@charset "UTF-8";

:root{
  --ink:#f2e9dc;
  --paper:#24221f;
  --paper-soft:#302d29;
  --accent:#cf9360;
  --accent-dark:#9e623e;
  --muted:#b5aa9d;
  --line:rgba(242,233,220,.18);
  --font-zh:"Songti TC","Noto Serif TC","PMingLiU",serif;
  --font-en:Georgia,"Times New Roman",serif;
  color:var(--ink);
  background:var(--paper);
  font-family:var(--font-zh);
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--font-zh)}
a{color:inherit;text-decoration:none}
[lang="en"]{font-family:var(--font-en)}
.line-float{position:fixed;right:max(20px,env(safe-area-inset-right));bottom:max(20px,env(safe-area-inset-bottom));width:54px;height:54px;border-radius:50%;background:#06c755;color:#fff;display:grid;place-items:center;box-shadow:0 10px 28px rgba(0,0,0,.34);z-index:81;transition:transform .2s ease,box-shadow .2s ease}
.line-float__bubble{position:relative;display:grid;place-items:center;width:37px;height:29px;border-radius:50%;background:#fff;color:#06a947;font:700 10px/1 Arial,sans-serif;letter-spacing:-.03em}
.line-float__bubble:after{content:"";position:absolute;left:7px;bottom:-4px;border-width:5px 5px 0 0;border-style:solid;border-color:#fff transparent transparent transparent;transform:rotate(9deg)}
.line-float:hover,.line-float:focus-visible{transform:translateY(-3px);box-shadow:0 14px 34px rgba(0,0,0,.4)}
.line-float:focus-visible{outline:3px solid #fffaf1;outline-offset:3px}
.back-to-top{position:fixed;right:max(20px,env(safe-area-inset-right));bottom:calc(max(20px,env(safe-area-inset-bottom)) + 66px);width:52px;height:52px;padding:0;border:1px solid rgba(242,233,220,.54);border-radius:50%;background:var(--accent);color:var(--paper);display:grid;place-items:center;font:700 25px/1 var(--font-en);box-shadow:0 10px 28px rgba(0,0,0,.32);cursor:pointer;z-index:80;opacity:0;visibility:hidden;pointer-events:none;transform:translateY(14px);transition:opacity .22s ease,transform .22s ease,visibility .22s ease,background-color .2s ease,color .2s ease}
.back-to-top.is-visible{opacity:1;visibility:visible;pointer-events:auto;transform:translateY(0)}
.back-to-top:hover,.back-to-top:focus-visible{background:#fffaf1;color:#123840;transform:translateY(-3px)}
.back-to-top:focus-visible{outline:3px solid var(--accent);outline-offset:3px}

.site-header{min-height:72px;padding:0 clamp(20px,5vw,72px);border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:24px;background:rgba(36,34,31,.96);position:sticky;top:0;z-index:20;backdrop-filter:blur(12px)}
.brand{display:flex;align-items:center;gap:11px;font-weight:700;letter-spacing:.13em}
.brand-mark{width:34px;height:34px;background:var(--accent);color:var(--paper);display:grid;place-items:center;font-family:var(--font-en)}
.back-link{color:var(--accent);font-size:14px;letter-spacing:.04em}

.category-hero{min-height:62vh;padding:clamp(72px,10vw,150px) clamp(20px,8vw,128px) 70px;display:grid;grid-template-columns:minmax(0,1.35fr) minmax(280px,.65fr);gap:clamp(48px,8vw,130px);align-items:end;border-bottom:1px solid var(--line);position:relative;overflow:hidden}
.category-hero:after{content:"";position:absolute;width:min(48vw,680px);aspect-ratio:1;border:1px solid rgba(207,147,96,.4);border-radius:50%;right:-14vw;top:-20vw;pointer-events:none}
.kicker{margin:0 0 20px;color:var(--accent);font:700 12px/1.4 var(--font-en);letter-spacing:.18em}
h1{max-width:900px;margin:0;font-size:clamp(52px,8vw,118px);font-weight:400;line-height:.94;letter-spacing:-.045em}
.hero-note{margin:28px 0 0;max-width:720px;color:var(--muted);font-size:clamp(16px,1.45vw,20px);line-height:1.9}
.content-meta{margin:14px 0 0;color:#a99e91;font:12px/1.6 var(--font-en);letter-spacing:.06em}
.hero-meta{border-top:1px solid var(--accent);padding-top:22px;position:relative;z-index:1}
.hero-meta p{margin:0 0 12px;color:var(--muted);font-size:14px;line-height:1.7}
.hero-meta strong{display:block;color:var(--ink);font-size:28px;font-weight:400}

