/* ==========================================================================
   S4Core Docs - Stylesheet
   Dark theme inspired by S4Core Docs.
   Organized into logical sections for maintainability.
   ========================================================================== */

/* --------------------------------------------------------------------------
   Design Tokens (CSS Custom Properties)
   --------------------------------------------------------------------------
   Theme system uses data-theme attribute on <html> element.
   - Dark theme is the default (fallback in :root)
   - Light theme overrides via [data-theme="light"]
   - System preference respected via prefers-color-scheme media query
   -------------------------------------------------------------------------- */

:root {
    /* ======================================================================
       Dark Theme (Default)
       ====================================================================== */

    /* Background colors */
    --color-bg-default: #171321;
    --color-bg-subtle: #1e1c28;
    --color-bg-elevated: #252330;
    --color-bg-header: #171321;
    --color-bg-sidebar: #1e1c28;
    --color-bg-card: #252330;
    --color-bg-code: #2b2838;
    --color-bg-hover: rgba(255, 255, 255, 0.05);
    --color-bg-active: rgba(226, 67, 41, 0.08);

    /* Text colors */
    --color-text-default: #d4d4d8;
    --color-text-subtle: #89888d;
    --color-text-strong: #ffffff;
    --color-text-link: #7b8cf5;
    --color-text-code: #ff9e64;

    /* Accent & brand (consistent across themes) */
    --color-accent: #e24329;
    --color-accent-hover: #fc6d26;

    /* Borders & dividers */
    --color-border: rgba(255, 255, 255, 0.08);
    --color-border-strong: rgba(255, 255, 255, 0.15);

    /* ======================================================================
       Shared Design Tokens (theme-independent)
       ====================================================================== */

    /* Typography */
    --font-sans:
        -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans",
        Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
    --font-mono:
        "JetBrains Mono", "Fira Code", "Source Code Pro", Menlo, Monaco,
        Consolas, "Liberation Mono", monospace;

    /* Layout dimensions */
    --header-top-height: 56px;
    --header-nav-height: 48px;
    --header-height: calc(var(--header-top-height) + var(--header-nav-height));
    --sidebar-width: 280px;
    --content-max-width: 900px;
    --layout-max-width: 1400px;

    /* Animation */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;

    /* Radii */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
}

/* ==========================================================================
   Light Theme
   ==========================================================================
   GitLab-inspired light color palette.
   Activated via data-theme="light" on the <html> element.
   ========================================================================== */

[data-theme="light"] {
    /* Background colors */
    --color-bg-default: #ffffff;
    --color-bg-subtle: #fafafa;
    --color-bg-elevated: #f5f5f5;
    --color-bg-header: #ffffff;
    --color-bg-sidebar: #fafafa;
    --color-bg-card: #ffffff;
    --color-bg-code: #f6f8fa;
    --color-bg-hover: rgba(0, 0, 0, 0.04);
    --color-bg-active: rgba(226, 67, 41, 0.08);

    /* Text colors */
    --color-text-default: #1f1f1f;
    --color-text-subtle: #626262;
    --color-text-strong: #000000;
    --color-text-link: #1068bf;
    --color-text-code: #c41a16;

    /* Borders & dividers */
    --color-border: rgba(0, 0, 0, 0.08);
    --color-border-strong: rgba(0, 0, 0, 0.15);
}

/* Override highlight.js theme for light mode */
[data-theme="light"] pre code.hljs {
    color: var(--color-text-default);
}

/* Search highlight in light mode */
[data-theme="light"] .search-result-title mark,
[data-theme="light"] .search-result-snippet mark {
    background: rgba(226, 67, 41, 0.15);
    color: #c41a16;
}

/* --------------------------------------------------------------------------
   Reset & Base
   -------------------------------------------------------------------------- */

*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-y: scroll; /* always show scrollbar — prevents layout shift */
}

body {
    font-family: var(--font-sans);
    background-color: var(--color-bg-default);
    color: var(--color-text-default);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* --------------------------------------------------------------------------
   Typography
   -------------------------------------------------------------------------- */

h1,
h2,
h3,
h4,
h5,
h6 {
    color: var(--color-text-strong);
    font-weight: 600;
    line-height: 1.3;
}

h1 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
}
h2 {
    font-size: 1.5rem;
    margin-top: 2.5rem;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--color-border);
}
h3 {
    font-size: 1.25rem;
    margin-top: 2rem;
    margin-bottom: 0.75rem;
}
h4 {
    font-size: 1.1rem;
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
}

p {
    margin-bottom: 1rem;
}

a {
    color: var(--color-text-link);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-accent-hover);
    text-decoration: underline;
}

ul,
ol {
    margin-bottom: 1rem;
    padding-left: 1.5rem;
}

li {
    margin-bottom: 0.4rem;
}

/* Inline code */
code {
    font-family: var(--font-mono);
    font-size: 0.875em;
    background: var(--color-bg-code);
    color: var(--color-text-code);
    padding: 0.15em 0.4em;
    border-radius: var(--radius-sm);
}

