/* ==========================================================================
   Go Design Patterns — OpenRouter-Inspired Documentation Theme
   Modern, clean, and minimal design for technical documentation
   ========================================================================== */

/* ---------- CSS Variables: Light Themes ---------- */
.light,
.rust {
    --gp-primary: #8b5cf6;
    --gp-primary-hover: #7c3aed;
    --gp-accent: #a78bfa;
    --gp-bg: #FFFFFF;
    --gp-bg-secondary: #f8fafc;
    --gp-bg-tertiary: #f1f5f9;
    --gp-bg-code: #f8fafc;
    --gp-text: #0f172a;
    --gp-text-secondary: #475569;
    --gp-text-muted: #64748b;
    --gp-border: #e2e8f0;
    --gp-border-light: #f1f5f9;
    --gp-sidebar-bg: #fafafa;
    --gp-sidebar-hover: #f5f5f5;
    --gp-sidebar-active: rgba(139, 92, 246, 0.1);
    --gp-link: #8b5cf6;
    --gp-link-hover: #7c3aed;
    --gp-shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --gp-shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --gp-table-header-bg: #f8fafc;
    --gp-table-stripe: #fafafa;
}

/* ---------- CSS Variables: Dark Themes ---------- */
.coal,
.navy,
.ayu {
    --gp-primary: #a78bfa;
    --gp-primary-hover: #c4b5fd;
    --gp-accent: #8b5cf6;
    --gp-bg: #0a0a0a;
    --gp-bg-secondary: #141414;
    --gp-bg-tertiary: #1a1a1a;
    --gp-bg-code: #0f0f0f;
    --gp-text: #fafafa;
    --gp-text-secondary: #d4d4d4;
    --gp-text-muted: #a3a3a3;
    --gp-border: #1f1f1f;
    --gp-border-light: #171717;
    --gp-sidebar-bg: #000000;
    --gp-sidebar-hover: #0f0f0f;
    --gp-sidebar-active: rgba(139, 92, 246, 0.15);
    --gp-link: #a78bfa;
    --gp-link-hover: #c4b5fd;
    --gp-shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --gp-shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
    --gp-table-header-bg: #0f0f0f;
    --gp-table-stripe: #0a0a0a;
}

/* ---------- Typography ---------- */
body,
.content,
.sidebar {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif !important;
    font-size: 15px;
    line-height: 1.6;
    color: var(--gp-text);
}

code,
pre > code,
.hljs {
    font-family: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace !important;
}

/* ---------- Headings ---------- */
.content main h1 {
    color: var(--gp-text);
    font-weight: 700;
    font-size: 2rem;
    letter-spacing: -0.02em;
    line-height: 1.25;
    margin-top: 0;
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--gp-border);
}

.content main h2 {
    color: var(--gp-text);
    font-weight: 600;
    font-size: 1.5rem;
    letter-spacing: -0.015em;
    margin-top: 2.5rem;
    margin-bottom: 1rem;
}

.content main h3 {
    color: var(--gp-text);
    font-weight: 600;
    font-size: 1.25rem;
    letter-spacing: -0.01em;
    margin-top: 1.5rem;
    margin-bottom: 0.75rem;
}

/* ---------- Links ---------- */
.content main a {
    color: var(--gp-text);
    text-decoration: none;
    transition: color 0.15s ease;
}

.content main a:hover {
    color: var(--gp-primary);
}

.content main a code {
    color: inherit;
}

.coal .content main a,
.navy .content main a,
.ayu .content main a {
    color: #fafafa;
}

.coal .content main a:hover,
.navy .content main a:hover,
.ayu .content main a:hover {
    color: #a78bfa;
}

/* ---------- Code Blocks ---------- */
.content main pre {
    background: var(--gp-bg-secondary) !important;
    border-radius: 6px !important;
    border: 1px solid var(--gp-border) !important;
    padding: 1rem !important;
    margin: 1.5rem 0 !important;
    overflow-x: auto;
    font-size: 13px;
}

