:root {
  --paper: #f6f2e9;
  --ink: #17202a;
  --muted: #68727c;
  --line: #d8d1c3;
  --green: #174b43;
  --lime: #c9e36b;
  --orange: #e46536;
  --white: #fffdf8;
  --serif: "Noto Serif SC", "Songti SC", STSong, serif;
  --sans: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--paper); font: 16px/1.75 var(--sans); }
a { color: inherit; }
.rail { width: min(1180px, calc(100% - 48px)); margin-inline: auto; }
.skip { position: fixed; top: -60px; left: 16px; z-index: 99; padding: 9px 14px; color: white; background: var(--ink); }
.skip:focus { top: 12px; }
.site-header { position: sticky; top: 0; z-index: 20; border-bottom: 1px solid rgba(216,209,195,.9); background: rgba(246,242,233,.93); backdrop-filter: blur(14px); }
.site-header .rail { min-height: 74px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.brand { display: flex; align-items: center; gap: 13px; text-decoration: none; font-weight: 800; }
.brand img { width: 96px; height: 44px; object-fit: contain; }
.brand span { padding-left: 13px; border-left: 1px solid var(--line); font-size: 13px; }
.nav { display: flex; gap: 24px; }
.nav a { min-height: 44px; display: inline-flex; align-items: center; color: var(--muted); text-decoration: none; font-size: 13px; font-weight: 700; }
.nav a:hover { color: var(--green); }
.eyebrow { margin: 0 0 15px; color: var(--orange); font-size: 11px; font-weight: 850; letter-spacing: .16em; }
.hero { position: relative; overflow: hidden; padding: clamp(70px, 9vw, 128px) 0 90px; color: white; background: var(--green); }
.hero::after { content: "RE"; position: absolute; right: -2vw; bottom: -8vw; color: transparent; -webkit-text-stroke: 1px rgba(255,255,255,.13); font: 900 clamp(190px, 36vw, 520px)/.8 var(--sans); }
.hero-grid { position: relative; z-index: 1; display: grid; grid-template-columns: 1.12fr minmax(250px, 390px); gap: clamp(46px, 8vw, 110px); align-items: center; }
.hero h1 { margin: 0 0 18px; font: 800 clamp(58px, 8.5vw, 116px)/.94 var(--serif); letter-spacing: -.055em; }
.hero h1 em { display: block; color: var(--lime); font-style: normal; }
.hero-lead { max-width: 650px; margin: 0; color: #d8e5df; font-size: clamp(17px, 1.6vw, 21px); }
.hero-note { padding: 26px 0 4px; border-top: 2px solid var(--lime); }
.hero-note span { display: block; color: var(--lime); font-size: 11px; font-weight: 850; letter-spacing: .13em; }
.hero-note strong { display: block; margin-top: 15px; font: 700 24px/1.35 var(--serif); }
.hero-cover { margin: 0; }
.hero-cover img { width: 100%; height: auto; border: 1px solid rgba(255,255,255,.22); box-shadow: 0 30px 70px rgba(2,11,22,.38); }
.hero-cover figcaption { margin-top: 13px; color: #a9c2bb; font-size: 11px; letter-spacing: .08em; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 34px; }
.button { min-height: 48px; display: inline-flex; align-items: center; justify-content: center; padding: 0 19px; border: 1px solid currentColor; text-decoration: none; font-size: 13px; font-weight: 800; }
.button.primary { color: var(--green); border-color: var(--lime); background: var(--lime); }
.button.ghost { color: #d9e5e0; }
.button.disabled { cursor: default; color: #8ea39d; border-color: #50736c; }
.section { padding: clamp(72px, 9vw, 116px) 0; border-bottom: 1px solid var(--line); }
.section-head { display: grid; grid-template-columns: 150px 1fr; gap: 34px; margin-bottom: 48px; }
.section-no { color: var(--orange); font-size: 11px; font-weight: 850; letter-spacing: .12em; }
.section h2 { max-width: 850px; margin: 0; font: 750 clamp(36px, 5vw, 64px)/1.12 var(--serif); letter-spacing: -.025em; }
.question-grid { display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid var(--ink); border-left: 1px solid var(--line); }
.question-grid article { min-height: 230px; display: flex; flex-direction: column; padding: 24px; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); background: rgba(255,255,255,.4); }
.question-grid span { color: var(--orange); font-size: 11px; font-weight: 850; }
.question-grid strong { margin: 24px 0 10px; font: 700 21px/1.35 var(--serif); }
.question-grid p { margin: auto 0 0; color: var(--muted); font-size: 13px; }
