:root {
  --paper: #FAFAFC; --white: #FFFFFF; --ink: #1a1a1a; --muted: #536174;
  --blue: #1E3D7A; --coral: #EE7184; --soft: #EEF2F8; --line: #E1E6EF;
  --radius: 18px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 104px; }
body { margin: 0; color: var(--ink); background: var(--paper); font-family: "Noto Sans JP", "Yu Gothic", "游ゴシック", "Hiragino Kaku Gothic ProN", "ヒラギノ角ゴ ProN", sans-serif; font-size: 16px; line-height: 1.8; letter-spacing: .05em; }
button, input { font: inherit; }
a { color: var(--blue); text-underline-offset: 4px; }
button, a { -webkit-tap-highlight-color: transparent; }
button { cursor: pointer; }
button:focus-visible, a:focus-visible, summary:focus-visible { outline: 3px solid var(--blue); outline-offset: 4px; }
h1, h2, h3, h4, p { margin: 0; }
h1, h2, h3, h4 { letter-spacing: .02em; font-weight: 600; overflow-wrap: anywhere; }
h2 { font-size: 28px; line-height: 1.5; }
h3 { font-size: 24px; line-height: 1.5; }
h4 { font-size: 20px; line-height: 1.6; }
img { display: block; max-width: 100%; }
[hidden] { display: none !important; }
.page-width { width: min(100% - 32px, 1200px); margin-inline: auto; }
.skip-link { position: fixed; left: 16px; top: -120px; z-index: 100; padding: 16px 24px; background: var(--white); border: 1px solid var(--blue); border-radius: var(--radius); }
.skip-link:focus { top: 8px; }
.site-header { background: rgba(250,250,252,.94); border-bottom: 1px solid rgba(225,230,239,.7); position: sticky; top: 0; z-index: 30; backdrop-filter: blur(16px); }
.header-inner { max-width: 1200px; margin: auto; min-height: 80px; padding: 8px 16px; display: flex; justify-content: space-between; align-items: center; gap: 16px; }
.wordmark { display: flex; align-items: center; gap: 8px; text-decoration: none; font-size: 16px; font-weight: 600; letter-spacing: .01em; line-height: 1.4; }
.wordmark small { display: block; color: var(--muted); font-size: 12px; font-weight: 400; letter-spacing: .05em; margin-top: 4px; }
.brand-symbol { display: grid; grid-template-columns: 1fr 1fr; gap: 4px; width: 24px; height: 24px; transform: rotate(-8deg); flex-shrink: 0; }
.brand-symbol i { background: var(--blue); border-radius: 3px; }
.brand-symbol i:last-child { background: var(--coral); }
.site-header nav { display: flex; gap: 8px; }
.site-header nav a { display: flex; align-items: center; min-height: 44px; padding: 8px; font-size: 14px; text-decoration: none; color: var(--muted); }
.site-header nav a:hover { color: var(--blue); }
.hero { padding-top: 48px; display: grid; }
.eyebrow { font-size: 12px; letter-spacing: .12em; color: var(--muted); font-weight: 600; line-height: 1.8; }
.hero .eyebrow { font-size: 14px; display: flex; align-items: center; gap: 8px; }
.coral-line { width: 24px; height: 2px; background: var(--coral); display: inline-block; }
h1 { font-size: 32px; line-height: 1.45; margin-top: 16px; }
h1 span { color: var(--blue); letter-spacing: .01em; }
.hero-description { color: var(--muted); margin-top: 16px; font-size: 16px; }
.platform-choices { display: grid; grid-template-columns: 1fr; gap: 8px; margin-top: 24px; }
.platform-choice { color: var(--blue); background: var(--white); border: 1px solid var(--line); border-radius: var(--radius); min-height: 80px; display: flex; align-items: center; gap: 16px; text-align: left; padding: 16px; transition: background .2s, color .2s, border-color .2s; min-width: 0; }
.platform-choice svg { width: 32px; height: 32px; flex-shrink: 0; fill: none; stroke: currentColor; stroke-width: 1.6; }
.platform-choice[data-select-platform="windows"] svg { stroke: none; fill: currentColor; }
.platform-choice > span:first-of-type { flex: 1; font-size: 16px; font-weight: 600; }
.platform-choice small { display: block; font-size: 12px; font-weight: 400; opacity: .8; line-height: 1.5; letter-spacing: .03em; }
.choice-arrow { font-size: 24px; }
.platform-choice:hover { border-color: var(--blue); background: var(--soft); }
.platform-choice[aria-pressed="true"] { background: var(--blue); color: var(--white); border-color: var(--blue); }
.hero-note { color: var(--muted); font-size: 14px; margin-top: 16px; }
.platform-status { font-size: 14px; color: var(--blue); margin-top: 8px; min-height: 32px; }
.hero-art { position: relative; margin-top: 16px; align-self: center; isolation: isolate; will-change: transform; }
.hero-characters { position: relative; z-index: 1; width: 100%; height: auto; mix-blend-mode: multiply; }
