/* 参考 KiddoSheet base：顶栏渐变、侧栏导航、回到顶部 */

.site-header {
    background: linear-gradient(
        90deg,
        #dbeafe 0%,
        #ede9fe 25%,
        #fee2e2 50%,
        #fef9c3 75%,
        #dcfce7 100%
    );
    border-bottom: 1px solid #e5e7eb;
    backdrop-filter: blur(8px);
    background-opacity: 0.95;
}

.site-logo img {
    filter: drop-shadow(0 1px 1px rgba(0, 0, 0, 0.06));
}

.site-logo-wrap {
    min-width: 0;
}

.nav-link {
    display: block;
    padding: 0.5rem 0.75rem;
    border-radius: 0.5rem;
    font-size: 0.875rem;
    color: #374151;
    transition: background 0.15s, color 0.15s;
}

.nav-link:hover {
    background: #eff6ff;
    color: #2563eb;
}

.nav-group-toggle[aria-expanded="true"] svg {
    transform: rotate(0deg);
}

.nav-group-children:not(.hidden) {
    display: block;
}

.article-body p {
    margin-bottom: 1rem;
    line-height: 1.75;
    color: #374151;
}

.article-body strong {
    color: #111827;
}

.back-to-top {
    position: fixed;
    right: 1.5rem;
    bottom: 1.5rem;
    width: 2.75rem;
    height: 2.75rem;
    border-radius: 9999px;
    background: #fff;
    border: 1px solid #e5e7eb;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    color: #4b5563;
    font-size: 1.25rem;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.2s, visibility 0.2s;
    z-index: 60;
}

.back-to-top.is-visible {
    opacity: 1;
    visibility: visible;
}

.line-clamp-2 {
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

@media print {
    .no-print {
        display: none !important;
    }
}