/* ============================================================
   网络赛道 · 刷题 — 「答卷 · 纸墨」
   零外部依赖：不使用 Web 字体、CDN、框架。
   ============================================================ */

/* ---------- 设计令牌 ---------- */
:root{
  --paper:#F6F3EC;      --paper-2:#FFFDF8;    --paper-3:#EFEAE0;
  --ink:#1A1A18;        --ink-2:#4B4B45;      --ink-3:#7C7C73;
  --line:#DED7C7;       --line-strong:#C6BCA7;
  --seal:#A8352A;       --seal-soft:#F3E2DE;
  --jade:#256B57;       --jade-soft:#DFEDE7;
  --amber:#A9761F;      --amber-soft:#F5EAD3;
  --seal-press:#8C2A21;
  --jade-press:#1C5747;
  --shadow:0 1px 0 rgba(26,26,24,.06), 0 8px 24px -18px rgba(26,26,24,.45);
  --shadow-lift:0 2px 0 rgba(26,26,24,.05), 0 18px 40px -30px rgba(26,26,24,.6);
  --radius:10px;        --radius-sm:7px;
  --font-display:"Noto Serif SC","Songti SC","SimSun",Georgia,serif;
  --font-body:system-ui,-apple-system,"PingFang SC","Microsoft YaHei","Noto Sans SC",sans-serif;
  --font-mono:ui-monospace,"Cascadia Mono",Consolas,"Courier New",monospace;
  --font-scale:1;
  --tab-h:56px;
  --safe-b:env(safe-area-inset-bottom,0px);
  --ease:cubic-bezier(.22,.61,.36,1);
}
[data-theme="dark"]{
  --paper:#141619; --paper-2:#1B1E23; --paper-3:#22262C;
  --ink:#ECEAE2;   --ink-2:#B7B5AC;   --ink-3:#8A8880;
  --line:#2E3238;  --line-strong:#3D434B;
  --seal:#E36A5C;  --seal-soft:#3A2422;
  --jade:#54B393;  --jade-soft:#16302A;
  --amber:#D8A64E; --amber-soft:#332A18;
  --seal-press:#C65548;
  --jade-press:#3F9079;
  --shadow:0 1px 0 rgba(0,0,0,.4), 0 10px 26px -20px #000;
  --shadow-lift:0 2px 0 rgba(0,0,0,.35), 0 22px 44px -30px #000;
}

/* ---------- 基础 ---------- */
*,*::before,*::after{box-sizing:border-box}
[hidden]{display:none!important}
html{
  font-size:calc(16px * var(--font-scale,1));
  -webkit-text-size-adjust:100%;
  scroll-behavior:smooth;
}
body{
  margin:0;
  min-height:100vh;
  color:var(--ink);
  background-color:var(--paper);
  background-image:
    radial-gradient(1100px 520px at 82% -12%, color-mix(in srgb, var(--seal) 6%, transparent), transparent 62%),
    repeating-linear-gradient(90deg, color-mix(in srgb, var(--ink) 2%, transparent) 0 1px, transparent 1px 4px);
  font-family:var(--font-body);
  font-size:1rem;
  line-height:1.7;
  font-feature-settings:"tnum" 0;
  -webkit-font-smoothing:antialiased;
}
[data-theme="dark"] body{
  background-image:
    radial-gradient(1100px 520px at 82% -12%, color-mix(in srgb, var(--seal) 9%, transparent), transparent 62%),
    repeating-linear-gradient(90deg, color-mix(in srgb, var(--ink) 2.4%, transparent) 0 1px, transparent 1px 4px);
}
h1,h2,h3,h4,p,figure,blockquote{margin:0}
h1,h2,h3,h4{font-family:var(--font-display);font-weight:600;line-height:1.35;letter-spacing:.01em}
a{color:var(--seal);text-decoration-thickness:1px;text-underline-offset:3px}
button{font:inherit;color:inherit}
svg{display:block}
img{max-width:100%}
:focus-visible{outline:2px solid var(--seal);outline-offset:2px}
::selection{background:var(--amber-soft);color:var(--ink)}
.ico{flex:none;width:20px;height:20px}
.sr-only{
  position:absolute!important;width:1px;height:1px;padding:0;margin:-1px;
  overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0;
}
.skip-link{
  position:fixed;left:12px;top:-64px;z-index:90;
  padding:10px 16px;border-radius:0 0 var(--radius-sm) var(--radius-sm);
  background:var(--seal);color:var(--paper-2);text-decoration:none;
  transition:top .2s var(--ease);
}
.skip-link:focus{top:0}
.noscript{margin:20px;padding:16px;border:1px solid var(--line);border-radius:var(--radius);background:var(--paper-2)}

