/* =====================================================================
 * 选型题库 —— 移动优先样式
 * 画布 390×844；桌面内容居中，最大宽度 540px
 * 主色 青绿 #0d9488 ；正确 #16a34a ；错误 #dc2626
 * ================================================================== */

:root{
  --teal-800:#115e59;
  --teal-700:#0f766e;
  --teal-600:#0d9488;
  --teal-500:#14b8a6;
  --teal-100:#ccfbf1;
  --teal-50:#f0fdfa;
  --ok:#16a34a;   --ok-bg:#f0fdf4;  --ok-line:#bbf7d0;  --ok-ink:#14532d;
  --bad:#dc2626;  --bad-bg:#fef2f2; --bad-line:#fecaca;
  --amber:#d97706; --amber-bg:#fffbeb;
  --bg:#f5f7f9;
  --card:#ffffff;
  --line:#e5e9ee;
  --line-soft:#eef2f5;
  --ink:#0f172a;
  --ink-2:#334155;
  --muted:#64748b;
  --muted-2:#94a3b8;
  --r-lg:16px;
  --r-md:14px;
  --r-sm:10px;
  --shadow:0 2px 8px rgba(0,0,0,.06);
  --shadow-md:0 4px 16px rgba(15,23,42,.08);
  --shadow-lg:0 12px 36px rgba(15,23,42,.16);
  --tab-h:56px;
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei","Source Han Sans SC","Noto Sans CJK SC",sans-serif;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,"Liberation Mono",monospace;
}

*,*::before,*::after{box-sizing:border-box}

html{-webkit-text-size-adjust:100%}

body{
  margin:0;
  background:var(--bg);
  color:var(--ink);
  font-family:var(--font);
  font-size:15.5px;
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
}

a{color:inherit}
h1,h2,h3{letter-spacing:-.01em}
.is-hidden{display:none !important}
.mono{font-family:var(--mono);font-variant-numeric:tabular-nums}
.muted{color:var(--muted)}

/* ===================== 布局骨架 ===================== */
.app{
  max-width:540px;
  margin:0 auto;
  padding:14px 14px calc(var(--tab-h) + env(safe-area-inset-bottom) + 22px);
}
body.no-tabbar .app{padding-bottom:26px}
body.has-actionbar .app{padding-bottom:calc(112px + env(safe-area-inset-bottom))}

.topbar{
  position:sticky;top:0;z-index:30;
  background:#fff;
  border-bottom:1px solid var(--line);
}
.topbar-inner{
  max-width:540px;margin:0 auto;height:52px;padding:0 14px;
  display:flex;align-items:center;justify-content:space-between;gap:10px;
}
.brand{display:inline-flex;align-items:center;gap:8px;text-decoration:none;color:var(--ink)}
.brand-mark{
  width:28px;height:28px;flex:0 0 auto;border-radius:9px;
  background:var(--teal-600);color:#fff;
  display:flex;align-items:center;justify-content:center;
}
.brand-text{font-size:16px;font-weight:700;letter-spacing:-.01em}
.whoami{font-size:12.5px;color:var(--muted);max-width:44%;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}

/* ===================== 底部 Tab 栏 ===================== */
.tabbar{
  position:fixed;left:50%;bottom:0;transform:translateX(-50%);
  width:100%;max-width:540px;z-index:40;
  display:grid;grid-template-columns:repeat(4,1fr);
  background:#fff;border-top:1px solid var(--line);
  padding-bottom:env(safe-area-inset-bottom);
  box-shadow:0 -2px 14px rgba(15,23,42,.05);
}
.tab{
  position:relative;
  display:flex;flex-direction:column;align-items:center;justify-content:center;gap:3px;
  min-height:var(--tab-h);min-width:44px;
  color:var(--muted);text-decoration:none;
  -webkit-tap-highlight-color:transparent;
  transition:color .18s ease;
}
.tab-ico{width:22px;height:22px;transition:transform .18s ease}
.tab-label{font-size:11.5px;letter-spacing:.01em}
.tab.active{color:var(--teal-600);font-weight:700}
.tab.active .tab-ico{transform:translateY(-1px) scale(1.06)}
.tab:active .tab-ico{transform:scale(.9)}
.tab-badge{
  position:absolute;top:5px;left:calc(50% + 5px);
  min-width:16px;height:16px;padding:0 4px;border-radius:999px;
  background:var(--bad);color:#fff;
  font-size:10px;font-style:normal;font-weight:700;line-height:16px;text-align:center;
}

