/* =========================================================
   山中居 · 个人博客 —— 共享样式
   ========================================================= */
/* ---------- Design Tokens ---------- */
:root{
  --bg:#f4f0e8;
  --bg-soft:#ede7db;
  --surface:#faf8f2;
  --surface-2:#f0eadf;
  --ink:#28251f;
  --ink-soft:#4b463c;
  --muted:#7d7768;
  --line:#ded7c8;
  --line-soft:#e9e3d6;
  --accent:#2f6b5e;
  --accent-strong:#245548;
  --accent-ink:#eff5f1;
  --accent-soft:rgba(47,107,94,.12);
  --shadow:0 10px 30px -14px rgba(40,37,31,.18);
  --shadow-lg:0 24px 60px -24px rgba(40,37,31,.28);
  --radius:16px;
  --maxw:1120px;
  --font-display:"Noto Serif SC","Songti SC","STSong",serif;
  --font-body:"Noto Sans SC","PingFang SC","Microsoft YaHei",sans-serif;
  --ease:cubic-bezier(.22,.61,.36,1);
}
html[data-theme="dark"]{
  --bg:#15141a;
  --bg-soft:#1c1a21;
  --surface:#201e26;
  --surface-2:#29262f;
  --ink:#edeae1;
  --ink-soft:#c6c1b5;
  --muted:#8f8879;
  --line:#34303c;
  --line-soft:#2b2832;
  --accent:#79b4a0;
  --accent-strong:#9cc7b6;
  --accent-ink:#12241e;
  --accent-soft:rgba(121,180,160,.15);
  --shadow:0 10px 30px -14px rgba(0,0,0,.5);
  --shadow-lg:0 24px 60px -24px rgba(0,0,0,.6);
}

*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:var(--font-body);
  background:var(--bg);
  color:var(--ink);
  line-height:1.75;
  font-weight:400;
  -webkit-font-smoothing:antialiased;
  transition:background .45s var(--ease),color .45s var(--ease);
}
::selection{background:var(--accent);color:var(--accent-ink)}
img{display:block;max-width:100%}
a{color:inherit;text-decoration:none}
button{font-family:inherit;cursor:pointer;border:none;background:none;color:inherit}
h1,h2,h3,h4{font-family:var(--font-display);font-weight:700;line-height:1.25;letter-spacing:.01em}
.container{max-width:var(--maxw);margin:0 auto;padding:0 24px}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}

/* ---------- Header / Nav ---------- */
.site-header{
  position:sticky;top:0;z-index:60;
  backdrop-filter:saturate(1.2) blur(14px);
  -webkit-backdrop-filter:saturate(1.2) blur(14px);
  background:color-mix(in srgb,var(--bg) 78%,transparent);
  border-bottom:1px solid var(--line-soft);
  transition:border-color .45s,background .45s;
}
.nav{display:flex;align-items:center;justify-content:space-between;height:68px;gap:16px}
.brand{display:flex;align-items:center;gap:11px;font-family:var(--font-display);font-weight:700;font-size:19px;letter-spacing:.05em}
.brand .mark{width:34px;height:34px;flex:none;border-radius:9px;background:var(--accent);display:grid;place-items:center}
.brand .mark svg{width:19px;height:19px;stroke:var(--accent-ink)}
.nav-links{display:flex;align-items:center;gap:4px}
.nav-link{
  padding:9px 15px;border-radius:10px;font-size:15px;color:var(--ink-soft);
  position:relative;transition:color .2s,background .2s;
}
.nav-link:hover{color:var(--ink);background:var(--surface-2)}
.nav-link.active{color:var(--accent-strong);background:var(--accent-soft);font-weight:500}
.nav-actions{display:flex;align-items:center;gap:10px}
.theme-toggle{
  width:40px;height:40px;border-radius:10px;display:grid;place-items:center;
  border:1px solid var(--line);background:var(--surface);color:var(--ink-soft);
  transition:transform .3s var(--ease),background .2s,color .2s;
  flex-shrink:0;
}
.theme-toggle:hover{transform:rotate(12deg);color:var(--ink)}
.theme-toggle svg{width:20px;height:20px}
.theme-toggle .icon-sun{display:none}
html[data-theme="dark"] .theme-toggle .icon-sun{display:block}
html[data-theme="dark"] .theme-toggle .icon-moon{display:none}
.nav-burger{display:none}
.mobile-menu{display:none}
.mobile-menu.open{display:flex;flex-direction:column}

