:root {
  --sand: #faf7f2;
  --sand-deep: #f1ece2;
  --card: #ffffff;
  --trail: #4a7c59;
  --trail-deep: #345940;
  --sunset: #d88a5a;
  --ink: #2c3a35;
  --dusk: #5b6b7d;
  --stone: #9a9a9a;
  --line: #e7e1d6;
  --radius: 16px;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--sand);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Roboto, sans-serif;
  font-size: 17px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

/* ---------- 顶栏 ---------- */

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 22px;
  background: rgba(250, 247, 242, 0.88);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--line);
}

.brand {
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 700;
  font-size: 17px;
  color: var(--ink);
  text-decoration: none;
  letter-spacing: -0.01em;
}

.brand .mark {
  width: 26px;
  height: 26px;
  border-radius: 8px;
  background: linear-gradient(150deg, var(--trail) 0%, var(--trail-deep) 100%);
  display: grid;
  place-items: center;
  color: #fff;
  font-size: 14px;
  line-height: 1;
}

.nav {
  display: flex;
  gap: 4px;
  margin-left: auto;
  align-items: center;
  flex-wrap: wrap;
}

.nav a {
  color: var(--dusk);
  text-decoration: none;
  font-size: 15px;
  padding: 6px 10px;
  border-radius: 9px;
}

.nav a:hover { background: var(--sand-deep); color: var(--ink); }
.nav a.active { color: var(--trail); font-weight: 600; }

.lang-switch {
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--dusk);
  border-radius: 999px;
  padding: 5px 13px;
  font-size: 14px;
  font-family: inherit;
  white-space: nowrap;
  text-decoration: none;
  line-height: 1.4;
}

.lang-switch:hover { border-color: var(--trail); color: var(--trail); background: var(--card); }

/* ---------- 版面 ---------- */

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 40px 22px 96px;
}

h1 {
  font-size: 30px;
  line-height: 1.3;
  margin: 0 0 6px;
  letter-spacing: -0.02em;
}

h2 {
  font-size: 20px;
  margin: 40px 0 10px;
  letter-spacing: -0.01em;
}

h3 { font-size: 17px; margin: 26px 0 6px; }

p { margin: 0 0 14px; }

.updated {
  color: var(--stone);
  font-size: 14px;
  margin-bottom: 34px;
}

.lede {
  font-size: 18px;
  color: var(--dusk);
  margin-bottom: 30px;
}

ul, ol { padding-left: 22px; margin: 0 0 14px; }
li { margin-bottom: 7px; }

a { color: var(--trail); text-underline-offset: 3px; }

strong { color: var(--ink); }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px 22px;
  margin: 20px 0;
}

.card h3 { margin-top: 0; }
.card :last-child { margin-bottom: 0; }

.callout {
  background: linear-gradient(160deg, #f3f7f4 0%, #eef4f0 100%);
  border: 1px solid #dbe7de;
  border-radius: var(--radius);
  padding: 18px 22px;
  margin: 22px 0;
}

.callout :last-child { margin-bottom: 0; }

.muted { color: var(--dusk); }

code {
  background: var(--sand-deep);
  padding: 2px 6px;
  border-radius: 6px;
  font-size: 15px;
  font-family: "SF Mono", ui-monospace, Menlo, Consolas, monospace;
}

hr { border: 0; border-top: 1px solid var(--line); margin: 40px 0; }

/* ---------- 首页 ---------- */

.hero { text-align: center; padding: 46px 0 12px; }

.hero .mark-lg {
  width: 78px;
  height: 78px;
  border-radius: 22px;
  margin: 0 auto 22px;
  background: linear-gradient(150deg, var(--trail) 0%, var(--trail-deep) 100%);
  display: grid;
  place-items: center;
  color: #fff;
  font-size: 36px;
  box-shadow: 0 12px 30px rgba(74, 124, 89, 0.22);
}

.hero h1 { font-size: 40px; }

.hero .tagline {
  font-size: 19px;
  color: var(--dusk);
  max-width: 460px;
  margin: 8px auto 0;
}

.links-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 14px;
  margin-top: 38px;
}

.link-card {
  display: block;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 20px;
  text-decoration: none;
  color: var(--ink);
  transition: border-color 0.16s ease, transform 0.16s ease;
}

.link-card:hover { border-color: var(--trail); transform: translateY(-2px); }
.link-card .t { font-weight: 650; margin-bottom: 3px; }
.link-card .d { font-size: 14px; color: var(--stone); line-height: 1.5; }

/* ---------- 页脚 ---------- */

footer {
  border-top: 1px solid var(--line);
  padding: 26px 22px 46px;
  text-align: center;
  color: var(--stone);
  font-size: 14px;
}

footer a { color: var(--dusk); text-decoration: none; margin: 0 8px; }
footer a:hover { color: var(--trail); }

/* ---------- 分语言排版微调 ----------
   英文与中文的舒适行距不同：中文需要更松，英文过松会显得散。
   页面本身已按语言分站，这里只按 <html lang> 做字体与行距的差异化。 */

html[lang="en"] body {
  line-height: 1.68;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI",
    Roboto, Helvetica, Arial, sans-serif;
}

html[lang="en"] .lede,
html[lang="en"] .hero .tagline { line-height: 1.55; }

html[lang^="zh"] body {
  line-height: 1.78;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
}

/* 中文正文里的西文数字/单词，避免与汉字贴太紧 */
html[lang^="zh"] strong { font-weight: 600; }

@media (max-width: 560px) {
  body { font-size: 16px; }
  h1 { font-size: 26px; }
  .hero h1 { font-size: 32px; }
  main { padding: 30px 18px 70px; }
  .topbar { padding: 12px 16px; gap: 10px; }
  .nav a { padding: 5px 7px; font-size: 14px; }
}