.article-index{padding:54px clamp(20px,8vw,128px);background:#eee6d9;color:#24221f;border-bottom:1px solid #cf9360;display:grid;grid-template-columns:minmax(200px,.45fr) minmax(0,1.55fr);gap:48px}
.article-index h2{margin:0;font-size:30px;font-weight:400}
.article-index ol{list-style:none;margin:0;padding:0;border-top:1px solid rgba(36,34,31,.3);counter-reset:chapter}
.article-index li{counter-increment:chapter;border-bottom:1px solid rgba(36,34,31,.3)}
.article-index a{padding:18px 0;display:grid;grid-template-columns:42px 1fr auto;gap:12px;align-items:center;font-size:18px}
.article-index a:before{content:counter(chapter,decimal-leading-zero);color:var(--accent-dark);font:italic 14px/1 var(--font-en)}
.article-index a:after{content:"↘";color:var(--accent-dark);font-size:18px}

.articles{max-width:1280px;margin:0 auto;padding:clamp(70px,9vw,140px) clamp(20px,7vw,96px)}
.article{display:grid;grid-template-columns:150px minmax(0,760px);justify-content:space-between;gap:clamp(38px,8vw,110px);padding:clamp(60px,7vw,104px) 0;border-top:1px solid var(--line)}
.article:first-child{border-top:0;padding-top:0}
.article-no{color:var(--accent);font:italic clamp(42px,5vw,76px)/1 var(--font-en)}
.article-kicker{margin:0 0 14px;color:var(--accent);font:700 11px/1.4 var(--font-en);letter-spacing:.16em}
.article h2{margin:0 0 30px;font-size:clamp(34px,4.4vw,64px);font-weight:400;line-height:1.15;letter-spacing:-.025em}
.article h3{margin:42px 0 14px;color:var(--accent);font-size:22px;font-weight:400}
.article p,.article li{color:var(--muted);font-size:17px;line-height:1.95}
.article p{margin:0 0 18px}
.article ul,.article ol{margin:20px 0 28px;padding-left:1.35em}
.article li{margin-bottom:12px;padding-left:6px}
.article strong{color:var(--ink);font-weight:600}
.note{margin:32px 0!important;padding:22px 24px;border-left:3px solid var(--accent);background:var(--paper-soft);color:var(--ink)!important}
.formula{margin:28px 0;padding:24px;border:1px solid rgba(207,147,96,.48);font-size:clamp(21px,2vw,30px);line-height:1.55;color:var(--ink)}
.concept-flow{margin:34px 0;display:grid;grid-template-columns:repeat(5,1fr);border:1px solid rgba(207,147,96,.48)}
.concept-flow span{min-height:92px;padding:18px 12px;display:grid;place-items:center;text-align:center;color:var(--ink);border-right:1px solid rgba(207,147,96,.48);font-size:15px;line-height:1.5;position:relative}
.concept-flow span:last-child{border-right:0}
.concept-flow span:not(:last-child):after{content:"→";position:absolute;right:-9px;top:50%;transform:translateY(-50%);color:var(--accent);background:var(--paper);padding:4px 1px;z-index:1;font-family:var(--font-en)}
.concept-flow--three{grid-template-columns:repeat(3,1fr)}
.steps{list-style:none!important;padding:0!important;counter-reset:step}
.steps li{counter-increment:step;display:grid;grid-template-columns:44px 1fr;gap:16px;align-items:start}
.steps li:before{content:counter(step,decimal-leading-zero);color:var(--accent);font:italic 18px/1.8 var(--font-en)}
.comparison-wrap{margin:30px 0;overflow-x:auto;border:1px solid rgba(207,147,96,.48)}
.comparison-table{width:100%;min-width:680px;border-collapse:collapse;color:var(--muted);font-size:15px;line-height:1.65}
.comparison-table th,.comparison-table td{padding:18px 20px;text-align:left;vertical-align:top;border-right:1px solid var(--line);border-bottom:1px solid var(--line)}
.comparison-table th:last-child,.comparison-table td:last-child{border-right:0}.comparison-table tr:last-child th,.comparison-table tr:last-child td{border-bottom:0}
.comparison-table thead th{background:var(--paper-soft);color:var(--accent);font-weight:600}.comparison-table tbody th{color:var(--ink);font-weight:600;white-space:nowrap}
.direction-list{list-style:none!important;padding:0!important;margin:28px 0!important;counter-reset:direction}
.direction-list li{counter-increment:direction;display:grid;grid-template-columns:44px 1fr;gap:16px;margin:0!important;padding:20px 0!important;border-top:1px solid var(--line)}
.direction-list li:last-child{border-bottom:1px solid var(--line)}
.direction-list li:before{content:counter(direction,decimal-leading-zero);color:var(--accent);font:italic 18px/1.8 var(--font-en)}
.source-note{max-width:1120px;margin:0 auto;padding:0 clamp(20px,7vw,96px) clamp(70px,9vw,120px)}
.source-note h2{margin:0 0 18px;font-size:clamp(32px,4vw,52px);font-weight:400}.source-note>p:not(.article-kicker),.source-note li{color:var(--muted);font-size:15px;line-height:1.8}.source-note ul{margin:24px 0 0;padding-left:1.2em}.source-note li{margin-bottom:10px}.source-note a{color:var(--accent);text-decoration:underline;text-underline-offset:4px}

