:root {
    --bg: #EEF0F8;
    --bg-deep: #E0E4F2;
    --panel: #F7F8FD;
    --panel-2: #EBEEF8;
    --text: #2C2A48;
    --title: #1A1840;
    --muted: #5A5680;
    --soft: #7A76A0;
    --purple: #5B4BDB;
    --blue: #3A6BD4;
    --dark: #1C1A3A;
    --mist: #8AA4E0;
    --lilac: #8A6AD4;
    --border: rgba(58,107,212,0.18);
    --border-strong: rgba(91,75,219,0.42);
    --shadow: 0 12px 28px rgba(28,26,58,0.08);
    --radius: 12px;
    --top-h: 118px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--text); font: 15px/1.7 -apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",Arial,sans-serif; overflow-x: hidden; }
body.ui-locked { overflow: hidden; }
a { color: inherit; text-decoration: none; }
button, input { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
img { display: block; max-width: 100%; }
.skip-link { position: fixed; left: 12px; top: -80px; z-index: 1000; background: var(--dark); color: var(--panel); padding: 10px 14px; border-radius: 8px; }
.skip-link:focus { top: 8px; }
.address-bar { position: fixed; z-index: 90; inset: 0 0 auto 0; height: 22px; background: var(--dark); color: #F7F8FD; font-size: 12px; }
.top-shell, .masthead-shell, .chip-nav-inner, .site-main, .footer-shell { width: min(1000px, calc(100% - 32px)); margin: 0 auto; }
.top-shell { height: 22px; display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.address-brand { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.text-action { min-width: 44px; height: 22px; padding: 0 8px; border: 0; background: transparent; color: #F7F8FD; cursor: pointer; }
.window-masthead { position: fixed; z-index: 89; top: 22px; left: 0; right: 0; height: 54px; background: var(--bg-deep); border-bottom: 1px solid var(--border-strong); }
.masthead-shell { height: 54px; display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; gap: 12px; }
.brand-home { justify-self: start; min-height: 44px; display: inline-flex; align-items: center; max-width: 210px; }
.brand-logo, .drawer-logo, .footer-logo { height: 24px; width: auto; object-fit: contain; object-position: center; }
.brand-fallback { font-weight: 800; color: var(--title); font-size: 16px; }
.app-entry, .drawer-trigger { min-height: 44px; display: inline-flex; align-items: center; justify-content: center; font-size: 14px; border-radius: 10px; }
.app-entry { padding: 0 16px; color: var(--purple); font-weight: 800; }
.drawer-trigger { justify-self: end; min-width: 74px; border: 1px solid var(--border-strong); color: var(--title); background: var(--panel); cursor: pointer; }
.chip-nav { position: fixed; z-index: 88; top: 76px; left: 0; right: 0; height: 42px; background: var(--panel); border-bottom: 1px solid var(--border); }
.chip-nav-inner { height: 42px; display: flex; align-items: center; justify-content: center; gap: 8px; flex-wrap: wrap; overflow: hidden; }
.chip-link { min-height: 30px; padding: 4px 14px; display: inline-flex; align-items: center; justify-content: center; border: 1px solid var(--border); border-radius: 999px; color: var(--title); font-size: 13px; background: var(--panel-2); }
.chip-link.is-current { background: var(--purple); color: #F7F8FD; border-color: var(--purple); }
.site-main { padding-top: calc(var(--top-h) + 28px); padding-bottom: 64px; min-height: 65vh; }
.hero-narrow, .content-section, .article-panel, .window-card, .product-card, .clause-block, .help-block, .route-card, .tool-row, .memo-item, .faq-item, .contact-panel, .brand-statement { background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow); }
.hero-narrow { padding: 24px; margin-bottom: 26px; }
