:root {
    color-scheme: light;
    --ink: #111;
    --muted: #666;
    --line: #d9d9d9;
    --paper: #fff;
}

* { box-sizing: border-box; }
html { background: var(--paper); }
body {
    margin: 0;
    background: var(--paper);
    color: var(--ink);
    font-family: "Noto Sans SC", "Microsoft YaHei", sans-serif;
    line-height: 1.75;
}

a { color: inherit; text-underline-offset: 0.18em; }
.faq-shell { width: min(900px, calc(100% - 40px)); margin: 0 auto; padding: 28px 0 56px; }
.topbar { display: flex; justify-content: space-between; gap: 20px; align-items: center; border-bottom: 1px solid var(--line); padding-bottom: 18px; font-size: 0.9rem; }
.site-mark, .eyebrow { letter-spacing: 0.12em; font-size: 0.75rem; }
.hero { padding: 88px 0 52px; border-bottom: 1px solid var(--line); }
.hero h1 { margin: 8px 0 12px; font-size: clamp(2.4rem, 7vw, 5rem); line-height: 1.05; letter-spacing: -0.04em; }
.hero p:last-child { max-width: 620px; color: var(--muted); margin: 0; }
.faq-list { padding: 12px 0; }
details { border-bottom: 1px solid var(--line); padding: 24px 0; }
summary { cursor: pointer; font-size: 1.12rem; font-weight: 600; list-style-position: outside; }
details p { max-width: 720px; color: #333; margin: 14px 0 0 22px; }
.site-footer { display: flex; flex-wrap: wrap; gap: 20px; margin-top: 36px; color: var(--muted); font-size: 0.9rem; }

@media (max-width: 560px) {
    .faq-shell { width: min(100% - 28px, 900px); padding-top: 18px; }
    .topbar { align-items: flex-start; flex-direction: column; gap: 6px; }
    .hero { padding: 64px 0 36px; }
    details { padding: 20px 0; }
    details p { margin-left: 0; }
}