* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
html,body, header, footer {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: #f5f7fa;
  color: #333;
  min-width:1597px;
  overflow-x: auto;
}
.img-placeholder {
  border-radius: 4px;
  display: flex;
  align-items: center;
  /* justify-content: center; */
  font-size: 14px;
  color: #909399;
}

/* ===== 头部容器 ===== */
.header-wrapper {
  width: 100%;
  background: rgba(0, 0, 0, 0.2);
  backdrop-filter: blur(2px);
  position: fixed;
  top: 0;
  z-index: 1000;
}
.header-inner {
  /* max-width: 1200px; */
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 250px;
  height: 64px;
}

/* ===== Logo ===== */
.logo {
  width: 242px;
  height: 38px;
}
.logo img {
  width: 100%;
  height: 100%;
}
/* ===== 导航 ===== */
.nav {
  display: flex;
  align-items: center;                 
  gap: 40px;
}
.nav a {
  position: relative;
  margin: 8px 16px;
  padding:10px 0;
  font-size: 17px;
  color: #fff;
  text-decoration: none;
  /* border-radius: 4px; */
  transition: 0.2s;
}
.nav a:hover {
  border-bottom: 2px solid #003edf;
  color: #003edf;
}
.nav a.active {
  color: #003edf;
  font-weight: 500;
}
.nav a.active {
  border-bottom: 2px solid #003edf;
}

/* ===== 管理后台按钮 ===== */
.nav .btn-admin {
  background: #0d4699;
  color: #fff;
  padding: 8px 16px;
  border-radius: 4px;
  margin-left: 12px;
  transition: 0.3s;
}
.nav .btn-admin:hover {
  background: #083674;
}

/* ===== 小屏折叠 ===== */
.menu-toggle {
  display: none;
  font-size: 20px;
  background: 0;
  border: 0;
  cursor: pointer;
}
@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }
  .nav {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: #fff;
    flex-direction: column;
    padding: 12px 24px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.06);
    display: none;
  }
  .nav.show {
    display: flex;
  }
  .nav a {
    width: 100%;
    margin: 4px 0;
  }
  .nav .btn-admin {
    width: 100%;
    margin: 8px 0 0 0;
  }
}

/* 滚动后 header 样式 */
.header-wrapper.scrolled {
  background: #fff !important;
  box-shadow: 0 2px 6px rgba(0,0,0,.06);
}
.header-wrapper.scrolled .nav a {
  color: #000 !important;
}
.header-wrapper.scrolled .nav a.active,
.header-wrapper.scrolled .nav a:hover {
  color: #0D4699 !important;
  border-bottom: 2px solid #0D4699;
}
.header-wrapper.scrolled .btn-admin {
  background: #0D4699 !important;
  color: #fff !important;
}