:root {
  --ink: #0d0905;
  --ink-soft: #17100a;
  --ink-warm: #24180f;
  --amber: #c8a96e;
  --amber-bright: #e4c98c;
  --paper: #f5f0e8;
  --paper-soft: rgba(245, 240, 232, 0.78);
  --paper-muted: rgba(245, 240, 232, 0.58);
  --line: rgba(228, 201, 140, 0.2);
  --max: 1120px;
  --measure: 720px;
}
* { box-sizing: border-box; }
html { background: var(--ink); overflow-x: hidden; scroll-behavior: smooth; }
body {
  margin: 0;
  background: radial-gradient(circle at 50% 0%, rgba(200,169,110,.12), transparent 32rem), linear-gradient(180deg, var(--ink) 0%, #110c08 44%, var(--ink) 100%);
  color: var(--paper);
  font-family: ui-serif, Georgia, Cambria, "Times New Roman", serif;
  line-height: 1.65;
  overflow-x: hidden;
}
body::selection { background: rgba(228, 201, 140, .28); }
a { color: inherit; }
img { display: block; max-width: 100%; height: auto; }
.page-shell { width: min(var(--max), calc(100% - 32px)); margin: 0 auto; }
.index-shell { min-height: 100svh; padding: clamp(32px, 6vw, 72px) 0 clamp(48px, 8vw, 88px); }
.index-lead { max-width: 930px; margin: 0 0 clamp(34px, 6vw, 72px); color: var(--amber-bright); font-size: clamp(28px, 4.6vw, 58px); font-weight: 620; line-height: 1.08; }
.index-grid { display: grid; gap: clamp(20px, 4vw, 38px); }
.index-entry { display: grid; grid-template-columns: minmax(0, .48fr) minmax(0, .52fr); align-items: center; gap: clamp(20px, 4vw, 54px); padding: clamp(18px, 3vw, 28px) 0; border-top: 1px solid rgba(228,201,140,.18); text-decoration: none; }
.index-entry:last-child { border-bottom: 1px solid rgba(228,201,140,.18); }
.index-entry img { width: 100%; border: 1px solid rgba(228,201,140,.18); border-radius: 8px; box-shadow: 0 22px 70px rgba(0,0,0,.34); }
.index-entry h2 { margin: 0 0 10px; color: var(--paper); font-size: clamp(31px, 5vw, 64px); font-weight: 620; line-height: 1.02; }
.index-entry p { margin: 0; max-width: 520px; color: var(--paper-soft); font-size: clamp(18px, 2.1vw, 24px); line-height: 1.42; }
.index-entry:hover h2, .index-entry:focus-visible h2 { color: var(--amber-bright); }
.section-top { position: sticky; top: 0; z-index: 10; border-bottom: 1px solid rgba(228,201,140,.16); background: rgba(13,9,5,.78); backdrop-filter: blur(18px); }
.section-top-inner { display: flex; align-items: center; justify-content: space-between; gap: 18px; min-height: 58px; }
.top-actions { display: flex; align-items: center; justify-content: flex-end; gap: 14px; margin-left: auto; }
.language-menu { position: relative; display: inline-flex; }
.language-menu summary { display: inline-flex; align-items: center; justify-content: center; width: 28px; height: 28px; border: 1px solid rgba(228,201,140,.28); background: rgba(13,9,5,.34); cursor: pointer; font-size: 15px; line-height: 1; list-style: none; }
.language-menu summary::-webkit-details-marker { display: none; }
.language-menu-panel { position: absolute; top: calc(100% + 10px); right: 0; display: grid; gap: 6px; min-width: 84px; padding: 8px; border: 1px solid rgba(228,201,140,.24); background: rgba(13,9,5,.96); box-shadow: 0 18px 50px rgba(0,0,0,.42); }
.language-menu-panel a { display: flex; align-items: center; justify-content: space-between; gap: 9px; padding: 7px 8px; border: 1px solid transparent; color: var(--paper); font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; font-size: 14px; line-height: 1; text-decoration: none; opacity: .72; }
.language-menu-panel a span { color: var(--paper-muted); font-size: 9px; font-weight: 800; letter-spacing: .12em; }
.language-menu-panel a[aria-current="page"], .language-menu-panel a:hover, .language-menu-panel a:focus-visible, .language-menu summary:hover, .language-menu summary:focus-visible { border-color: rgba(228,201,140,.62); opacity: 1; }

.brand, .return-link, .text-link, .index-menu summary, .section-footer a { color: rgba(245,240,232,.82); font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; font-size: 11px; font-weight: 800; letter-spacing: .08em; text-decoration: none; text-transform: uppercase; white-space: nowrap; }
.brand { color: var(--paper); }
.return-link, .text-link { color: var(--amber-bright); }
.index-menu { position: relative; }
.index-menu summary { display: inline-flex; align-items: center; gap: 7px; color: var(--amber-bright); cursor: pointer; list-style: none; }
.index-menu summary::-webkit-details-marker { display: none; }
.index-menu summary::after { content: "+"; color: rgba(228,201,140,.72); font-size: 13px; line-height: 1; }
