/* 全局基础样式 */
* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Inter", "PingFang SC", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  background: #f7f7f9;
  color: #1a1a1a;
}

/* 顶部大背景（极光渐变） */
header {
  background: linear-gradient(135deg, #5be0ff 0%, #7b5cff 40%, #ff4fd8 100%);
  padding: 90px 20px 80px;
  text-align: center;
  color: #ffffff;
  position: relative;
  overflow: hidden;
}

.header-inner {
  max-width: 900px;
  margin: 0 auto;
}

header h1 {
  font-size: 42px;
  margin: 0;
  font-weight: 800;
  letter-spacing: 0.04em;
}

header p {
  font-size: 18px;
  margin-top: 12px;
  opacity: 0.9;
}

/* 容器与布局 */
.container {
  width: 90%;
  max-width: 1100px;
  margin: 40px auto;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}

/* 顶部导航栏 */
.top-nav {
  width: 100%;
  background: rgba(255,255,255,0.78); /* 方案B：纯白半透明导航 */
  backdrop-filter: blur(16px);
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: 0 2px 10px rgba(0,0,0,0.08);
}

.nav-container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 10px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* 左侧 LOGO + 标题 */
.nav-left {
  display: flex;
  align-items: center;
  gap: 10px;
}

.site-logo {
  width: 34px;
  height: 34px;
}

.site-name {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.05em;
  background: linear-gradient(135deg, #ff4fd8 0%, #7b5cff 50%, #5be0ff 100%);
  -webkit-background-clip: text;
  color: transparent;
  text-shadow: 0 2px 8px rgba(0,0,0,0.15), 0 0 12px rgba(123,92,255,0.28);
}

/* 右侧导航（PC） */
.nav-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.nav-right a {
  padding: 8px 20px;
  border-radius: 999px;
  font-size: 15px;
  text-decoration: none;
  color: #333333;
  border: 1px solid rgba(160,160,160,0.6);
  background: rgba(255,255,255,0.9);
  transition: 0.2s;
}

.nav-right a:hover {
  background: linear-gradient(135deg, #ff4fd8, #7b5cff);
  color: #ffffff;
  border-color: transparent;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  transform: translateY(-1px);
}

/* 移动端汉堡按钮 */
.hamburger {
  width: 28px;
  height: 22px;
  display: none;
  flex-direction: column;
  justify-content: space-between;
  cursor: pointer;
}

.hamburger span {
  display: block;
  height: 3px;
  background: #333;
  border-radius: 3px;
}

/* 移动端弹出菜单 */
.mobile-menu {
  display: none;
  position: fixed;
  top: 70px;
  right: 16px;
  background: rgba(255,255,255,0.96);
  backdrop-filter: blur(14px);
  border-radius: 16px;
  padding: 14px 16px;
  box-shadow: 0 10px 26px rgba(0,0,0,0.18);
  flex-direction: column;
  gap: 10px;
  z-index: 999;
  min-width: 140px;
}

.mobile-menu a {
  display: block;
  padding: 8px 10px;
  border-radius: 10px;
  color: #333;
  text-decoration: none;
  font-size: 15px;
}

.mobile-menu a:hover {
  background: linear-gradient(135deg, #ff4fd8, #7b5cff);
  color: #fff;
}

/* 背景遮罩 */
.menu-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.12);
  z-index: 998;
}

/* menu-open 状态 */
body.menu-open .mobile-menu {
  display: flex;
}

body.menu-open .menu-backdrop {
  display: block;
}

/* 卡片：极光渐变细描边 */
.card {
  border-radius: 18px;
  padding: 24px;
  background:
    linear-gradient(#ffffff, #ffffff) padding-box,
    linear-gradient(135deg,
      rgba(91,224,255,0.8),
      rgba(123,92,255,0.8),
      rgba(255,79,216,0.8)
    ) border-box;  /* 渐变细描边 */
  border: 1px solid transparent;
  box-shadow: 0 6px 20px rgba(0,0,0,0.06);
  transition: 0.25s;
  text-decoration: none;
  color: inherit;
  display: block;
}

.card h3 {
  margin-top: 0;
  font-size: 22px;
  font-weight: 600;
}

.card p {
  opacity: 0.8;
  line-height: 1.7;
  margin-bottom: 0;
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 24px rgba(0,0,0,0.08);
}

/* 关于模块 */
.about-block {
  margin-top: 60px;
}

.about-block h2 {
  font-size: 26px;
  margin-bottom: 16px;
  font-weight: 600;
}

.about-block p {
  line-height: 1.8;
  opacity: 0.9;
}

/* 页脚 */
footer {
  margin-top: 60px;
  padding: 30px;
  text-align: center;
  color: #777;
  font-size: 14px;
}

/* 响应式适配 */
@media (max-width: 860px) {
  .nav-right {
    display: none;
  }
  .hamburger {
    display: flex;
  }
  header {
    padding: 80px 16px 60px;
  }
  header h1 {
    font-size: 32px;
  }
  header p {
    font-size: 16px;
  }
}

@media (min-width: 861px) {
  .mobile-menu,
  .menu-backdrop {
    display: none !important;
  }
  body.menu-open .mobile-menu,
  body.menu-open .menu-backdrop {
    display: none !important;
  }
}