:root{
  --paper:#fbf5e8;
  --paper-2:#f1e3c9;
  --ink:#191613;
  --muted:#62584c;
  --red:#b4221c;
  --red-deep:#7f1813;
  --teal:#286a65;
  --line:#d8c2a1;
  --white:#fffaf0;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);font-family:Inter,"Noto Sans SC","Microsoft YaHei",Arial,sans-serif;line-height:1.65}
body::before{content:"";position:fixed;inset:0;pointer-events:none;background:linear-gradient(90deg,rgba(25,22,19,.035) 1px,transparent 1px),linear-gradient(180deg,rgba(25,22,19,.025) 1px,transparent 1px);background-size:42px 42px;mix-blend-mode:multiply}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
.ukiyo-header{position:sticky;top:0;z-index:20;display:flex;align-items:center;justify-content:space-between;gap:18px;padding:14px clamp(18px,4vw,48px);background:rgba(251,245,232,.92);backdrop-filter:blur(14px);border-bottom:1px solid var(--line)}
.brand-mark{display:flex;align-items:center;gap:10px;font-weight:800;min-width:0}
.brand-mark span:last-child{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.mark-wave{width:30px;height:30px;border:2px solid var(--ink);background:radial-gradient(circle at 68% 35%,var(--teal) 0 16%,transparent 17%),linear-gradient(135deg,var(--red) 0 50%,var(--paper) 51%);transform:rotate(-6deg)}
.site-nav{display:flex;gap:6px;align-items:center}
.site-nav a{padding:9px 10px;border-bottom:2px solid transparent;color:var(--muted);font-size:14px}
.site-nav a:hover{color:var(--ink);border-color:var(--red)}
.menu-toggle{display:none;border:1px solid var(--ink);background:var(--paper);padding:8px 11px;font:inherit}
.redsea-hero{min-height:calc(100vh - 112px);display:grid;grid-template-columns:72px minmax(280px,500px) minmax(320px,1fr);gap:24px;align-items:center;padding:22px clamp(18px,4vw,54px);border-bottom:1px solid var(--line)}
.chapter-rail{align-self:stretch;display:flex;flex-direction:column;justify-content:center;gap:10px;border-right:1px solid var(--line);padding-right:18px}
.chapter-rail a{writing-mode:vertical-rl;letter-spacing:0;border:1px solid var(--line);padding:12px 6px;background:rgba(255,250,240,.62);color:var(--muted)}
.chapter-rail a:hover{background:var(--red);color:var(--white);border-color:var(--red)}
.hero-copy{position:relative;z-index:2}
.kicker,.section-kicker{margin:0 0 10px;color:var(--teal);text-transform:uppercase;font-size:12px;letter-spacing:.08em;font-weight:800}
h1,h2,h3,p{overflow-wrap:anywhere}
h1{font-size:clamp(34px,4.2vw,56px);line-height:1.06;margin:0 0 16px;letter-spacing:0;font-weight:900}
h2{font-size:clamp(25px,3.4vw,44px);line-height:1.16;margin:0 0 16px;letter-spacing:0}
h3{font-size:20px;line-height:1.25;margin:0 0 8px;letter-spacing:0}
.lead{font-size:clamp(16px,1.7vw,19px);color:var(--muted);margin:0 0 18px;max-width:760px}
.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin:18px 0}
.ink-btn,.line-btn{display:inline-flex;align-items:center;justify-content:center;min-height:44px;padding:10px 16px;border:1px solid var(--ink);font-weight:800}
.ink-btn{background:var(--ink);color:var(--white)}
.line-btn{background:transparent;color:var(--ink)}
.line-btn.light{border-color:var(--white);color:var(--white)}
.hero-notes{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;background:var(--line);border:1px solid var(--line);margin:24px 0 0;max-width:720px}
.hero-notes div{background:rgba(255,250,240,.78);padding:10px}
.hero-notes dt{font-weight:900;color:var(--red);margin-bottom:4px}
.hero-notes dd{margin:0;color:var(--muted);font-size:14px}
.hero-art{margin:0;align-self:stretch;display:flex;align-items:center}
.hero-art img{width:100%;max-height:calc(100vh - 168px);aspect-ratio:16/9;object-fit:cover;border:1px solid var(--ink);box-shadow:10px 10px 0 var(--red-deep)}
.paper-strip,.manual-spread,.article-current,.faq-fold,.page-hero,.download-scroll,.paper-steps,.two-column-note,.mobile-ink,.device-ledger.full,.issue-river,.reply-note,.article-page,.about-plain,.contact-sheet,.legal-copy,.archive-note{width:min(1140px,calc(100% - 36px));margin:0 auto}
.paper-strip{padding:54px 0}
.device-ledger{display:grid;border-top:2px solid var(--ink);margin-top:20px}
.ledger-row{display:grid;grid-template-columns:120px minmax(180px,290px) 1fr;gap:18px;align-items:center;padding:18px 0;border-bottom:1px solid var(--line)}
.ledger-row span{font-weight:900;color:var(--red)}
.ledger-row strong{font-size:20px}
.ledger-row em{font-style:normal;color:var(--muted)}
.ledger-row:hover strong{text-decoration:underline;text-decoration-thickness:2px;text-decoration-color:var(--red)}
.manual-spread{display:grid;grid-template-columns:1.15fr repeat(3,1fr);gap:18px;padding:54px 0;border-top:1px solid var(--line)}
.manual-spread.compact{grid-template-columns:repeat(3,1fr);border-top:0;padding-top:18px}
.chapter-title{padding-right:24px;border-right:1px solid var(--line)}
.guide-leaf{background:var(--white);border:1px solid var(--line);padding:22px}