/* ===================== 按钮 ===================== */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:6px;
  height:44px;padding:0 16px;
  border:1px solid transparent;border-radius:var(--r-sm);
  font:inherit;font-size:15px;font-weight:600;line-height:1;
  text-decoration:none;white-space:nowrap;cursor:pointer;
  -webkit-tap-highlight-color:transparent;
  transition:transform .12s ease,background-color .18s ease,border-color .18s ease,color .18s ease,box-shadow .18s ease;
}
.btn:active:not(:disabled){transform:scale(.975)}
.btn:disabled{opacity:.42;cursor:not-allowed}
.btn-lg{height:48px;font-size:16px}
.btn-sm{height:36px;font-size:13.5px;padding:0 12px;border-radius:9px}
.btn-block{width:100%}

.btn-primary{background:var(--teal-600);color:#fff}
.btn-primary:hover:not(:disabled){background:var(--teal-700)}
.btn-ok{background:var(--ok);color:#fff}
.btn-ok:hover:not(:disabled){background:#15803d}
.btn-bad{background:#fff;border-color:var(--bad);color:var(--bad)}
.btn-bad:hover:not(:disabled){background:var(--bad-bg)}
.btn-outline{background:#fff;border-color:var(--teal-600);color:var(--teal-700)}
.btn-outline:hover:not(:disabled){background:var(--teal-50)}
.btn-ghost{background:#fff;border-color:var(--line);color:var(--ink-2)}
.btn-ghost:hover:not(:disabled){background:#f8fafc}
.btn-solid-danger{background:var(--bad);color:#fff}
.btn-solid-danger:hover:not(:disabled){background:#b91c1c}

.btn-icon{
  flex:0 0 auto;width:42px;height:42px;padding:0;
  border:1px solid var(--line);border-radius:11px;background:#fff;color:var(--ink-2);
  display:inline-flex;align-items:center;justify-content:center;cursor:pointer;
  transition:transform .12s ease,background-color .18s ease;
  -webkit-tap-highlight-color:transparent;
}
.btn-icon:active{transform:scale(.94)}
.btn-icon svg{width:19px;height:19px}

/* ===================== 表单 ===================== */
.field{display:block;margin-bottom:14px}
.field > span{display:block;font-size:13px;font-weight:600;color:var(--ink-2);margin-bottom:6px}
.field input,.field select{
  width:100%;height:46px;padding:0 13px;
  font:inherit;font-size:15.5px;color:var(--ink);
  background:#fff;border:1px solid var(--line);border-radius:var(--r-sm);
  outline:none;
  transition:border-color .18s ease,box-shadow .18s ease;
}
.field input:focus,.field select:focus{
  border-color:var(--teal-600);
  box-shadow:0 0 0 3px rgba(13,148,136,.14);
}
.form-error{font-size:13px;color:var(--bad);margin:10px 0 0;min-height:18px;line-height:1.5}
.form-ok{color:var(--ok)}

/* ===================== 卡片 / 分区 ===================== */
.card{
  background:var(--card);
  border:1px solid rgba(15,23,42,.035);
  border-radius:var(--r-lg);
  padding:16px;
  box-shadow:var(--shadow);
  margin-bottom:12px;
}
.card h2{font-size:15px;font-weight:700;margin:0 0 12px}

.page-head{margin:4px 0 14px}
.page-head h1{font-size:20px;font-weight:700;margin:0 0 3px}
.page-head .sub{font-size:13px;color:var(--muted);margin:0}

.section-title{
  display:flex;align-items:baseline;justify-content:space-between;gap:8px;
  font-size:14px;font-weight:700;margin:18px 2px 10px;
}
.section-title .sub{font-size:12px;font-weight:400;color:var(--muted)}

/* ===================== 进度条 ===================== */
.progress{height:7px;border-radius:999px;background:#e9eef2;overflow:hidden}
.progress-bar{height:100%;border-radius:999px;background:var(--teal-600);transition:width .4s ease}
.progress.thin{height:5px}