/* ---------- 顶栏 ---------- */
.topbar{
  position:sticky;top:0;z-index:40;
  border-top:3px double var(--line-strong);
  border-bottom:1px solid var(--line);
  background:color-mix(in srgb, var(--paper) 90%, transparent);
  -webkit-backdrop-filter:blur(10px);
  backdrop-filter:blur(10px);
}
.topbar-inner{
  max-width:1140px;margin:0 auto;padding:0 16px;min-height:56px;
  display:flex;align-items:center;justify-content:space-between;gap:12px;
}
.brand{display:inline-flex;align-items:center;gap:9px;min-height:44px;color:var(--ink);text-decoration:none}
.brand-seal{
  width:26px;height:26px;flex:none;display:grid;place-items:center;
  background:var(--seal);color:var(--paper-2);
  font-family:var(--font-display);font-size:.875rem;line-height:1;border-radius:3px;
  box-shadow:0 1px 0 color-mix(in srgb, var(--ink) 20%, transparent);
}
.brand-text{font-family:var(--font-display);font-size:1.0625rem;letter-spacing:.04em;white-space:nowrap}
.brand-dot{color:var(--seal);padding:0 1px}
.topbar-right{display:flex;align-items:center;gap:6px}
.topbar-progress{
  font-size:.75rem;color:var(--ink-2);letter-spacing:.04em;
  font-variant-numeric:tabular-nums;white-space:nowrap;
}
.icon-btn{
  width:44px;height:44px;display:grid;place-items:center;
  border:1px solid transparent;border-radius:999px;background:transparent;
  color:var(--ink-2);cursor:pointer;
  transition:background .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease);
}
.icon-btn:hover{background:var(--paper-3);color:var(--ink);border-color:var(--line)}
.theme-icon-moon{display:none}
[data-theme="dark"] .theme-icon-sun{display:none}
[data-theme="dark"] .theme-icon-moon{display:block}

/* ---------- 布局 ---------- */
.layout{max-width:1140px;margin:0 auto}
.content{
  max-width:860px;margin:0 auto;width:100%;
  padding:18px 16px calc(var(--tab-h) + var(--safe-b) + 28px);
}
.content:focus{outline:none}
.sidenav{display:none}
@media (min-width:1024px){
  .topbar-inner{min-height:64px;padding:0 24px}
  .layout{display:grid;grid-template-columns:220px minmax(0,1fr);gap:36px;padding:0 24px;max-width:1140px}
  .content{padding:34px 0 80px;margin:0 auto;max-width:860px}
  .sidenav{display:block;position:sticky;top:100px;align-self:start;padding-top:8px}
}
.sidenav-title{
  font-size:.6875rem;letter-spacing:.22em;text-transform:uppercase;
  color:var(--ink-2);margin:0 12px 10px;
}
.nav-link{
  display:flex;align-items:center;gap:10px;position:relative;
  min-height:44px;padding:0 12px;margin-bottom:2px;
  border-left:2px solid transparent;border-radius:0 var(--radius-sm) var(--radius-sm) 0;
  color:var(--ink-2);text-decoration:none;font-size:.9375rem;
  transition:background .18s var(--ease),color .18s var(--ease),border-color .18s var(--ease);
}
.nav-link:hover{background:var(--paper-2);color:var(--ink)}
.nav-link.is-active{background:var(--paper-2);color:var(--ink);border-left-color:var(--seal);box-shadow:var(--shadow)}
.nav-label{flex:1}
.nav-count{
  min-width:22px;height:22px;padding:0 6px;display:grid;place-items:center;
  border-radius:999px;background:var(--seal);color:var(--paper-2);
  font-size:.6875rem;font-variant-numeric:tabular-nums;
}
.sidenav-foot{
  margin:24px 12px 0;padding-top:14px;border-top:1px solid var(--line);
  font-size:.75rem;line-height:1.8;color:var(--ink-2);
}

/* ---------- 底部标签栏 ---------- */
.tabbar{
  position:fixed;left:0;right:0;bottom:0;z-index:35;
  display:grid;grid-template-columns:repeat(4,1fr);
  height:calc(var(--tab-h) + var(--safe-b));
  padding-bottom:var(--safe-b);
  background:color-mix(in srgb, var(--paper-2) 94%, transparent);
  -webkit-backdrop-filter:blur(12px);
  backdrop-filter:blur(12px);
  border-top:1px solid var(--line);
}
.tab-item{
  position:relative;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:3px;
  min-height:44px;color:var(--ink-2);text-decoration:none;
  font-size:.6875rem;letter-spacing:.06em;
  transition:color .18s var(--ease);
}
.tab-item .ico{width:20px;height:20px}
.tab-item.is-active{color:var(--seal)}
.tab-item.is-active::after{
  content:"";position:absolute;top:6px;width:18px;height:2px;border-radius:2px;background:var(--seal);
}
.tab-item .nav-count{position:absolute;top:5px;left:calc(50% + 6px);min-width:18px;height:18px;padding:0 5px;font-size:.625rem}
body[data-view="quiz"] .tabbar{display:none}
@media (min-width:1024px){
  .tabbar{display:none}
  body[data-view="quiz"] .tabbar{display:none}
}

