/* Industrial/Brutalist Editorial System */

:root {
    /* Deep blue-tinted mechanical dark */
    --bg-base: oklch(0.18 0.01 250);
    --bg-surface: oklch(0.22 0.01 250);
    --bg-elevated: oklch(0.28 0.01 250);
    --border: oklch(0.35 0.01 250);
    --text-primary: oklch(0.95 0.01 250);
    --text-secondary: oklch(0.75 0.01 250);
    --text-muted: oklch(0.55 0.01 250);

    /* Safety-gear accents */
    --accent-amber: oklch(0.75 0.15 60);
    --accent-blue: oklch(0.70 0.12 250);
    --accent-green: oklch(0.70 0.15 150);
    --accent-purple: oklch(0.70 0.15 300);
    --accent-red: oklch(0.60 0.20 25);
    --accent-orange: oklch(0.65 0.18 45);

    --font-heading: 'Domine', serif;
    --font-body: 'Atkinson Hyperlegible Next', sans-serif;
    --font-mono: 'Courier Prime', monospace;

    /* Fluid type for headings */
    --text-xs: clamp(0.75rem, 1vw, 0.8rem);
    --text-sm: clamp(0.875rem, 1.2vw, 0.95rem);
    --text-base: clamp(1rem, 1.5vw, 1.1rem);
    --text-lg: clamp(1.25rem, 2vw, 1.4rem);
    --text-xl: clamp(1.5rem, 2.5vw, 1.8rem);
    --text-2xl: clamp(2rem, 4vw, 2.5rem);
    
    --sidebar-width: 300px;
    --ease-out: cubic-bezier(0.23, 1, 0.32, 1);
    --ease-in-out: cubic-bezier(0.77, 0, 0.175, 1);
    --transition-fast: 160ms var(--ease-out);
    --transition-base: 300ms var(--ease-out);
}

.light-mode {
    --bg-base: oklch(0.98 0.005 250);
    --bg-surface: oklch(0.96 0.005 250);
    --bg-elevated: oklch(0.93 0.01 250);
    --border: oklch(0.88 0.01 250);
    --text-primary: oklch(0.20 0.02 250);
    --text-secondary: oklch(0.40 0.02 250);
    --text-muted: oklch(0.55 0.02 250);

    --accent-amber: oklch(0.60 0.12 60);
    --accent-blue: oklch(0.55 0.15 250);
    --accent-green: oklch(0.50 0.15 150);
    --accent-purple: oklch(0.55 0.15 300);
    --accent-red: oklch(0.55 0.20 25);
    --accent-orange: oklch(0.60 0.18 45);
}

/* Base resets */
* { margin: 0; padding: 0; box-sizing: border-box; }
html, body { 
    overflow-x: hidden; 
    width: 100%; 
    position: relative; 
}
html { scroll-behavior: smooth; font-size: 16px; }
body { 
    background: var(--bg-base); 
    color: var(--text-primary); 
    font-family: var(--font-body); 
    line-height: 1.6;
    height: 100vh;
    display: flex;
    transition: background 300ms var(--ease-out), color 300ms var(--ease-out), border-color 300ms var(--ease-out);
}

/* Global Transition for smooth theme switching */
*, *::before, *::after {
    transition: background-color 300ms var(--ease-out), border-color 300ms var(--ease-out), color 300ms var(--ease-out), box-shadow 300ms var(--ease-out);
}

/* Custom Scrollbar Styling */
::-webkit-scrollbar {
    width: 6px;
}
::-webkit-scrollbar-track {
    background: transparent;
}
::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 0;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* Sidebar */
#sidebar {
    width: var(--sidebar-width);
    height: 100vh;
    background: var(--bg-surface);
    border-right: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    flex-direction: column;
    overflow: hidden; /* Prevent body scroll bleed */
    transition: transform 400ms var(--ease-out);
}

.sidebar-header { 
    padding: 1.5rem; 
    border-bottom: 1px solid var(--border); 
    background: var(--bg-elevated);
    flex-shrink: 0;
}
.brand { 
    font-family: var(--font-heading); 
    font-size: var(--text-xl); 
    font-weight: 700; 
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-primary);
}

.search-container { margin-top: 1rem; }
#search {
    width: 100%;
    background: var(--bg-base);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 0.8rem;
    font-family: var(--font-mono);
    font-size: var(--text-xs);
    border-radius: 0; /* Brutalist */
    outline: none;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}
#search:focus { border-color: var(--accent-amber); box-shadow: inset 4px 0 0 var(--accent-amber); }