.art-orbit { position: absolute; width: 88%; aspect-ratio: 1; border: 1px solid var(--line); border-radius: 50%; left: 6%; top: 4%; z-index: -1; }
.art-orbit::after { content: ""; position: absolute; width: 8px; height: 8px; background: var(--coral); border-radius: 50%; top: 16%; left: 12%; }
.art-caption { display: block; text-align: right; color: var(--muted); font-size: 12px; letter-spacing: .16em; margin-top: 8px; }
.hero-bottom { border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); display: flex; flex-wrap: wrap; align-items: center; gap: 8px 24px; padding: 16px 0; margin-top: 32px; color: var(--muted); font-size: 14px; }
.hero-bottom > span:first-child::before { content: ""; width: 8px; height: 8px; border: 1px solid var(--blue); border-radius: 50%; display: inline-block; margin-right: 8px; }
.hero-bottom a { display: flex; align-items: center; justify-content: space-between; gap: 24px; margin-left: auto; min-height: 44px; text-decoration: none; }
.hero-bottom a span { font-size: 20px; }
.guide-section { padding-top: 64px; }
.section-intro { display: flex; flex-direction: column; gap: 16px; margin-bottom: 32px; }
.section-intro h2 { margin-top: 8px; }
.section-intro > p { color: var(--muted); font-size: 14px; }
.guide-layout { display: grid; grid-template-columns: minmax(0, 1fr); gap: 24px; }
.guide-sidebar { min-width: 0; }
.sidebar-inner { padding-bottom: 8px; }
.sidebar-label { display: none; }
.step-nav { display: flex; gap: 8px; overflow-x: auto; padding: 8px 0; scrollbar-width: thin; }
.step-nav a { display: inline-flex; gap: 8px; align-items: center; text-decoration: none; color: var(--muted); font-size: 14px; white-space: nowrap; background: var(--white); border: 1px solid var(--line); border-radius: var(--radius); min-height: 44px; padding: 8px 16px; }
.step-nav a span { color: var(--blue); font-size: 12px; letter-spacing: .06em; }
.step-nav a[aria-current="step"] { color: var(--blue); border-color: var(--blue); }
.sidebar-platform { display: flex; gap: 8px; margin-top: 16px; }
.sidebar-platform button { min-height: 44px; flex: 1; padding: 8px 16px; border-radius: var(--radius); border: 1px solid var(--line); color: var(--blue); background: var(--white); font-size: 14px; }
.sidebar-platform button[aria-pressed="true"] { color: var(--white); background: var(--blue); border-color: var(--blue); }
.sidebar-note { font-size: 12px; color: var(--muted); margin-top: 16px; }
.steps, .chapter { min-width: 0; }
.chapter + .chapter { margin-top: 48px; }
.chapter-heading { display: flex; align-items: center; gap: 16px; margin-bottom: 24px; }
.chapter-heading h3 { margin-top: 8px; }
.chapter-heading > div:last-child { min-width: 0; }
.chapter-heading > div:last-child > p:last-child { color: var(--muted); font-size: 14px; margin-top: 8px; }
.guide-avatar { width: 80px; height: 112px; flex-shrink: 0; overflow: hidden; position: relative; border-radius: var(--radius); background: var(--soft); }
.guide-avatar img { width: 320px; max-width: none; position: absolute; top: -8px; mix-blend-mode: multiply; }
.avatar-one img { left: -56px; }
.avatar-two img { left: -120px; }
.avatar-three img { left: -184px; }
.step-card { background: var(--white); padding: 24px 16px; border: 1px solid var(--line); border-radius: var(--radius); scroll-margin-top: 104px; }
.step-card + .step-card { margin-top: 16px; }
.step-heading { display: flex; gap: 16px; align-items: baseline; margin-bottom: 16px; }
.step-number { font-size: 14px; color: var(--blue); border-bottom: 2px solid var(--coral); letter-spacing: .08em; padding-bottom: 8px; flex-shrink: 0; }
.step-card > p { margin-top: 16px; }
.requirements { display: flex; flex-wrap: wrap; gap: 8px 24px; align-items: center; padding: 16px; background: var(--soft); border-radius: var(--radius); margin-top: 16px; font-size: 14px; }
.requirements > span { font-weight: 600; color: var(--blue); }
.requirements a { min-height: 44px; display: inline-flex; align-items: center; }
.os-content { margin-top: 24px; }
.os-content + .os-content { padding-top: 24px; border-top: 1px solid var(--line); }
.os-label { display: inline-block; color: var(--blue); font-weight: 600; font-size: 14px; margin-bottom: 8px; border-left: 2px solid var(--coral); padding-left: 8px; }
.instruction-list { margin: 16px 0; padding-left: 24px; }
.instruction-list li + li { margin-top: 8px; }