/* ===================== 环形进度 ===================== */
.ring-box{position:relative;width:104px;height:104px;flex:0 0 auto}
.ring{width:104px;height:104px;transform:rotate(-90deg)}
.ring circle{fill:none;stroke-width:9;stroke-linecap:round}
.ring-track{stroke:#e9eef2}
.ring-value{stroke:var(--teal-600);transition:stroke-dashoffset .7s ease}
.ring-center{
  position:absolute;inset:0;
  display:flex;flex-direction:column;align-items:center;justify-content:center;
}
.ring-pct{font-size:24px;font-weight:700;line-height:1;font-variant-numeric:tabular-nums}
.ring-lab{font-size:11px;color:var(--muted);margin-top:4px}

/* ===================== 统计卡 ===================== */
.stat-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-bottom:12px}
.stat{
  background:#fff;border:1px solid rgba(15,23,42,.035);
  border-radius:var(--r-md);padding:13px 8px;text-align:center;box-shadow:var(--shadow);
}
.stat-num{font-size:21px;font-weight:700;line-height:1.15;font-variant-numeric:tabular-nums}
.stat-lab{font-size:12px;color:var(--muted);margin-top:3px}
.stat.is-done .stat-num{color:var(--teal-600)}
.stat.is-ok .stat-num{color:var(--ok)}
.stat.is-bad .stat-num{color:var(--bad)}

/* ===================== 首页模块手风琴 ===================== */
.module{
  background:#fff;border:1px solid rgba(15,23,42,.035);
  border-radius:var(--r-lg);box-shadow:var(--shadow);
  margin-bottom:10px;overflow:hidden;
}
.module-head{
  display:flex;align-items:center;gap:12px;width:100%;min-height:64px;
  padding:13px 15px;background:none;border:0;font:inherit;text-align:left;cursor:pointer;
  -webkit-tap-highlight-color:transparent;
}
.module-ico{
  width:38px;height:38px;flex:0 0 auto;border-radius:11px;
  background:var(--teal-50);color:var(--teal-700);
  display:flex;align-items:center;justify-content:center;
}
.module-ico svg{width:19px;height:19px}
.module-main{flex:1;min-width:0}
.module-title{display:block;font-size:15.5px;font-weight:650}
.module-meta{display:block;font-size:12px;color:var(--muted);margin-top:3px}
.module-chev{flex:0 0 auto;color:var(--muted-2);transition:transform .25s ease}
.module-chev svg{width:18px;height:18px;display:block}
.module.open .module-chev{transform:rotate(180deg)}
.module-bar{padding:0 15px 2px}
.module-body{display:grid;grid-template-rows:0fr;transition:grid-template-rows .28s ease}
.module.open .module-body{grid-template-rows:1fr}
.module-body > div{overflow:hidden;min-height:0}
.module-chapters{padding:8px 8px 10px}

/* ===================== 章节行 ===================== */
.ch-row{
  display:flex;align-items:center;gap:10px;min-height:58px;
  padding:10px 11px;border-radius:var(--r-sm);text-decoration:none;color:inherit;
  transition:background-color .16s ease;
}
.ch-row:hover{background:#f8fafc}
.ch-no{
  flex:0 0 auto;padding:3px 7px;border-radius:7px;
  background:var(--teal-50);color:var(--teal-700);
  font-size:12px;font-weight:700;font-variant-numeric:tabular-nums;
}
.ch-main{flex:1;min-width:0}
.ch-title{font-size:14.5px;font-weight:500;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.ch-sub{display:flex;align-items:center;gap:8px;margin-top:6px}
.ch-sub .progress{flex:1}
.ch-count{flex:0 0 auto;font-size:11.5px;color:var(--muted);font-variant-numeric:tabular-nums}
.ch-rate{
  flex:0 0 auto;font-size:11px;font-weight:700;padding:2px 7px;border-radius:999px;
  background:var(--teal-50);color:var(--teal-700);font-variant-numeric:tabular-nums;
}
.ch-rate.is-ok{background:var(--ok-bg);color:var(--ok)}
.ch-rate.is-bad{background:var(--bad-bg);color:var(--bad)}
.ch-rate.is-idle{background:#f1f5f9;color:var(--muted)}

