:root{
  --graphite:#3E4651;
  --graphite-deep:#2A313A;
  --ink:#1F2937;
  --text:#374151;
  --muted:#6B7280;
  --line:#D1D5DB;
  --wash:#F7F8FA;
  --paper:#FFFFFF;
  --gold:#F9BE00;
  --serif:"Noto Serif TC","Songti TC","Source Han Serif TC",serif;
  --sans:-apple-system,BlinkMacSystemFont,"PingFang TC","Noto Sans TC","Microsoft JhengHei","Heiti TC",sans-serif;
  --wrap:68rem;
  --measure:40rem;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
body{margin:0;background:var(--paper);color:var(--text);font-family:var(--sans);font-size:1.0625rem;line-height:1.9;}
img{max-width:100%;height:auto}
a{color:var(--graphite);text-underline-offset:.22em;text-decoration-thickness:1px}
a:hover{color:var(--ink);text-decoration-thickness:2px}
a:focus-visible{outline:2px solid var(--gold);outline-offset:3px}
.wrap{max-width:var(--wrap);margin:0 auto;padding:0 1.25rem}
.skip{position:absolute;left:-999px}
.skip:focus{left:1rem;top:1rem;background:#fff;padding:.5rem 1rem;z-index:9}

/* 頁首 */
.site-head{border-bottom:1px solid var(--line);background:var(--paper)}
.site-head .wrap{display:flex;align-items:center;justify-content:space-between;gap:1rem;min-height:4.5rem;flex-wrap:wrap;padding-top:.75rem;padding-bottom:.75rem}
.brand{display:block;line-height:0}
.brand img{height:2.25rem;width:auto}
.nav{display:flex;gap:1.75rem;font-size:.95rem}
.nav a{text-decoration:none;color:var(--text);padding:.35rem 0;border-bottom:2px solid transparent}
.nav a:hover{border-bottom-color:var(--line)}
.nav a[aria-current="page"]{color:var(--ink);border-bottom-color:var(--gold)}

/* 首頁 */
.hero{background:var(--graphite);color:#fff}
.hero .wrap{padding-top:4.5rem;padding-bottom:4.5rem}
.hero h1{font-family:var(--serif);font-weight:700;font-size:clamp(2.1rem,6vw,3.6rem);line-height:1.3;letter-spacing:.04em;margin:0 0 1.5rem;text-wrap:balance}
.hero p{margin:0;max-width:34rem;color:#E3E6EA;font-size:1.0625rem}
.hero .rule{display:block;width:3.5rem;height:3px;background:var(--gold);margin-bottom:2rem}

.block{padding:3.5rem 0}
.block + .block{border-top:1px solid var(--line)}
.block h2{font-family:var(--serif);font-size:1.5rem;color:var(--ink);margin:0 0 1.75rem;letter-spacing:.03em}
.two{display:grid;grid-template-columns:1fr;gap:1rem}
@media (min-width:56rem){.two{grid-template-columns:14rem 1fr;gap:3rem}.two > h2{margin:0}}

.entry{display:block;text-decoration:none;color:inherit;padding:0 0 1.75rem;border-bottom:1px solid var(--line);margin-bottom:1.75rem}
.entry:last-child{border-bottom:0;margin-bottom:0;padding-bottom:0}
.entry h3{text-wrap:balance;font-family:var(--serif);font-size:clamp(1.3rem,3.4vw,1.75rem);line-height:1.5;color:var(--ink);margin:.35rem 0 .6rem}
.entry:hover h3{text-decoration:underline;text-decoration-thickness:1px;text-underline-offset:.25em}
.entry p{margin:0;max-width:var(--measure)}
.meta{font-size:.875rem;color:var(--muted);display:flex;gap:1rem;flex-wrap:wrap}
.meta .cat{color:var(--graphite);font-weight:600}

.topics{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:1fr;column-gap:3rem}
@media (min-width:40rem){.topics{grid-template-columns:1fr 1fr}}
.topics li{display:flex;justify-content:space-between;gap:1rem;padding:.7rem 0;border-bottom:1px solid var(--line);color:var(--ink)}
.topics span{color:var(--muted);font-size:.875rem;white-space:nowrap}