.eyebrow { margin: 0 0 6px; color: var(--purple); font-size: 13px; font-weight: 800; letter-spacing: .04em; }
h1,h2,h3 { margin-top: 0; color: var(--title); line-height: 1.3; }
h1 { font-size: 24px; margin-bottom: 12px; }
h2 { font-size: 20px; margin-bottom: 12px; }
h3 { font-size: 16px; margin-bottom: 8px; }
p { margin: 0 0 12px; }
.lead { font-size: 16px; color: var(--muted); }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 20px; margin-bottom: 16px; }
.section-head p { color: var(--muted); margin: 0; max-width: 600px; }
.content-section { padding: 24px; margin: 22px 0; }
.content-section.plain { box-shadow: none; background: transparent; border: 0; padding: 0; }
.image-slot { width: 100%; min-height: 148px; display: flex; align-items: center; justify-content: center; overflow: hidden; background: var(--panel-2); border: 1px solid var(--border); border-radius: 12px; }
.image-slot img { width: 100%; height: 100%; object-fit: contain; object-position: center; }
.banner-slot { height: 168px; margin: 14px 0 18px; }
.wide-slot { height: 176px; margin-bottom: 18px; }
.app-slot { height: 300px; }
.medium-slot { height: 190px; }
.small-slot { height: 150px; }
.icon-slot { width: 72px; min-height: 72px; height: 72px; margin: 0 auto 12px; }
.icon-slot img { width: 48px; height: 48px; }
.button-row { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 18px; }
.centered-buttons { justify-content: center; }
.primary-btn, .secondary-btn { min-height: 42px; padding: 9px 18px; border-radius: 10px; display: inline-flex; align-items: center; justify-content: center; font-size: 14px; font-weight: 800; white-space: nowrap; }
.primary-btn { background: linear-gradient(135deg,#8AA4E0 0%,#5B4BDB 55%,#3A6BD4 100%); color: #F7F8FD; }
.secondary-btn { background: var(--panel-2); border: 1px solid var(--border-strong); color: var(--dark); }
a:hover, button:hover { filter: brightness(.98); }
a:focus-visible, button:focus-visible, input:focus-visible { outline: 3px solid rgba(91,75,219,.28); outline-offset: 2px; }
.long-copy { max-width: 820px; }
.long-copy p:last-child { margin-bottom: 0; }
.stair-stack { display: grid; gap: 14px; max-width: 780px; }
.stair-card { background: var(--panel); border: 1px solid var(--border); border-radius: 12px; padding: 18px; box-shadow: var(--shadow); }
.stair-card:nth-child(2) { margin-left: 24px; }
.stair-card:nth-child(3) { margin-left: 48px; }
.tag-wrap { display: flex; flex-wrap: wrap; gap: 10px; margin: 14px 0 18px; }
.tag-pill { min-height: 40px; padding: 8px 16px; display: inline-flex; align-items: center; border: 1px solid var(--border-strong); background: var(--panel-2); color: var(--dark); border-radius: 999px; font-weight: 700; }
.compare-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.compare-pane { background: var(--panel); border: 1px solid var(--border); border-radius: 12px; overflow: hidden; }
.compare-pane .pane-copy { padding: 18px; }
.compare-pane.primary-pane { border-color: var(--border-strong); }
.route-strip { display: grid; grid-template-columns: repeat(3,1fr); gap: 12px; margin-top: 16px; }
.route-card { padding: 18px; box-shadow: none; }
.center-cards { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 16px; max-width: 780px; margin: 0 auto; }
.center-card { text-align: center; background: var(--panel); border: 1px solid var(--border); border-radius: 12px; padding: 22px; }
.product-card { max-width: 760px; margin: 0 auto; padding: 24px; text-align: center; }
.product-copy { max-width: 650px; margin: 0 auto; }
.icon-and-title { display: grid; justify-items: center; margin-bottom: 14px; }
.faq-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.faq-item { padding: 18px; box-shadow: none; }