/* ===================== 空状态 ===================== */
.empty{display:flex;flex-direction:column;align-items:center;text-align:center;padding:38px 18px}
.empty-art{width:104px;height:104px;color:var(--teal-500);margin-bottom:14px}
.empty-title{font-size:16.5px;font-weight:700}
.empty-desc{font-size:13.5px;color:var(--muted);line-height:1.7;max-width:270px;margin-top:6px}
.empty .btn{margin-top:18px}

/* ===================== 加载 ===================== */
.loading{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:12px;padding:56px 0;color:var(--muted);font-size:13.5px}
.spinner{
  width:26px;height:26px;border-radius:50%;
  border:2.5px solid var(--teal-100);border-top-color:var(--teal-600);
  animation:spin .75s linear infinite;
}
@keyframes spin{to{transform:rotate(360deg)}}

/* ===================== 刷题入口大卡 ===================== */
.mode-list{display:flex;flex-direction:column;gap:11px}
.mode-card{
  display:flex;align-items:center;gap:13px;width:100%;min-height:74px;
  padding:15px;background:#fff;border:1px solid rgba(15,23,42,.045);
  border-radius:var(--r-lg);box-shadow:var(--shadow);
  font:inherit;text-align:left;cursor:pointer;
  -webkit-tap-highlight-color:transparent;
  transition:transform .12s ease,box-shadow .2s ease,border-color .2s ease;
}
.mode-card:hover:not(:disabled){box-shadow:var(--shadow-md);border-color:var(--teal-100)}
.mode-card:active:not(:disabled){transform:scale(.985)}
.mode-card:disabled{opacity:.5;cursor:not-allowed}
.mode-ico{width:44px;height:44px;flex:0 0 auto;border-radius:13px;display:flex;align-items:center;justify-content:center}
.mode-ico svg{width:22px;height:22px}
.mode-card[data-mode="all"] .mode-ico{background:var(--teal-50);color:var(--teal-700)}
.mode-card[data-mode="wrong"] .mode-ico{background:var(--bad-bg);color:var(--bad)}
.mode-card[data-mode="unfinished"] .mode-ico{background:var(--amber-bg);color:var(--amber)}
.mode-body{flex:1;min-width:0}
.mode-title{display:block;font-size:15.5px;font-weight:650}
.mode-desc{display:block;font-size:12.5px;color:var(--muted);line-height:1.5;margin-top:3px}
.mode-count{flex:0 0 auto;text-align:right}
.mode-count b{display:block;font-size:19px;font-weight:700;line-height:1.1;font-variant-numeric:tabular-nums}
.mode-count span{font-size:11px;color:var(--muted)}

/* 分段控件（题量） */
.seg{display:grid;grid-template-columns:repeat(4,1fr);gap:5px;background:#f1f5f9;border-radius:var(--r-sm);padding:4px}
.seg button{
  height:38px;border:0;border-radius:8px;background:transparent;
  font:inherit;font-size:14px;font-weight:600;color:var(--muted);cursor:pointer;
  -webkit-tap-highlight-color:transparent;
  transition:background-color .18s ease,color .18s ease,box-shadow .18s ease;
}
.seg button.on{background:#fff;color:var(--teal-700);box-shadow:0 1px 3px rgba(15,23,42,.1)}
.seg-hint{font-size:12px;color:var(--muted-2);margin:9px 2px 0}

