/* DAP iQ Design System */

:root {
    /* Base - Dark blue-gray (GitHub Dark inspired) */
    --color-bg-primary: #0d1117;
    --color-bg-secondary: #161b22;
    --color-bg-tertiary: #21262d;

    /* Text */
    --color-text-primary: #e6edf3;
    --color-text-secondary: #8b949e;
    --color-text-muted: #848E9B;

    /* Accent - Blue */
    --color-accent: #3b82f6;
    --color-accent-hover: #60a5fa;

    /* Brand gradient (logo-derived) */
    --gradient-brand: linear-gradient(135deg, #ec4899, #8b5cf6, #3b82f6);

    /* Semantic */
    --color-border: #30363d;
    --color-success: #3fb950;
    --color-warning: #d29922;
    --color-error: #f85149;

    /* Code blocks */
    --color-code-bg: #161b22;
    --color-code-border: #30363d;

    /* System font stacks */
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", Helvetica, Arial, sans-serif;
    --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

    /* Scale (1.25 ratio) */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    --text-4xl: 2.25rem;

    /* Line heights */
    --leading-tight: 1.25;
    --leading-normal: 1.5;
    --leading-relaxed: 1.75;

    /* Spacing (4px base) */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;

    /* Layout */
    --layout-max-width: 1200px;

    /* Shape */
    --radius-sm: 4px;
    --radius-md: 6px;
    --radius-lg: 8px;
    --radius-pill: 9999px;

    /* Elevation */
    --shadow-popover: 0 8px 24px rgba(0, 0, 0, 0.4);
    --shadow-card-hover: 0 8px 24px rgba(0, 0, 0, 0.3);
}

/* Reset */
*, *::before, *::after {
    box-sizing: border-box;
}

* {
    margin: 0;
}

html {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    scroll-behavior: smooth;
}

/* Selection */
::selection {
    background: var(--color-accent);
    color: var(--color-text-primary);
}

/* Focus states for accessibility */
:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

body {
    font-family: var(--font-sans);
    font-size: var(--text-base);
    line-height: var(--leading-relaxed);
    color: var(--color-text-primary);
    background-color: var(--color-bg-primary);
    min-height: 100vh;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    line-height: var(--leading-tight);
    font-weight: 600;
    color: var(--color-text-primary);
}

h1 { font-size: var(--text-4xl); }
h2 { font-size: var(--text-3xl); }
h3 { font-size: var(--text-2xl); }
h4 { font-size: var(--text-xl); }

p {
    margin-bottom: var(--space-4);
}

/* Links */
a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color 0.15s;
}

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

/* Header */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: rgba(13, 17, 23, 0.85);
    -webkit-backdrop-filter: blur(12px);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
}

.header-nav {
    max-width: var(--layout-max-width);
    margin: 0 auto;
    padding: var(--space-4);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-weight: 700;
    font-size: var(--text-xl);
    color: var(--color-text-primary);
    text-decoration: none;
}

.logo:hover {
    background: var(--gradient-brand);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-6);
}

/* Unified nav link styles for both <a> and dropdown toggle */
.nav-links a,
.nav-dropdown-toggle {
    color: var(--color-text-secondary);
    text-decoration: none;
    font-family: inherit;
    font-size: var(--text-sm);
    font-weight: 400;
    line-height: 1.5;
    transition: color 0.15s;
}

.nav-links a:hover,
.nav-dropdown-toggle:hover {
    color: var(--color-text-primary);
}

/* Nav Dropdown */
.nav-dropdown {
    position: relative;
}

.nav-dropdown-toggle {
    display: flex;
    align-items: center;
    gap: var(--space-1);
    padding: 0;
    background: transparent;
    border: none;
    cursor: pointer;
}

.dropdown-chevron {
    transition: transform 0.2s;
}

.nav-dropdown.open .dropdown-chevron {
    transform: rotate(180deg);
}

.nav-dropdown-menu {
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    margin-top: var(--space-2);
    min-width: 160px;
    padding: var(--space-2) 0;
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-popover);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.15s, visibility 0.15s;
    z-index: 200;
}