.path { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; padding: 16px; background: var(--soft); border-radius: var(--radius); margin-top: 16px; font-size: 14px; }
.path span { color: var(--blue); font-weight: 500; }
.path b { color: var(--muted); font-weight: 400; font-size: 20px; }
.small-note { margin-top: 16px; color: var(--muted); font-size: 14px; }
.checkpoint { color: var(--blue); font-size: 14px; display: flex; gap: 8px; align-items: baseline; }
.check-mark { font-size: 16px; flex-shrink: 0; }
details { border-top: 1px solid var(--line); }
summary { cursor: pointer; list-style: none; position: relative; padding: 16px 32px 16px 0; min-height: 44px; font-size: 14px; font-weight: 500; overflow-wrap: anywhere; }
summary::-webkit-details-marker { display: none; }
summary::after { content: "+"; color: var(--blue); position: absolute; right: 8px; top: 16px; font-size: 20px; font-weight: 400; line-height: 1.5; }
details[open] > summary::after { content: "−"; }
details > p, details > a { font-size: 14px; color: var(--muted); margin-bottom: 16px; }
details > a { color: var(--blue); display: inline-flex; min-height: 44px; align-items: center; }
.step-help { margin-top: 24px; }
.git-body { padding-bottom: 24px; min-width: 0; }
.git-instructions summary { font-size: 16px; padding-block: 24px; }
.git-instructions summary::after { top: 24px; }
.git-option { overflow-wrap: anywhere; }
.architecture-table { margin-top: 16px; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; }
.architecture-table > div { display: flex; flex-wrap: wrap; gap: 8px 16px; justify-content: space-between; padding: 16px; font-size: 14px; }
.architecture-table > div + div { border-top: 1px solid var(--line); }
.architecture-table strong { color: var(--blue); }
.action-link { display: flex; align-items: center; justify-content: center; gap: 16px; min-height: 48px; padding: 16px; border: 1px solid var(--blue); border-radius: var(--radius); background: var(--blue); color: var(--white); text-decoration: none; font-size: 14px; margin-top: 24px; text-align: center; }
.action-link:hover { background: #294E91; }
.install-diagram { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; justify-content: center; padding: 24px 16px; background: var(--soft); border-radius: var(--radius); margin-top: 16px; font-size: 14px; }
.diagram-app { background: var(--white); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px; color: var(--blue); }
.diagram-arrow { font-size: 24px; color: var(--muted); padding: 0 8px; }
.diagram-folder { color: var(--blue); border-bottom: 2px solid var(--coral); padding: 16px 0; }
.note-box { margin-top: 16px; background: var(--soft); border-radius: var(--radius); padding: 16px; font-size: 14px; }
.note-box strong { font-weight: 600; color: var(--blue); }
.note-box p { margin-top: 8px; }
.code-indicator { display: flex; flex-wrap: wrap; gap: 16px; align-items: center; background: var(--soft); border-radius: var(--radius); padding: 16px; margin-top: 16px; }
.code-indicator > span { color: var(--blue); font-family: monospace; font-size: 24px; }
.code-indicator small { font-size: 14px; color: var(--muted); }
.connection-card { border-color: #BDCBDF; }
.prompt-box { border: 1px solid var(--line); background: var(--soft); border-radius: var(--radius); padding: 16px; margin-top: 24px; }
#connection-prompt { user-select: text; overflow-wrap: anywhere; }
#copy-prompt { display: flex; align-items: center; justify-content: center; gap: 8px; padding: 8px 16px; min-height: 48px; border-radius: var(--radius); border: 1px solid var(--blue); color: var(--white); background: var(--blue); margin-top: 16px; width: 100%; font-size: 14px; }
#copy-prompt svg { width: 24px; height: 24px; fill: none; stroke: currentColor; stroke-width: 1.5; }
.copy-status { min-height: 32px; color: var(--blue); font-size: 14px; }
.paste-tip { display: flex; flex-wrap: wrap; gap: 8px 24px; color: var(--muted); font-size: 14px; }
kbd { font: inherit; font-size: 12px; padding: 4px 8px; background: var(--soft); border: 1px solid var(--line); border-radius: 4px; }
.success-example { display: flex; gap: 16px; border-top: 1px solid var(--line); margin-top: 24px; padding-top: 24px; }
.success-dot { width: 8px; height: 8px; background: var(--coral); border-radius: 50%; flex-shrink: 0; margin-top: 8px; }
.success-example strong { display: block; color: var(--blue); font-size: 18px; margin-top: 8px; }