/* Code blocks */
pre {
    background: var(--color-bg-code);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 1rem 1.25rem;
    margin-bottom: 1.5rem;
    overflow-x: auto;
    line-height: 1.5;
}

pre code {
    background: none;
    padding: 0;
    font-size: 0.85rem;
    color: var(--color-text-default);
}

/* Override highlight.js background */
pre code.hljs {
    background: transparent !important;
    padding: 0 !important;
}

/* Code block wrapper with copy button */
.code-block {
    position: relative;
    margin-bottom: 1.5rem;
}

.code-block pre {
    margin-bottom: 0;
}

.copy-btn {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.375rem;
    padding: 0.375rem 0.625rem;
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border-strong);
    border-radius: var(--radius-sm);
    color: var(--color-text-subtle);
    font-family: var(--font-sans);
    font-size: 0.75rem;
    cursor: pointer;
    opacity: 0;
    transition:
        opacity var(--transition-fast),
        background var(--transition-fast),
        color var(--transition-fast);
}

.code-block:hover .copy-btn {
    opacity: 1;
}

.copy-btn:hover {
    background: var(--color-bg-hover);
    color: var(--color-text-strong);
}

.copy-btn.copied {
    color: #4ade80;
    border-color: #4ade80;
}

/* Heading anchor links */
.heading-anchor {
    display: inline-flex;
    align-items: center;
    margin-left: 0.5rem;
    color: var(--color-text-subtle);
    opacity: 0;
    transition:
        opacity var(--transition-fast),
        color var(--transition-fast);
    vertical-align: middle;
}

h2:hover .heading-anchor,
h3:hover .heading-anchor,
.heading-anchor:focus {
    opacity: 1;
}

.heading-anchor:hover {
    color: var(--color-accent);
    text-decoration: none;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 1.5rem;
}

th,
td {
    padding: 0.75rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--color-border);
}

th {
    color: var(--color-text-strong);
    font-weight: 600;
    background: var(--color-bg-subtle);
}

tr:hover td {
    background: var(--color-bg-hover);
}

/* Horizontal rules */
hr {
    border: none;
    border-top: 1px solid var(--color-border);
    margin: 2rem 0;
}

/* Blockquotes */
blockquote {
    border-left: 3px solid var(--color-accent);
    padding: 0.75rem 1.25rem;
    margin: 0 0 1.5rem 0;
    background: var(--color-bg-subtle);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

blockquote p:last-child {
    margin-bottom: 0;
}

/* --------------------------------------------------------------------------
   Site Header
   -------------------------------------------------------------------------- */

.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: var(--color-bg-header);
    border-bottom: 1px solid var(--color-border);
}

/* Centered inner wrapper */
.header-inner {
    max-width: var(--layout-max-width);
    margin: 0 auto;
}

/* Top row: logo + hamburger (mobile) */
.header-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--header-top-height);
    padding: 0 2rem;
    border-bottom: 1px solid var(--color-border);
}

.site-logo {
    display: flex;
    align-items: center;
    gap: 0.625rem;
    color: var(--color-text-strong);
    text-decoration: none;
    font-weight: 700;
    font-size: 1.7rem;
}

.site-logo:hover {
    color: var(--color-text-strong);
    text-decoration: none;
}

.logo-icon {
    flex-shrink: 0;
}

/* Hamburger button (hidden on desktop) */
.sidebar-toggle {
    display: none; /* shown via media query */
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    background: none;
    border: 1px solid var(--color-border-strong);
    border-radius: var(--radius-sm);
    color: var(--color-text-default);
    cursor: pointer;
    transition: background var(--transition-fast);
}

.sidebar-toggle:hover {
    background: var(--color-bg-hover);
}

/* Bottom row: section tabs */
.header-nav {
    height: var(--header-nav-height);
    padding: 0 2rem;
    display: flex;
    align-items: center;
    overflow-x: auto;
}