.nav-dropdown.open .nav-dropdown-menu {
    opacity: 1;
    visibility: visible;
}

.nav-dropdown-menu a {
    display: block;
    padding: var(--space-2) var(--space-4);
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
    text-decoration: none;
    transition: background 0.15s, color 0.15s;
}

.nav-dropdown-menu a:hover,
.nav-dropdown-menu a:focus {
    background: var(--color-bg-tertiary);
    color: var(--color-text-primary);
}

/* Nav Search */
.nav-search {
    display: flex;
    align-items: center;
    gap: 0;
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: border-color 0.15s;
}

.nav-search:focus-within {
    border-color: var(--color-accent);
}

.nav-search input {
    width: 140px;
    padding: var(--space-2) var(--space-3);
    background: transparent;
    border: none;
    color: var(--color-text-primary);
    font-size: var(--text-sm);
    outline: none;
}

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

.nav-search button {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-2);
    background: transparent;
    border: none;
    color: var(--color-text-muted);
    cursor: pointer;
    transition: color 0.15s;
}

.nav-search button:hover {
    color: var(--color-text-primary);
}

/* Scroll Breadcrumb */
.scroll-breadcrumb {
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    z-index: 99;
    background: var(--color-bg-secondary);
    border-bottom: 1px solid var(--color-border);
    opacity: 0;
    transform: translateY(-100%);
    transition: opacity 0.2s, transform 0.2s;
    pointer-events: none;
}

.scroll-breadcrumb.visible {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
}

.breadcrumb-inner {
    max-width: var(--layout-max-width);
    margin: 0 auto;
    padding: 16px 16px 9px; 
    font-size: var(--text-sm);
    line-height: 1.5;
    display: flex;
    align-items: center;
}

.breadcrumb-category {
    color: var(--color-accent);
}

a.breadcrumb-category {
    text-decoration: none;
}

a.breadcrumb-category:hover {
    text-decoration: underline;
}

.breadcrumb-separator {
    color: var(--color-text-muted);
    margin: 0 var(--space-2);
}

.breadcrumb-middle {
    color: var(--color-accent);
}

a.breadcrumb-middle {
    text-decoration: none;
}

a.breadcrumb-middle:hover {
    text-decoration: underline;
}

.breadcrumb-title {
    color: var(--color-text-secondary);
}

/* Main Content */
main {
    padding-top: 80px;
    min-height: calc(100vh - 160px);
}

/* Content Container */
.content-container {
    max-width: 75ch;
    margin: 0 auto;
    padding: var(--space-8) var(--space-4);
    width: 100%;
}

/* Page Header */
.page-header {
    margin-bottom: var(--space-8);
}

.page-header h1 {
    margin-bottom: var(--space-4);
}

.page-header--centered {
    text-align: center;
    padding: var(--space-16) 0;
}

.page-description {
    color: var(--color-text-secondary);
    margin-top: var(--space-2);
}

.search-results {
    margin-top: var(--space-2);
}

/* In-page breadcrumb (Article/Index filter view) */
.filter-breadcrumb {
    margin-bottom: var(--space-4);
    font-size: var(--text-sm);
}

.filter-breadcrumb-separator {
    color: var(--color-text-muted);
    margin: 0 var(--space-2);
}

.filter-breadcrumb-current {
    color: var(--color-text-secondary);
}

/* Search result type badge */
.search-result-type {
    color: var(--color-accent);
    font-size: var(--text-xs);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-2);
}

/* Article List */
.article-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-8);
}

.article-card {
    padding: var(--space-6);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

.article-card:hover {
    border-color: var(--color-accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow-card-hover);
}

.series-order {
    color: var(--color-accent);
    font-size: var(--text-sm);
    font-weight: 600;
    margin-bottom: var(--space-2);
}

.pagination {
    margin-top: var(--space-8);
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--space-4);
}

.pagination-status {
    color: var(--color-text-muted);
}

.article-card h2 {
    font-size: var(--text-2xl);
    margin-bottom: var(--space-2);
}

.article-content .article-card h3 {
    font-size: var(--text-2xl);
    margin-top: 0;
    margin-bottom: var(--space-2);
}