/* ---------- 通用排版 ---------- */
.view{display:block;animation:view-in .22s var(--ease) both}
@keyframes view-in{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
.page-head{
  display:flex;align-items:flex-end;justify-content:space-between;gap:16px;
  padding-bottom:14px;margin-bottom:20px;border-bottom:1px solid var(--line);
}
.eyebrow{
  display:flex;align-items:center;gap:8px;
  font-size:.6875rem;letter-spacing:.2em;text-transform:uppercase;
  color:var(--seal);margin-bottom:8px;
}
.eyebrow::before{content:"";width:22px;height:1px;background:currentColor;opacity:.7;flex:none}
.page-title{font-size:1.75rem;line-height:1.25;letter-spacing:.02em}
.page-desc{margin-top:8px;color:var(--ink-2);font-size:.9375rem;max-width:56ch}
.muted{color:var(--ink-2)}
.card{
  background:var(--paper-2);border:1px solid var(--line);border-radius:var(--radius);
  box-shadow:var(--shadow);padding:18px;margin-bottom:18px;
}
@media (min-width:640px){.card{padding:22px}}
.card-head{display:flex;align-items:flex-start;justify-content:space-between;gap:14px;margin-bottom:14px}
.card-title{font-size:1.25rem;letter-spacing:.02em}
.card-hint{color:var(--ink-2);font-size:.8125rem;text-align:right;max-width:22ch;line-height:1.5}
.tag{
  display:inline-flex;align-items:center;gap:4px;
  padding:1px 7px;border:1px solid var(--line-strong);border-radius:3px;
  font-size:.6875rem;letter-spacing:.12em;color:var(--ink-2);
  background:var(--paper-3);white-space:nowrap;
}
.section-head{display:flex;align-items:baseline;justify-content:space-between;gap:12px;margin:4px 0 12px}
.section-title{font-size:1.0625rem;letter-spacing:.02em}

/* ---------- 按钮 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  min-height:44px;padding:0 16px;
  border:1px solid var(--line-strong);border-radius:var(--radius-sm);
  background:var(--paper-2);color:var(--ink);
  font-size:.9375rem;line-height:1.2;text-decoration:none;cursor:pointer;
  transition:background .18s var(--ease),border-color .18s var(--ease),color .18s var(--ease),transform .18s var(--ease);
}
.btn:hover{background:var(--paper-3);border-color:var(--ink-2)}
.btn:active{transform:translateY(1px)}
.btn-primary{background:var(--seal);border-color:var(--seal);color:var(--paper-2)}
.btn-primary:hover{background:var(--seal-press);border-color:var(--seal-press);color:var(--paper-2)}
.btn-ghost{background:transparent;border-color:transparent;color:var(--ink-2)}
.btn-ghost:hover{background:var(--paper-3);border-color:var(--line);color:var(--ink)}
.btn-danger{background:transparent;border-color:var(--seal);color:var(--seal)}
.btn-danger:hover{background:var(--seal-soft);border-color:var(--seal);color:var(--seal)}
.btn-danger.is-armed{background:var(--seal);color:var(--paper-2)}
.btn[disabled],.btn[aria-disabled="true"]{opacity:.45;cursor:not-allowed;transform:none}
.btn-sm{min-height:44px;padding:0 12px;font-size:.875rem}
.btn .ico{width:18px;height:18px}
.btn-block{width:100%}

/* ---------- 首页 ---------- */
.hero{position:relative;padding:22px 0 26px;border-bottom:1px solid var(--line);margin-bottom:20px}
.hero-main{padding-right:72px}
.hero-title{font-size:clamp(1.75rem,6vw,2.125rem);line-height:1.3;margin-bottom:10px}
.hero-lead{color:var(--ink-2);font-size:.9375rem;max-width:52ch}
.hero-actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:18px}
.hero-stamp{
  position:absolute;right:2px;top:18px;width:52px;height:74px;
  display:grid;grid-template-rows:1fr 1fr;place-items:center;
  border:2px solid var(--seal);border-radius:4px;color:var(--seal);
  font-family:var(--font-display);font-size:1.25rem;line-height:1;
  transform:rotate(4deg);opacity:.55;pointer-events:none;
}
.hero-stamp span{padding-top:2px}
.stat-strip{
  display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:1px;
  background:var(--line);border:1px solid var(--line);border-radius:var(--radius);
  overflow:hidden;box-shadow:var(--shadow);margin-bottom:20px;
}
.stat{background:var(--paper-2);padding:13px 16px;min-width:0}
.stat-label{font-size:.75rem;letter-spacing:.14em;color:var(--ink-2);margin-bottom:2px}
.stat-value{font-family:var(--font-display);font-size:1.625rem;line-height:1.25;font-variant-numeric:tabular-nums;white-space:nowrap}
.stat-unit{font-family:var(--font-body);font-size:.75rem;color:var(--ink-2);margin-left:3px;letter-spacing:0}
@media (min-width:640px){.stat-strip{grid-template-columns:repeat(4,minmax(0,1fr))}}

