.handbook-layout {
    display: grid;
    grid-template-columns: 260px 1fr;
    gap: 1.5rem;
    align-items: start;
}

@media (max-width: 992px) {
    .handbook-layout {
        grid-template-columns: 1fr;
    }
    .handbook-sidebar {
        position: static !important;
    }
}

.handbook-sidebar {
    position: sticky;
    top: 5.5rem;
    max-height: calc(100vh - 6.5rem);
    overflow-y: auto;
}

.handbook-sidebar .list-group-item {
    border: none;
    border-radius: 8px !important;
    margin-bottom: 4px;
    padding: 0.5rem 0.75rem;
    font-size: 0.9rem;
}

.handbook-sidebar .list-group-item.active {
    background: linear-gradient(135deg, #3b82f6, #2563eb);
    border: none;
}

.handbook-group-header {
    padding: 0.75rem 1.25rem 0.35rem;
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: #3b82f6;
    background: linear-gradient(90deg, rgba(59, 130, 246, 0.08), transparent);
    border-top: 1px solid #e2e8f0;
}

.handbook-group-header:first-child {
    border-top: none;
}

.handbook-sidebar .category-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: #64748b;
    font-weight: 600;
    padding: 0.5rem 0.75rem 0.25rem;
}

.handbook-hero {
    background: linear-gradient(135deg, #1e3a5f 0%, #0f172a 100%);
    color: #fff;
    border-radius: 14px;
    padding: 2rem;
    margin-bottom: 1.5rem;
}

.handbook-hero h1 {
    font-size: 1.75rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
}

.handbook-category-card {
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    height: 100%;
    cursor: pointer;
    text-decoration: none;
    color: inherit;
    display: block;
}

.handbook-category-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(15, 23, 42, 0.12);
    color: inherit;
}

.handbook-category-card .icon-wrap {
    width: 56px;
    height: 56px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.handbook-article-body {
    line-height: 1.75;
}

.handbook-article-body h2 {
    margin-top: 1.75rem;
    margin-bottom: 0.75rem;
    font-size: 1.25rem;
    font-weight: 700;
    padding-bottom: 0.35rem;
    border-bottom: 2px solid #e2e8f0;
}

.handbook-article-body h2:first-child {
    margin-top: 0;
}

.handbook-article-body table {
    font-size: 0.9rem;
}

.handbook-article-body pre {
    background: #1e293b;
    color: #e2e8f0;
    border-radius: 8px;
    padding: 1rem;
    overflow-x: auto;
}

.handbook-article-body code {
    background: #f1f5f9;
    padding: 0.15em 0.4em;
    border-radius: 4px;
    font-size: 0.88em;
}

.handbook-article-body pre code {
    background: none;
    padding: 0;
    color: inherit;
}

.handbook-breadcrumb {
    font-size: 0.875rem;
    margin-bottom: 1rem;
}

.handbook-breadcrumb a {
    text-decoration: none;
    color: #3b82f6;
}

.article-list-item {
    transition: background-color 0.2s ease, padding-left 0.2s ease;
    border-left: 3px solid transparent;
}

.article-list-item:hover {
    background-color: rgba(59, 130, 246, 0.06);
    border-left-color: #3b82f6;
    padding-left: 1.25rem !important;
}