.header-tabs {
    display: flex;
    list-style: none;
    gap: 1.5rem;
    margin: 0;
    padding: 0;
    height: 100%;
    white-space: nowrap;
}

.header-tabs li {
    margin: 0;
    height: 100%;
    display: flex;
    align-items: center;
}

.header-tabs a {
    display: flex;
    align-items: center;
    height: 100%;
    color: var(--color-text-subtle);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    padding: 0 0.25rem;
    border-bottom: 2px solid transparent;
    transition:
        color var(--transition-fast),
        border-color var(--transition-fast);
}

.header-tabs a:hover {
    color: var(--color-text-strong);
    text-decoration: none;
}

.header-tabs a.active {
    color: var(--color-text-strong);
    border-bottom-color: var(--color-accent);
}

/* --- Header Search --- */

.header-search {
    position: relative;
    flex: 1;
    max-width: 480px;
    margin: 0 1.5rem;
}

.search-input-wrap {
    position: relative;
    display: flex;
    align-items: center;
}

.search-icon {
    position: absolute;
    left: 0.75rem;
    color: var(--color-text-subtle);
    pointer-events: none;
}

.search-input {
    width: 100%;
    height: 36px;
    padding: 0 2.5rem 0 2.25rem;
    background: var(--color-bg-subtle);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text-default);
    font-family: var(--font-sans);
    font-size: 0.875rem;
    outline: none;
    transition:
        border-color var(--transition-fast),
        background var(--transition-fast);
}

.search-input::placeholder {
    color: var(--color-text-subtle);
}

.search-input:focus {
    border-color: var(--color-border-strong);
    background: var(--color-bg-elevated);
}

/* Clear the native search cancel button */
.search-input::-webkit-search-cancel-button {
    -webkit-appearance: none;
}

.search-kbd {
    position: absolute;
    right: 0.5rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 22px;
    height: 22px;
    padding: 0 0.375rem;
    border: 1px solid var(--color-border-strong);
    border-radius: var(--radius-sm);
    background: var(--color-bg-default);
    color: var(--color-text-subtle);
    font-family: var(--font-sans);
    font-size: 0.6875rem;
    line-height: 1;
    pointer-events: none;
}

/* Search results dropdown */

.search-results {
    position: absolute;
    top: calc(100% + 6px);
    left: 0;
    right: 0;
    max-height: 400px;
    overflow-y: auto;
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border-strong);
    border-radius: var(--radius-md);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
    z-index: 200;
    scrollbar-width: thin;
    scrollbar-color: var(--color-border-strong) transparent;
}

.search-results[hidden] {
    display: none;
}

.search-result-item {
    display: block;
    padding: 0.75rem 1rem;
    color: var(--color-text-default);
    text-decoration: none;
    border-bottom: 1px solid var(--color-border);
    transition: background var(--transition-fast);
}

.search-result-item:last-child {
    border-bottom: none;
}

.search-result-item:hover,
.search-result-item.focused {
    background: var(--color-bg-hover);
    text-decoration: none;
    color: var(--color-text-default);
}

.search-result-title {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-text-strong);
    margin-bottom: 0.25rem;
}

.search-result-snippet {
    font-size: 0.8125rem;
    color: var(--color-text-subtle);
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.search-result-title mark,
.search-result-snippet mark {
    background: rgba(226, 67, 41, 0.25);
    color: var(--color-accent-hover);
    border-radius: 2px;
    padding: 0 1px;
}

.search-no-results {
    padding: 1.5rem 1rem;
    text-align: center;
    color: var(--color-text-subtle);
    font-size: 0.875rem;
}

/* --- Header Links (GitHub, Website icons) --- */

.header-links {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-left: auto;
    margin-right: 1rem;
}

.header-icon-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    color: var(--color-text-subtle);
    border-radius: var(--radius-sm);
    transition:
        color var(--transition-fast),
        background var(--transition-fast);
}

.header-icon-link:hover {
    color: var(--color-text-strong);
    background: var(--color-bg-hover);
    text-decoration: none;
}

/* --- Version Selector --- */

.version-selector {
    position: relative;
}

.version-selector summary {
    display: flex;
    align-items: center;
    gap: 0.375rem;
    height: 36px;
    padding: 0 0.625rem;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    background: var(--color-bg-subtle);
    color: var(--color-text-default);
    font-size: 0.8125rem;
    font-weight: 600;
    cursor: pointer;
    list-style: none;
    transition:
        border-color var(--transition-fast),
        background var(--transition-fast),
        color var(--transition-fast);
}