.article-card h2 a {
    color: var(--color-text-primary);
    text-decoration: none;
}

.article-content .article-card h3 a {
    color: var(--color-text-primary);
    text-decoration: none;
}

.article-card h2 a:hover {
    color: var(--color-accent);
}

.article-content .article-card h3 a:hover {
    color: var(--color-accent);
}

.article-card .tldr {
    color: var(--color-text-secondary);
    margin-bottom: var(--space-4);
}

.article-meta {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    color: var(--color-text-muted);
    font-size: var(--text-sm);
}

/* Article Detail */
.article-header {
    margin-bottom: var(--space-8);
}

.article-header h1 {
    margin-bottom: var(--space-4);
    font-size: var(--text-4xl);
}

.series-nav {
    margin-top: var(--space-4);
    padding: var(--space-3) var(--space-4);
    background: var(--color-bg-secondary);
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
}

.series-nav a {
    color: var(--color-accent);
}

/* TLDR Section */
.tldr-section {
    background: var(--color-bg-secondary);
    border-left: 3px solid var(--color-accent);
    padding: var(--space-4) var(--space-6);
    margin: var(--space-6) 0;
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.tldr-section .tldr-label {
    color: var(--color-accent);
    font-size: var(--text-sm);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    display: block;
    margin-bottom: var(--space-2);
}

/* Article Content */
.article-content {
    font-size: var(--text-lg);
    line-height: var(--leading-relaxed);
}

.article-content p {
    margin-bottom: var(--space-6);
}

.article-content h2 {
    margin-top: var(--space-12);
    margin-bottom: var(--space-4);
    padding-bottom: var(--space-2);
    border-bottom: 1px solid var(--color-border);
}

.article-content h3 {
    margin-top: var(--space-8);
    margin-bottom: var(--space-3);
}

.article-content a {
    text-decoration: underline;
    text-decoration-color: var(--color-border);
    text-underline-offset: 2px;
}

.article-content a:hover {
    text-decoration-color: var(--color-accent);
}

.article-content ul,
.article-content ol {
    margin-bottom: var(--space-6);
    padding-left: var(--space-6);
}

.article-content li {
    margin-bottom: var(--space-2);
}

.article-content blockquote {
    border-left: 3px solid var(--color-border);
    padding-left: var(--space-4);
    margin: var(--space-6) 0;
    color: var(--color-text-secondary);
    font-style: italic;
}

/* Markdown media */
.article-content img {
    max-width: 100%;
    height: auto;
    display: block;
    margin: var(--space-6) 0;
    border-radius: var(--radius-md);
}

.article-content figure {
    margin: var(--space-8) 0;
}

.article-content figcaption {
    margin-top: var(--space-2);
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
}

.article-content iframe,
.article-content video {
    width: 100%;
    max-width: 100%;
    aspect-ratio: 16 / 9;
    border: 0;
    display: block;
    margin: var(--space-6) 0;
    border-radius: var(--radius-md);
    background: var(--color-bg-secondary);
}

/* Markdown tables */
.article-content table {
    width: 100%;
    border-collapse: collapse;
    margin: var(--space-6) 0;
    display: block;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.article-content th,
.article-content td {
    border: 1px solid var(--color-border);
    padding: var(--space-2) var(--space-3);
    text-align: left;
    vertical-align: top;
    white-space: nowrap;
}

.article-content th {
    background: var(--color-bg-secondary);
    font-weight: 600;
}

/* Code */
pre {
    background: var(--color-code-bg);
    border: 1px solid var(--color-code-border);
    border-radius: var(--radius-md);
    padding: var(--space-4);
    overflow-x: auto;
    margin: var(--space-6) 0;
    max-width: 100%;
    position: relative;
}

pre code {
    font-family: var(--font-mono);
    font-size: var(--text-sm);
    line-height: var(--leading-normal);
    background: none;
    padding: 0;
    border-radius: 0;
}

code {
    font-family: var(--font-mono);
    font-size: 0.875em;
    background: var(--color-bg-tertiary);
    padding: 0.2em 0.4em;
    border-radius: 3px;
}

/* Tags */
.tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
    list-style: none;
    padding: 0;
    margin: var(--space-6) 0;
}