.chips{display:flex;flex-wrap:wrap;gap:8px}
.chip{
  min-height:44px;padding:0 14px;display:inline-flex;align-items:center;gap:6px;
  border:1px solid var(--line-strong);border-radius:999px;
  background:var(--paper-2);color:var(--ink-2);
  font-size:.875rem;cursor:pointer;
  transition:background .18s var(--ease),border-color .18s var(--ease),color .18s var(--ease);
}
.chip:hover{border-color:var(--ink-2);color:var(--ink)}
.chip.is-on{background:var(--ink);border-color:var(--ink);color:var(--paper-2)}
.chip .chip-count{font-size:.75rem;opacity:.75;font-variant-numeric:tabular-nums}
.setup-row{display:flex;align-items:center;gap:14px;flex-wrap:wrap;margin-top:16px}
.field-label{font-size:.8125rem;letter-spacing:.08em;color:var(--ink-2)}
.segmented{display:inline-flex;border:1px solid var(--line-strong);border-radius:var(--radius-sm);overflow:hidden;background:var(--paper-2)}
.seg-btn{
  min-height:44px;padding:0 14px;border:0;border-right:1px solid var(--line);
  background:transparent;color:var(--ink-2);font-size:.875rem;cursor:pointer;
  transition:background .18s var(--ease),color .18s var(--ease);
}
.seg-btn:last-child{border-right:0}
.seg-btn:hover{background:var(--paper-3);color:var(--ink)}
.seg-btn[aria-pressed="true"]{background:var(--ink);color:var(--paper-2)}
.setup-foot{display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap;margin-top:18px;padding-top:16px;border-top:1px dashed var(--line)}
.setup-foot p{font-size:.8125rem}
.topic-list{display:grid;gap:1px;background:var(--line);border:1px solid var(--line);border-radius:var(--radius-sm);overflow:hidden}
.topic-row{display:flex;align-items:center;gap:12px;background:var(--paper-2);padding:10px 14px;min-height:48px}
.topic-name{flex:1;font-size:.9375rem;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.topic-meta{font-size:.75rem;color:var(--ink-2);font-variant-numeric:tabular-nums;white-space:nowrap}
.topic-bar{width:64px;height:4px;border-radius:99px;background:var(--paper-3);overflow:hidden;flex:none}
.topic-fill{display:block;height:100%;background:var(--jade);border-radius:99px}
.home-exam{display:flex;align-items:center;justify-content:space-between;gap:18px;flex-wrap:wrap}
.home-exam .home-exam-text{max-width:46ch}
.home-exam p{color:var(--ink-2);font-size:.875rem;margin-top:4px}
.home-exam h2{font-size:1.25rem}

/* ---------- 空状态 ---------- */
.empty{
  border:1px dashed var(--line-strong);border-radius:var(--radius);
  background:color-mix(in srgb, var(--paper-2) 70%, transparent);
  padding:36px 22px;text-align:center;
}
.empty-icon{width:40px;height:40px;margin:0 auto 12px;color:var(--ink-3)}
.empty-icon .ico{width:40px;height:40px;stroke-width:1.2}
.empty-title{font-size:1.25rem;margin-bottom:6px}
.empty-desc{color:var(--ink-2);font-size:.9375rem;max-width:44ch;margin:0 auto}
.empty-actions{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin-top:18px}

