:root {
  --ink: #17212b;
  --muted: #5e6b76;
  --line: #dce4ea;
  --paper: #ffffff;
  --wash: #f4f8fb;
  --accent: #1769e0;
  --accent-dark: #0e4da8;
}
body.marksnap { --accent: #ff5b73; --accent-dark: #c93652; --wash: #fff9f0; --line: #e9e4de; }
body.marksnap .notice { background: #fff0f2; }
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--wash); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif; line-height: 1.75; }
a { color: var(--accent-dark); }
.shell { width: min(1040px, calc(100% - 40px)); margin: 0 auto; }
header { background: var(--paper); border-bottom: 1px solid var(--line); }
.nav { display: flex; justify-content: space-between; align-items: center; min-height: 72px; gap: 20px; }
.brand { font-weight: 800; font-size: 1.18rem; letter-spacing: -.02em; text-decoration: none; color: var(--ink); }
nav { display: flex; gap: 18px; flex-wrap: wrap; }
nav a { text-decoration: none; font-size: .93rem; color: var(--muted); }
nav a:hover, nav a[aria-current="page"] { color: var(--accent); }
.lang-switch { display: inline-flex; gap: 3px; padding: 3px; border: 1px solid var(--line); border-radius: 999px; background: var(--wash); }
.lang-switch button { appearance: none; border: 0; border-radius: 999px; padding: 5px 10px; background: transparent; color: var(--muted); font: inherit; font-size: .82rem; cursor: pointer; }
.lang-switch button[aria-pressed="true"] { background: var(--paper); color: var(--ink); box-shadow: 0 1px 4px rgba(23,33,43,.12); }
[data-lang] { }
html[data-language="zh"] [data-lang="en"], html[data-language="en"] [data-lang="zh"] { display: none !important; }
main { padding: 52px 0 70px; }
.hero { padding: 28px 0 32px; }
.eyebrow { color: var(--accent); text-transform: uppercase; letter-spacing: .12em; font-size: .76rem; font-weight: 800; }
h1 { font-size: clamp(2rem, 5vw, 3.5rem); line-height: 1.15; letter-spacing: -.04em; margin: 10px 0 16px; }
h2 { margin-top: 36px; line-height: 1.3; }
h3 { margin-top: 24px; line-height: 1.35; }
.lead { max-width: 700px; color: var(--muted); font-size: 1.12rem; }
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 18px; margin-top: 28px; }
.card, article { background: var(--paper); border: 1px solid var(--line); border-radius: 14px; padding: 24px; box-shadow: 0 8px 24px rgba(23, 33, 43, .04); }
.card { text-decoration: none; color: inherit; transition: transform .18s ease, border-color .18s ease; }
.card:hover { transform: translateY(-2px); border-color: #a9c7ef; }
.card h2 { margin: 0 0 6px; font-size: 1.15rem; }
.card p { margin: 0; color: var(--muted); font-size: .94rem; }
.meta { color: var(--muted); font-size: .9rem; }
article { max-width: 820px; margin: 0 auto; }
article ul { padding-left: 1.3rem; }
.notice { background: #eef5ff; border-left: 4px solid var(--accent); padding: 14px 16px; margin: 22px 0; }
.contact { display: inline-block; overflow-wrap: anywhere; font-weight: 700; }
footer { border-top: 1px solid var(--line); color: var(--muted); font-size: .88rem; padding: 24px 0 36px; }
@media (max-width: 600px) { .shell { width: min(100% - 28px, 1040px); } .nav { align-items: flex-start; flex-direction: column; padding: 16px 0; } main { padding-top: 30px; } article, .card { padding: 19px; } }