:root {
    --background: #121212;
    --surface: #242424;
    --surface-soft: #1b1b1b;
    --surface-raised: #2d2d2d;
    --orange: #F97316;
    --orange-light: #FDBA74;
    --white: #FFFFFF;
    --text: #f5f5f5;
    --muted: #aaa7a3;
    --border: rgba(255,255,255,.1);
    --orange-border: rgba(249,115,22,.35);
    --container: 1180px;
    --radius: 6px;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 86px; }
body { margin: 0; min-width: 320px; background: var(--background); color: var(--text); font-family: "Microsoft YaHei", "PingFang SC", Arial, sans-serif; font-size: 16px; line-height: 1.72; letter-spacing: 0; -webkit-font-smoothing: antialiased; }
body.menu-open { overflow: hidden; }
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
h1, h2, h3, p { margin-top: 0; }
h1, h2, h3 { line-height: 1.25; letter-spacing: 0; }
p { color: var(--muted); }
:focus-visible { outline: 3px solid var(--orange-light); outline-offset: 3px; }
.container { width: min(calc(100% - 40px), var(--container)); margin-inline: auto; }
.skip-link { position: fixed; top: -80px; left: 16px; z-index: 1000; padding: 10px 16px; background: var(--white); color: var(--background); border-radius: 4px; font-weight: 800; }
.skip-link:focus { top: 12px; }

.site-header { position: fixed; inset: 0 0 auto; z-index: 100; height: 76px; border-bottom: 1px solid var(--border); background: rgba(18,18,18,.94); transition: background .2s ease, box-shadow .2s ease; }
.site-header.is-scrolled { background: rgba(18,18,18,.99); box-shadow: 0 10px 28px rgba(0,0,0,.3); }
.header-inner { height: 100%; display: flex; align-items: center; gap: 30px; }
.site-brand { min-width: 215px; display: inline-flex; align-items: center; gap: 12px; }
.brand-mark { width: 43px; height: 43px; flex: 0 0 43px; display: flex; align-items: end; justify-content: center; gap: 4px; padding: 9px; border: 1px solid var(--orange-border); border-radius: 5px; background: rgba(249,115,22,.1); }
.brand-mark i { display: block; width: 5px; background: var(--orange); }
.brand-mark i:nth-child(1) { height: 12px; }
.brand-mark i:nth-child(2) { height: 20px; }
.brand-mark i:nth-child(3) { height: 16px; }
.brand-copy { display: flex; flex-direction: column; line-height: 1.2; }
.brand-copy strong { color: var(--white); font-size: 17px; }
.brand-copy small { margin-top: 4px; color: var(--orange-light); font-size: 11px; }
.site-nav { margin-left: auto; display: flex; align-items: center; gap: 4px; }
.site-nav a { position: relative; min-height: 44px; display: inline-flex; align-items: center; padding: 0 13px; color: #c6c3c0; font-size: 14px; font-weight: 700; transition: color .18s ease, background .18s ease; }
.site-nav a:hover, .site-nav a.is-active { color: var(--white); background: rgba(249,115,22,.08); }
.site-nav a.is-active::after { content: ""; position: absolute; left: 13px; right: 13px; bottom: 2px; height: 2px; background: var(--orange); }
.header-action { min-height: 44px; display: inline-flex; align-items: center; padding: 0 17px; border: 1px solid var(--orange); border-radius: 5px; color: var(--orange-light); font-size: 13px; font-weight: 800; }
.header-action:hover { background: var(--orange); color: #1a0b02; }
.menu-toggle { display: none; width: 44px; height: 44px; border: 1px solid var(--border); border-radius: 5px; background: transparent; cursor: pointer; }
.menu-toggle span { display: block; width: 19px; height: 2px; margin: 4px auto; background: var(--white); transition: transform .2s ease, opacity .2s ease; }
.menu-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.menu-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.menu-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

.button { min-height: 48px; display: inline-flex; align-items: center; justify-content: center; padding: 0 22px; border: 1px solid transparent; border-radius: 5px; cursor: pointer; font-weight: 800; line-height: 1.2; transition: transform .18s ease, background .18s ease, border-color .18s ease, color .18s ease; }
.button:hover { transform: translateY(-2px); }
.button-primary { background: var(--orange); color: #1b0c03; }
.button-primary:hover { background: var(--orange-light); }
.button-secondary { border-color: rgba(255,255,255,.28); background: rgba(18,18,18,.55); color: var(--white); }
.button-secondary:hover { border-color: var(--orange); color: var(--orange-light); }
.text-link { display: inline-flex; align-items: center; gap: 7px; color: var(--orange-light); font-weight: 800; }
.text-link:hover { color: var(--white); }
.text-link span { transition: transform .18s ease; }
.text-link:hover span { transform: translateX(4px); }
.section-index { display: inline-flex; color: var(--orange-light); font-size: 12px; font-weight: 900; text-transform: uppercase; }
.sample-badge { display: inline-flex; align-items: center; min-height: 26px; padding: 0 9px; border: 1px solid var(--orange-border); border-radius: 4px; background: rgba(249,115,22,.08); color: var(--orange-light); font-size: 11px; font-weight: 800; }

.site-footer { padding-top: 62px; border-top: 1px solid var(--orange-border); background: #0d0d0d; }
.footer-top { display: grid; grid-template-columns: 1.5fr .75fr 1fr 1.15fr; gap: 50px; padding-bottom: 50px; }
.footer-brand .site-brand { margin-bottom: 18px; }
.footer-brand p { max-width: 370px; margin: 0; font-size: 13px; }
.footer-column { display: flex; flex-direction: column; align-items: flex-start; gap: 8px; }
.footer-column h2 { margin: 0 0 11px; color: var(--white); font-size: 15px; }
.footer-column a, .footer-column p { color: var(--muted); font-size: 13px; }
.footer-column a:hover { color: var(--orange-light); }
.footer-notice p { margin: 0 0 8px; }
.footer-notice .text-link { color: var(--orange-light); }
.footer-bottom { min-height: 70px; display: flex; align-items: center; justify-content: space-between; gap: 25px; border-top: 1px solid var(--border); }
.footer-bottom p, .footer-bottom a { margin: 0; color: #77736f; font-size: 12px; }
.back-to-top { position: fixed; right: 22px; bottom: 22px; z-index: 90; width: 46px; height: 46px; border: 1px solid var(--orange-border); border-radius: 5px; background: var(--surface); color: var(--orange-light); cursor: pointer; font-size: 21px; opacity: 0; visibility: hidden; transform: translateY(12px); transition: opacity .2s ease, visibility .2s ease, transform .2s ease, background .2s ease; }
.back-to-top.is-visible { opacity: 1; visibility: visible; transform: none; }
.back-to-top:hover { background: var(--orange); color: #1b0c03; }
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .36s ease, transform .36s ease; }
.reveal.is-visible { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
    .reveal { opacity: 1; transform: none; }
}