/* ===================== 题目列表 ===================== */
.q-list{display:flex;flex-direction:column;gap:8px;list-style:none;margin:0;padding:0}
.q-item{
  display:flex;align-items:center;gap:11px;min-height:60px;
  padding:12px 13px;background:#fff;border:1px solid rgba(15,23,42,.035);
  border-radius:var(--r-md);box-shadow:var(--shadow);cursor:pointer;
  transition:transform .12s ease,box-shadow .2s ease;
}
.q-item:active{transform:scale(.99)}
.q-no{
  flex:0 0 auto;width:27px;height:27px;border-radius:8px;
  background:#f1f5f9;color:var(--muted);
  display:flex;align-items:center;justify-content:center;
  font-size:12px;font-weight:700;font-variant-numeric:tabular-nums;
}
.q-main{flex:1;min-width:0}
.q-stem{
  font-size:14.5px;line-height:1.55;color:var(--ink-2);
  display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;
}
.q-sub{font-size:12px;color:var(--muted);margin-top:4px}
.q-answer{margin-top:11px;padding-top:11px;border-top:1px dashed var(--line)}
.q-mark{
  flex:0 0 auto;width:22px;height:22px;border-radius:50%;
  display:flex;align-items:center;justify-content:center;
}
.q-mark svg{width:13px;height:13px}
.q-mark.is-ok{background:var(--ok-bg);color:var(--ok)}
.q-mark.is-bad{background:var(--bad-bg);color:var(--bad)}
.q-mark.is-idle{background:#f1f5f9;color:var(--muted-2)}
.q-times{
  flex:0 0 auto;font-size:11px;font-weight:700;padding:2px 7px;border-radius:999px;
  background:var(--bad-bg);color:var(--bad);
}

/* ===================== 做题页 ===================== */
.practice-head{display:flex;align-items:center;gap:9px;margin-bottom:11px}
.practice-title{
  flex:1;min-width:0;font-size:14.5px;font-weight:600;
  overflow:hidden;text-overflow:ellipsis;white-space:nowrap;
}
.practice-count{flex:0 0 auto;font-size:12.5px;color:var(--muted);font-variant-numeric:tabular-nums}

.qcard-head{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-bottom:12px}
.chip{
  padding:2px 8px;border-radius:999px;
  background:var(--teal-50);color:var(--teal-700);
  font-size:12px;font-weight:700;font-variant-numeric:tabular-nums;
}
.chip-title{font-size:12.5px;color:var(--muted)}
.qid{margin-left:auto;font-family:var(--mono);font-size:11px;color:var(--muted-2)}
.judge-flag{
  padding:2px 8px;border-radius:999px;font-size:11.5px;font-weight:700;
}
.judge-flag.is-ok{background:var(--ok-bg);color:var(--ok)}
.judge-flag.is-bad{background:var(--bad-bg);color:var(--bad)}

.stem{font-size:16px;line-height:1.78;color:var(--ink);white-space:pre-wrap;word-break:break-word}
.stem .mono{font-family:var(--mono)}

.imgs{display:grid;gap:11px;margin-top:15px}
.imgs figure{margin:0}
.imgs img{
  width:100%;display:block;border-radius:var(--r-sm);
  border:1px solid var(--line);background:#fff;cursor:zoom-in;
}
.imgs figcaption{font-size:11.5px;color:var(--muted-2);text-align:center;margin-top:5px}

/* 答案区（展开动画：grid 0fr→1fr，不会裁切长内容） */
.reveal{display:grid;grid-template-rows:0fr;opacity:0;transition:grid-template-rows .25s ease,opacity .25s ease}
.reveal.is-open{grid-template-rows:1fr;opacity:1}
.reveal > div{overflow:hidden;min-height:0}

.answer{
  background:var(--ok-bg);border:1px solid var(--ok-line);
  border-radius:var(--r-md);padding:15px;margin-top:15px;
}
.answer-lab{display:inline-flex;align-items:center;gap:6px;font-size:12.5px;font-weight:700;color:var(--ok);margin-bottom:9px}
.answer-lab svg{width:15px;height:15px}
.answer-body{font-size:15.5px;line-height:1.78;color:var(--ok-ink);white-space:pre-wrap;word-break:break-word}
.answer-body .mono{font-family:var(--mono)}
.basis{
  display:flex;align-items:flex-start;gap:7px;
  margin-top:13px;padding-top:12px;border-top:1px dashed var(--ok-line);
  font-size:12.5px;color:var(--muted);line-height:1.6;
}
.basis svg{width:14px;height:14px;flex:0 0 auto;margin-top:2px}
.basis .crumb{word-break:break-word}

.reveal-note{font-size:12.5px;color:var(--muted);text-align:center;margin:12px 0 0;line-height:1.6}

