list-item:hover{border-color:var(--primary);transform:translateX(3px)}
.list-no{flex:0 0 52px;font-size:12px;color:var(--text-dim);padding-top:3px}
.list-body{flex:1;min-width:0}
.list-stem{font-size:14px;line-height:1.65;margin-bottom:6px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.list-tags{display:flex;gap:8px;font-size:11.5px;color:var(--text-dim);flex-wrap:wrap}
.list-tags .t{background:rgba(120,160,255,.12);padding:2px 8px;border-radius:20px}
.list-ops{display:flex;gap:8px;flex:0 0 auto}
.mini{padding:6px 12px;border-radius:9px;border:1px solid var(--border);background:var(--panel2);color:var(--text-dim);cursor:pointer;font-size:12px;transition:.2s}
.mini:hover{color:var(--text);border-color:var(--primary)}
.mini.del:hover{color:var(--err);border-color:var(--err)}
.empty{padding:60px 20px;text-align:center;color:var(--text-dim);font-size:14px}
/* 收藏 / 不懂 / 错题本 的空状态：一张居中卡片，空时替代整个列表 */
.empty-state{display:flex;flex-direction:column;align-items:center;gap:6px;padding:52px 20px;
  border-radius:var(--radius);background:var(--panel);border:1px dashed var(--border);text-align:center}
.es-icon{font-size:40px;line-height:1;opacity:.9}
.es-title{margin-top:6px;font-size:15px;font-weight:700;color:var(--text)}
.es-desc{font-size:12.5px;color:var(--text-dim);max-width:340px;line-height:1.7}
.es-btn{margin-top:14px}

/* 联系与赞助 */
.donate-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:18px}
.qr-card{
  padding:20px;border-radius:14px;background:var(--panel2);border:1px solid var(--border);
  display:flex;flex-direction:column;align-items:center;gap:10px;text-align:center;
}
.qr-canvas{
  width:236px;height:236px;border-radius:12px;background:#fff;
  padding:8px;box-shadow:0 8px 20px rgba(0,0,0,.22);
}
.qr-title{font-size:14.5px;font-weight:700}
.qr-tip{font-size:12.5px;color:var(--text-dim);line-height:1.75;max-width:280px}
.qr-bad{padding:24px;font-size:13px;color:var(--err);border:1px dashed var(--err);border-radius:12px}

/* 统计 */
.stat-cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:14px;margin-bottom:18px}
.stat-card{padding:18px;border-radius:var(--radius);background:var(--panel);border:1px solid var(--border);box-shadow:var(--shadow);backdrop-filter:blur(10px)}
.stat-card .sv{font-size:26px;font-weight:800;background:linear-gradient(135deg,var(--primary),var(--primary2));-webkit-background-clip:text;background-clip:text;color:transparent}
.stat-card .sl{font-size:12px;color:var(--text-dim);margin-top:6px}
/* 顶部概览：环形进度 + 指标小卡 */
.stat-hero{display:flex;align-items:center;gap:24px;flex-wrap:wrap;padding:18px 20px}
.hero-ring{--p:0;flex:none;width:120px;height:120px;border-radius:50%;display:grid;place-items:center;
  background:conic-gradient(var(--primary) calc(var(--p) * 1%), var(--panel2) 0);
  box-shadow:var(--shadow);transition:background .45s ease}
.hero-ring>span{width:95px;height:95px;border-radius:50%;background:var(--panel);
  display:flex;flex-direction:column;align-items:center;justify-content:center;gap:3px}
.hero-ring b{font-size:25px;font-weight:800;line-height:1;font-variant-numeric:tabular-nums;
  background:linear-gradient(135deg,var(--primary),var(--primary2));-webkit-background-clip:text;background-clip:text;color:transparent}
.hero-ring i{font-style:normal;font-size:11px;color:var(--text-dim);font-variant-numeric:tabular-nums}
.stat-hero .stat-cards{flex:1;min-width:240px;margin-bottom:0;grid-template-columns:repeat(auto-fit,minmax(112px,1fr));gap:10px}
.stat-hero .stat-card{padding:11px 13px;border-radius:11px;background:var(--panel2);box-shadow:none;
  border:1px solid var(--border);border-left:3px solid var(--border)}
.stat-hero .stat-card .sv{font-size:20px}
.stat-hero .stat-card .sl{font-size:11px;margin-top:2px}
/* 指标卡按语义上色（正确率达标绿、收藏/不懂黄、错题红） */
.stat-card.ok{border-left-color:var(--ok)}
.stat-card.ok .sv{background:none;-webkit-text-fill-color:var(--ok);color:var(--ok)}
.stat-card.warn{border-left-color:var(--warn)}
.stat-card.warn .sv{background:none;-webkit-text-fill-color:var(--warn);color:var(--warn)}
.stat-card.err{border-left-color:var(--err)}
.stat-card.err .sv{background:none;-webkit-text-fill-color:var(--err);color:var(--err)}
/* 各模块正确率：小方块网格，一屏能放下所有模块 */
.mod-list{display:grid;grid-template-columns:repeat(auto-fit,minmax(148px,1fr));gap:10px}
.mod-card{display:flex;flex-direction:column;gap:3px;min-width:0;
  padding:10px 12px;border-radius:10px;background:var(--panel2);
  border:1px solid var(--border);border-left:3px solid var(--border);font-size:13px}
.mod-head{display:flex;align-items:baseline;justify-content:space-between;gap:8px;min-width:0}
.mod-name{overflow:hidden;text-overflow:ellipsis;white-space:nowrap;color:var(--text-dim);font-weight:600;font-size:12px;min-width:0}
.mod-total{flex:none;color:var(--text-dim);font-size:11px;opacity:.85;white-space:nowrap}
.mod-pct{font-size:23px;font-weight:800;font-variant-numeric:tabular-nums;letter-spacing:.5px;line-height:1.15}
.mod-cov{display:block;height:3px;border-radius:2px;background:var(--border);overflow:hidden;margin:1px 0 2px}
.mod-cov i{display:block;height:100%;background:var(--primary);opacity:.75}
.mod-det{color:var(--text-dim);font-size:11.5px;font-variant-numeric:tabular-nums;line-height:1.5}
.mod-det b{color:var(--text);font-weight:600}
/* 正确率分档配色：一眼看出哪个模块拖后腿（左侧竖条 + 数字同色） */
.mod-card.hi{border-left-color:var(--ok)}
.mod-card.hi .mod-pct{color:var(--ok)}
.mod-card.mid{border-left-color:var(--warn)}
.mod-card.mid .mod-pct{color:var(--warn)}
.mod-card.low{border-left-color:var(--err)}
.mod-card.low .mod-pct{color:var(--err)}
/* 未练过的模块：整块压暗，避免被当成「红 = 拖后腿」 */
.mod-card.none{opacity:.62}
.mod-card.none:hover{opacity:1}
.mod-card.none .mod-pct{color:var(--text-dim);font-size:17px}
.mod-card.none .mod-cov{opacity:.5}
.mod-note{margin-top:12px;padding-top:10px;border-top:1px dashed var(--border);font-size:11.5px;color:var(--text-dim);line-height:1.7}
/* 模考成绩折线图 */
.score-chart-wrap{margin-top:18px;padding:14px 16px 10px;border-radius:var(--radius);background:var(--panel2);border:1px solid var(--border)}
.sc-head{display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap}
.sc-title{font-size:13px;color:var(--text);letter-spacing:.4px;font-weight:600}
.sc-ctl{width:150px;flex:none}
.sc-stats{display:flex;flex-wrap:wrap;gap:8px 18px;margin:10px 0 4px;font-size:12px;color:var(--text-dim)}
.sc-stats b{color:var(--text);font-weight:600}
.sc-stats .up{color:var(--ok)}
.sc-stats .down{color:var(--err)}
.score-chart-wrap canvas{display:block;width:100%;height:230px;margin-top:6px}
body[data-theme="light"] .score-chart-wrap{background:rgba(255,255,255,.6)}