/* ---------- 页面通用 ---------- */
.page-head{padding:66px 0 34px;text-align:center}
.page-head .eyebrow{
  display:inline-flex;align-items:center;gap:9px;font-size:13px;letter-spacing:.22em;
  color:var(--accent);font-weight:500;margin-bottom:14px;
}
.page-head .eyebrow::before,.page-head .eyebrow::after{content:"";width:26px;height:1px;background:var(--accent);opacity:.5}
.page-head h1{font-size:clamp(30px,5vw,46px);font-weight:900;letter-spacing:.04em}
.page-head p{margin:14px auto 0;max-width:560px;color:var(--muted);font-size:16px}

/* ---------- 首页 Hero ---------- */
.hero{padding:64px 0 40px}
.hero-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:48px;align-items:center}
.hero-copy .hero-kicker{font-size:14px;letter-spacing:.2em;color:var(--accent);font-weight:500;margin-bottom:18px}
.hero-copy h1{font-size:clamp(34px,5.4vw,58px);font-weight:900;letter-spacing:.02em;line-height:1.18}
.hero-copy h1 .accent{color:var(--accent)}
.hero-copy .lead{margin:22px 0 30px;font-size:17px;color:var(--ink-soft);max-width:520px;line-height:1.9}
.hero-cta{display:flex;gap:14px;flex-wrap:wrap}
.btn{
  display:inline-flex;align-items:center;gap:9px;padding:13px 26px;border-radius:12px;
  font-size:15px;font-weight:500;transition:transform .25s var(--ease),box-shadow .25s,background .2s;
}
.btn-primary{background:var(--accent);color:var(--accent-ink);box-shadow:0 8px 20px -10px var(--accent)}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 12px 26px -10px var(--accent);background:var(--accent-strong);color:#fff}
.btn-ghost{border:1px solid var(--line);background:var(--surface);color:var(--ink)}
.btn-ghost:hover{border-color:var(--accent);color:var(--accent);transform:translateY(-2px)}
.hero-media{position:relative}
.hero-media .frame{border-radius:20px;overflow:hidden;box-shadow:var(--shadow-lg)}
.hero-media .frame img{width:100%;height:420px;object-fit:cover;object-position:center}
.hero-media::before{
  content:"";position:absolute;inset:-18px -18px auto auto;width:70%;height:70%;
  border-radius:22px;background:var(--accent-soft);z-index:-1;
}
.hero-stats{margin-top:64px;display:grid;grid-template-columns:repeat(3,1fr);gap:0;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface);overflow:hidden;box-shadow:var(--shadow)}
.stat{padding:26px 30px;text-align:center}
.stat + .stat{border-left:1px solid var(--line)}
.stat b{display:block;font-family:var(--font-display);font-size:34px;font-weight:900;color:var(--accent-strong)}
.stat span{font-size:14px;color:var(--muted);letter-spacing:.06em}

/* ---------- 区块标题 ---------- */
.section{padding:58px 0}
.section-head{display:flex;align-items:flex-end;justify-content:space-between;gap:20px;margin-bottom:30px}
.section-head h2{font-size:clamp(24px,3.4vw,32px);font-weight:800;position:relative;padding-bottom:12px}
.section-head h2::after{content:"";position:absolute;left:0;bottom:0;width:40px;height:3px;border-radius:2px;background:var(--accent)}
.section-head .more{font-size:14px;color:var(--muted);display:inline-flex;align-items:center;gap:6px;transition:color .2s}
.section-head .more:hover{color:var(--accent)}
.section-head .more svg{width:15px;height:15px;transition:transform .25s}
.section-head .more:hover svg{transform:translateX(3px)}