.version-selector summary::-webkit-details-marker {
    display: none;
}

.version-selector summary:hover {
    border-color: var(--color-border-strong);
    background: var(--color-bg-hover);
    color: var(--color-text-strong);
}

.version-chevron {
    flex-shrink: 0;
    transition: transform var(--transition-fast);
}

.version-selector[open] .version-chevron {
    transform: rotate(180deg);
}

.version-menu {
    position: absolute;
    top: calc(100% + 6px);
    right: 0;
    min-width: 160px;
    padding: 0.375rem;
    border: 1px solid var(--color-border-strong);
    border-radius: var(--radius-md);
    background: var(--color-bg-elevated);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.35);
    z-index: 210;
}

.version-menu-item {
    display: block;
    padding: 0.5rem 0.625rem;
    border-radius: var(--radius-sm);
    color: var(--color-text-subtle);
    font-size: 0.8125rem;
    font-weight: 500;
    text-decoration: none;
    white-space: nowrap;
}

.version-menu-item:hover {
    background: var(--color-bg-hover);
    color: var(--color-text-strong);
    text-decoration: none;
}

.version-menu-item.active {
    background: rgba(226, 67, 41, 0.14);
    color: var(--color-accent-hover);
}

/* --- Theme Toggle Button --- */

.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    padding: 0;
    background: none;
    border: none;
    border-radius: var(--radius-sm);
    color: var(--color-text-subtle);
    cursor: pointer;
    transition:
        color var(--transition-fast),
        background var(--transition-fast);
}

.theme-toggle:hover {
    color: var(--color-text-strong);
    background: var(--color-bg-hover);
}

/* Show/hide icons based on current theme */
.theme-toggle .icon-sun,
.theme-toggle .icon-moon {
    width: 20px;
    height: 20px;
}

/* Dark theme: show sun icon (to switch to light) */
.theme-toggle .icon-sun {
    display: block;
}

.theme-toggle .icon-moon {
    display: none;
}

/* Light theme: show moon icon (to switch to dark) */
[data-theme="light"] .theme-toggle .icon-sun {
    display: none;
}

[data-theme="light"] .theme-toggle .icon-moon {
    display: block;
}

/* --------------------------------------------------------------------------
   Site Layout (sidebar + content)
   -------------------------------------------------------------------------- */

.site-layout {
    display: flex;
    margin-top: var(--header-height);
    min-height: calc(100vh - var(--header-height));
    width: 100%;
    max-width: var(--layout-max-width);
    margin-left: auto;
    margin-right: auto;
    flex: 1;
}

/* --------------------------------------------------------------------------
   Sidebar
   -------------------------------------------------------------------------- */

.sidebar {
    position: sticky;
    top: var(--header-height);
    width: var(--sidebar-width);
    height: calc(100vh - var(--header-height));
    flex-shrink: 0;
    overflow-y: auto;
    overflow-x: hidden;
    padding: 1.5rem 1rem;
    border-right: 1px solid var(--color-border);
    background: var(--color-bg-sidebar);
    scrollbar-width: thin;
    scrollbar-color: var(--color-border-strong) transparent;
}

.sidebar::-webkit-scrollbar {
    width: 6px;
}
.sidebar::-webkit-scrollbar-track {
    background: transparent;
}
.sidebar::-webkit-scrollbar-thumb {
    background: var(--color-border-strong);
    border-radius: 3px;
}

/* --- Navigation items --- */

.nav-item {
    margin-bottom: 1px;
}

.nav-link {
    display: block;
    padding: 0.375rem 0.75rem;
    color: var(--color-text-default);
    font-size: 0.875rem;
    text-decoration: none;
    border-radius: var(--radius-sm);
    transition:
        background var(--transition-fast),
        color var(--transition-fast);
}

.nav-link:hover {
    color: var(--color-text-strong);
    background: var(--color-bg-hover);
    text-decoration: none;
}

.nav-link.active {
    color: var(--color-accent);
    background: var(--color-bg-active);
    font-weight: 600;
}

.nav-link.active-trail {
    color: var(--color-text-strong);
    font-weight: 600;
}

/* --- Collapsible sections (using <details>) --- */

.nav-section {
    margin-bottom: 1px;
}

.nav-section > summary {
    display: flex;
    align-items: center;
    list-style: none; /* remove default marker */
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: background var(--transition-fast);
}

/* Hide the native disclosure triangle */
.nav-section > summary::-webkit-details-marker {
    display: none;
}
.nav-section > summary::marker {
    display: none;
    content: "";
}