.history{display:grid;grid-template-columns:repeat(auto-fill,minmax(215px,1fr));gap:10px;margin-top:10px}
.history-row{display:flex;align-items:center;gap:12px;min-width:0;
  padding:11px 14px;border-radius:11px;background:var(--panel2);
  border:1px solid var(--border);border-left:3px solid var(--border);font-size:12.5px;color:var(--text-dim)}
.history-row.pass{border-left-color:var(--ok)}
.history-row.fail{border-left-color:var(--err)}
.h-score{flex:none;font-size:26px;font-weight:800;line-height:1;font-variant-numeric:tabular-nums;min-width:52px}
.h-score small{font-size:11px;font-weight:600;margin-left:2px;opacity:.75}
.history-row.pass .h-score{color:var(--ok)}
.history-row.fail .h-score{color:var(--err)}
.h-meta{flex:1;min-width:0;line-height:1.6;font-variant-numeric:tabular-nums}
.h-meta b{color:var(--text);font-weight:600}
.h-tag{flex:none;font-size:11px;padding:2px 8px;border-radius:999px;border:1px solid currentColor;opacity:.9}
.history-row.pass .h-tag{color:var(--ok)}
.history-row.fail .h-tag{color:var(--err)}

/* 回到顶部：只在长列表页（收藏 / 不懂 / 错题本）滚动后出现 */
.to-top{
  position:fixed;right:26px;bottom:74px;z-index:1200;
  width:42px;height:42px;display:grid;place-items:center;
  border-radius:50%;cursor:pointer;color:var(--text);
  background:var(--panel);border:1px solid var(--border);
  box-shadow:0 10px 26px rgba(0,0,0,.35);
  -webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);
  opacity:0;visibility:hidden;transform:translateY(10px) scale(.9);
  transition:opacity .22s,transform .22s,visibility .22s,color .2s,border-color .2s;
}
.to-top.show{opacity:1;visibility:visible;transform:none}
.to-top:hover{color:var(--primary);border-color:var(--primary);transform:translateY(-2px)}
.to-top:active{transform:scale(.94)}

/* toast：放顶部（底部贴着版权条看不清），从上方滑入 */
.toast{
  position:fixed;left:50%;top:22px;transform:translate(-50%,-16px);opacity:0;pointer-events:none;
  padding:12px 24px;border-radius:12px;background:linear-gradient(135deg,var(--primary),var(--primary2));
  color:#fff;font-size:14px;font-weight:500;box-shadow:0 12px 30px rgba(0,0,0,.4);transition:.26s;z-index:5000;
  max-width:min(560px,calc(100vw - 32px));text-align:center;line-height:1.5
}
.toast.show{opacity:1;transform:translate(-50%,0)}

::-webkit-scrollbar{width:10px;height:10px}
::-webkit-scrollbar-thumb{background:rgba(120,160,255,.25);border-radius:6px}
::-webkit-scrollbar-track{background:transparent}