.page-footer{padding:52px clamp(20px,8vw,128px);border-top:1px solid var(--line);display:flex;justify-content:space-between;gap:24px;color:var(--muted);font-size:14px}
.page-footer a{color:var(--accent)}

@media(max-width:800px){
  .site-header{min-height:64px}.brand-name{font-size:13px}.back-link{font-size:13px}
  .category-hero{min-height:auto;padding:76px 20px 58px;display:block}.category-hero:after{width:100vw;right:-55vw;top:-18vw}.hero-note{font-size:16px;line-height:1.8}.hero-meta{margin-top:48px}.hero-meta strong{font-size:24px}
  .article-index{padding:44px 20px;display:block}.article-index h2{margin-bottom:26px}.article-index a{font-size:17px}
  .articles{padding:72px 20px}.article{display:block;padding:68px 0}.article-no{margin-bottom:26px;font-size:48px}.article h2{font-size:38px;line-height:1.2}.article p,.article li{font-size:16px;line-height:1.85}.article h3{margin-top:34px;font-size:21px}.note{padding:20px}.formula{font-size:22px}
  .concept-flow{grid-template-columns:1fr}.concept-flow span{min-height:68px;border-right:0;border-bottom:1px solid rgba(207,147,96,.48)}.concept-flow span:last-child{border-bottom:0}.concept-flow span:not(:last-child):after{content:"↓";right:50%;top:auto;bottom:-14px;transform:translateX(50%);padding:0 6px}
  .comparison-wrap{margin-inline:-4px}.comparison-table th,.comparison-table td{padding:15px 16px}.direction-list li{grid-template-columns:36px 1fr;gap:10px}.source-note{padding:0 20px 64px}
  .page-footer{display:block;padding:42px 20px}.page-footer p{margin:0 0 16px}
}

@media(max-width:430px){
  h1{font-size:48px;line-height:1.02}.category-hero{padding-top:58px}.article-index a{grid-template-columns:34px 1fr auto;gap:8px}.article h2{font-size:34px}.article p,.article li{font-size:16px}.steps li{grid-template-columns:36px 1fr;gap:10px}
  .line-float{right:max(14px,env(safe-area-inset-right));bottom:max(14px,env(safe-area-inset-bottom));width:50px;height:50px}.line-float__bubble{width:34px;height:27px;font-size:9px}
  .back-to-top{right:max(14px,env(safe-area-inset-right));bottom:calc(max(14px,env(safe-area-inset-bottom)) + 62px);width:48px;height:48px;font-size:23px}
}

@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .back-to-top{transition:none}
}