/* 文章與一般頁面 */
.page-head{background:var(--wash);border-bottom:1px solid var(--line)}
.page-head .wrap{padding-top:3rem;padding-bottom:2.5rem}
.page-head h1{font-family:var(--serif);font-weight:700;color:var(--ink);font-size:clamp(1.75rem,5vw,2.6rem);line-height:1.45;letter-spacing:.02em;margin:.5rem 0 0;max-width:20em;text-wrap:balance}
.page-head .lead{margin:1.25rem 0 0;max-width:var(--measure);font-size:1.0625rem}
.layout{display:grid;grid-template-columns:1fr;gap:2rem;padding-top:2.5rem;padding-bottom:4rem}
@media (min-width:62rem){.layout{grid-template-columns:14rem minmax(0,var(--measure));gap:4rem}.toc{position:sticky;top:2rem;align-self:start}}
.toc{font-size:.9rem;line-height:1.6}
.toc p{margin:0 0 .75rem;color:var(--muted)}
.toc ol{list-style:none;margin:0;padding:0;border-left:1px solid var(--line)}
.toc li a{display:block;padding:.4rem 0 .4rem 1rem;text-decoration:none;color:var(--text);margin-left:-1px;border-left:2px solid transparent}
.toc li a:hover{border-left-color:var(--gold);color:var(--ink)}
.prose{max-width:var(--measure);font-size:1.125rem;line-height:2}
.prose > :first-child{margin-top:0}
.prose p{margin:0 0 1.5rem}
.prose h2{font-family:var(--serif);color:var(--ink);font-size:1.55rem;line-height:1.55;margin:3.25rem 0 1.25rem;padding-top:1.5rem;border-top:1px solid var(--line);letter-spacing:.02em}
.prose strong{color:var(--ink)}
.prose ul{margin:0 0 1.5rem;padding-left:1.4rem}
.prose li{margin-bottom:.6rem}
.prose li::marker{color:var(--muted)}
.prose hr{border:0;border-top:3px solid var(--graphite);margin:3.5rem 0 2rem;width:3.5rem;margin-left:0}
.prose hr ~ *{font-size:.95rem;line-height:1.85;color:var(--muted)}
.prose hr ~ * strong{color:var(--text)}
.back{margin-top:3rem;font-size:.95rem}

/* 頁尾 */
.site-foot{background:var(--graphite-deep);color:#C9CED6;font-size:.9rem}
.site-foot .wrap{padding-top:2.5rem;padding-bottom:2.5rem;display:flex;flex-wrap:wrap;gap:1.5rem 3rem;align-items:center;justify-content:space-between}
.site-foot img{height:2rem;width:auto;display:block}
.site-foot nav{display:flex;flex-wrap:wrap;gap:.5rem 1.5rem}
.site-foot a{color:#fff;text-decoration:none}
.site-foot a:hover{text-decoration:underline}
.site-foot .fine{flex-basis:100%;margin:0;color:#9AA2AD;font-size:.8125rem}
.prose .refer{margin-top:1.5rem;padding:1rem 1.25rem;background:var(--wash);border-left:3px solid var(--graphite);color:var(--text)}
.site-foot .fine a{color:#C9CED6;text-decoration:underline}
.site-foot .fine + .fine{margin-top:-1rem}