.content main pre > code {
    font-size: 13px;
    line-height: 1.6;
}

.content main :not(pre) > code {
    background: var(--gp-bg-secondary);
    border: 1px solid var(--gp-border);
    border-radius: 4px;
    padding: 0.125rem 0.375rem;
    font-size: 0.875em;
    color: var(--gp-primary);
}

/* ---------- Tables ---------- */
.content main table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    border-radius: 6px;
    overflow: hidden;
    border: 1px solid var(--gp-border);
    margin: 1.5rem 0;
    font-size: 14px;
}

.content main table thead tr {
    background: var(--gp-table-header-bg);
    border-bottom: 1px solid var(--gp-border);
}

.content main table thead th {
    color: var(--gp-text) !important;
    font-weight: 600;
    padding: 0.75rem 1rem;
    text-align: left;
    font-size: 13px;
    letter-spacing: 0;
}

.content main table tbody td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--gp-border);
    color: var(--gp-text-secondary);
}

.content main table tbody tr:nth-child(even) {
    background: var(--gp-table-stripe);
}

.content main table tbody tr:last-child td {
    border-bottom: none;
}

.content main table tbody tr:hover {
    background: var(--gp-bg-secondary);
}

/* ---------- Menu Bar ---------- */
#menu-bar,
#menu-bar.bordered {
    background-color: #000000 !important;
    background: #000000 !important;
    border-bottom: 1px solid var(--gp-border);
}

.coal #menu-bar,
.navy #menu-bar,
.ayu #menu-bar,
.coal #menu-bar.bordered,
.navy #menu-bar.bordered,
.ayu #menu-bar.bordered {
    background-color: #000000 !important;
    background: #000000 !important;
}

body.coal,
body.navy,
body.ayu {
    --bg: #0a0a0a !important;
}

/* Force black on all possible menu bar selectors */
.coal .menu-bar,
.navy .menu-bar,
.ayu .menu-bar {
    background-color: #000000 !important;
    background: #000000 !important;
}

#menu-bar > *,
#menu-bar .left-buttons,
#menu-bar .right-buttons {
    background: transparent !important;
}

#menu-bar .menu-title {
    color: var(--gp-text);
    font-weight: 600;
    font-size: 1rem;
}

.coal #menu-bar .menu-title,
.navy #menu-bar .menu-title,
.ayu #menu-bar .menu-title {
    color: #fafafa !important;
}

/* ---------- Sidebar ---------- */
.sidebar {
    background: var(--gp-sidebar-bg) !important;
    border-right: 1px solid var(--gp-border);
}

.coal .sidebar,
.navy .sidebar,
.ayu .sidebar {
    background: #000000 !important;
}

.sidebar .sidebar-scrollbox {
    padding-top: 1rem;
}

/* Reset mdBook's default chapter-item spacing */
.sidebar .chapter > li.chapter-item {
    margin: 0;
    padding: 0;
    line-height: 1;
}

/* Collapse the wrapper li that contains only a part-title or spacer */
.sidebar .chapter > li.chapter-item:has(> li.part-title),
.sidebar .chapter > li.chapter-item:has(> li.spacer) {
    display: contents;
}

/* Hide the first spacer (between title and first category) */
.sidebar .chapter li.spacer {
    display: block;
    height: 0.5rem;
    border: none;
}

/* Sidebar category headers (part titles) */
.sidebar .chapter li.part-title {
    display: flex;
    align-items: center;
    justify-content: space-between;
    text-transform: uppercase;
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.05em;
    color: var(--gp-text-muted);
    margin: 1.5rem 0 0.5rem 0;
    padding: 0.5rem 1rem;
    line-height: 1.3;
    cursor: pointer;
    transition: color 0.15s ease;
    user-select: none;
}