/* ---------- 文章卡片 ---------- */
.card-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.article-card{
  background:var(--surface);border:1px solid var(--line-soft);border-radius:var(--radius);
  padding:26px 26px 24px;display:flex;flex-direction:column;gap:14px;position:relative;
  transition:transform .3s var(--ease),box-shadow .3s,border-color .3s;
}
.article-card:hover{transform:translateY(-6px);box-shadow:var(--shadow-lg);border-color:var(--line)}
.article-card .meta{display:flex;align-items:center;gap:10px;font-size:12.5px;color:var(--muted);letter-spacing:.04em}
.article-card .tag{
  background:var(--accent-soft);color:var(--accent-strong);padding:3px 11px;border-radius:999px;font-weight:500;
}
.article-card h3{font-size:20px;font-weight:700;line-height:1.45}
.article-card p{color:var(--ink-soft);font-size:14.5px;line-height:1.85;flex:1;display:-webkit-box;-webkit-line-clamp:3;-webkit-box-orient:vertical;overflow:hidden}
.article-card .read{display:inline-flex;align-items:center;gap:7px;font-size:13px;color:var(--muted)}
.article-card .read svg{width:14px;height:14px}
.article-card .read:hover{color:var(--accent)}

/* ---------- 首页画廊预览 ---------- */
.grid-mini{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.grid-mini a{position:relative;border-radius:14px;overflow:hidden;aspect-ratio:4/3;box-shadow:var(--shadow)}
.grid-mini img{width:100%;height:100%;object-fit:cover;transition:transform .5s var(--ease)}
.grid-mini a:hover img{transform:scale(1.06)}
.grid-mini a::after{content:"";position:absolute;inset:0;background:linear-gradient(to top,rgba(0,0,0,.28),transparent 55%);opacity:0;transition:opacity .3s}
.grid-mini a:hover::after{opacity:1}

/* ---------- CTA 色带 ---------- */
.cta-band{margin:20px 0 10px;border-radius:22px;overflow:hidden;position:relative;padding:56px 40px;text-align:center;background:linear-gradient(135deg,var(--accent),var(--accent-strong));color:#fff}
.cta-band h2{font-size:clamp(24px,4vw,36px);font-weight:800;color:#fff}
.cta-band p{color:rgba(255,255,255,.85);max-width:520px;margin:12px auto 26px;font-size:15px}
.cta-band .btn{background:#fff;color:var(--accent-strong)}
.cta-band .btn:hover{transform:translateY(-2px);box-shadow:0 12px 26px -10px rgba(0,0,0,.4)}

/* ---------- 随笔：筛选与列表 ---------- */
.filters{display:flex;justify-content:center;gap:10px;flex-wrap:wrap;margin:6px 0 34px}
.filter-btn{padding:8px 20px;border-radius:999px;border:1px solid var(--line);background:var(--surface);color:var(--ink-soft);font-size:14px;transition:all .2s}
.filter-btn:hover{border-color:var(--accent);color:var(--accent)}
.filter-btn.active{background:var(--accent);color:var(--accent-ink);border-color:var(--accent);font-weight:500}
.essay-list{display:flex;flex-direction:column;gap:18px;max-width:860px;margin:0 auto}
.essay-row{
  display:grid;grid-template-columns:96px 1fr auto;gap:22px;align-items:center;
  background:var(--surface);border:1px solid var(--line-soft);border-radius:var(--radius);
  padding:24px 28px;transition:transform .3s var(--ease),box-shadow .3s,border-color .3s;
}
.essay-row:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg);border-color:var(--line)}
.essay-row .date{font-family:var(--font-display);font-size:14px;color:var(--muted);line-height:1.4;letter-spacing:.04em}
.essay-row .date b{display:block;font-size:24px;font-weight:900;color:var(--accent-strong)}
.essay-row .body .tag{font-size:12px;color:var(--accent-strong);letter-spacing:.12em;font-weight:500}
.essay-row .body h3{font-size:19px;font-weight:700;margin:5px 0 6px;transition:color .2s}
.essay-row:hover .body h3{color:var(--accent)}
.essay-row .body p{color:var(--muted);font-size:14px;line-height:1.8}
.essay-row .time{font-size:13px;color:var(--muted);white-space:nowrap}