.route { color: white; background: var(--ink); }
.route .section-no { color: var(--lime); }
.route-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px; background: rgba(255,255,255,.18); }
.route-grid article { min-height: 230px; padding: 28px; background: var(--ink); }
.route-grid span { color: var(--lime); font-size: 11px; font-weight: 800; }
.route-grid h3 { margin: 48px 0 12px; font: 700 27px/1.2 var(--serif); }
.route-grid p { margin: 0; color: #aeb8c3; font-size: 14px; }
.cta { padding: 70px 0; background: var(--orange); color: white; }
.cta .rail { display: flex; align-items: center; justify-content: space-between; gap: 40px; }
.cta h2 { margin: 0; font: 750 clamp(30px, 4vw, 50px)/1.15 var(--serif); }
.cta .button { color: white; }
.footer { padding: 26px 0; color: #79818a; font-size: 12px; }
.footer .rail { display: flex; justify-content: space-between; gap: 20px; }

/* Reading */
.reading-main { padding: clamp(54px, 8vw, 98px) 0; }
.reading-shell { width: min(820px, calc(100% - 40px)); margin-inline: auto; }
.reading-kicker { margin: 0 0 14px; color: var(--orange); font-size: 11px; font-weight: 850; letter-spacing: .13em; }
.reading-shell > h1 { margin: 0 0 16px; font: 750 clamp(42px, 6vw, 72px)/1.08 var(--serif); }
.reading-intro { color: var(--muted); font-size: 19px; }
.version-note { margin: 34px 0 58px; padding: 20px 22px; border-left: 4px solid var(--lime); background: var(--white); }
.version-note strong { display: block; margin-bottom: 5px; }
.version-note p { margin: 0; color: var(--muted); }
.toc-part { margin-top: 55px; }
.toc-part h2 { margin: 0 0 10px; font: 750 31px/1.2 var(--serif); }
.toc-part > p { margin: 0 0 20px; color: var(--muted); }
.toc { margin: 0; padding: 0; list-style: none; border-top: 2px solid var(--ink); }
.toc li { display: grid; grid-template-columns: 48px 1fr auto; gap: 16px; align-items: start; padding: 19px 0; border-bottom: 1px solid var(--line); }
.toc .num { color: var(--orange); font-size: 11px; font-weight: 900; }
.toc strong { display: block; font: 700 19px/1.35 var(--serif); }
.toc p { margin: 5px 0 0; color: var(--muted); font-size: 13px; }
.toc a { color: var(--green); font-size: 12px; font-weight: 850; text-decoration: none; }
.pending { color: #92989e; font-size: 11px; white-space: nowrap; }
.reading-content { font-size: 18px; line-height: 1.95; }
.reading-content h1 { margin: 0 0 35px; padding-bottom: 24px; border-bottom: 2px solid var(--ink); font: 750 clamp(36px, 5vw, 58px)/1.2 var(--serif); }
.reading-content h2 { margin: 55px 0 18px; font: 720 clamp(27px, 3.1vw, 38px)/1.3 var(--serif); }
.reading-content h3 { margin: 38px 0 14px; font: 700 23px/1.35 var(--serif); }
.reading-content p, .reading-content ul, .reading-content ol { margin: 0 0 22px; }
.reading-content blockquote { margin: 30px 0; padding: 18px 24px; border-left: 3px solid var(--orange); background: var(--white); color: #4f5962; }
.reading-content a { color: var(--green); text-underline-offset: 4px; }
.reading-content hr { margin: 40px 0; border: 0; border-top: 1px solid var(--line); }
.reader-pager { display: grid; grid-template-columns: 1fr 1fr; margin-top: 64px; border-top: 1px solid var(--line); }
.reader-pager a { padding: 22px 0; color: var(--green); text-decoration: none; font-weight: 800; }
.reader-pager a:last-child { text-align: right; }
.source-note { margin-top: 24px; padding: 17px 19px; border: 1px solid var(--line); color: var(--muted); font-size: 12px; }
@media (max-width: 900px) { .hero-grid, .section-head { grid-template-columns: 1fr; } .hero-cover { width: min(390px, 88%); } .question-grid, .route-grid { grid-template-columns: repeat(2,1fr); } }
@media (max-width: 680px) { .rail { width: min(100% - 30px, 1180px); } .brand img { width: 78px; } .brand span, .nav { display: none; } .hero { padding-top: 60px; } .question-grid, .route-grid { grid-template-columns: 1fr; } .cta .rail, .footer .rail { align-items: flex-start; flex-direction: column; } .toc li { grid-template-columns: 38px minmax(0, 1fr); } .toc li > :last-child { grid-column: 2; } }
@media (prefers-reduced-motion: reduce) { * { scroll-behavior: auto !important; } }