.guide-leaf h3{color:var(--red)}
.redsea-band{display:grid;grid-template-columns:1fr 1.25fr auto;gap:24px;align-items:center;background:var(--red-deep);color:var(--white);padding:38px clamp(18px,4vw,54px);margin:22px 0}
.redsea-band.pale{background:var(--teal)}
.redsea-band p{margin:0;color:rgba(255,250,240,.88)}
.article-current,.faq-fold{padding:54px 0;border-top:1px solid var(--line)}
.section-head{display:flex;justify-content:space-between;gap:18px;align-items:end;margin-bottom:18px}
.section-head a{font-weight:800;color:var(--red)}
.article-river{display:grid;gap:0;border-top:2px solid var(--ink)}
.article-river.list{margin-top:24px}
.article-line{display:grid;grid-template-columns:120px 92px 1fr;gap:18px;padding:20px 0;border-bottom:1px solid var(--line);align-items:start}
.article-line time,.article-line span{color:var(--muted);font-size:14px}
.article-line h3{margin:0}
.article-line p{grid-column:3;margin:0;color:var(--muted)}
.faq-fold details{border-top:1px solid var(--line);padding:16px 0}
.faq-fold details:last-child{border-bottom:1px solid var(--line)}
.faq-fold summary{cursor:pointer;font-weight:900;font-size:18px}
.faq-fold p{margin:10px 0 0;color:var(--muted)}
.page-hero{padding:58px 0 28px;border-bottom:1px solid var(--line)}
.page-hero h1{max-width:960px}
.download-scroll,.paper-steps,.two-column-note,.mobile-ink,.device-ledger.full,.issue-river,.reply-note,.about-plain,.contact-sheet,.legal-copy,.archive-note{padding:34px 0}
.platform-ledger{display:grid;gap:14px}
.platform-row,.system-row{border:1px solid var(--line);background:var(--white);padding:22px}
.platform-row span,.system-row span{color:var(--red);font-weight:900}
.platform-row a{font-weight:900;color:var(--teal)}
.paper-steps ol{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;list-style:none;padding:0;margin:0}
.paper-steps li{border:1px solid var(--line);background:rgba(255,250,240,.72);padding:18px}
.two-column-note,.contact-sheet{display:grid;grid-template-columns:1fr 1fr;gap:18px}
.mobile-ink{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.issue-river{display:flex;flex-wrap:wrap;gap:10px}
.issue-river a{border:1px solid var(--line);background:var(--white);padding:10px 12px;font-weight:800}
.reply-note,.archive-note{border-top:2px solid var(--ink);border-bottom:1px solid var(--line)}
.article-page{padding:42px 0 58px;max-width:900px}
.breadcrumb{display:flex;gap:8px;color:var(--muted);font-size:14px;margin-bottom:18px}
.article-page header{border-bottom:2px solid var(--ink);padding-bottom:20px;margin-bottom:28px}
.article-page section{border-bottom:1px solid var(--line);padding:24px 0}
.article-page section p{font-size:18px;color:var(--muted)}
.article-next{display:flex;gap:12px;flex-wrap:wrap;margin-top:26px}
.about-plain,.legal-copy{max-width:850px}
.about-plain p,.legal-copy p,.archive-note p{font-size:18px;color:var(--muted)}
.legal-copy h2{font-size:26px;margin-top:28px}
.site-footer{display:grid;grid-template-columns:1.3fr repeat(3,1fr);gap:24px;padding:34px clamp(18px,4vw,54px);border-top:2px solid var(--ink);background:#efe1c7}
.site-footer nav{display:grid;gap:6px;align-content:start}
.site-footer span,.site-footer strong{font-weight:900}
.site-footer a,.site-footer p{color:var(--muted);margin:0}
[id]{scroll-margin-top:88px}
@media (max-width:900px){
  .menu-toggle{display:inline-flex}
  .site-nav{display:none;position:absolute;left:18px;right:18px;top:60px;background:var(--paper);border:1px solid var(--ink);padding:10px;flex-direction:column;align-items:stretch}
  .site-nav.is-open{display:flex}
  .redsea-hero{grid-template-columns:1fr;min-height:auto;padding:16px clamp(14px,4vw,28px) 22px;gap:14px}
  .chapter-rail{display:none}
  .chapter-rail a{writing-mode:horizontal-tb;white-space:nowrap}
  .hero-art{order:-1}
  .hero-art img{height:230px;max-height:230px;object-position:center 58%;box-shadow:7px 7px 0 var(--red-deep)}
  .hero-notes{display:none}
  .manual-spread,.manual-spread.compact,.paper-steps ol,.mobile-ink,.two-column-note,.contact-sheet,.site-footer{grid-template-columns:1fr}
  .chapter-title{border-right:0;border-bottom:1px solid var(--line);padding:0 0 16px}
  .redsea-band{grid-template-columns:1fr}
  .article-line{grid-template-columns:1fr;gap:8px}
  .article-line p{grid-column:auto}
  .ledger-row{grid-template-columns:1fr;gap:4px}
}
@media (max-width:520px){
  .ukiyo-header{padding:12px 14px}
  .brand-mark{max-width:72%}
  h1{font-size:30px;line-height:1.08}
  h2{font-size:26px}
  .lead{font-size:15px;line-height:1.58}
  .hero-art img{height:190px;max-height:190px}
  .paper-strip,.manual-spread,.article-current,.faq-fold,.page-hero,.download-scroll,.paper-steps,.two-column-note,.mobile-ink,.device-ledger.full,.issue-river,.reply-note,.article-page,.about-plain,.contact-sheet,.legal-copy,.archive-note{width:min(100% - 28px,1140px)}
  .hero-actions{flex-direction:column}
  .ink-btn,.line-btn{width:100%}
}