/* ---------- 画廊 ---------- */
.masonry{columns:3 300px;column-gap:18px}
.masonry-item{break-inside:avoid;margin-bottom:18px;border-radius:14px;overflow:hidden;position:relative;cursor:zoom-in;box-shadow:var(--shadow);background:var(--surface-2)}
.masonry-item img{width:100%;height:auto;transition:transform .5s var(--ease)}
.masonry-item:hover img{transform:scale(1.05)}
.masonry-item .cap{
  position:absolute;left:0;right:0;bottom:0;padding:34px 18px 14px;color:#fff;
  background:linear-gradient(to top,rgba(0,0,0,.55),transparent);opacity:0;transition:opacity .3s;
  font-size:14px;font-weight:500;
}
.masonry-item:hover .cap{opacity:1}
.gallery-count{text-align:center;color:var(--muted);font-size:14px;margin-top:8px;letter-spacing:.05em}

/* ---------- 灯箱 ---------- */
.lightbox{position:fixed;inset:0;z-index:100;background:rgba(10,9,12,.92);display:none;align-items:center;justify-content:center;padding:30px;backdrop-filter:blur(6px)}
.lightbox.open{display:flex;animation:fadeIn .3s}
.lightbox img{max-width:min(92vw,1080px);max-height:82vh;border-radius:12px;box-shadow:0 30px 80px rgba(0,0,0,.5);animation:scaleIn .35s var(--ease)}
.lightbox .lb-cap{position:absolute;bottom:26px;left:50%;transform:translateX(-50%);color:#fff;font-size:15px;background:rgba(0,0,0,.35);padding:8px 18px;border-radius:999px}
.lightbox .lb-close{position:absolute;top:22px;right:26px;width:44px;height:44px;border-radius:50%;background:rgba(255,255,255,.12);color:#fff;font-size:22px;display:grid;place-items:center;transition:background .2s}
.lightbox .lb-close:hover{background:rgba(255,255,255,.25)}
.lightbox .lb-nav{position:absolute;top:50%;transform:translateY(-50%);width:46px;height:46px;border-radius:50%;background:rgba(255,255,255,.12);color:#fff;display:grid;place-items:center;font-size:20px;transition:background .2s}
.lightbox .lb-nav:hover{background:rgba(255,255,255,.25)}
.lightbox .lb-prev{left:26px}.lightbox .lb-next{right:26px}

/* ---------- 留言 ---------- */
.msg-wrap{max-width:860px;margin:0 auto;display:grid;grid-template-columns:1fr 360px;gap:36px;align-items:start}
.form-card{background:var(--surface);border:1px solid var(--line-soft);border-radius:var(--radius);padding:30px;box-shadow:var(--shadow)}
.form-card h3{font-size:20px;font-weight:700;margin-bottom:6px}
.form-card .hint{color:var(--muted);font-size:13.5px;margin-bottom:22px}
.field{margin-bottom:18px}
.field label{display:block;font-size:14px;color:var(--ink-soft);margin-bottom:7px;font-weight:500}
.field input,.field textarea{
  width:100%;padding:12px 15px;border:1px solid var(--line);border-radius:11px;background:var(--bg-soft);
  color:var(--ink);font-family:inherit;font-size:15px;transition:border-color .2s,box-shadow .2s;resize:vertical;
}
.field input:focus,.field textarea:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-soft)}
.field textarea{min-height:130px}
.form-actions{display:flex;align-items:center;justify-content:space-between;gap:12px}
.form-actions .btn{padding:11px 24px;font-size:14.5px}
.char-count{font-size:12.5px;color:var(--muted)}
.comments{display:flex;flex-direction:column;gap:14px}
.comments h3{font-size:19px;font-weight:700;display:flex;align-items:baseline;gap:9px;margin-bottom:6px}
.comments h3 span{font-size:14px;color:var(--muted);font-weight:400}
.comment{background:var(--surface);border:1px solid var(--line-soft);border-radius:13px;padding:18px 20px;animation:fadeUp .4s var(--ease)}
.comment .who{display:flex;align-items:center;gap:11px;margin-bottom:9px}
.comment .avatar{width:34px;height:34px;border-radius:50%;background:var(--accent-soft);color:var(--accent-strong);display:grid;place-items:center;font-family:var(--font-display);font-weight:700;font-size:14px}
.comment .who b{font-size:14.5px;font-weight:600}
.comment .who time{font-size:12px;color:var(--muted);margin-left:auto}
.comment p{font-size:14.5px;color:var(--ink-soft);line-height:1.85}

