/* MPLab 实验室主页：纯静态、零 JS、无外部字体/CDN（国内网络与隐私友好）。
   配色沿用 StrainBank 的 token；深色模式跟随系统。所有样式都在本文件内（nginx 的 CSP 为 style-src 'self'，不要写内联 style=）。 */

:root {
  --bg: #f4f6f9; --surface: #ffffff; --surface-3: #e5eaf0;
  --text: #17212b; --text-2: #55657a;
  --line: #e1e7ee; --line-2: #c9d3de;
  --primary: #1c5d86; --primary-hover: #174c6e; --primary-soft: #e4eef6; --on-primary: #ffffff;
  --accent: #1d7f4f; --accent-soft: #dff3e8;
  --hero-1: #e9f2f9; --hero-2: #f4f6f9;
  --shadow-1: 0 1px 2px rgba(16,24,40,.06), 0 1px 3px rgba(16,24,40,.05);
  --shadow-2: 0 10px 30px rgba(16,24,40,.10);
  --r: 14px;
  --maxw: 1120px; --header-h: 64px;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1419; --surface: #171d25; --surface-3: #283240;
    --text: #e6ebf1; --text-2: #a2adbb;
    --line: #273140; --line-2: #34404f;
    --primary: #5aa5d6; --primary-hover: #7ab8e0; --primary-soft: #16303f; --on-primary: #0f1419;
    --accent: #5ec48f; --accent-soft: #15301f;
    --hero-1: #13222e; --hero-2: #0f1419;
    --shadow-1: 0 1px 2px rgba(0,0,0,.4); --shadow-2: 0 10px 30px rgba(0,0,0,.5);
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--header-h) + 12px); -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font: 16px/1.65 -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
}
a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-hover); }
a:focus-visible, .btn:focus-visible { outline: 3px solid var(--primary); outline-offset: 2px; border-radius: 6px; }
h1, h2, h3, p { margin: 0; }
svg { display: block; }
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.skip { position: absolute; left: -999px; top: 8px; background: var(--surface); padding: 8px 12px; border-radius: 6px; z-index: 100; }
.skip:focus { left: 8px; }

/* ---------- 顶栏 ---------- */
.site-header {
  position: sticky; top: 0; z-index: 20; height: var(--header-h);
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  -webkit-backdrop-filter: saturate(1.4) blur(10px); backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--line);
}
.site-header .wrap { height: 100%; display: flex; align-items: center; gap: 24px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); font-weight: 700; letter-spacing: .02em; white-space: nowrap; }
.brand:hover { color: var(--text); }
.brand .mark { width: 32px; height: 32px; }
.nav { margin-left: auto; display: flex; gap: 4px; }
.nav a { color: var(--text-2); padding: 8px 12px; border-radius: 8px; font-size: .92rem; white-space: nowrap; }
.nav a:hover { color: var(--primary); background: var(--primary-soft); }

/* ---------- 按钮 / 不可点击元素 ---------- */
.btn { display: inline-flex; align-items: center; gap: 8px; min-height: 44px; padding: 10px 20px; border-radius: 10px; font-weight: 600; font-size: .95rem; border: 1px solid transparent; cursor: pointer; }
.btn.primary { background: var(--primary); color: var(--on-primary); box-shadow: var(--shadow-1); }
.btn.primary:hover { background: var(--primary-hover); color: var(--on-primary); }
.btn.ghost { background: transparent; border-color: var(--line-2); color: var(--text-2); }
/* .ph：不是链接，点击没有任何效果（给尚未上线的入口用） */
.ph { cursor: default; user-select: none; }
.tag { display: inline-block; padding: 2px 9px; border-radius: 999px; font-size: .72rem; font-weight: 600; letter-spacing: .02em; background: var(--surface-3); color: var(--text-2); vertical-align: middle; }
.tag.live { background: var(--accent-soft); color: var(--accent); }

/* ---------- 首屏（纯文字） ---------- */
.hero { background: linear-gradient(160deg, var(--hero-1), var(--hero-2) 70%); border-bottom: 1px solid var(--line); }
.hero .wrap { padding-top: 88px; padding-bottom: 88px; }
.hero h1 { font-size: clamp(2.6rem, 6vw, 4rem); line-height: 1.05; letter-spacing: -.01em; margin-bottom: 14px; }
.hero .tagline { font-size: clamp(1.1rem, 2.2vw, 1.35rem); font-weight: 500; }
.hero .lead { margin-top: 14px; color: var(--text-2); max-width: 38em; }
.hero .cta { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }

/* ---------- 通用分区 ---------- */
section.block { padding: 72px 0; }
section.block.alt { background: var(--surface); border-top: 1px solid var(--line); }
.sec-head { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; flex-wrap: wrap; margin-bottom: 28px; }
.sec-head h2 { font-size: 1.6rem; letter-spacing: -.005em; }
.sec-head p { color: var(--text-2); font-size: .95rem; }
.grid { display: grid; gap: 20px; }
.grid.c3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r); padding: 24px; box-shadow: var(--shadow-1); }
section.block.alt .card { background: var(--bg); box-shadow: none; }
.card h3 { font-size: 1.08rem; margin: 14px 0 6px; }
.card p { color: var(--text-2); font-size: .93rem; }
.icon { width: 44px; height: 44px; border-radius: 12px; background: var(--primary-soft); color: var(--primary); display: grid; place-items: center; }
.icon svg { width: 24px; height: 24px; }
.card.dashed { border-style: dashed; border-color: var(--line-2); box-shadow: none; background: transparent; }

/* 平台卡 */
.platform { display: flex; flex-direction: column; }
.platform .top { display: flex; justify-content: space-between; align-items: flex-start; }
.platform .go { margin-top: auto; padding-top: 18px; font-weight: 600; font-size: .92rem; display: inline-flex; align-items: center; gap: 6px; }
a.card.platform { color: inherit; transition: transform .15s, box-shadow .15s, border-color .15s; }
a.card.platform:hover { transform: translateY(-2px); box-shadow: var(--shadow-2); border-color: var(--primary); }
a.card.platform .go { color: var(--primary); }

/* 页脚 */
.site-footer { border-top: 1px solid var(--line); padding: 36px 0 44px; color: var(--text-2); font-size: .88rem; }
.site-footer .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px 24px; align-items: center; }
.site-footer a { color: var(--text-2); }
.site-footer a:hover { color: var(--primary); }
.site-footer .links { display: flex; flex-wrap: wrap; gap: 4px 20px; }

/* ---------- 响应式 ---------- */
@media (max-width: 720px) {
  .wrap { padding: 0 18px; }
  .site-header .wrap { gap: 12px; }
  .hero .wrap { padding-top: 56px; padding-bottom: 56px; }
  section.block { padding: 52px 0; }
  .grid.c3 { grid-template-columns: 1fr; }
  .hero .cta .btn { flex: 1 1 100%; justify-content: center; }
}