.faq-item p:last-child { margin-bottom: 0; }
.use-points { counter-reset: item; display: grid; gap: 10px; }
.use-point { position: relative; padding: 16px 18px 16px 54px; background: var(--panel-2); border: 1px solid var(--border); border-radius: 12px; }
.use-point::before { counter-increment: item; content: counter(item); position: absolute; left: 16px; top: 14px; width: 28px; height: 28px; border-radius: 50%; display: grid; place-items: center; background: var(--purple); color: #fff; font-weight: 800; }
.window-demo { border: 1px solid var(--border-strong); border-radius: 12px; overflow: hidden; background: var(--panel); box-shadow: var(--shadow); margin-bottom: 22px; }
.window-demo-bar { height: 34px; display: flex; align-items: center; gap: 6px; padding: 0 12px; background: var(--bg-deep); border-bottom: 1px solid var(--border); }
.window-demo-bar i { width: 8px; height: 8px; display: block; border-radius: 50%; background: var(--mist); }
.window-demo-body { padding: 20px; }
.window-demo-body .image-slot { margin-bottom: 18px; }
.feature-notes { display: grid; grid-template-columns: 1.1fr .9fr; gap: 18px; }
.note-panel { padding: 20px; background: var(--panel); border: 1px solid var(--border); border-radius: 12px; }
.stack-steps { display: grid; gap: 14px; }
.stack-step { background: var(--panel); border: 1px solid var(--border); border-radius: 12px; padding: 20px; box-shadow: var(--shadow); }
.stack-step:nth-child(2) { margin-left: 22px; }
.stack-step:nth-child(3) { margin-left: 44px; }
.stack-step:nth-child(4) { margin-left: 66px; }
.bookmark-layout { display: grid; grid-template-columns: minmax(0,1fr) minmax(0,.8fr); gap: 20px; align-items: start; }
.bookmark-board { padding: 20px; background: var(--panel); border: 1px solid var(--border); border-radius: 12px; }
.reading-sheet { max-width: 820px; margin: 0 auto; background: var(--panel); border: 1px solid var(--border); border-radius: 12px; padding: 30px; box-shadow: var(--shadow); }
.reading-controls { display: flex; flex-wrap: wrap; gap: 10px; margin: 18px 0; }
.reading-controls span { border: 1px solid var(--border); background: var(--panel-2); padding: 8px 12px; border-radius: 8px; }
.tool-list { display: grid; gap: 12px; }
.tool-row { padding: 18px; display: grid; grid-template-columns: 150px 1fr; gap: 18px; box-shadow: none; }
.tool-row strong { color: var(--title); }
.split-demo { display: grid; grid-template-columns: 1fr 1fr; border: 1px solid var(--border-strong); background: var(--panel); border-radius: 12px; overflow: hidden; box-shadow: var(--shadow); }
.split-demo > div { padding: 22px; }
.split-demo > div + div { border-left: 1px solid var(--border); background: var(--panel-2); }
.route-flow { display: grid; grid-template-columns: repeat(3,1fr); gap: 14px; }
.route-card .route-name { color: var(--purple); font-weight: 800; }
.memo-list { display: grid; gap: 12px; }
.memo-item { padding: 18px 18px 18px 56px; position: relative; box-shadow: none; }
.memo-item::before { content: ''; position: absolute; left: 20px; top: 21px; width: 20px; height: 20px; border-radius: 6px; background: var(--mist); border: 2px solid var(--purple); }
.extension-center { max-width: 760px; margin: 0 auto; text-align: center; }
.extension-pair { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 18px; }
.extension-card { background: var(--panel); border: 1px solid var(--border); border-radius: 12px; padding: 22px; }
.clause-stack { display: grid; gap: 14px; }
.clause-block { padding: 20px; box-shadow: none; }
.clause-block h2 { border-bottom: 1px solid var(--border); padding-bottom: 10px; }