/* ---------- 关于 ---------- */
.about-top{display:grid;grid-template-columns:240px 1fr;gap:42px;align-items:center;max-width:860px;margin:0 auto 20px}
.about-avatar{position:relative}
.about-avatar .ring{border-radius:50%;overflow:hidden;width:230px;height:230px;margin:auto;box-shadow:var(--shadow-lg);border:5px solid var(--surface)}
.about-avatar img{width:100%;height:100%;object-fit:cover}
.about-avatar::after{content:"";position:absolute;inset:-10px -10px auto auto;width:64px;height:64px;border-radius:50%;background:var(--accent);opacity:.85}
.about-intro h2{font-size:clamp(26px,3.6vw,34px);font-weight:800;margin-bottom:8px}
.about-intro .role{color:var(--accent);font-size:15px;letter-spacing:.06em;margin-bottom:16px;font-weight:500}
.about-intro p{color:var(--ink-soft);font-size:15px;line-height:1.95;margin-bottom:12px}
.about-intro p:last-child{margin-bottom:0}
.about-tags{margin:34px auto;max-width:860px}
.about-tags h3{font-size:19px;font-weight:700;margin-bottom:16px;display:flex;align-items:center;gap:10px}
.about-tags h3 svg{width:20px;height:20px;color:var(--accent)}
.tag-cloud{display:flex;flex-wrap:wrap;gap:10px}
.pill{padding:8px 16px;border-radius:999px;background:var(--surface);border:1px solid var(--line-soft);color:var(--ink-soft);font-size:14px;transition:all .2s}
.pill:hover{border-color:var(--accent);color:var(--accent);transform:translateY(-2px)}

/* ---------- 时间轴 ---------- */
.timeline-block{max-width:860px;margin:14px auto}
.timeline-block h3{font-size:19px;font-weight:700;margin-bottom:22px;display:flex;align-items:center;gap:10px}
.timeline-block h3 svg{width:20px;height:20px;color:var(--accent)}
.timeline{display:flex;flex-direction:column}
.tl-row{position:relative;display:grid;grid-template-columns:120px 40px 1fr;align-items:start;column-gap:14px}
.tl-row .tl-time{font-family:var(--font-display);font-weight:700;font-size:15px;color:var(--accent-strong);padding-top:2px;text-align:right;letter-spacing:.03em}
.tl-row .tl-rail{position:relative;justify-self:center;width:2px;height:100%;background:var(--line);margin-top:8px}
.tl-row:not(:last-child) .tl-rail{height:calc(100% + 14px)}
.tl-row .tl-dot{position:sticky;top:4px;justify-self:center;width:14px;height:14px;border-radius:50%;background:var(--accent);box-shadow:0 0 0 4px var(--accent-soft);grid-column:2;grid-row:1;z-index:1}
.tl-row .tl-body{grid-column:3;grid-row:1;padding-bottom:30px}
.tl-body h4{font-size:17px;font-weight:700;margin-bottom:4px}
.tl-body p{color:var(--muted);font-size:14px;line-height:1.8}

