/* 头部导航 - 改为绝对定位，叠加在banner上方 */
.header {
    background-image: url('https://lanhu-oss-2537-2.lanhuapp.com/8ab293b9bd30dfd4fa6a09b3820fdd77');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    padding: 10px 20px;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 10;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.company-name {
    color: white;
    font-size: 24px;
    font-weight: bold;
    text-shadow: 0 1px 2px rgba(0,0,0,0.5);
}

.nav {
    display: flex;
    justify-content: flex-end;
    gap: 40px;
    margin-right: 6%;
}

.nav a {
    font-family: "SourceHanSansCN", sans-serif;
    font-weight: 400;
    font-size: 18px;
    color: #FFFFFF;
    line-height: 48px;
    text-shadow: 0 1px 2px rgba(0,0,0,0.5);
    position: relative;
}

/* 导航栏文字悬停显示图片效果 */
/* 导航栏文字悬停/激活显示图片效果 */
.nav a::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -5px;
    width: 100%;
    height: 4px;
    background-image: url('https://lanhu-oss-2537-2.lanhuapp.com/5a5ee279e858d03efb6a6f05608df000');
    background-size: contain;
    background-repeat: no-repeat;
    background-position: center;
    opacity: 0;
    transition: opacity 0.3s ease;
}

/* 悬停或激活状态都显示图片 */
.nav a:hover::after,
.nav a.active::after {
    opacity: 1;
}