.index-menu[open] summary::after { content: "-"; }
.index-menu-panel { position: absolute; top: calc(100% + 14px); right: 0; width: min(820px, calc(100vw - 32px)); max-height: min(calc(100vh - 70px), 780px); overflow: auto; padding: 22px; border: 1px solid rgba(228,201,140,.24); background: rgba(13,9,5,.96); box-shadow: 0 24px 80px rgba(0,0,0,.48); }
.index-menu-list, .index-menu-list ul { margin: 0; padding: 0; list-style: none; }
.index-menu-list { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px 24px; }
.index-menu-primary { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 8px; margin: 0 0 18px; padding: 0 0 16px; border-bottom: 1px solid rgba(228,201,140,.18); }
.index-menu-primary a { display: flex; min-height: 42px; align-items: center; justify-content: center; padding: 8px 7px; border: 1px solid rgba(228,201,140,.24); color: var(--paper); font-size: 10px; line-height: 1.18; text-align: center; white-space: normal; }
.index-menu-primary a:hover, .index-menu-primary a:focus-visible { border-color: rgba(228,201,140,.68); color: var(--amber-bright); }
.index-menu-list > li { min-width: 0; }
.index-menu-list ul { display: grid; gap: 7px; margin-top: 10px; }
.index-menu-list ul ul { margin: 7px 0 2px 12px; padding-left: 12px; border-left: 1px solid rgba(228,201,140,.24); }
.index-menu-panel a { display: inline; color: rgba(245,240,232,.72); font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; font-size: 10px; font-weight: 800; letter-spacing: .07em; line-height: 1.35; text-decoration: none; text-transform: uppercase; }
.index-menu-panel .index-menu-section-link { color: var(--paper); font-family: ui-serif, Georgia, Cambria, "Times New Roman", serif; font-size: clamp(18px, 2vw, 24px); font-weight: 650; letter-spacing: 0; line-height: 1.08; text-transform: none; }
.index-menu-panel ul ul ul a { color: rgba(228,201,140,.72); }
.index-menu-panel a:hover, .index-menu-panel a:focus-visible { color: var(--amber-bright); }
.hero { position: relative; display: grid; min-height: 58svh; place-items: end start; isolation: isolate; overflow: hidden; padding: 116px 0 74px; }
.hero::before { position: absolute; inset: 0 calc(50% - 50vw); z-index: -3; background: linear-gradient(180deg, rgba(13,9,5,.18), rgba(13,9,5,.48) 54%, rgba(13,9,5,.94)), url("/walkthrough-ro/images/01-the-store-before-anything.jpg") center / cover no-repeat; content: ""; filter: saturate(1.02) contrast(1.05); }
.hero::after { position: absolute; inset: 0 calc(50% - 50vw); z-index: -2; background: radial-gradient(circle at 38% 46%, rgba(245,240,232,.08), transparent 27rem), linear-gradient(90deg, rgba(13,9,5,.72), rgba(13,9,5,.18) 62%, rgba(13,9,5,.62)); content: ""; }
.kicker { margin: 0 0 16px; color: var(--amber); font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; font-size: 12px; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
h1, h2, p { margin-top: 0; }
h1 { max-width: 900px; margin-bottom: 0; color: var(--paper); font-size: clamp(48px, 7vw, 96px); font-weight: 650; line-height: .98; text-shadow: 0 8px 44px rgba(0,0,0,.72); }
.content-band { padding: clamp(64px, 9vw, 112px) 0 clamp(86px, 12vw, 148px); border-top: 1px solid var(--line); background: linear-gradient(180deg, rgba(36,24,15,.5), rgba(13,9,5,.08)), var(--ink-soft); }
.content { display: grid; gap: clamp(48px, 7vw, 82px); }
.content-section { width: min(var(--measure), 100%); }
.content-section[id] { scroll-margin-top: 86px; }
.content-section.full { width: 100%; }
h2 { margin-bottom: 22px; color: var(--paper); font-size: clamp(32px, 4.3vw, 58px); font-weight: 620; line-height: 1.04; }
.prose { color: var(--paper-soft); font-size: clamp(18px, 2vw, 23px); line-height: 1.62; }
.prose h3 { margin: 1.75em 0 .7em; color: var(--amber-bright); font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; font-size: 12px; font-weight: 800; letter-spacing: .12em; line-height: 1.35; text-transform: uppercase; }
.prose p { margin-bottom: 1.12em; }
.prose p:last-child { margin-bottom: 0; }
.prose em, .prose strong { color: var(--amber-bright); }
.walk-figure, .figure-pair { margin: clamp(22px, 3.8vw, 38px) 0; }
.walk-figure { width: min(100%, var(--measure)); }
.walk-figure.standard-figure { width: min(100%, var(--measure)); }
.walk-figure.wide-strip { width: 100%; }
.walk-figure.line-drawing { width: min(100%, 860px); }
.walk-figure.paired { width: 100%; margin: 0; }