.success-example > div > p:last-child { font-size: 14px; color: var(--muted); margin-top: 8px; }
.video-slot:empty { display: none; }
.video-slot:not(:empty) { margin-top: 24px; }
.video-slot video { width: 100%; display: block; border-radius: var(--radius); background: var(--soft); }
.video-slot p { font-size: 14px; color: var(--muted); margin-bottom: 8px; }
.help-section { padding-top: 64px; }
.faq-grid { display: grid; grid-template-columns: 1fr; gap: 0 32px; border-bottom: 1px solid var(--line); }
.faq-grid details { min-width: 0; }
.faq-grid summary { padding-block: 24px; }
.faq-grid summary::after { top: 24px; }
.support-line { display: flex; flex-direction: column; gap: 16px; margin-top: 24px; padding: 24px; border-radius: var(--radius); background: var(--soft); font-size: 14px; color: var(--muted); }
.support-line a { min-height: 44px; display: flex; align-items: center; gap: 8px; white-space: nowrap; }
.sources-section { padding-top: 48px; padding-bottom: 48px; margin-top: 48px; border-top: 1px solid var(--line); color: var(--muted); font-size: 14px; }
.sources-section h2 { font-size: 18px; color: var(--ink); margin-bottom: 16px; }
.sources-section > p + p { margin-top: 8px; }
.sources-section details { margin-top: 24px; }
.source-links { margin-top: 0; padding-left: 24px; }
.source-links li + li { margin-top: 8px; }
.source-links a { display: inline-block; min-height: 44px; padding: 8px 0; overflow-wrap: anywhere; }
.site-footer { display: flex; flex-wrap: wrap; gap: 16px; align-items: center; justify-content: space-between; font-size: 12px; color: var(--muted); border-top: 1px solid var(--line); padding-top: 16px; padding-bottom: 24px; }
.site-footer a { display: inline-flex; align-items: center; gap: 8px; min-height: 44px; text-decoration: none; }
.reveal { opacity: 1; transform: none; }
.motion-enabled .reveal:not(.is-visible) { opacity: 0; transform: translateY(16px); }
.motion-enabled .reveal { transition: opacity 480ms ease-out, transform 480ms ease-out; }
.motion-enabled .chapter-heading { transition-delay: 80ms; }
@media (min-width: 768px) {
  .page-width { width: min(100% - 64px, 1200px); }
  .header-inner { padding-inline: 32px; }
  .hero { grid-template-columns: 1fr 1fr; align-items: center; column-gap: 24px; padding-top: 48px; }
  h1 { font-size: 40px; }
  .hero-copy { padding-block: 24px; }
  .hero-art { margin-top: 0; }
  .hero-bottom { grid-column: 1 / -1; margin-top: 32px; }
  .platform-choices { grid-template-columns: 1fr; }
  .section-intro { flex-direction: row; align-items: flex-end; justify-content: space-between; gap: 24px; margin-bottom: 48px; }
  .guide-layout { grid-template-columns: 192px minmax(0, 1fr); gap: 32px; }
  .sidebar-inner { position: sticky; top: 104px; }
  .sidebar-label { display: block; font-size: 12px; color: var(--muted); letter-spacing: .12em; margin-bottom: 16px; }
  .step-nav { flex-direction: column; padding: 0; gap: 8px; overflow: visible; }
  .step-nav a { border: none; background: none; padding: 8px 0; white-space: normal; font-size: 14px; }
  .step-nav a span { width: 24px; flex-shrink: 0; }
  .step-nav a[aria-current="step"] { font-weight: 600; }
  .sidebar-platform { flex-direction: column; margin-top: 24px; }
  .sidebar-note { margin-top: 24px; }
  .step-card { padding: 32px; }
  .chapter-heading { gap: 24px; }
  .action-link { display: inline-flex; padding-inline: 24px; }
  #copy-prompt { width: auto; margin-left: auto; }
  .faq-grid { grid-template-columns: 1fr 1fr; }
  .support-line { flex-direction: row; align-items: center; justify-content: space-between; gap: 24px; padding: 24px 32px; }
}
@media (min-width: 1200px) {
  .hero { grid-template-columns: 5fr 7fr; column-gap: 32px; padding-top: 64px; }
  .hero-description { font-size: 18px; margin-top: 24px; }
  .platform-choices { grid-template-columns: 1fr 1fr; margin-top: 32px; }
  .platform-choice { gap: 8px; }
  .platform-choice svg { width: 24px; height: 24px; }
  .choice-arrow { font-size: 20px; }
  .platform-choice > span:first-of-type { font-size: 16px; }
  .hero-bottom { margin-top: 48px; }
  .guide-section, .help-section { padding-top: 120px; }
  .guide-layout { grid-template-columns: 232px minmax(0,1fr); gap: 64px; }
  .sidebar-platform { flex-direction: row; }
  .chapter + .chapter { margin-top: 64px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .hero-art, .reveal, .motion-enabled .reveal:not(.is-visible) { opacity: 1 !important; transform: none !important; }
}