/* Tags can render inside `.article-content` (e.g., About page recent insights).
   Override markdown list spacing so tags don't get indented or spaced like prose lists. */
.article-content ul.tags,
.article-content ol.tags {
    padding-left: 0;
    margin-bottom: 0;
}

.article-content .tags li {
    margin-bottom: 0;
}

/* In list cards, tags should not add bottom whitespace */
.article-card .tags {
    margin: var(--space-4) 0 0;
}

.tags a {
    display: inline-block;
    padding: var(--space-1) var(--space-3);
    background: var(--color-bg-tertiary);
    border-radius: 9999px;
    font-size: var(--text-xs);
    color: var(--color-text-secondary);
    text-decoration: none;
    transition: background 0.15s, color 0.15s;
}

.tags a:hover {
    background: var(--color-accent);
    color: var(--color-text-primary);
}

/* Article Like */
.article-like {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    margin: var(--space-6) 0;
}

.article-like--meta {
    margin: 0;
}

.like-button {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-3);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: 9999px;
    color: var(--color-text-secondary);
    cursor: pointer;
    font-family: inherit;
    font-size: var(--text-sm);
    line-height: 1;
    transition: background 0.15s, border-color 0.15s, color 0.15s;
}

.like-button:hover {
    background: var(--color-bg-tertiary);
    border-color: var(--color-text-muted);
    color: var(--color-text-primary);
}

.like-button[aria-pressed="true"] {
    border-color: var(--color-accent);
    color: var(--color-text-primary);
}

.like-icon {
    width: 16px;
    height: 16px;
}

.like-count {
    color: var(--color-text-muted);
    font-size: var(--text-sm);
}

/* Tag Cloud Page */
.tag-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-3);
}

.tag-cloud-item {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-4);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    text-decoration: none;
    transition: border-color 0.15s, background 0.15s;
}

.tag-cloud-item:hover {
    border-color: var(--color-accent);
    background: var(--color-bg-tertiary);
}

.tag-cloud-item .tag-name {
    color: var(--color-text-primary);
    font-weight: 500;
}

.tag-cloud-item .tag-count {
    color: var(--color-text-muted);
    font-size: var(--text-xs);
    background: var(--color-bg-tertiary);
    padding: var(--space-1) var(--space-2);
    border-radius: var(--radius-pill);
}

/* Footer */
.site-footer {
    border-top: 1px solid var(--color-border);
    padding: var(--space-8) 0;
    margin: var(--space-8) 0 0;
}

.footer-inner {
    max-width: var(--layout-max-width);
    margin: 0 auto;
    padding: 0 var(--space-4);
    text-align: center;
    color: var(--color-text-muted);
    font-size: var(--text-sm);
}

.footer-inner .license-notice {
    font-size: var(--text-xs);
    margin-top: var(--space-2);
    margin-bottom: 0;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: var(--space-16) var(--space-4);
    color: var(--color-text-secondary);
}

.empty-state h2 {
    color: var(--color-text-secondary);
    margin-bottom: var(--space-4);
}

.empty-state h3 {
    color: var(--color-text-secondary);
    margin-top: 0;
    margin-bottom: var(--space-4);
}

.about-recent-insights .article-list {
    margin-top: var(--space-6);
    margin-bottom: var(--space-6);
}

.about-recent-insights .empty-state {
    margin-top: var(--space-6);
}

/* Responsive */
@media (max-width: 640px) {
    /* Mobile: Header scrolls with content (not fixed) */
    .site-header {
        position: relative;
    }

    .header-nav {
        flex-direction: column;
        gap: var(--space-3);
    }

    .nav-links {
        display: flex;
        flex-direction: column;
        align-items: stretch;
        gap: var(--space-3);
        width: 100%;
    }

    /* Nav links and dropdown toggle centered on mobile */
    .nav-links > a {
        text-align: center;
        padding: var(--space-2) 0;
    }

    /* Mobile dropdown container */
    .nav-dropdown {
        display: flex;
        flex-direction: column;
        align-items: center;
        width: 100%;
    }

    .nav-dropdown-toggle {
        justify-content: center;
        padding: var(--space-2) 0;
    }