.walk-figure img { width: 100%; border: 1px solid rgba(228,201,140,.18); border-radius: 8px; background: #050302; box-shadow: 0 22px 70px rgba(0,0,0,.34); }
.walk-figure.wide-strip img { border-radius: 4px; }
.walk-figure.line-drawing img { padding: 24px; background: rgba(245,240,232,.03); }
.walk-figure figcaption { margin-top: 10px; color: rgba(228,201,140,.74); font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; font-size: 10px; font-weight: 800; letter-spacing: .1em; line-height: 1.4; text-transform: uppercase; }
.figure-pair { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: clamp(14px, 2.4vw, 24px); width: min(100%, 900px); }
.child-links { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; width: min(100%, var(--measure)); margin-top: 24px; }
.child-card { display: grid; gap: 7px; padding: 18px; border: 1px solid rgba(228,201,140,.22); color: var(--paper); text-decoration: none; }
.child-card span { color: var(--amber); font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; font-size: 10px; font-weight: 800; letter-spacing: .1em; text-transform: uppercase; }
.child-card strong { color: var(--paper); font-size: clamp(18px, 2vw, 22px); line-height: 1.24; }
.section-toc { width: min(100%, var(--measure)); padding: 18px 0 20px; border-top: 1px solid rgba(228,201,140,.18); border-bottom: 1px solid rgba(228,201,140,.18); }
.section-toc p { margin: 0 0 12px; color: var(--amber); font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; font-size: 10px; font-weight: 800; letter-spacing: .12em; line-height: 1.4; text-transform: uppercase; }
.section-toc-links { display: flex; flex-wrap: wrap; gap: 9px 18px; }
.section-toc-links a { color: rgba(245,240,232,.78); font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; font-size: 11px; font-weight: 800; letter-spacing: .08em; line-height: 1.45; text-decoration: none; text-transform: uppercase; border-bottom: 1px solid rgba(228,201,140,.32); }
.section-toc-links a.section-toc-sub { color: rgba(245,240,232,.58); padding-left: 10px; }
.section-toc-links a:hover, .section-toc-links a:focus-visible { color: var(--amber-bright); border-bottom-color: var(--amber-bright); }
.section-footer { display: flex; justify-content: space-between; gap: 14px; width: min(var(--max), calc(100% - 32px)); margin: 0 auto; padding: 28px 0 54px; border-top: 1px solid rgba(228,201,140,.18); }
.section-footer a { color: var(--amber-bright); }
.placeholder-note { width: min(var(--measure), 100%); color: var(--paper-muted); font-size: clamp(16px, 1.8vw, 20px); }
@media (max-width: 960px) {
  .index-menu-list { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 760px) {
  .index-entry { grid-template-columns: 1fr; }
  .index-menu-panel { right: -16px; width: calc(100vw - 32px); padding: 18px; }
  .index-menu-list { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px 16px; }
  .index-menu-primary { gap: 6px; margin-bottom: 14px; padding-bottom: 14px; }
  .index-menu-primary a { min-height: 44px; padding: 7px 5px; font-size: 9px; }
  .section-top-inner { min-height: 54px; }
  .top-actions { gap: 10px; }
  .language-menu summary { width: 26px; height: 26px; font-size: 14px; }
  .hero { min-height: 48svh; padding-top: 96px; }
  .figure-pair, .child-links { grid-template-columns: 1fr; }
  .section-footer { flex-direction: column; }
}


.interface-note { width: min(100%, var(--measure)); margin: -12px 0 8px; color: rgba(228,201,140,.74); font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; font-size: 10px; font-weight: 800; letter-spacing: .1em; line-height: 1.5; text-transform: uppercase; }
.index-interface-note { margin: calc(clamp(34px, 6vw, 72px) * -0.55) 0 clamp(28px, 5vw, 58px); }
html[lang="ja"] body { font-family: "Hiragino Mincho ProN", "Yu Mincho", YuMincho, "Noto Serif JP", ui-serif, Georgia, serif; }
html[lang="ja"] .brand, html[lang="ja"] .return-link, html[lang="ja"] .text-link, html[lang="ja"] .index-menu summary, html[lang="ja"] .section-footer a, html[lang="ja"] .index-menu-panel a, html[lang="ja"] .kicker, html[lang="ja"] .prose h3, html[lang="ja"] .walk-figure figcaption, html[lang="ja"] .child-card span, html[lang="ja"] .section-toc p, html[lang="ja"] .section-toc-links a, html[lang="ja"] .interface-note { font-family: "Hiragino Sans", "Yu Gothic", YuGothic, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; letter-spacing: .06em; }
html[lang="ja"] .interface-note { text-transform: none; }