/* 固定頁首 */
.site-head{position:sticky;top:0;z-index:50}
html{scroll-padding-top:5.5rem}
@media (min-width:62rem){.toc{top:6.5rem}}
@media (max-width:40rem){
  .site-head .wrap{min-height:3.5rem;flex-wrap:nowrap;padding-top:.5rem;padding-bottom:.5rem}
  .brand img{height:1.6rem}
  .nav{gap:.9rem;font-size:.875rem;white-space:nowrap}
}
@media (max-width:22.5rem){.brand img{height:1.6rem;width:3.6rem;object-fit:cover;object-position:left}}
/* 圖示 */
svg{fill:none;stroke:currentColor;stroke-width:1.5;stroke-linecap:round;stroke-linejoin:round}
.topics li{justify-content:flex-start;align-items:center}
.topics i{flex:none;width:1.6rem;height:1.6rem;color:var(--graphite)}
.topics b{font-weight:400;flex:1}
.hero .wrap{position:relative}
.hero-art{display:none}
@media (min-width:56rem){.hero-art{display:grid;grid-template-columns:repeat(3,4.5rem);gap:1.5rem;position:absolute;right:1.25rem;top:50%;transform:translateY(-50%);color:#8E98A6}
.hero-art svg{width:4.5rem;height:4.5rem;stroke-width:1}
.hero-art svg:first-child{color:var(--gold)}}
/* 浮動按鈕 */
.float{opacity:.92;position:fixed;right:.75rem;bottom:1.25rem;z-index:60;display:flex;flex-direction:column;border-radius:1.6rem;overflow:hidden;background:var(--graphite);box-shadow:0 4px 14px rgba(31,41,55,.28)}
.float[hidden]{display:none}
.float a,.float button{display:grid;place-items:center;width:2.75rem;height:2.75rem;color:#fff;background:none;border:0;padding:0;cursor:pointer}
.float a{border-bottom:1px solid rgba(255,255,255,.22)}
.float a:hover,.float button:hover{background:var(--graphite-deep);color:#fff}
.float svg{width:1.35rem;height:1.35rem}
.float button:focus-visible{outline:2px solid var(--gold);outline-offset:-3px}
/* 文章圖解 */
.prose .fig{margin:2rem 0 2.25rem;font-size:1rem;line-height:1.6;color:var(--ink)}
.fig svg{width:2rem;height:2rem;color:var(--graphite)}
.fig b{display:block}
.fig small{display:block;color:var(--muted);font-size:.85rem}
.steps{display:grid;gap:.75rem;grid-template-columns:1fr}
.step{position:relative;background:var(--wash);border:1px solid var(--line);border-radius:.5rem;padding:1rem 1rem 1rem 3.25rem}
.step .n{position:absolute;left:1rem;top:1rem;width:1.6rem;height:1.6rem;border-radius:50%;background:var(--graphite);color:#fff;display:grid;place-items:center;font-size:.85rem;font-weight:700}
.step svg{float:right;margin-left:.5rem}
.step:not(:last-child)::after{content:"";position:absolute;left:1.72rem;bottom:-.8rem;width:2px;height:.8rem;background:var(--gold)}
@media (min-width:40rem){
  .steps{grid-template-columns:repeat(3,1fr);gap:1.25rem}
  .step{padding:3.25rem 1rem 1rem}
  .step svg{position:absolute;right:1rem;top:.85rem;float:none}
  .step:not(:last-child)::after{left:auto;right:-1.25rem;bottom:auto;top:50%;width:1.25rem;height:2px}
}
.four{display:grid;grid-template-columns:repeat(2,1fr);gap:.75rem;text-align:center}
@media (min-width:40rem){.four{grid-template-columns:repeat(4,1fr)}}
.four div{border:1px solid var(--line);border-radius:.5rem;padding:1rem .5rem}
.four svg{display:block;margin:0 auto .4rem}
.routes{display:grid;gap:.75rem}
@media (min-width:40rem){.routes{grid-template-columns:1fr 1fr;gap:1.25rem}}
.route{border:1px solid var(--line);border-top:3px solid var(--graphite);border-radius:.25rem;padding:1rem 1.1rem;background:var(--wash)}
.route dl{margin:.6rem 0 0}
.route dt{color:var(--muted);font-size:.85rem;margin-top:.6rem}
.route dd{margin:0}

/* 語言切換 */
.nav .lang{border:1px solid var(--line);border-radius:1rem;padding:.15rem .7rem;font-size:.85rem;color:var(--graphite);align-self:center}
.nav .lang:hover{border-color:var(--graphite);border-bottom-color:var(--graphite)}
.nav{align-items:center}
/* 英文版 */
html[lang="en"]{--serif:"Source Serif 4",Georgia,"Times New Roman",serif;--measure:42rem}
html[lang="en"] body{line-height:1.7}
html[lang="en"] .hero h1,html[lang="en"] .page-head h1,html[lang="en"] .block h2,html[lang="en"] .prose h2{letter-spacing:0}
html[lang="en"] .hero h1{line-height:1.15;font-size:clamp(2rem,5.2vw,3.2rem);max-width:15em}
html[lang="en"] .page-head h1{line-height:1.2;max-width:24em}
html[lang="en"] .entry h3{line-height:1.3}
html[lang="en"] .prose{line-height:1.75}
html[lang="en"] .prose h2{line-height:1.3}
html[lang="en"] .toc{line-height:1.45}
@media (min-width:56rem){html[lang="en"] .hero h1{max-width:11.5em}}
@media (max-width:40rem){.nav .lang{padding:.1rem .55rem}html[lang="en"] .nav{gap:.7rem;font-size:.8125rem}}
.brand{flex:none}
@media (max-width:27rem){.brand img{height:1.6rem;width:3.7rem;object-fit:cover;object-position:left center}}