/* 底部固定操作栏 */
.actionbar{
  position:fixed;left:50%;bottom:0;transform:translateX(-50%);
  width:100%;max-width:540px;z-index:40;
  background:#fff;border-top:1px solid var(--line);
  padding:10px 14px calc(10px + env(safe-area-inset-bottom));
  box-shadow:0 -2px 14px rgba(15,23,42,.06);
}
.actionbar-inner{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.actionbar .btn{height:48px;font-size:16px}
.actionbar-single{display:block}
.actionbar-hint{font-size:11.5px;color:var(--muted);text-align:center;margin:7px 0 0}

/* 本轮小结 */
.summary-card{background:#fff;border-radius:var(--r-lg);padding:24px 18px;box-shadow:var(--shadow);text-align:center}
.summary-card h1{font-size:20px;font-weight:700;margin:0 0 4px}
.summary-card .sub{font-size:13px;color:var(--muted);margin:0 0 18px}
.summary-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-bottom:20px}
.summary-grid b{display:block;font-size:24px;font-weight:700;font-variant-numeric:tabular-nums;line-height:1.2}
.summary-grid span{font-size:12px;color:var(--muted)}
.summary-actions{display:grid;gap:9px}

/* ===================== 我的 ===================== */
.me-card{display:flex;align-items:center;gap:13px}
.me-avatar{
  width:52px;height:52px;flex:0 0 auto;border-radius:15px;
  background:var(--teal-50);color:var(--teal-700);
  display:flex;align-items:center;justify-content:center;
}
.me-avatar svg{width:26px;height:26px}
.me-name{font-size:17px;font-weight:700;word-break:break-all}
.me-meta{font-size:12.5px;color:var(--muted);margin-top:2px}

.menu{background:#fff;border:1px solid rgba(15,23,42,.035);border-radius:var(--r-lg);box-shadow:var(--shadow);overflow:hidden}
.menu-item{
  display:flex;align-items:center;gap:12px;width:100%;min-height:56px;
  padding:13px 15px;background:none;border:0;border-bottom:1px solid var(--line-soft);
  font:inherit;font-size:15px;color:var(--ink);text-align:left;text-decoration:none;cursor:pointer;
  -webkit-tap-highlight-color:transparent;
  transition:background-color .16s ease;
}
.menu-item:last-child{border-bottom:0}
.menu-item:hover{background:#f8fafc}
.menu-item svg{width:19px;height:19px;flex:0 0 auto;color:var(--muted)}
.menu-item .menu-lab{flex:1;min-width:0}
.menu-item .menu-sub{font-size:12px;color:var(--muted);margin-top:2px}
.menu-item .menu-chev{color:var(--muted-2);width:17px;height:17px}
.menu-item.is-danger{color:var(--bad)}
.menu-item.is-danger svg{color:var(--bad)}

/* ===================== 登录页 ===================== */
.auth{
  min-height:calc(100vh - 40px);
  display:flex;flex-direction:column;justify-content:center;
  max-width:400px;margin:0 auto;padding:20px 0 30px;
}
.auth-logo{
  width:60px;height:60px;border-radius:18px;margin:0 auto 16px;
  background:var(--teal-600);color:#fff;
  display:flex;align-items:center;justify-content:center;
  box-shadow:0 10px 22px rgba(13,148,136,.26);
}
.auth-logo svg{width:30px;height:30px}
.auth h1{font-size:23px;font-weight:700;text-align:center;margin:0 0 5px}
.auth-sub{font-size:13.5px;color:var(--muted);text-align:center;margin:0 0 24px}
.auth-card{background:#fff;border-radius:20px;padding:22px 20px;box-shadow:var(--shadow-md)}
.auth-foot{font-size:12px;color:var(--muted-2);text-align:center;margin-top:18px;line-height:1.7}

/* ===================== 轻提示 ===================== */
.toast{
  position:fixed;left:50%;bottom:calc(var(--tab-h) + env(safe-area-inset-bottom) + 18px);
  transform:translate(-50%,10px);
  z-index:99;max-width:min(90vw,420px);
  padding:11px 16px;border-radius:11px;
  background:#0f172a;color:#fff;font-size:13.5px;line-height:1.5;
  box-shadow:var(--shadow-lg);
  opacity:0;pointer-events:none;
  transition:opacity .2s ease,transform .2s ease;
}
.toast.show{opacity:1;transform:translate(-50%,0)}
.toast.is-ok{background:#15803d}
.toast.is-bad{background:#b91c1c}