/* ---------- 答题 ---------- */
.quiz-top{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap;margin-bottom:14px}
.quiz-top-left{display:flex;align-items:center;gap:10px;flex-wrap:wrap;min-width:0}
.quiz-index{font-size:.8125rem;color:var(--ink-2);font-variant-numeric:tabular-nums;letter-spacing:.04em}
.exam-timer{
  display:inline-flex;align-items:center;gap:6px;
  font-family:var(--font-mono);font-size:.8125rem;font-variant-numeric:tabular-nums;
  color:var(--amber);background:var(--amber-soft);
  border:1px solid color-mix(in srgb, var(--amber) 35%, transparent);
  padding:2px 9px;border-radius:99px;
}
.exam-timer .ico{width:15px;height:15px}
.quiz-top-actions{display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.qcard{
  position:relative;background:var(--paper-2);border:1px solid var(--line);
  border-radius:var(--radius);box-shadow:var(--shadow);padding:22px 18px 20px;
}
.qcard::before{
  content:"";position:absolute;left:18px;top:-1px;width:52px;height:3px;background:var(--seal);
}
@media (min-width:640px){.qcard{padding:26px 26px 22px}}
.qnum{display:flex;align-items:center;gap:10px;margin-bottom:14px;flex-wrap:wrap}
.qnum-idx{font-family:var(--font-display);font-size:1.625rem;line-height:1;letter-spacing:.02em;font-variant-numeric:tabular-nums}
.qnum-rule{width:2px;height:24px;background:var(--seal);opacity:.85;flex:none}
.qnum-meta{font-size:.75rem;color:var(--ink-2);letter-spacing:.06em;min-width:0;overflow-wrap:anywhere}
.stem{font-size:1.0625rem;line-height:1.85;overflow-wrap:anywhere}
@media (min-width:640px){.stem{font-size:1.125rem}}
.stem p{margin:0 0 .55em}
.stem p:last-child{margin-bottom:0}
.cmd{
  font-family:var(--font-mono);font-size:.8125rem;line-height:1.75;
  background:var(--paper-3);color:var(--ink);
  border-left:3px solid var(--line-strong);
  border-radius:0 var(--radius-sm) var(--radius-sm) 0;
  padding:12px 14px;margin:12px 0;
  white-space:pre;overflow-x:auto;max-width:100%;
  -webkit-overflow-scrolling:touch;
}
.q-hint{display:flex;align-items:center;gap:6px;color:var(--amber);font-size:.8125rem;margin-top:12px}
.q-hint .ico{width:16px;height:16px}
.options{display:grid;gap:10px;margin-top:18px}
.option{
  position:relative;display:grid;grid-template-columns:28px minmax(0,1fr) 20px;gap:13px;align-items:center;
  width:100%;min-height:52px;padding:12px 14px 12px 17px;text-align:left;
  border:1px solid var(--line);border-radius:var(--radius-sm);
  background:var(--paper-2);color:var(--ink);cursor:pointer;
  transition:border-color .18s var(--ease),background .18s var(--ease),box-shadow .18s var(--ease);
}
.option::before{
  content:"";position:absolute;left:0;top:8px;bottom:8px;width:3px;border-radius:0 2px 2px 0;
  background:transparent;transition:background .18s var(--ease);
}
.option:hover{border-color:var(--line-strong);background:var(--paper-3)}
.option.is-picked{border-color:var(--ink);background:var(--paper-3)}
.option.is-picked::before{background:var(--seal)}
.option.is-correct{border-color:var(--jade);background:var(--jade-soft)}
.option.is-correct::before{background:var(--jade)}
.option.is-wrong{border-color:var(--seal);background:var(--seal-soft)}
.option.is-wrong::before{background:var(--seal)}
.option[aria-disabled="true"]{cursor:default}
.letter{
  width:28px;height:28px;display:grid;place-items:center;
  border:1px solid var(--line-strong);border-radius:3px;
  font-family:var(--font-display);font-size:.9375rem;line-height:1;color:var(--ink-2);
  transition:border-color .18s var(--ease),color .18s var(--ease);
}
.option.is-picked .letter{border-color:var(--ink);color:var(--ink)}
.option.is-correct .letter{border-color:var(--jade);color:var(--jade)}
.option.is-wrong .letter{border-color:var(--seal);color:var(--seal)}
.opt-text{font-size:.9375rem;line-height:1.65;overflow-wrap:anywhere;min-width:0}
.opt-mark{display:grid;place-items:center;color:var(--ink-2)}
.option.is-correct .opt-mark{color:var(--jade)}
.option.is-wrong .opt-mark, .option.is-wrong .opt-text{color:var(--seal)}
.verdict{
  display:flex;align-items:flex-start;gap:12px;margin-top:18px;padding:12px 14px;
  border:1px solid var(--line);border-left:3px solid var(--ink-2);
  border-radius:0 var(--radius-sm) var(--radius-sm) 0;background:var(--paper-3);
}
.verdict .ico{width:20px;height:20px;margin-top:3px}
.verdict.is-correct{border-color:var(--jade);border-left-color:var(--jade);background:var(--jade-soft);color:var(--jade)}
.verdict.is-wrong{border-color:var(--seal);border-left-color:var(--seal);background:var(--seal-soft);color:var(--seal)}
.verdict-title{font-size:.9375rem;font-weight:600;letter-spacing:.04em}
.verdict-text{font-size:.8125rem;color:var(--ink-2);margin-top:2px;overflow-wrap:anywhere}
.verdict.is-correct .verdict-text,.verdict.is-wrong .verdict-text{color:var(--ink-2)}
.answer-tools{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin-top:16px}
.answer-tools .q-hint{margin:0}
.explain{margin-top:18px;border-top:1px solid var(--line);padding-top:14px}
.explain-toggle{
  display:flex;align-items:center;gap:10px;width:100%;min-height:44px;
  padding:0;border:0;background:transparent;color:var(--ink);cursor:pointer;text-align:left;
}
.explain-toggle .explain-state{margin-left:auto;font-size:.8125rem;color:var(--ink-2)}
.explain-toggle .chev{transition:transform .18s var(--ease)}
.explain-toggle[aria-expanded="true"] .chev{transform:rotate(180deg)}
.explain-body{padding-top:6px}
.explain-text{font-size:.9375rem;line-height:1.8;color:var(--ink-2);overflow-wrap:anywhere}
.explain-empty{font-size:.875rem;color:var(--ink-2);font-style:italic}
.note{margin-top:16px;padding-top:14px;border-top:1px dashed var(--line)}
.note-label{display:block;font-size:.8125rem;letter-spacing:.08em;color:var(--ink-2);margin-bottom:6px}
.note-input{
  width:100%;min-height:78px;padding:10px 12px;resize:vertical;
  border:1px solid var(--line);border-radius:var(--radius-sm);
  background:var(--paper);color:var(--ink);font-family:var(--font-body);font-size:.9375rem;line-height:1.7;
}
.note-input::placeholder{color:var(--ink-2);opacity:.8}
.note-input:focus-visible{outline:2px solid var(--seal);outline-offset:2px}
.note-hint{font-size:.75rem;color:var(--ink-2);margin-top:6px}
.page-open{margin-top:14px}
.quiz-actions{
  position:sticky;bottom:0;z-index:20;
  display:grid;grid-template-columns:1fr 1.3fr 1fr;gap:10px;
  margin:20px 0 0;padding:12px 0 calc(12px + var(--safe-b));
  background:var(--paper);border-top:1px solid var(--line);
}
.quiz-actions .btn{padding:0 10px;white-space:nowrap}
.kbd-hint{font-size:.75rem;color:var(--ink-2);margin-top:14px;letter-spacing:.02em}
@media (min-width:1024px){.quiz-actions{background:color-mix(in srgb, var(--paper) 94%, transparent);-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px)}}