    /* Mobile dropdown menu - hidden by default, shown when open */
    .nav-dropdown-menu {
        display: none;
        position: static;
        transform: none;
        margin-top: var(--space-2);
        width: 100%;
        max-width: 200px;
        box-shadow: none;
        border-radius: 4px;
        text-align: center;
        opacity: 1;
        visibility: visible;
    }

    .nav-dropdown.open .nav-dropdown-menu {
        display: block;
        margin-bottom: var(--space-2);
    }

    .nav-search {
        order: 1;
        width: 100%;
    }

    .nav-search input {
        flex: 1;
        width: auto;
    }

    /* No padding-top needed - header is relative, not fixed */
    main {
        padding-top: 0;
    }

    /* Scroll breadcrumb hidden on mobile - header scrolls with page */
    .scroll-breadcrumb {
        display: none;
    }

    .breadcrumb-inner {
        padding: 10px 12px 10px;  /* Extra top padding for visual balance */
        font-size: var(--text-xs);
    }

    /* Truncate long breadcrumb titles on mobile */
    .breadcrumb-title {
        max-width: 270px;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
        display: inline-block;
        vertical-align: bottom;
    }

    /* Hide middle breadcrumb on very small screens */
    .breadcrumb-middle,
    .breadcrumb-middle + .breadcrumb-separator {
        display: none;
    }

    .article-header h1 {
        font-size: var(--text-3xl);
    }

    .article-content {
        font-size: var(--text-base);
    }

    /* Better code block handling on mobile */
    pre {
        padding: var(--space-3);
        font-size: var(--text-xs);
        border-radius: 4px;
    }

    /* Tighter spacing on mobile */
    .content-container {
        padding: var(--space-6) var(--space-4);
    }

    .page-header {
        margin-bottom: var(--space-6);
    }

    .page-header h1 {
        font-size: var(--text-3xl);
    }
}

/* Tablet adjustments */
@media (min-width: 641px) and (max-width: 1024px) {
    .content-container {
        padding: var(--space-8) var(--space-6);
    }
}

/* =========================================
   Reading Enhancements
   ========================================= */

/* Reading Progress Indicator */
.reading-progress-container {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--color-bg-tertiary);
    z-index: 1000;
}

.reading-progress-bar {
    height: 100%;
    background: var(--color-accent);
    width: 0%;
    transition: width 0.1s ease-out;
}

/* Copy Code Buttons */
.copy-code-button {
    position: absolute;
    top: var(--space-2);
    right: var(--space-2);
    padding: var(--space-1) var(--space-3);
    font-size: var(--text-xs);
    font-family: var(--font-mono);
    color: var(--color-text-secondary);
    background: var(--color-bg-tertiary);
    border: 1px solid var(--color-border);
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.15s;
    z-index: 10;
}

.copy-code-button:hover {
    color: var(--color-text-primary);
    background: var(--color-bg-primary);
    border-color: var(--color-accent);
}

.copy-code-button.copied {
    color: var(--color-success);
    border-color: var(--color-success);
}

/* Table of Contents */
.article-page {
    position: relative;
}

/* TOC: Hidden by default on mobile/tablet */
.table-of-contents {
    display: none;
}

/* Desktop: Fixed sidebar TOC */
@media (min-width: 1200px) {
    .table-of-contents {
        display: block;
        position: fixed;
        /* Position relative to centered content */
        left: max(1rem, calc(50% - 37.5ch - 260px));
        /* Below header (60px) + breadcrumb (~47px) + breathing room */
        top: 7.5rem;
        width: 220px;
        max-height: calc(100vh - 9rem);
        overflow-y: auto;
        background: var(--color-bg-secondary);
        border: 1px solid var(--color-border);
        border-radius: var(--radius-lg);
        padding: var(--space-4);
    }

    .table-of-contents .toc-heading {
        font-size: var(--text-base);
        margin-bottom: var(--space-4);
    }

    .table-of-contents .toc-list {
        columns: 1;
    }
}

/* Base TOC heading styles (overridden by media queries above) */
.toc-heading {
    font-weight: 600;
    color: var(--color-text-primary);
}

