* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
html {
  scroll-behavior: smooth;
}
body {
  background: #f8fafc;
  font-family:
    "Segoe UI",
    system-ui,
    -apple-system,
    "PingFang SC",
    "Microsoft YaHei",
    sans-serif;
  min-height: 100vh;
  color: #334155;
  line-height: 1.6;
  overflow-x: hidden;
  background:
    radial-gradient(
      circle at 20% 25%,
      rgba(226, 232, 240, 0.35) 0%,
      transparent 45%
    ),
    linear-gradient(180deg, #ffffff 0%, #f1f5f9 100%);
  padding-bottom: 20px;
}
:root {
  --primary-color: #2563eb;
  --text-color: #1f2937;
  --bg-color: #ffffff;
  --border-color: #e5e7eb;
}
/* 导航栏 - 修改为 fixed 固定定位并铺满宽度 */
nav {
  width: 100%;
  position: fixed; /* 固定在页面顶部 */
  top: 0;
  left: 0;
  background: rgba(248, 250, 252, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  z-index: 1000;
}
nav.sticky {
  border-bottom: 1px solid rgba(203, 213, 225, 0.3);
  box-shadow: 0 4px 20px -10px rgba(0, 0, 0, 0.1); /* 增加一点悬浮阴影 */
}
/* 导航栏内部容器，限制宽度并居中 */
.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1.2rem 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
/* 占位符，防止 fixed 导航栏遮挡内容 */
.nav-placeholder {
  height: 110px; /* 与导航栏高度保持一致 */
}
.logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.3rem;
  font-weight: 700;
  color: #0f172a;
  text-decoration: none;
}
.logo-icon {
  font-size: 1.8rem;
  background: #fef3c7;
  border-radius: 0.8rem;
  padding: 0.2rem;
  transition: transform 0.3s ease;
}
.logo:hover .logo-icon {
  transform: rotate(-10deg) scale(1.1);
}
.nav-links {
  display: flex;
  gap: 2rem;
  align-items: center;
}
.nav-links a {
  text-decoration: none;
  color: #475569;
  font-weight: 500;
  font-size: 0.95rem;
  position: relative;
  transition: color 0.2s;
}
.nav-links a::after {
  content: "";
  position: absolute;
  width: 0;
  height: 2px;
  bottom: -4px;
  left: 0;
  background: #0f172a;
  transition: width 0.3s ease;
}
.nav-links a:hover::after {
  width: 100%;
}
.nav-links a:hover {
  color: #0f172a;
}