/* 答题卡 */
.sheet-legend{display:flex;flex-wrap:wrap;gap:8px 16px;margin-bottom:14px;font-size:.75rem;color:var(--ink-2)}
.legend-item{display:inline-flex;align-items:center;gap:6px}
.dot{width:12px;height:12px;border-radius:2px;border:1px solid var(--line-strong);background:var(--paper-2)}
.dot-current{background:var(--ink);border-color:var(--ink)}
.dot-correct{background:var(--jade-soft);border-color:var(--jade)}
.dot-wrong{background:var(--seal-soft);border-color:var(--seal)}
.sheet-grid{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:8px}
@media (min-width:640px){.sheet-grid{grid-template-columns:repeat(6,minmax(0,1fr))}}
.sheet-cell{
  width:100%;height:44px;display:grid;place-items:center;
  border:1px solid var(--line-strong);border-radius:var(--radius-sm);
  background:var(--paper-2);color:var(--ink-2);
  font-family:var(--font-display);font-size:.9375rem;font-variant-numeric:tabular-nums;cursor:pointer;
  transition:background .16s var(--ease),color .16s var(--ease),border-color .16s var(--ease);
}
.sheet-cell:hover{border-color:var(--ink-2);color:var(--ink)}
.sheet-cell.is-correct{background:var(--jade-soft);border-color:var(--jade);color:var(--jade)}
.sheet-cell.is-wrong{background:var(--seal-soft);border-color:var(--seal);color:var(--seal)}
.sheet-cell.is-current{background:var(--ink);border-color:var(--ink);color:var(--paper-2)}
.sheet-cell.is-current.is-correct{box-shadow:inset 0 0 0 2px var(--jade)}
.sheet-cell.is-current.is-wrong{box-shadow:inset 0 0 0 2px var(--seal)}
.sheet-foot{margin-top:16px;font-size:.8125rem;color:var(--ink-2);display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap}

/* ---------- 结果 ---------- */
.result-head{display:flex;align-items:flex-end;gap:20px;flex-wrap:wrap;padding-bottom:18px;border-bottom:1px solid var(--line);margin-bottom:20px}
.result-score{font-family:var(--font-display);font-size:3.5rem;line-height:1;letter-spacing:.02em;font-variant-numeric:tabular-nums}
.result-score small{font-size:1rem;color:var(--ink-2);font-family:var(--font-body);margin-left:4px}
.result-stats{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:1px;background:var(--line);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;margin-bottom:18px}
@media (min-width:640px){.result-stats{grid-template-columns:repeat(4,minmax(0,1fr))}}
.result-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:18px}
.result-list{display:grid;gap:8px;margin:0;padding:0;list-style:none}
.result-item{
  display:grid;grid-template-columns:auto minmax(0,1fr);gap:12px;align-items:start;
  padding:12px 14px;border:1px solid var(--line);border-radius:var(--radius-sm);background:var(--paper-2);
}
.result-item .tag{margin-top:2px}
.result-item p{font-size:.875rem;line-height:1.65;overflow-wrap:anywhere;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}