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

.toc-item {
    margin-bottom: var(--space-2);
    break-inside: avoid;
}

.toc-item-h3 {
    margin-left: var(--space-4);
    font-size: var(--text-sm);
}

.toc-item a {
    color: var(--color-text-secondary);
    text-decoration: none;
    transition: color 0.15s;
    display: block;
    padding: var(--space-1) 0;
}

.toc-item a:hover {
    color: var(--color-accent);
}

/* Series Navigation */
.series-navigation {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-4);
    margin-top: var(--space-12);
    padding-top: var(--space-8);
    border-top: 1px solid var(--color-border);
}

.series-nav-button {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
    padding: var(--space-4);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    text-decoration: none;
    transition: all 0.15s;
}

/* About: Start Here navigation */
.start-here-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-4);
    margin-top: var(--space-6);
}

.article-content .start-here-card {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
    padding: var(--space-5);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    text-decoration: none;
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

.article-content .start-here-card:hover {
    border-color: var(--color-accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow-card-hover);
}

.start-here-label {
    font-size: var(--text-xs);
    color: var(--color-text-muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.start-here-title {
    font-size: var(--text-base);
    color: var(--color-text-primary);
    font-weight: 600;
}

.start-here-desc {
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    line-height: var(--leading-normal);
}

/* Contact Page Layout */
.contact-layout {
    display: flex;
    flex-direction: column;
    gap: var(--space-6);
}

.contact-info {
    padding-top: 0;
}

.contact-info p {
    color: var(--color-text-secondary);
    font-size: var(--text-lg);
    line-height: 1.6;
    margin-bottom: 0;
}

.contact-info a {
    color: var(--color-accent);
    font-weight: 500;
}

.contact-info a:hover {
    text-decoration: underline;
}

/* Contact Form */
.contact-success {
    padding: var(--space-3) var(--space-4);
    margin-bottom: 0;
    border: 1px solid var(--color-border);
    border-left: 3px solid var(--color-success);
    background: var(--color-bg-secondary);
}

.contact-form {
    padding: var(--space-6);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background: var(--color-bg-secondary);
}

.contact-validation-summary {
    margin-bottom: var(--space-4);
    color: var(--color-error);
}

.form-field {
    margin-bottom: var(--space-4);
}

.form-label {
    display: block;
    margin-bottom: var(--space-2);
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
}

.form-input,
.form-textarea {
    width: 100%;
    padding: var(--space-3);
    background: var(--color-bg-tertiary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text-primary);
    font-family: inherit;
    font-size: var(--text-base);
}

.form-textarea {
    resize: vertical;
}

.form-input:focus,
.form-textarea:focus {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

.form-validation {
    display: block;
    margin-top: var(--space-2);
    font-size: var(--text-sm);
    color: var(--color-error);
}

.form-actions {
    margin-top: var(--space-6);
}

.contact-submit {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-3) var(--space-5);
    background: var(--color-accent);
    border: 1px solid transparent;
    border-radius: var(--radius-md);
    color: var(--color-text-primary);
    font-size: var(--text-sm);
    font-weight: 600;
    cursor: pointer;
    transition: background 0.15s;
}

.contact-submit:hover {
    background: var(--color-accent-hover);
}

.series-nav-button:hover {
    border-color: var(--color-accent);
    background: var(--color-bg-tertiary);
}

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

.series-nav-next {
    text-align: right;
}

.series-nav-label {
    font-size: var(--text-sm);
    color: var(--color-text-muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.series-nav-title {
    font-size: var(--text-base);
    color: var(--color-text-primary);
    font-weight: 500;
}

.series-nav-placeholder {
    /* Empty spacer for alignment when only one nav button exists */
}

/* Tablet and mobile: Series nav stacks */
@media (max-width: 640px) {
    .series-navigation {
        grid-template-columns: 1fr;
    }

    .start-here-grid {
        grid-template-columns: 1fr;
    }

    .contact-layout {
        gap: var(--space-6);
    }

    .contact-info {
        padding-top: 0;
    }
}

/* Reduce motion for accessibility */
@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }

    .reading-progress-bar {
        transition: none;
    }
}