.install-timeline { display: grid; gap: 14px; position: relative; }
.install-step { padding: 20px 20px 20px 70px; background: var(--panel); border: 1px solid var(--border); border-radius: 12px; position: relative; }
.install-step::before { content: attr(data-step); position: absolute; left: 18px; top: 18px; width: 36px; height: 36px; border-radius: 10px; display: grid; place-items: center; background: var(--purple); color: #fff; font-weight: 800; }
.help-columns { columns: 2 320px; column-gap: 16px; }
.help-block { padding: 18px; margin: 0 0 16px; break-inside: avoid; box-shadow: none; }
.contact-panels { display: grid; grid-template-columns: repeat(2,1fr); gap: 16px; }
.contact-panel { padding: 20px; box-shadow: none; }
.brand-statement { padding: 26px; }
.about-image { margin: 18px 0; }
.site-footer { background: var(--dark); color: #EEF0F8; border-top: 1px solid var(--mist); font-size: 13px; padding: 34px 0 calc(34px + env(safe-area-inset-bottom)); }
.footer-brand-row { display: flex; gap: 12px; align-items: center; margin-bottom: 24px; }
.footer-brand-row div:last-child { display: grid; gap: 2px; }
.footer-brand-row strong { font-size: 16px; }
.footer-brand-row span { color: #C9CFE6; }
.footer-columns { display: grid; grid-template-columns: repeat(4,1fr); gap: 18px; }
.footer-columns h2 { color: #F7F8FD; font-size: 14px; margin-bottom: 8px; }
.footer-columns a { display: block; min-height: 32px; color: #E6E9F5; }
.footer-note { color: #D9DDF0; border-top: 1px solid rgba(138,164,224,.25); margin-top: 22px; padding-top: 18px; }
.copyright { color: #BFC6E2; margin: 0; }
.ui-overlay { position: fixed; inset: 0; z-index: 110; background: rgba(28,26,58,.38); opacity: 0; visibility: hidden; pointer-events: none; transition: .2s ease; }
.ui-overlay.is-open { opacity: 1; visibility: visible; pointer-events: auto; }
.tool-drawer { position: fixed; z-index: 120; right: 20px; bottom: 20px; width: 360px; max-width: calc(100% - 32px); max-height: 70vh; background: var(--panel); border: 1px solid var(--border-strong); border-radius: 14px; box-shadow: 0 22px 56px rgba(28,26,58,.24); transform: translateY(18px) scale(.98); opacity: 0; visibility: hidden; pointer-events: none; transition: .2s ease; overflow: hidden; }
.tool-drawer.is-open { transform: none; opacity: 1; visibility: visible; pointer-events: auto; }
.drawer-head { min-height: 58px; display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 10px 12px; border-bottom: 1px solid var(--border); background: var(--bg-deep); }
.drawer-brand { display: flex; align-items: center; gap: 10px; font-weight: 800; color: var(--title); }
.icon-button { min-height: 44px; padding: 0 14px; border-radius: 10px; border: 1px solid var(--border-strong); background: var(--panel); color: var(--title); cursor: pointer; }
.drawer-scroll { max-height: calc(70vh - 58px); overflow-y: auto; overscroll-behavior: contain; padding: 12px; }
.drawer-group { padding: 8px 0 14px; }
.drawer-group h2 { font-size: 14px; color: var(--purple); margin: 0 0 6px; }
.drawer-group a { display: grid; grid-template-columns: 106px 1fr; gap: 10px; padding: 10px 8px; border-radius: 8px; }
.drawer-group a:hover { background: var(--panel-2); }
.drawer-group span { color: var(--muted); font-size: 13px; }
.search-layer { position: fixed; z-index: 121; top: 84px; left: 50%; transform: translate(-50%,-10px); width: min(720px, calc(100% - 32px)); background: var(--bg-deep); border: 1px solid var(--border-strong); border-radius: 14px; box-shadow: 0 22px 56px rgba(28,26,58,.2); opacity: 0; visibility: hidden; pointer-events: none; transition: .2s ease; padding: 18px; }