/* ---------- 错题 ---------- */
.wrong-toolbar{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap;margin-bottom:16px}
.wrong-actions{display:flex;gap:8px;flex-wrap:wrap}
.wrong-list{display:grid;gap:10px;margin:0;padding:0;list-style:none}
.wrong-item{
  background:var(--paper-2);border:1px solid var(--line);border-radius:var(--radius);
  padding:14px 16px;box-shadow:var(--shadow);
}
.wi-head{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin-bottom:6px;font-size:.75rem;color:var(--ink-2)}
.wi-stem{
  font-size:.9375rem;line-height:1.7;overflow-wrap:anywhere;
  display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;
}
.wi-actions{display:flex;gap:8px;flex-wrap:wrap;margin-top:12px}
.pagination{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-top:18px}
.page-info{font-size:.8125rem;color:var(--ink-2);font-variant-numeric:tabular-nums}

/* ---------- 统计 ---------- */
.mastery-list{display:grid;gap:14px}
.mastery-row{display:grid;gap:6px}
.mastery-head{display:flex;align-items:baseline;justify-content:space-between;gap:12px;font-size:.875rem}
.mastery-name{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.mastery-value{color:var(--ink-2);font-variant-numeric:tabular-nums;white-space:nowrap}
.bar{height:8px;border-radius:99px;background:var(--paper-3);overflow:hidden;border:1px solid var(--line)}
.bar-fill{display:block;height:100%;background:var(--jade);border-radius:99px;transition:width .22s var(--ease)}
.bar-fill.is-empty{background:transparent}
.chart{display:grid;grid-template-columns:repeat(7,minmax(0,1fr));gap:8px;align-items:end}
.day{display:flex;flex-direction:column;align-items:center;justify-content:flex-end;gap:6px;height:158px}
.day-count{font-family:var(--font-display);font-size:.8125rem;color:var(--ink-2);font-variant-numeric:tabular-nums}
.day-bar{width:100%;max-width:30px;min-height:4px;background:var(--paper-3);border:1px solid var(--line);border-bottom:0;border-radius:3px 3px 0 0;transition:height .22s var(--ease)}
.day-bar.has-data{background:var(--jade);border-color:var(--jade)}
.day.is-today .day-bar.has-data{background:var(--seal);border-color:var(--seal)}
.day-label{font-size:.6875rem;color:var(--ink-2);letter-spacing:.04em}
.chart-caption{display:flex;justify-content:space-between;gap:12px;margin-top:10px;font-size:.75rem;color:var(--ink-2);flex-wrap:wrap}

/* ---------- 设置 ---------- */
.settings-group{margin-bottom:18px}
.setting-row{
  display:flex;align-items:center;justify-content:space-between;gap:16px;
  padding:13px 0;border-bottom:1px solid var(--line);
}
.setting-row:first-of-type{padding-top:0}
.setting-row:last-of-type{border-bottom:0;padding-bottom:0}
.setting-text{min-width:0;flex:1}
.setting-title{font-size:.9375rem;margin-bottom:2px}
.setting-desc{font-size:.8125rem;color:var(--ink-2);line-height:1.6;max-width:44ch}
.setting-control{flex:none;display:flex;align-items:center;gap:8px}
.switch{
  width:52px;height:44px;padding:0;border:0;background:transparent;position:relative;cursor:pointer;flex:none;
}
.switch::before{
  content:"";position:absolute;left:2px;right:2px;top:50%;height:26px;transform:translateY(-50%);
  border-radius:99px;background:var(--paper-3);border:1px solid var(--line-strong);
  transition:background .18s var(--ease),border-color .18s var(--ease);
}
.switch::after{
  content:"";position:absolute;top:50%;left:7px;width:18px;height:18px;border-radius:50%;
  background:var(--ink-2);transform:translateY(-50%);
  transition:left .18s var(--ease),background .18s var(--ease);
}
.switch[aria-checked="true"]::before{background:var(--jade-soft);border-color:var(--jade)}
.switch[aria-checked="true"]::after{left:29px;background:var(--jade)}
.data-actions{display:grid;gap:10px}
.data-actions .btn{justify-content:flex-start}
.file-input{position:absolute;width:1px;height:1px;opacity:0;pointer-events:none}
.kv{display:grid;grid-template-columns:auto minmax(0,1fr);gap:6px 16px;font-size:.875rem}
.kv dt{color:var(--ink-2);white-space:nowrap}
.kv dd{margin:0;overflow-wrap:anywhere}
.settings-note{font-size:.75rem;color:var(--ink-2);margin-top:12px;line-height:1.7}