.nav-section > summary:hover {
    background: var(--color-bg-hover);
}

.nav-section > summary .nav-link,
.nav-section > summary .nav-label {
    flex: 1;
    display: block;
    padding: 0.375rem 0.75rem;
    font-size: 0.875rem;
    color: var(--color-text-default);
    text-decoration: none;
    border-radius: var(--radius-sm);
}

.nav-section > summary .nav-label {
    font-weight: 600;
    color: var(--color-text-subtle);
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.05em;
}

.nav-section > summary .nav-link.active-trail {
    color: var(--color-text-strong);
    font-weight: 600;
}
.nav-section > summary .nav-link.active {
    color: var(--color-accent);
    font-weight: 600;
}

/* Chevron arrow */
.chevron {
    flex-shrink: 0;
    width: 16px;
    height: 16px;
    margin-right: 0.5rem;
    color: var(--color-text-subtle);
    transition: transform var(--transition-fast);
}

.nav-section[open] > summary .chevron {
    transform: rotate(90deg);
}

/* Nested children */
.nav-children {
    padding-left: 0.75rem;
    margin-left: 0.75rem;
    border-left: 1px solid var(--color-border);
}

/* --------------------------------------------------------------------------
   Main Content
   -------------------------------------------------------------------------- */

.main-content {
    flex: 1;
    min-width: 0;
    display: flex;
    flex-direction: row;
}

.content-area {
    max-width: var(--content-max-width);
    width: 100%;
    padding: 2rem 3rem;
    flex: 1;
    min-width: 0;
}

/* --------------------------------------------------------------------------
   TOC Sidebar (right)
   -------------------------------------------------------------------------- */

.toc-sidebar {
    position: sticky;
    top: var(--header-height);
    width: 220px;
    height: calc(100vh - var(--header-height));
    flex-shrink: 0;
    overflow-y: auto;
    padding: 2rem 1rem 2rem 0;
    scrollbar-width: thin;
    scrollbar-color: var(--color-border-strong) transparent;
}

.toc-sidebar::-webkit-scrollbar {
    width: 4px;
}
.toc-sidebar::-webkit-scrollbar-track {
    background: transparent;
}
.toc-sidebar::-webkit-scrollbar-thumb {
    background: var(--color-border-strong);
    border-radius: 2px;
}

.toc-nav {
    border-left: 1px solid var(--color-border);
    padding-left: 1rem;
}

.toc-heading {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-text-subtle);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.75rem;
}

.toc-nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.toc-nav li {
    margin-bottom: 0.25rem;
}

.toc-nav a {
    display: block;
    padding: 0.25rem 0;
    font-size: 0.8125rem;
    color: var(--color-text-subtle);
    text-decoration: none;
    line-height: 1.4;
    transition: color var(--transition-fast);
}

.toc-nav a:hover {
    color: var(--color-text-strong);
    text-decoration: none;
}

.toc-nav a.active {
    color: var(--color-accent);
    font-weight: 500;
}

/* Nested TOC items (h3 under h2) */
.toc-nav ul ul {
    padding-left: 0.75rem;
}

.toc-nav ul ul a {
    font-size: 0.75rem;
}

/* --- Breadcrumbs --- */

.breadcrumbs {
    margin-bottom: 1.5rem;
    font-size: 0.8125rem;
}

.breadcrumb-list {
    display: flex;
    flex-wrap: wrap;
    list-style: none;
    padding: 0;
    margin: 0;
}

.breadcrumb-item {
    display: flex;
    align-items: center;
    margin: 0;
}

.breadcrumb-item + .breadcrumb-item::before {
    content: ">";
    margin: 0 0.5rem;
    color: var(--color-text-subtle);
    font-size: 0.75rem;
}

.breadcrumb-item a {
    color: var(--color-text-subtle);
    text-decoration: none;
}

.breadcrumb-item a:hover {
    color: var(--color-text-link);
}
.breadcrumb-item.current span {
    color: var(--color-text-default);
}

/* --- Document content wrapper --- */

.doc-content {
    margin-bottom: 3rem;
}

/* --- Card grid (shown on index pages) --- */

.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1.25rem;
    margin-top: 2rem;
    margin-bottom: 2rem;
}

.card {
    display: flex;
    flex-direction: column;
    padding: 1.25rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    color: var(--color-text-default);
    text-decoration: none;
    transition:
        border-color var(--transition-fast),
        box-shadow var(--transition-fast);
}