/* ---------- 页脚 ---------- */
.site-footer{margin-top:80px;border-top:1px solid var(--line-soft);background:var(--bg-soft)}
.footer-inner{padding-block:52px 34px}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:36px;margin-bottom:40px}
.footer-brand .brand{margin-bottom:14px}
.footer-brand p{color:var(--muted);font-size:14px;max-width:300px;line-height:1.9}
.footer-col h4{font-size:14px;letter-spacing:.1em;color:var(--muted);margin-bottom:16px;font-weight:600}
.footer-col a{display:block;color:var(--ink-soft);font-size:14px;padding:6px 0;transition:color .2s}
.footer-col a:hover{color:var(--accent)}
.socials{display:flex;gap:10px;margin-top:6px}
.socials a{width:38px;height:38px;border-radius:10px;border:1px solid var(--line);display:grid;place-items:center;color:var(--ink-soft);transition:all .25s}
.socials a:hover{color:var(--accent);border-color:var(--accent);transform:translateY(-3px)}
.socials svg{width:18px;height:18px}
.footer-bottom{border-top:1px solid var(--line-soft);padding-top:24px;display:flex;align-items:center;justify-content:space-between;gap:14px;flex-wrap:wrap;color:var(--muted);font-size:13px}
.back-top{display:inline-flex;align-items:center;gap:7px;font-size:13px;color:var(--ink-soft);transition:color .2s}
.back-top:hover{color:var(--accent)}
.back-top svg{width:15px;height:15px}

/* ---------- 刷题界面 ---------- */
.quiz-layout{display:grid;grid-template-columns:300px 1fr;gap:22px;align-items:start;max-width:1020px;margin:0 auto}
.quiz-side{position:sticky;top:88px;display:flex;flex-direction:column;gap:16px}
.progress-card{background:var(--surface);border:1px solid var(--line-soft);border-radius:var(--radius);padding:22px 24px;box-shadow:var(--shadow)}
.progress-card .pc-top{display:flex;align-items:baseline;justify-content:space-between;margin-bottom:14px}
.progress-card .pc-top b{font-family:var(--font-display);font-size:26px;font-weight:900;color:var(--accent-strong)}
.progress-card .pc-top span{font-size:13px;color:var(--muted)}
.progress-bar{height:8px;border-radius:999px;background:var(--surface-2);overflow:hidden}
.progress-bar i{display:block;height:100%;border-radius:999px;background:var(--accent);transition:width .5s var(--ease)}
.progress-meta{display:flex;justify-content:space-between;margin-top:10px;font-size:12.5px;color:var(--muted)}
.quiz-list{background:var(--surface);border:1px solid var(--line-soft);border-radius:var(--radius);padding:12px;box-shadow:var(--shadow);max-height:480px;overflow:auto}
.quiz-list-title{font-size:13px;color:var(--muted);letter-spacing:.08em;padding:6px 10px 10px}
.quiz-item{display:flex;align-items:center;gap:11px;width:100%;padding:10px 12px;border-radius:10px;font-size:14px;color:var(--ink-soft);text-align:left;transition:background .18s,color .18s}
.quiz-item:hover{background:var(--surface-2);color:var(--ink)}
.quiz-item.active{background:var(--accent-soft);color:var(--accent-strong);font-weight:600}
.quiz-item .num{width:24px;height:24px;flex:none;border-radius:7px;background:var(--surface-2);display:grid;place-items:center;font-family:var(--font-display);font-size:13px;font-weight:700;color:var(--muted)}
.quiz-item.active .num{background:var(--accent);color:var(--accent-ink)}
.quiz-item .it{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.quiz-item .st{margin-left:auto;flex:none}
.quiz-item .st svg{width:16px;height:16px}
.st-done{color:var(--accent)}
.st-fail{color:#c25b4a}
.st-todo{color:var(--line)}

