/* ===============================================================
 * 全站基础样式
 * about.html 自带一套 .about-me 作用域内的样式，这里只负责
 * 骨架（导航 / 页头 / 内容容器 / 页脚）和排版底色，避免互相打架。
 * =============================================================== */

*, *::before, *::after { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue",
               "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: #24292f;
  background: #fff;
  -webkit-font-smoothing: antialiased;
}

a { color: #1f6feb; text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ---------------- 顶部导航 ---------------- */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid #e8ebef;
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 58px;
}
.nav-brand {
  font-weight: 700;
  font-size: 16px;
  color: #1f2328;
  letter-spacing: -0.2px;
}
.nav-brand:hover { color: #1f6feb; text-decoration: none; }
.nav-links { display: flex; gap: 22px; }
.nav-links a {
  font-size: 14.5px;
  color: #57606a;
}
.nav-links a:hover { color: #1f6feb; text-decoration: none; }

/* ---------------- 页头 ---------------- */
.intro-header {
  background: linear-gradient(135deg, #1b2430 0%, #2b3a55 100%);
  background-size: cover;
  background-position: center;
  color: #fff;
  padding: 72px 0 60px;
}
.intro-title {
  margin: 0;
  font-size: 40px;
  font-weight: 700;
  letter-spacing: -0.8px;
}
.intro-subtitle {
  margin: 10px 0 0;
  font-size: 16.5px;
  color: rgba(255, 255, 255, .82);
  font-weight: 400;
}

/* ---------------- 正文 ---------------- */
.page-content { padding: 44px 0 72px; }

/* ---------------- 页脚 ---------------- */
.site-footer {
  border-top: 1px solid #e8ebef;
  padding: 26px 0 34px;
  font-size: 13.5px;
  color: #8b949e;
}

@media (max-width: 768px) {
  .intro-header { padding: 52px 0 44px; }
  .intro-title { font-size: 30px; }
  .intro-subtitle { font-size: 15px; }
}