.card:hover {
    border-color: var(--color-border-strong);
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.3);
    text-decoration: none;
    color: var(--color-text-default);
}

.card-title {
    font-weight: 700;
    color: var(--color-text-strong);
    margin-bottom: 0.5rem;
    font-size: 1rem;
}

.card-text {
    color: var(--color-text-subtle);
    font-size: 0.875rem;
    line-height: 1.5;
}

/* --- Page feedback --- */

.page-feedback {
    margin-top: 3rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--color-border);
}

.feedback-inner {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.feedback-label {
    font-size: 0.875rem;
    color: var(--color-text-default);
}

.btn-feedback {
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    padding: 0.375rem 0.875rem;
    border: 1px solid var(--color-border-strong);
    border-radius: var(--radius-sm);
    background: transparent;
    color: var(--color-text-default);
    font-family: var(--font-sans);
    font-size: 0.8125rem;
    cursor: pointer;
    transition:
        background var(--transition-fast),
        border-color var(--transition-fast);
}

.btn-feedback:hover {
    background: var(--color-bg-hover);
    border-color: var(--color-text-subtle);
}

.btn-feedback svg {
    width: 16px;
    height: 16px;
}

/* --- Page navigation (prev/next) --- */

.page-nav {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--color-border);
}

.page-nav-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 1.25rem;
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text-default);
    text-decoration: none;
    transition:
        border-color var(--transition-fast),
        background var(--transition-fast);
    max-width: 48%;
}

.page-nav-link:hover {
    border-color: var(--color-border-strong);
    background: var(--color-bg-elevated);
    text-decoration: none;
}

.page-nav-link.prev {
    margin-right: auto;
}

.page-nav-link.next {
    margin-left: auto;
    text-align: right;
}

.page-nav-link svg {
    flex-shrink: 0;
    color: var(--color-text-subtle);
}

.page-nav-text {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    min-width: 0;
}

.page-nav-label {
    font-size: 0.75rem;
    color: var(--color-text-subtle);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.page-nav-title {
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--color-text-strong);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */

.site-footer {
    background: var(--color-bg-subtle);
    border-top: 1px solid var(--color-border);
    padding: 3rem 1.5rem;
    margin-top: auto;
}

.footer-inner {
    display: grid;
    grid-template-columns: 1.5fr repeat(3, 1fr);
    gap: 2rem;
    max-width: var(--layout-max-width);
    margin: 0 auto;
}

.footer-brand {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.footer-logo {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--color-text-strong);
    text-decoration: none;
    font-weight: 700;
    font-size: 0.9375rem;
}

.footer-logo:hover {
    color: var(--color-text-strong);
    text-decoration: none;
}

.footer-col h3 {
    font-size: 0.875rem;
    font-weight: 700;
    color: var(--color-text-strong);
    margin-bottom: 1rem;
}

.footer-col ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-col li {
    margin-bottom: 0.5rem;
}

.footer-col a {
    color: var(--color-text-subtle);
    font-size: 0.875rem;
    text-decoration: none;
}

.footer-col a:hover {
    color: var(--color-text-link);
}

/* --------------------------------------------------------------------------
   Responsive Design
   -------------------------------------------------------------------------- */

@media (max-width: 1200px) {
    .toc-sidebar {
        display: none;
    }
}

@media (max-width: 1024px) {
    .sidebar-toggle {
        display: flex;
    }

    .sidebar {
        position: fixed;
        left: 0;
        top: var(--header-height);
        z-index: 50;
        transform: translateX(-100%);
        transition: transform var(--transition-normal);
    }

    .sidebar.open {
        transform: translateX(0);
        box-shadow: 4px 0 20px rgba(0, 0, 0, 0.5);
    }

    .content-area {
        padding: 1.5rem;
    }
}

@media (max-width: 768px) {
    .header-top {
        padding: 0 1rem;
    }
    .header-nav {
        padding: 0 1rem;
    }
    .header-search {
        margin: 0 0.75rem;
    }

    .footer-inner {
        grid-template-columns: repeat(2, 1fr);
    }
    .cards-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .footer-inner {
        grid-template-columns: 1fr;
    }
    .header-tabs {
        gap: 1rem;
    }
    .search-kbd {
        display: none;
    }
    .header-search {
        margin: 0 0.5rem;
    }
    .version-selector summary {
        padding: 0 0.5rem;
    }
    .version-label {
        max-width: 4.5rem;
        overflow: hidden;
        text-overflow: ellipsis;
        white-space: nowrap;
    }
}
