/* LingoDesk 全站设计系统 v2 —— 深色玻璃质感,Linear/Stripe 式高端简洁 */
:root {
  --bg: #05060c;
  --panel: rgba(255, 255, 255, 0.03);
  --panel-2: rgba(255, 255, 255, 0.055);
  --border: rgba(255, 255, 255, 0.09);
  --text: #f2f5fa;
  --muted: #8f97ab;
  --accent: #4f8cff;
  --accent-2: #34d399;
  --violet: #8b5cf6;
  --warn: #f5b64e;
  --grad: linear-gradient(135deg, #4f8cff 0%, #8b5cf6 100%);
  --radius: 16px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Inter", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
/* 全站氛围光:两团克制的径向光晕 + 顶部微光 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(900px 500px at 15% -10%, rgba(79, 140, 255, 0.14), transparent 60%),
    radial-gradient(800px 500px at 90% 5%, rgba(139, 92, 246, 0.11), transparent 60%),
    radial-gradient(700px 500px at 50% 110%, rgba(52, 211, 153, 0.06), transparent 60%);
  pointer-events: none;
}
::selection { background: rgba(79, 140, 255, 0.35); }
code {
  background: var(--panel-2); border: 1px solid var(--border); border-radius: 6px;
  padding: 1px 7px; font-size: 13.5px; font-family: "SF Mono", ui-monospace, Menlo, Consolas, monospace;
  color: #a5d6ff; word-break: break-all;
}

/* ── 页头(两页一致):吸顶玻璃 ─────────────────────────────── */
header {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 10px 16px;
  padding: 16px 0;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  background: rgba(5, 6, 12, 0.65);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  margin: 0 -24px; padding-left: 24px; padding-right: 24px;
}
.logo { font-size: 19px; font-weight: 750; text-decoration: none; color: var(--text); white-space: nowrap; letter-spacing: -0.02em; }
.logo span { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
nav { display: flex; gap: 22px; align-items: center; flex-wrap: wrap; }
nav a { color: var(--muted); font-size: 14px; text-decoration: none; transition: color 0.2s; white-space: nowrap; }
nav a:hover { color: var(--text); }
nav a.active { color: var(--text); }
@media (max-width: 620px) {
  header { position: static; padding-top: 12px; padding-bottom: 12px; backdrop-filter: none; -webkit-backdrop-filter: none; }
  .logo { font-size: 17px; }
  nav { gap: 14px; }
  nav a { font-size: 13px; }
}

/* ── 语言切换器:胶囊 ─────────────────────────────────────── */
.lang-switch {
  display: flex; border: 1px solid var(--border); border-radius: 999px; overflow: hidden;
  background: var(--panel);
}
.lang-switch a { padding: 4px 12px; font-size: 12.5px; color: var(--muted); text-decoration: none; }
.lang-switch a + a { border-left: 1px solid var(--border); }
.lang-switch a.on { background: var(--panel-2); color: var(--text); font-weight: 600; }

/* ── 按钮体系 ────────────────────────────────────────────── */
.btn {
  display: inline-block; padding: 13px 30px; border-radius: 12px;
  font-size: 16px; font-weight: 650; text-decoration: none; text-align: center;
  background: var(--grad); color: #fff; letter-spacing: 0.01em;
  box-shadow: 0 8px 30px rgba(79, 140, 255, 0.35), inset 0 1px 0 rgba(255, 255, 255, 0.25);
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 14px 40px rgba(79, 140, 255, 0.45), inset 0 1px 0 rgba(255, 255, 255, 0.25); }
.btn.ghost {
  background: var(--panel); color: var(--text);
  border: 1px solid var(--border); box-shadow: none;
  backdrop-filter: blur(6px);
}
.btn.ghost:hover { border-color: rgba(255, 255, 255, 0.22); background: var(--panel-2); transform: translateY(-2px); box-shadow: none; }

/* ── 玻璃卡片基元 ────────────────────────────────────────── */
.glass {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.045), rgba(255, 255, 255, 0.02));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

/* .reveal 保留为空标记类(曾用于滚动浮现;为内容可见性的确定性而移除动画) */

/* ── 页脚(两页一致) ─────────────────────────────────────── */
footer {
  border-top: 1px solid rgba(255, 255, 255, 0.06); margin-top: 64px;
  padding: 30px 0 44px; text-align: center; color: var(--muted); font-size: 13px;
}
footer a { color: var(--muted); text-decoration: none; }
footer a:hover { color: var(--text); }