.sidebar .chapter li.part-title:hover {
    color: var(--gp-text);
}

/* Collapse indicator */
.sidebar .chapter li.part-title .collapse-indicator {
    font-size: 14px;
    font-weight: 400;
    color: var(--gp-text-muted);
    transition: transform 0.2s ease;
}

.sidebar .chapter li.part-title.collapsed .collapse-indicator {
    transform: rotate(0deg);
}

/* No top border on the very first category */
.sidebar .chapter li.spacer + li.chapter-item > li.part-title,
.sidebar .chapter li.part-title:first-of-type {
    margin-top: 0;
}

/* Sidebar links */
.sidebar .chapter li a,
.sidebar .chapter li .chapter-link-wrapper a {
    display: block;
    font-size: 14px;
    font-weight: 400;
    padding: 0.375rem 1rem;
    transition: all 0.15s ease;
    line-height: 1.5;
    color: var(--gp-text-secondary);
}

/* Hide nested sub-items in sidebar */
.sidebar .chapter li.chapter-item ol {
    display: none !important;
}

.sidebar .chapter-item .section li {
    display: none !important;
}

.sidebar .chapter li a:hover,
.sidebar .chapter li .chapter-link-wrapper a:hover {
    background: var(--gp-sidebar-hover);
    color: var(--gp-text);
}

.sidebar .chapter li.chapter-item.expanded > .chapter-link-wrapper > a.active,
.sidebar .chapter li a.active {
    background: var(--gp-sidebar-active);
    color: var(--gp-primary);
    font-weight: 500;
}

/* "Go Design Patterns" top link — make it stand out */
.sidebar .chapter > li.chapter-item:first-child a {
    font-weight: 600;
    font-size: 14px;
    color: var(--gp-text);
    margin-bottom: 0.5rem;
}

/* "Contributing" bottom link */
.sidebar .chapter > li.chapter-item:last-child a {
    margin-top: 1rem;
    font-size: 13px;
    color: var(--gp-text-muted);
}

/* ---------- Difficulty Badges ---------- */
.gp-difficulty {
    display: inline-flex;
    align-items: center;
    font-size: 11px;
    font-weight: 500;
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    letter-spacing: 0;
    text-transform: uppercase;
    vertical-align: middle;
    margin-left: 0.75rem;
    border: 1px solid;
}

.gp-difficulty--easy {
    background: #dcfce7;
    color: #15803d;
    border-color: #86efac;
}

.gp-difficulty--medium {
    background: #fef3c7;
    color: #a16207;
    border-color: #fcd34d;
}

.gp-difficulty--hard {
    background: #fee2e2;
    color: #b91c1c;
    border-color: #fca5a5;
}

/* Dark theme badges */
.coal .gp-difficulty--easy,
.navy .gp-difficulty--easy,
.ayu .gp-difficulty--easy {
    background: rgba(34, 197, 94, 0.15);
    color: #4ade80;
    border-color: rgba(34, 197, 94, 0.3);
}

.coal .gp-difficulty--medium,
.navy .gp-difficulty--medium,
.ayu .gp-difficulty--medium {
    background: rgba(251, 191, 36, 0.15);
    color: #facc15;
    border-color: rgba(251, 191, 36, 0.3);
}

.coal .gp-difficulty--hard,
.navy .gp-difficulty--hard,
.ayu .gp-difficulty--hard {
    background: rgba(239, 68, 68, 0.15);
    color: #f87171;
    border-color: rgba(239, 68, 68, 0.3);
}

/* ---------- Blockquotes ---------- */
.content main blockquote {
    border-left: 3px solid var(--gp-primary);
    background: var(--gp-bg-secondary);
    padding: 1rem 1.25rem;
    margin: 1.5rem 0;
    border-radius: 0 6px 6px 0;
    color: var(--gp-text-secondary);
    font-style: normal;
    font-size: 14px;
}