#nav-content { 
    flex: 1; 
    overflow-y: auto; 
    padding: 1rem 0;
    scrollbar-width: thin;
    scrollbar-color: var(--border) transparent;
}
#nav-content details { 
    margin-bottom: 0.5rem; 
    border-bottom: 1px solid var(--border);
}
#nav-content summary { 
    font-family: var(--font-mono); 
    font-size: var(--text-sm);
    text-transform: uppercase;
    padding: 0.8rem 1.5rem; 
    cursor: pointer; 
    color: var(--text-secondary);
    font-weight: 700;
    list-style: none;
    transition: background-color var(--transition-fast), color var(--transition-fast);
}
#nav-content summary::-webkit-details-marker {
    display: none;
}
#nav-content summary::before {
    content: '▶';
    display: inline-block;
    margin-right: 0.5rem;
    font-size: 0.8em;
    transition: transform var(--transition-fast);
}
#nav-content details[open] summary::before {
    transform: rotate(90deg);
}
#nav-content summary:hover { color: var(--text-primary); background: var(--bg-elevated); }
#nav-content summary:active { background: var(--border); }

#nav-content ul { list-style: none; padding-left: 0; margin-top: 0.5rem; }
#nav-content li { margin-bottom: 0.2rem; }

#nav-content li a {
    display: block;
    padding: 0.6rem 1.5rem;
    font-family: var(--font-body);
    font-size: var(--text-sm);
    color: var(--text-secondary);
    text-decoration: none;
    transition: transform var(--transition-fast), background-color var(--transition-fast), color var(--transition-fast);
}
#nav-content li a:hover { 
    background: var(--bg-elevated); 
    color: var(--text-primary);
    transform: translateX(4px);
}
#nav-content li a:active {
    transform: translateX(2px) scale(0.98);
}
#nav-content li a.active {
    background: var(--bg-elevated);
    color: var(--text-primary);
    font-weight: 700;
    box-shadow: inset 3px 0 0 var(--accent-blue);
}

.sidebar-footer { 
    padding: 1.5rem; 
    border-top: 1px solid var(--border); 
    background: var(--bg-elevated);
}

.theme-slider-container { margin-top: 0.5rem; }

.theme-slider-alt {
    display: block;
    width: 100%;
    height: 32px;
    background: var(--bg-base);
    border: 1px solid var(--border);
    position: relative;
    cursor: pointer;
    overflow: hidden;
}

.slider-track {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: space-around;
    padding: 0 10px;
}

.slider-label {
    font-family: var(--font-mono);
    font-size: 0.6rem;
    font-weight: 700;
    color: var(--text-muted);
    z-index: 2;
    pointer-events: none;
    transition: color var(--transition-base);
}

.slider-thumb {
    position: absolute;
    top: 2px;
    left: 2px;
    width: calc(50% - 2px);
    height: calc(100% - 4px);
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    z-index: 1;
    transition: transform var(--transition-base), background-color var(--transition-base);
}

.theme-input:checked ~ .slider-track .slider-thumb {
    transform: translateX(100%);
    background: var(--accent-amber);
    border-color: var(--accent-amber);
}

.theme-input:checked ~ .slider-track .slider-label.light { color: var(--bg-base); }
.theme-input:not(:checked) ~ .slider-track .slider-label.dark { color: var(--text-primary); }

.theme-input { display: none; }

/* Main Content */
#content {
    flex: 1;
    overflow-y: auto;
    padding: 0 3rem 4rem 3rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative;
    scrollbar-width: thin;
    scrollbar-color: var(--border) transparent;
}

#progress-container {
    position: fixed;
    top: 0;
    right: 0;
    left: 300px; /* Sidebar width */
    height: 4px;
    background: transparent;
    z-index: 1000;
    pointer-events: none;
}

#progress-bar {
    height: 100%;
    width: 0%;
    background: var(--accent-blue);
    box-shadow: 0 0 15px var(--accent-blue);
    transition: width 150ms cubic-bezier(0.65, 0, 0.35, 1);
}

/* Sidebar Sub-topics */
.topic-list {
    margin-top: 0;
    margin-bottom: 0.5rem;
    padding-left: 2rem;
}