/* ===================== 图片放大 ===================== */
.lightbox{
  position:fixed;inset:0;z-index:90;
  background:rgba(15,23,42,.9);
  display:flex;align-items:center;justify-content:center;
  padding:16px;
  animation:pop .18s ease;
}
.lightbox img{max-width:100%;max-height:88vh;border-radius:8px;box-shadow:var(--shadow-lg)}
.lightbox-close{
  position:absolute;top:calc(14px + env(safe-area-inset-top));right:14px;
  width:44px;height:44px;border-radius:50%;border:0;
  background:rgba(255,255,255,.18);color:#fff;
  display:flex;align-items:center;justify-content:center;cursor:pointer;
  -webkit-tap-highlight-color:transparent;
}

/* ===================== 二次确认对话框 ===================== */
.dialog{
  position:fixed;inset:0;z-index:95;
  background:rgba(15,23,42,.45);
  display:flex;align-items:center;justify-content:center;
  padding:24px;
}
.dialog-card{
  width:100%;max-width:340px;
  background:#fff;border-radius:var(--r-lg);padding:20px;
  box-shadow:var(--shadow-lg);
  animation:pop .2s ease;
}
.dialog-card h3{font-size:16.5px;font-weight:700;margin:0 0 8px}
.dialog-card p{font-size:14px;color:var(--muted);line-height:1.7;margin:0 0 18px}
.dialog-actions{display:grid;grid-template-columns:1fr 1fr;gap:10px}

/* ===================== 动效 ===================== */
@keyframes rise{from{opacity:0;transform:translateY(9px)}to{opacity:1;transform:none}}
@keyframes pop{from{opacity:0;transform:scale(.96)}to{opacity:1;transform:none}}
.rise{animation:rise .34s cubic-bezier(.2,.7,.3,1) both;animation-delay:var(--d,0s)}

@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
  }
}

/* ===================== 局部补充（首页 / 我的 / 做题细节） ===================== */
.ico{width:18px;height:18px;flex:0 0 auto}
.btn-icon{text-decoration:none}

.welcome{margin:2px 2px 14px}
.welcome h1{font-size:19px;font-weight:700;margin:0 0 3px}
.welcome p{font-size:12.5px;color:var(--muted);margin:0}

.hero{display:flex;align-items:center;gap:18px}
.hero-main{flex:1;min-width:0}
.hero-k{font-size:12.5px;color:var(--muted)}
.hero-v{font-size:21px;font-weight:700;margin-top:2px;font-variant-numeric:tabular-nums}
.hero-v-sub{font-size:13px;font-weight:500;color:var(--muted)}
.hero-sub{font-size:12.5px;color:var(--muted);margin-top:7px;line-height:1.65}

.ch-row.is-empty{opacity:.55;cursor:default}

.toolbar{display:grid;gap:9px;margin:14px 0 4px}
.toolbar-row{display:grid;grid-template-columns:1fr 1fr;gap:9px}
.chapter-stats{font-size:12.5px;color:var(--muted);margin:9px 2px 0}

.me-main{flex:1;min-width:0}
.me-foot{font-size:12px;color:var(--muted-2);text-align:center;margin:22px 0 0}

.answer-imgs{margin-top:13px;padding-top:12px;border-top:1px dashed var(--ok-line)}
.answer-lab2{display:flex;align-items:center;gap:6px;font-size:12px;font-weight:700;color:var(--ok);margin-bottom:9px}
.answer-lab2 svg{width:14px;height:14px}
.thumb-strip{display:flex;gap:9px;overflow-x:auto;padding-bottom:3px;-webkit-overflow-scrolling:touch}
.thumb-strip img{
  height:76px;width:auto;flex:0 0 auto;border-radius:9px;
  border:1px solid var(--ok-line);background:#fff;cursor:zoom-in;
}

/* ===================== 桌面端 ===================== */
@media (min-width:560px){
  body{background:#eceff3}
  .app{
    background:var(--bg);
    min-height:100vh;
    padding-left:18px;padding-right:18px;
    box-shadow:0 0 0 1px rgba(15,23,42,.04);
  }
  .topbar-inner{padding:0 18px}
  .lightbox img{max-width:min(92vw,900px)}
}