.quiz-main{display:flex;flex-direction:column;gap:16px;min-width:0}
.quiz-card{background:var(--surface);border:1px solid var(--line-soft);border-radius:var(--radius);padding:30px 34px;box-shadow:var(--shadow)}
.quiz-head{display:flex;align-items:center;gap:12px;flex-wrap:wrap;margin-bottom:20px}
.quiz-head .qn{font-family:var(--font-display);font-size:15px;font-weight:700;color:var(--accent-strong);background:var(--accent-soft);padding:4px 13px;border-radius:999px}
.diff{font-size:12px;font-weight:600;padding:3px 11px;border-radius:999px;letter-spacing:.04em}
.diff-easy{background:rgba(47,107,94,.14);color:var(--accent-strong)}
.diff-mid{background:rgba(194,146,62,.16);color:#9c6f1d}
html[data-theme="dark"] .diff-mid{color:#d8a94a}
.diff-hard{background:rgba(194,91,74,.15);color:#b04a3b}
html[data-theme="dark"] .diff-hard{color:#e07a68}
.quiz-head .cat{margin-left:auto;font-size:12.5px;color:var(--muted)}
.quiz-q{font-size:19px;font-weight:600;line-height:1.7;margin-bottom:26px;font-family:var(--font-display)}
.quiz-q code{font-family:"SFMono-Regular",Consolas,Menlo,monospace;background:var(--surface-2);padding:2px 7px;border-radius:6px;font-size:.9em;color:var(--ink)}
.options{display:flex;flex-direction:column;gap:11px}
.option{display:flex;align-items:center;gap:13px;width:100%;padding:14px 18px;border:1px solid var(--line);border-radius:12px;font-size:15px;color:var(--ink-soft);text-align:left;background:var(--bg-soft);transition:border-color .18s,background .18s,color .18s,transform .12s}
.option:hover{border-color:var(--accent);color:var(--ink);transform:translateX(3px)}
.option .letter{width:28px;height:28px;flex:none;border-radius:8px;background:var(--surface-2);display:grid;place-items:center;font-family:var(--font-display);font-weight:700;font-size:13px;color:var(--muted)}
.option.selected{border-color:var(--accent);background:var(--accent-soft);color:var(--ink)}
.option.selected .letter{background:var(--accent);color:var(--accent-ink)}
.option.correct{border-color:var(--accent);background:rgba(47,107,94,.12);color:var(--ink)}
.option.correct .letter{background:var(--accent);color:var(--accent-ink)}
.option.wrong{border-color:#c25b4a;background:rgba(194,91,74,.1);color:var(--ink)}
.option.wrong .letter{background:#c25b4a;color:#fff}
.option:disabled{cursor:not-allowed;opacity:.85;transform:none}
.quiz-expl{margin-top:22px;padding:16px 18px;border-radius:12px;font-size:14px;line-height:1.8;display:none}
.quiz-expl.show{display:block;animation:fadeUp .35s var(--ease)}
.quiz-expl.ok{background:rgba(47,107,94,.12);color:var(--ink);border:1px solid rgba(47,107,94,.3)}
.quiz-expl.bad{background:rgba(194,91,74,.1);color:var(--ink);border:1px solid rgba(194,91,74,.3)}
.quiz-expl .xl{font-weight:700;margin-bottom:4px}
.quiz-expl.ok .xl{color:var(--accent-strong)}
.quiz-expl.bad .xl{color:#b04a3b}
.quiz-submit{margin-top:22px}
.quiz-actions{display:flex;align-items:center;gap:12px;justify-content:space-between;flex-wrap:wrap}
.quiz-nav{display:flex;gap:10px}
.quiz-nav button{padding:10px 18px;border-radius:10px;border:1px solid var(--line);background:var(--surface);color:var(--ink-soft);font-size:14px;display:inline-flex;align-items:center;gap:6px;transition:all .2s}
.quiz-nav button:hover:not(:disabled){border-color:var(--accent);color:var(--accent)}
.quiz-nav button:disabled{opacity:.4;cursor:not-allowed}
.quiz-nav svg{width:15px;height:15px}
.result-banner{background:linear-gradient(135deg,var(--accent),var(--accent-strong));color:#fff;border-radius:var(--radius);padding:30px;text-align:center;box-shadow:var(--shadow-lg)}
.result-banner b{display:block;font-family:var(--font-display);font-size:40px;font-weight:900;color:#fff;margin-bottom:6px}
.result-banner p{color:rgba(255,255,255,.9);font-size:15px}
.result-banner .btn{margin-top:20px;background:#fff;color:var(--accent-strong)}
@media (max-width:900px){
  .quiz-layout{grid-template-columns:1fr}
  .quiz-side{position:static}
  .quiz-list{max-height:none}
  .quiz-list .quiz-list-title{display:none}
  .quiz-list{display:flex;gap:8px;overflow-x:auto;padding:10px}
  .quiz-item{flex:none;width:auto;white-space:nowrap}
  .quiz-item .it{max-width:150px}
  .quiz-card{padding:24px 20px}
}