.topic-item {
    font-family: var(--font-mono);
    font-size: 0.65rem;
    color: var(--text-muted);
    padding: 0.3rem 0;
    cursor: pointer;
    transition: color var(--transition-fast), transform var(--transition-fast);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    display: block;
}
.topic-item::before { content: '→ '; opacity: 0.5; }
.topic-item:hover { 
    color: var(--text-primary); 
    background: color-mix(in oklch, var(--accent-blue) 5%, transparent);
}
.topic-item:active { transform: translateX(2px); }
.topic-item.active { 
    color: var(--accent-blue); 
    font-weight: 700; 
    background: color-mix(in oklch, var(--accent-blue) 12%, transparent);
    border-left: 3px solid var(--accent-blue);
    padding-left: 0.5rem;
    margin-left: -0.5rem;
    box-shadow: 2px 0 10px rgba(var(--accent-blue), 0.1);
}
.topic-item.active::before { opacity: 1; color: var(--accent-blue); }

#render-area {
    width: 100%;
    max-width: 800px;
}

#render-area.fade-in {
    animation: fadeIn 400ms var(--ease-out);
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(12px) scale(0.99); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

/* Typography in Content */
h1 { font-family: var(--font-heading); font-size: var(--text-2xl); line-height: 1.1; margin-bottom: 2rem; color: var(--text-primary); scroll-margin-top: 4rem; }
h2 { font-family: var(--font-heading); font-size: var(--text-xl); margin-top: 3.5rem; margin-bottom: 1.5rem; border-bottom: 2px solid var(--border); padding-bottom: 0.5rem; scroll-margin-top: 4rem; }
h3 { font-family: var(--font-heading); font-size: var(--text-lg); margin-top: 2.5rem; margin-bottom: 1rem; scroll-margin-top: 4rem; }
p { margin-bottom: 1.5rem; font-size: var(--text-base); max-width: 75ch; }
li { font-size: var(--text-base); max-width: 75ch; margin-bottom: 0.5rem; }
pre, code { font-family: var(--font-mono); font-size: var(--text-sm); }
pre { background: var(--bg-elevated); padding: 1rem; border: 1px solid var(--border); overflow-x: auto; }
code { background: var(--bg-elevated); padding: 0.2em 0.4em; }

/* Components */
.badge {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    font-weight: 700;
    padding: 0.2rem 0.5rem;
    display: inline-flex;
    align-items: center;
    gap: 4px;
    margin-right: 0.5rem;
    vertical-align: baseline;
    border: 1px solid;
    text-transform: uppercase;
}
.badge-sure { border-color: var(--accent-red); background: color-mix(in oklch, var(--accent-red) 15%, transparent); color: var(--text-primary); }
.badge-yield { border-color: var(--accent-orange); background: color-mix(in oklch, var(--accent-orange) 15%, transparent); color: var(--text-primary); }
.badge-pyq { border-color: var(--border); background: var(--bg-elevated); color: var(--text-secondary); }

/* Section Cards */
.section-card {
    margin: 3rem 0;
    padding: 2rem;
    border-top: 4px solid var(--accent-color);
    background: color-mix(in oklch, var(--accent-color) 5%, transparent);
    border-radius: 0;
}
.section-card h2, .section-card h3 { margin-top: 0; border: none; padding: 0; }
.section-card .section-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 1.5rem;
    font-family: var(--font-mono);
    font-size: var(--text-xs);
    text-transform: uppercase;
    font-weight: 700;
    color: var(--accent-color);
    letter-spacing: 0.05em;
}

.section-amber { --accent-color: var(--accent-amber); }
.section-blue { --accent-color: var(--accent-blue); }
.section-green { --accent-color: var(--accent-green); }
.section-purple { --accent-color: var(--accent-purple); }
.section-red { --accent-color: var(--accent-red); }

/* Analogy Blocks */
.analogy-block {
    margin: 2.5rem 0;
    padding: 2rem;
    background: transparent;
    border: 1px dashed var(--accent-amber);
    position: relative;
    font-family: var(--font-body);
}
.analogy-block::before {
    content: '[ANALOGY]';
    display: block;
    font-family: var(--font-mono);
    font-size: var(--text-xs);
    font-weight: 700;
    color: var(--accent-amber);
    margin-bottom: 1rem;
    letter-spacing: 0.05em;
}
.analogy-block p {
    font-style: italic;
    color: var(--text-primary);
    margin-bottom: 0;
}

/* Faithful ASCII Graphs */
.faithful-graph-container {
    margin: 3rem 0;
    border: 1px solid var(--border);
    background: var(--bg-surface);
}
.faithful-graph-caption {
    padding: 0.8rem 1rem;
    border-bottom: 1px solid var(--border);
    background: var(--bg-elevated);
    font-family: var(--font-mono);
    font-size: var(--text-xs);
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}
.blueprint-label {
    color: var(--accent-amber);
    font-weight: 700;
}
.faithful-graph-pre {
    margin: 0 !important;
    padding: 1.5rem !important;
    border: none !important;
    background: transparent !important;
    line-height: 1.3;
    overflow-x: auto;
}