.search-layer.is-open { transform: translate(-50%,0); opacity: 1; visibility: visible; pointer-events: auto; }
.search-head { display: flex; justify-content: space-between; gap: 16px; align-items: center; margin-bottom: 14px; }
.search-head > div { display: grid; }
.search-head span { color: var(--muted); font-size: 13px; }
.search-box { display: grid; gap: 6px; color: var(--muted); font-size: 13px; }
.search-box input { min-height: 44px; width: 100%; border: 1px solid var(--border-strong); border-radius: 10px; background: var(--panel); color: var(--title); padding: 10px 12px; }
.search-presets { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 14px; }
.search-presets a { min-height: 40px; display: inline-flex; align-items: center; padding: 8px 14px; background: var(--panel); border: 1px solid var(--border); border-radius: 999px; }
.search-empty { color: var(--muted); margin: 14px 0 0; }
.mobile-bottom { display: none; }
@media (max-width: 760px) {
    :root { --top-h: 76px; }
    .top-shell, .masthead-shell, .site-main, .footer-shell { width: calc(100% - 32px); }
    .chip-nav { display: none; }
    .masthead-shell { grid-template-columns: minmax(0,1fr) auto auto; }
    .brand-home { max-width: 132px; overflow: hidden; }
    .app-entry { padding: 0 8px; }
    .drawer-trigger { min-width: 70px; }
    .site-main { padding-top: calc(var(--top-h) + 22px); padding-bottom: 88px; }
    .hero-narrow, .content-section, .reading-sheet, .product-card, .brand-statement { padding: 20px; }
    .compare-grid, .feature-notes, .bookmark-layout, .split-demo, .route-flow, .center-cards, .extension-pair, .contact-panels, .faq-grid { grid-template-columns: 1fr; }
    .split-demo > div + div { border-left: 0; border-top: 1px solid var(--border); }
    .route-strip { grid-template-columns: 1fr; }
    .stair-card:nth-child(2), .stair-card:nth-child(3), .stack-step:nth-child(2), .stack-step:nth-child(3), .stack-step:nth-child(4) { margin-left: 0; }
    .tool-row { grid-template-columns: 1fr; gap: 6px; }
    .footer-columns { grid-template-columns: 1fr 1fr; }
    .tool-drawer { right: 4%; bottom: calc(58px + env(safe-area-inset-bottom)); width: 92%; max-width: 92%; max-height: 70vh; }
    .drawer-scroll { max-height: calc(70vh - 58px); }
    .search-layer { inset: 0; width: 100%; height: 100%; transform: none; border: 0; border-radius: 0; background: var(--dark); color: #F7F8FD; padding: 26px 16px calc(80px + env(safe-area-inset-bottom)); overflow-y: auto; }
    .search-layer.is-open { transform: none; }
    .search-head span, .search-box { color: #D4D9EB; }
    .search-head strong { color: #F7F8FD; }
    .search-box input, .search-presets a, .search-layer .icon-button { background: #F7F8FD; color: var(--dark); }
    .mobile-bottom { position: fixed; z-index: 100; left: 0; right: 0; bottom: 0; height: calc(48px + env(safe-area-inset-bottom)); padding-bottom: env(safe-area-inset-bottom); display: grid; grid-template-columns: repeat(4,1fr); background: var(--panel); border-top: 1px solid var(--border-strong); }
    .mobile-bottom a { min-height: 48px; display: grid; place-items: center; font-size: 13px; color: var(--title); }
    .mobile-bottom a.is-current { background: var(--purple); color: #F7F8FD; }
    .ui-overlay { z-index: 105; }
    .site-footer { padding-bottom: calc(76px + env(safe-area-inset-bottom)); }
    .app-slot { height: 280px; }
}
@media (max-width: 420px) {
    .address-brand { max-width: 250px; }
    .footer-columns { grid-template-columns: 1fr 1fr; gap: 12px; }
    .drawer-group a { grid-template-columns: 88px 1fr; }
}