:root {
    color-scheme: light;
    --background: #f7f8fa;
    --surface: #fff;
    --ink: #202b3c;
    --muted: #586579;
    --line: #e2e7ee;
    --accent: #176855;
    --accent-soft: #e8f3ef;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-height: 100vh; display: flex; flex-direction: column; background: var(--background); color: var(--ink); }
a { color: var(--accent); text-underline-offset: 4px; }
a:hover { color: #104b3e; }
a:focus-visible { outline: 3px solid var(--accent); outline-offset: 5px; border-radius: 3px; }
.skip-link { position: absolute; top: -80px; left: 16px; z-index: 10; padding: 12px 16px; background: var(--surface); }
.skip-link:focus { top: 12px; }
.site-header { background: var(--surface); border-bottom: 1px solid var(--line); }
.header-inner { width: min(1080px, calc(100% - 64px)); margin: 0 auto; min-height: 86px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.site-name { margin: 0; font-size: 1.35rem; font-weight: 650; letter-spacing: -.035em; line-height: 1.4; }
.site-name a { display: flex; align-items: center; gap: 11px; color: var(--ink); text-decoration: none; }
.brand-mark { width: 30px; height: 30px; display: grid; place-items: center; background: var(--accent); border-radius: 9px; color: #fff; font-size: 16px; font-weight: 700; letter-spacing: 0; flex-shrink: 0; }
.site-nav { display: flex; align-items: center; gap: 26px; flex-shrink: 0; }
.site-nav a { color: var(--muted); font-size: 14px; text-decoration: none; }
.site-nav a:hover { color: var(--accent); }
.site-main { width: min(1080px, calc(100% - 64px)); margin: 0 auto; flex: 1; }
.site-footer { width: min(1080px, calc(100% - 64px)); margin: 36px auto 0; padding: 23px 0 27px; border-top: 1px solid var(--line); text-align: center; }
.site-footer a { color: var(--muted); font-size: 13px; text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }
@media (max-width: 640px) {
    .header-inner, .site-main, .site-footer { width: calc(100% - 36px); }
    .header-inner { min-height: 100px; padding: 19px 0 16px; flex-direction: column; align-items: flex-start; gap: 16px; }
    .site-name { font-size: 1.15rem; }
    .brand-mark { width: 27px; height: 27px; font-size: 14px; }
    .site-nav { gap: 22px; }
    .site-nav a { font-size: 13px; }
    .site-footer { margin-top: 26px; }
}
@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after { transition: none !important; }
}