/* nav-enhance.css - 导航增强样式 */
.nav-bg-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--nav-bg-img-height, 420px);
    background-image: var(--nav-bg-img, none);
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    z-index: -1;
    border-radius: 0 0 16px 16px;
    transition: opacity 0.4s ease, transform 0.4s ease;
}
.nav-bg-layer.nav-bg-show {
    opacity: 1;
    transform: translateY(0);
}
.nav-bg-layer.nav-bg-hidden {
    opacity: 0;
    transform: translateY(-20px);
    pointer-events: none;
}