/* Smooth scroll */
html { scroll-behavior: smooth; }

/* Language switching */
.lang-zh { display: none; }
html.lang-zh-active .lang-en { display: none; }
html.lang-zh-active .lang-zh { display: revert; }

/* === Scrollbar: global === */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
    background: #e5e7eb;
    border-radius: 999px;
}
::-webkit-scrollbar-thumb:hover { background: #d1d5db; }
::-webkit-scrollbar-corner { background: transparent; }

/* Dark mode scrollbar */
.dark ::-webkit-scrollbar-thumb { background: #374151; }
.dark ::-webkit-scrollbar-thumb:hover { background: #4b5563; }

/* Sidebar scrollbar — thinner */
.sidebar-scroll::-webkit-scrollbar { width: 3px; }
.sidebar-scroll::-webkit-scrollbar-track { background: transparent; }
.sidebar-scroll::-webkit-scrollbar-thumb {
    background: #e5e7eb;
    border-radius: 999px;
}
.sidebar-scroll::-webkit-scrollbar-thumb:hover { background: #d1d5db; }
.dark .sidebar-scroll::-webkit-scrollbar-thumb { background: #2d3748; }
.dark .sidebar-scroll::-webkit-scrollbar-thumb:hover { background: #4a5568; }

/* Firefox */
* { scrollbar-width: thin; scrollbar-color: #e5e7eb transparent; }
.dark * { scrollbar-color: #374151 transparent; }

/* Nav active states */
.nav-link.active {
    color: var(--color-accent) !important;
    background: var(--color-accent-bg);
    font-weight: 600;
}

.nav-chevron.rotated {
    transform: rotate(90deg);
}

.sub-link.active {
    color: var(--color-accent) !important;
    background: var(--color-accent-bg);
    font-weight: 500;
}

/* Sub-nav expand/collapse */
.sub-nav {
    overflow: hidden;
    max-height: 0;
    opacity: 0;
    transition: max-height 0.25s ease, opacity 0.2s ease, margin 0.2s ease;
    margin-top: 0 !important;
    margin-bottom: 0 !important;
}

.sub-nav.expanded {
    display: block !important;
    max-height: 600px;
    opacity: 1;
    margin-top: 2px !important;
    margin-bottom: 4px !important;
}

/* === Prose Content === */
.prose-content h3 {
    font-size: 1.15rem;
    font-weight: 600;
    color: #111827;
    margin: 2rem 0 0.65rem;
    line-height: 1.45;
    scroll-margin-top: 5rem;
}

.prose-content h4 {
    font-size: 1rem;
    font-weight: 600;
    color: #1f2937;
    margin: 1.5rem 0 0.5rem;
}

.prose-content p {
    margin-bottom: 1rem;
    line-height: 1.85;
    color: #4b5563;
    font-size: 0.94rem;
}

.prose-content ul {
    margin: 0.5rem 0 1.15rem 0;
    padding-left: 0;
    list-style: none;
}

.prose-content ul li {
    position: relative;
    padding-left: 1.35rem;
    margin-bottom: 0.5rem;
    line-height: 1.75;
    color: #4b5563;
    font-size: 0.94rem;
}

.prose-content ul li::before {
    content: '';
    position: absolute;
    left: 0.15rem;
    top: 0.7rem;
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: var(--color-accent-light);
}

.prose-content ol {
    margin: 0.5rem 0 1.15rem;
    padding-left: 1.5rem;
}

.prose-content ol li {
    margin-bottom: 0.5rem;
    line-height: 1.75;
    color: #4b5563;
    font-size: 0.94rem;
}

.prose-content code {
    background: #f3f4f6;
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.85em;
    font-family: 'JetBrains Mono', 'SF Mono', monospace;
    color: #6366f1;
}

.prose-content pre {
    background: #1e293b;
    color: #e2e8f0;
    padding: 1rem 1.25rem;
    border-radius: 8px;
    overflow-x: auto;
    margin: 1rem 0;
    font-size: 0.84rem;
    line-height: 1.65;
}

.prose-content blockquote {
    border-left: 3px solid var(--color-accent-light);
    padding: 0.5rem 1rem;
    margin: 1rem 0;
    color: #6b7280;
    background: #f8fafc;
    border-radius: 0 6px 6px 0;
}

/* TOC link active */
.toc-link.active {
    color: var(--color-accent) !important;
    font-weight: 500;
}

/* === Dark Mode Prose overrides === */
.dark .prose-content h3 { color: #e5e7eb; }
.dark .prose-content h4 { color: #d1d5db; }
.dark .prose-content p  { color: #9ca3af; }
.dark .prose-content ul li { color: #9ca3af; }
.dark .prose-content ol li { color: #9ca3af; }
.dark .prose-content code { background: #1f2937; color: #a78bfa; }
.dark .prose-content pre  { background: #0d1117; color: #e2e8f0; }
.dark .prose-content blockquote { background: #161b22; color: #9ca3af; border-left-color: var(--color-accent-light); }

/* === Dark Mode TOC link === */
.dark .toc-link { color: #6b7280; }
.dark .toc-link:hover { color: #d1d5db; }

/* Responsive: content wrapper on small screens */
@media (max-width: 640px) {
    .content-wrapper {
        padding-left: 1rem;
        padding-right: 1rem;
    }
    .prose-content h3 {
        font-size: 1.05rem;
    }
    .doc-section h2 {
        font-size: 1.35rem !important;
    }
}