/* ---------- Toast ---------- */
.toast{position:fixed;bottom:34px;left:50%;transform:translate(-50%,80px);background:var(--ink);color:var(--bg);padding:13px 26px;border-radius:12px;font-size:14px;z-index:120;opacity:0;pointer-events:none;transition:all .4s var(--ease);box-shadow:var(--shadow-lg)}
.toast.show{transform:translate(-50%,0);opacity:1}

/* ---------- 动效 ---------- */
@keyframes fadeUp{from{opacity:0;transform:translateY(14px)}to{opacity:1;transform:none}}
@keyframes fadeIn{from{opacity:0}to{opacity:1}}
@keyframes scaleIn{from{opacity:0;transform:scale(.96)}to{opacity:1;transform:scale(1)}}

/* ---------- 响应式平板尺寸 ---------- */
@media (max-width:900px){
  .hero-grid{grid-template-columns:1fr;gap:34px}
  .hero-media .frame img{height:340px}
  .card-grid{grid-template-columns:repeat(2,1fr)}
  .footer-grid{grid-template-columns:1fr 1fr}
  .msg-wrap{grid-template-columns:1fr}
  .about-top{grid-template-columns:1fr;text-align:center}
  .about-avatar .ring{margin:0 auto}
  .about-avatar::after{display:none}
  .site-feats{grid-template-columns:repeat(2,1fr)}
  .stat-cards{grid-template-columns:repeat(2,1fr)}
  .charts-grid{grid-template-columns:1fr}
}

/* ---------- 移动端全屏菜单与独立按钮完美对齐修复 ---------- */
@media (max-width:640px){
  .site-feats{grid-template-columns:1fr}
  .stat-cards{grid-template-columns:1fr}
  .site-card{padding:26px 22px}
  
  .nav-links{display:none}
  
  /* 确保右侧动作区采用 Flex 并排且垂直居中，防止点完变形或错位 */
  .nav-actions{
    display:flex;
    align-items:center;
    gap:8px;
  }
  .nav-actions .theme-toggle{
    display:grid;
    width:40px;
    height:40px;
    border-radius:10px;
    flex-shrink:0;
  }
  
  .nav-burger{
    display:grid;
    width:40px;
    height:40px;
    border-radius:10px;
    border:1px solid var(--line);
    background:var(--surface);
    color:var(--ink-soft);
    place-items:center;
    flex-shrink:0;
    z-index:90;
  }
  .nav-burger svg{width:20px;height:20px}

  /* 彻底清理并撑满移动端菜单 */
  .mobile-menu{
    position:fixed;
    top:0;
    left:0;
    width:100vw;
    height:100vh;
    height:100dvh;
    z-index:80;
    background:var(--bg);
    padding:88px 28px 40px;
    display:none;
    flex-direction:column;
    gap:4px;
    overflow-y:auto;
    -webkit-overflow-scrolling:touch;
    animation:fadeIn .25s var(--ease);
  }
  .mobile-menu.open{
    display:flex;
  }
  .mobile-menu a{
    padding:14px 6px;
    font-size:19px;
    font-family:var(--font-display);
    font-weight:600;
    border-bottom:1px solid var(--line-soft);
    color:var(--ink);
  }
  .mobile-menu a.active{
    color:var(--accent-strong);
  }

  .card-grid,.grid-mini{grid-template-columns:1fr}
  .hero-stats{grid-template-columns:1fr}
  .stat + .stat{border-left:none;border-top:1px solid var(--line)}
  .essay-row{grid-template-columns:1fr;gap:10px;padding:20px}
  .essay-row .date{display:flex;align-items:baseline;gap:8px}
  .essay-row .time{display:none}
  .page-head{padding:48px 0 24px}
  .section{padding:42px 0}
  .footer-grid{grid-template-columns:1fr}
  .cta-band{padding:44px 24px}
  .lightbox .lb-nav{width:38px;height:38px}
  input,textarea{font-size:16px!important}
}

@media (prefers-reduced-motion:reduce){
  *{animation:none!important;transition:none!important}
  html{scroll-behavior:auto}
}