/* ---------- 抽屉 / 弹层 ---------- */
.drawer-root,.modal-root{position:fixed;inset:0;z-index:70}
.drawer-backdrop{
  position:absolute;inset:0;background:color-mix(in srgb, var(--ink) 42%, transparent);
  opacity:0;transition:opacity .2s var(--ease);
}
.drawer-root.is-in .drawer-backdrop,.modal-root.is-in .drawer-backdrop{opacity:1}
.drawer{
  position:absolute;left:0;right:0;bottom:0;max-height:80vh;
  display:flex;flex-direction:column;
  background:var(--paper-2);border:1px solid var(--line);border-bottom:0;
  border-radius:14px 14px 0 0;box-shadow:var(--shadow-lift);
  padding-bottom:var(--safe-b);
  transform:translateY(100%);transition:transform .22s var(--ease);
}
.drawer-root.is-in .drawer{transform:none}
@media (min-width:1024px){
  .drawer{left:auto;top:0;bottom:0;width:340px;max-height:none;border-radius:0;border-left:1px solid var(--line);padding-bottom:0;transform:translateX(100%)}
  .drawer-root.is-in .drawer{transform:none}
}
.drawer-head{
  display:flex;align-items:flex-start;justify-content:space-between;gap:12px;
  padding:16px 14px 12px 18px;border-bottom:1px solid var(--line);
}
.drawer-title{font-size:1.125rem;margin-top:2px}
.drawer-close{margin-top:-4px}
.drawer-body{padding:16px 18px 22px;overflow:auto;overscroll-behavior:contain}
.modal-root{display:grid;place-items:center;padding:20px;z-index:75}
.modal{
  position:relative;width:min(420px,100%);
  background:var(--paper-2);border:1px solid var(--line);border-radius:var(--radius);
  box-shadow:var(--shadow-lift);padding:22px;
  opacity:0;transform:translateY(8px) scale(.985);transition:opacity .2s var(--ease),transform .2s var(--ease);
}
.modal-root.is-in .modal{opacity:1;transform:none}
.modal-title{font-size:1.25rem;margin-bottom:8px}
.modal-text{font-size:.9375rem;color:var(--ink-2);line-height:1.75}
.modal-actions{display:flex;justify-content:flex-end;gap:10px;margin-top:20px;flex-wrap:wrap}
.page-viewer{
  position:relative;width:min(1100px,100%);height:100%;
  display:flex;flex-direction:column;gap:12px;
  background:var(--paper-2);border:1px solid var(--line);border-radius:var(--radius);
  padding:14px;box-shadow:var(--shadow-lift);
}
.page-viewer-head{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap}
.page-viewer-title{font-family:var(--font-display);font-size:1.0625rem}
.page-viewer-tools{display:flex;gap:8px;flex-wrap:wrap}
.page-viewer-stage{
  flex:1;min-height:0;overflow:auto;border:1px solid var(--line);border-radius:var(--radius);
  background:var(--paper-3);display:grid;place-items:center;padding:12px;
}
.page-viewer-img{width:100%;max-width:none;height:auto;transform-origin:top center;transition:width .18s var(--ease)}
.page-viewer-missing{display:grid;gap:8px;place-items:center;text-align:center;padding:32px 18px;color:var(--ink-2)}
.page-viewer-missing .ico{width:32px;height:32px;color:var(--ink-3)}
.modal-root.is-in .page-viewer{opacity:1;transform:none}
.page-viewer{opacity:0;transform:translateY(8px);transition:opacity .2s var(--ease),transform .2s var(--ease)}

/* ---------- Toast ---------- */
.toast-root{
  position:fixed;left:50%;bottom:calc(var(--tab-h) + var(--safe-b) + 16px);
  transform:translateX(-50%);z-index:85;
  display:flex;flex-direction:column;align-items:center;gap:8px;
  width:max-content;max-width:92vw;pointer-events:none;
}
.toast{
  max-width:92vw;padding:9px 16px;border-radius:99px;
  background:var(--ink);color:var(--paper-2);
  font-size:.875rem;line-height:1.5;box-shadow:var(--shadow-lift);
  opacity:0;transform:translateY(8px);transition:opacity .2s var(--ease),transform .2s var(--ease);
  overflow-wrap:anywhere;
}
.toast.is-in{opacity:1;transform:none}
.toast-error{background:var(--seal);color:var(--paper-2)}
.toast-jade{background:var(--jade);color:var(--paper-2)}
body[data-view="quiz"] .toast-root{bottom:calc(var(--safe-b) + 88px)}

/* ---------- 深色微调 ---------- */
[data-theme="dark"] .option.is-picked{background:var(--paper-3)}
[data-theme="dark"] .mesh{background:var(--paper-3)}

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

/* ---------- 打印（顺手可印成卷子） ---------- */
@media print{
  .topbar,.tabbar,.sidenav,.quiz-actions,.toast-root,.drawer-root,.modal-root{display:none!important}
  body{background:#fff;color:#000}
  .content{padding:0;max-width:none}
  .qcard,.card{box-shadow:none;border-color:#999}
}