.content main blockquote p {
    margin: 0;
}

/* ---------- Content Area ---------- */
.content {
    background: transparent;
    max-width: 900px;
    margin: 0 auto;
}

.content main {
    padding: 2rem 3rem;
    color: var(--gp-text);
    background: transparent;
}

html {
    background: var(--gp-bg) !important;
}

body {
    background: var(--gp-bg) !important;
}

.coal html,
.navy html,
.ayu html {
    background: #0a0a0a !important;
}

.coal body,
.navy body,
.ayu body {
    background: #0a0a0a !important;
}

.coal .page-wrapper,
.navy .page-wrapper,
.ayu .page-wrapper {
    background: #0a0a0a !important;
}

.content main p {
    color: var(--gp-text-secondary);
    line-height: 1.7;
    margin-bottom: 1rem;
}

.content main ul,
.content main ol {
    color: var(--gp-text-secondary);
    line-height: 1.7;
    margin: 1rem 0;
}

.content main li {
    margin-bottom: 0.5rem;
}

/* ---------- Scrollbar ---------- */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: var(--gp-border);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--gp-text-muted);
}

/* ---------- Nav Buttons ---------- */
.nav-chapters {
    display: none !important;
}

/* ---------- Page Transition ---------- */
.content main {
    animation: gp-fade-in 0.2s ease;
}

@keyframes gp-fade-in {
    from { opacity: 0; transform: translateY(4px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ---------- Table of Contents (On this page) ---------- */
.toc-container {
    position: fixed;
    right: 2rem;
    top: 8rem;
    width: 220px;
    max-height: calc(100vh - 10rem);
    overflow-y: auto;
}

.toc-title {
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--gp-text-muted);
    margin-bottom: 0.75rem;
}

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

.toc-list li {
    margin: 0;
}

.toc-h2 {
    margin-top: 0.5rem;
}

.toc-h3 {
    padding-left: 1rem;
    margin-top: 0.25rem;
}

.toc-link {
    display: block;
    font-size: 13px;
    color: var(--gp-text-muted);
    text-decoration: none;
    padding: 0.25rem 0;
    line-height: 1.4;
    transition: all 0.15s ease;
    border-left: 3px solid transparent;
    padding-left: 0.75rem;
    margin-left: -0.75rem;
}

.toc-link:hover {
    color: var(--gp-text);
}

.toc-link.active {
    color: var(--gp-primary);
    border-left-color: var(--gp-primary);
    font-weight: 500;
}

.coal .toc-link.active,
.navy .toc-link.active,
.ayu .toc-link.active {
    color: #a78bfa;
    border-left-color: #8b5cf6;
}

/* Hide TOC on smaller screens */
@media (max-width: 1400px) {
    .toc-container {
        display: none;
    }
}

/* ---------- Page Navigation (Previous/Next) ---------- */
.page-navigation {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-top: 4rem;
    padding-top: 2rem;
    border-top: 1px solid var(--gp-border);
}

.page-nav-button {
    display: flex;
    flex-direction: column;
    padding: 1rem;
    border: 1px solid var(--gp-border);
    border-radius: 6px;
    background: var(--gp-bg-secondary);
    text-decoration: none;
    transition: all 0.15s ease;
}

.page-nav-button:hover {
    border-color: var(--gp-primary);
    background: var(--gp-bg-tertiary);
}

.page-nav-prev {
    text-align: left;
}

.page-nav-next {
    text-align: right;
    grid-column: 2;
}

.page-nav-label {
    font-size: 12px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--gp-text-muted);
    margin-bottom: 0.25rem;
}

.page-nav-title {
    font-size: 14px;
    font-weight: 500;
    color: var(--gp-text);
}

.page-nav-button:hover .page-nav-title {
    color: var(--gp-primary);
}

@media (max-width: 768px) {
    .page-navigation {
        grid-template-columns: 1fr;
    }
    
    .page-nav-next {
        grid-column: 1;
    }
}