/* Tables */
table { width: 100%; border-collapse: collapse; margin: 2.5rem 0; font-size: var(--text-sm); font-family: var(--font-body); }
th { 
    background: var(--bg-elevated); 
    text-align: left; 
    padding: 1rem; 
    font-family: var(--font-mono); 
    text-transform: uppercase;
    border-bottom: 2px solid var(--border);
    border-top: 1px solid var(--border);
}
td { padding: 1rem; border-bottom: 1px solid var(--border); }
tr:hover td { background: color-mix(in oklch, var(--bg-elevated) 50%, transparent); }

/* KaTeX */
.katex-display {
    padding: 2rem;
    background: var(--bg-surface);
    border-radius: 0;
    border: 1px solid var(--border);
    overflow-x: auto;
    margin: 2rem 0;
}

/* Mobile Bar */
#mobile-bar {
    display: none;
    height: 48px;
    background: var(--bg-elevated);
    border-bottom: 1px solid var(--border);
    padding: 0 0.4rem;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 1000;
}

#mobile-bar .brand {
    font-size: 0.9rem;
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    pointer-events: none;
}

#menu-toggle {
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 8px;
    display: flex;
    flex-direction: column;
    gap: 4px;
    z-index: 3000; /* Highest to remain clickable */
}

#menu-toggle span {
    display: block;
    width: 20px;
    height: 1.5px;
    background: var(--text-primary);
    transition: transform 300ms var(--ease-out), opacity 300ms var(--ease-out);
}

/* Hamburger to X Morph using body state */
body.sidebar-open #menu-toggle span:nth-child(1) { transform: translateY(5.5px) rotate(45deg); }
body.sidebar-open #menu-toggle span:nth-child(2) { opacity: 0; }
body.sidebar-open #menu-toggle span:nth-child(3) { transform: translateY(-5.5px) rotate(-45deg); }

/* Mobile Theme Slider */
.theme-slider {
    position: absolute;
    right: 0.4rem;
    top: 50%;
    transform: translateY(-50%);
    width: 40px;
    height: 20px;
    cursor: pointer;
}

.theme-slider .slider {
    position: absolute;
    inset: 0;
    background: var(--bg-base);
    border: 1px solid var(--border);
    transition: var(--transition-base);
}

.theme-slider .slider:before {
    content: "";
    position: absolute;
    height: 12px;
    width: 12px;
    left: 3px;
    bottom: 3px;
    background: var(--text-muted);
    transition: var(--transition-base);
}

.theme-input:checked + .slider { background: var(--bg-elevated); }
.theme-input:checked + .slider:before {
    transform: translateX(20px);
    background: var(--accent-amber);
}

@media (max-width: 768px) {
    body { flex-direction: column; }
    
    /* Auto-zoom prevention */
    #search, #nav-content li a, .topic-item { font-size: 16px !important; }
    
    #sidebar {
        position: fixed;
        left: 0;
        top: 0;
        transform: translateX(-100%);
        z-index: 2000;
        box-shadow: 10px 0 30px rgba(0,0,0,0.5);
        height: 100vh;
        visibility: hidden;
        pointer-events: none;
        transition: transform 400ms var(--ease-out), visibility 400ms var(--ease-out);
    }
    body.sidebar-open #sidebar { 
        transform: translateX(0); 
        visibility: visible;
        pointer-events: auto;
    }
    
    #sidebar-overlay {
        display: block;
        position: fixed;
        inset: 0;
        background: rgba(0,0,0,0.7);
        z-index: 1500;
        backdrop-filter: blur(4px);
        opacity: 0;
        pointer-events: none;
        transition: opacity 300ms var(--ease-out);
    }
    body.sidebar-open #sidebar-overlay {
        opacity: 1;
        pointer-events: auto;
    }
    
    #mobile-bar { 
        display: flex; 
        z-index: 1000;
    }
    
    #content { padding: 0 1rem 2rem 1rem; }
    
    #progress-container {
        position: fixed;
        top: 48px; 
        left: 0;
        width: 100%;
        z-index: 900; /* Behind header and sidebar */
    }
}

@media print {
    #sidebar, #mobile-bar { display: none !important; }
    #content { padding: 0; width: 100%; }
    #render-area { max-width: none; }
    .section-card { background: transparent !important; border: 1px solid #ccc; }
}