/* ===================================================================
   GWERN-INSPIRED MINIMAL CSS
   
   Design principles:
   - Strict monochrome palette (#000000, #FFFFFF, grays)
   - Maximum readability with generous whitespace
   - Mobile-first responsive design
   - No decorative elements - pure function
   - Print-friendly by default
   =================================================================== */

/* CSS Custom Properties for theming */
:root {
    /* Colors - Light Mode */
    --color-bg: #FFFFFF;
    --color-text: #000000;
    --color-text-muted: #666666;
    --color-border: #CCCCCC;
    --color-bg-alt: #F5F5F5;
    --color-link: #000000;
    --color-code-accent: #0000FF;
    
    /* Typography */
    --font-serif: 'Georgia', 'Times New Roman', serif;
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    --font-mono: 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', monospace;
    
    /* Sizing */
    --font-size-base: 18px;
    --line-height: 1.6;
    --content-width: 760px;
    --sidenote-width: 280px;
    --sidenote-gap: 40px;
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 2rem;
    --space-xl: 4rem;
    
    /* Transitions */
    --transition-speed: 150ms;
}

/* Dark mode overrides */
.dark-mode {
    --color-bg: #000000;
    --color-text: #FFFFFF;
    --color-text-muted: #999999;
    --color-border: #333333;
    --color-bg-alt: #0A0A0A;
    --color-link: #FFFFFF;
}

/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: var(--font-size-base);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

body {
    font-family: var(--font-serif);
    line-height: var(--line-height);
    color: var(--color-text);
    background-color: var(--color-bg);
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-sans);
    font-weight: 600;
    line-height: 1.2;
    margin-top: var(--space-lg);
    margin-bottom: var(--space-md);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 1.875rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--space-md);
    hanging-punctuation: first allow-end last;
}

/* Small caps for subtle emphasis */
.subtitle,
.experiment-meta,
cite {
    font-variant: small-caps;
    letter-spacing: 0.05em;
    font-size: 0.9em;
    color: var(--color-text-muted);
}

/* Links */
a {
    color: var(--color-link);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color var(--transition-speed);
}

a:hover {
    border-bottom-color: var(--color-border);
}

/* Navigation */
.site-nav {
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-md) 0;
    position: sticky;
    top: 0;
    background-color: var(--color-bg);
    z-index: 100;
    backdrop-filter: blur(10px);
}

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

.nav-home {
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: 1.125rem;
}

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

.nav-links a {
    font-family: var(--font-sans);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Theme toggle button */
.theme-toggle {
    background: none;
    border: 1px solid var(--color-border);
    padding: var(--space-xs) var(--space-sm);
    cursor: pointer;
    font-family: var(--font-sans);
    font-size: 0.75rem;
    color: var(--color-text);
    transition: all var(--transition-speed);
    border-radius: 2px;
}

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

.theme-icon::before {
    content: '☀';
}

.dark-mode .theme-icon::before {
    content: '☾';
}

/* Main content */
.content {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: var(--space-xl) var(--space-md);
}

/* Page header */
.page-header {
    margin-bottom: var(--space-xl);
    text-align: center;
}

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

/* Introduction section */
.intro-section {
    margin-bottom: var(--space-xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.intro-section p {
    margin-bottom: var(--space-lg);
}

/* Dropcap */
.dropcap {
    float: left;
    font-size: 4rem;
    line-height: 1;
    font-weight: 400;
    margin-right: var(--space-sm);
    margin-top: -0.1em;
    font-family: var(--font-sans);
}

/* Sections */
.section {
    margin: var(--space-xl) 0;
}

/* Experiment grid */
.experiment-grid {
    display: grid;
    gap: var(--space-lg);
    margin-top: var(--space-lg);
}

.experiment-card {
    border: 1px solid var(--color-border);
    padding: var(--space-lg);
    transition: all var(--transition-speed);
}

.experiment-card:hover {
    background-color: var(--color-bg-alt);
}

.experiment-card h3 {
    margin-top: 0;
    margin-bottom: var(--space-xs);
}

.read-more {
    font-family: var(--font-sans);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Collapsible sections */
.collapsible {
    border: 1px solid var(--color-border);
    margin-bottom: var(--space-md);
}

.collapsible summary {
    padding: var(--space-md);
    cursor: pointer;
    font-family: var(--font-sans);
    font-weight: 600;
    list-style: none;
    user-select: none;
    transition: background-color var(--transition-speed);
}

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

.collapsible summary::before {
    content: '▸';
    display: inline-block;
    margin-right: var(--space-sm);
    transition: transform var(--transition-speed);
}

.collapsible[open] summary::before {
    transform: rotate(90deg);
}

.collapsible summary:hover {
    background-color: var(--color-bg-alt);
}

.collapsible-content {
    padding: 0 var(--space-md) var(--space-md);
}

/* Blockquotes */
blockquote {
    margin: var(--space-lg) 0;
    padding-left: var(--space-lg);
    border-left: 3px solid var(--color-border);
    font-style: italic;
}

blockquote cite {
    display: block;
    text-align: right;
    margin-top: var(--space-sm);
    font-style: normal;
}

/* Lists */
ul, ol {
    margin-bottom: var(--space-md);
    padding-left: var(--space-lg);
}

li {
    margin-bottom: var(--space-xs);
}

/* Code */
code {
    font-family: var(--font-mono);
    font-size: 0.875em;
    background-color: var(--color-bg-alt);
    padding: 0.125em 0.25em;
    border-radius: 2px;
}

pre {
    background-color: var(--color-bg-alt);
    padding: var(--space-md);
    overflow-x: auto;
    margin-bottom: var(--space-md);
    border-radius: 2px;
}

pre code {
    background: none;
    padding: 0;
}

/* Dark mode code syntax accent */
.dark-mode pre .keyword,
.dark-mode pre .function {
    color: var(--color-code-accent);
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: var(--space-md);
    font-variant-numeric: tabular-nums;
}

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

th {
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

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

/* Images */
img {
    max-width: 100%;
    height: auto;
    display: block;
    margin: var(--space-lg) auto;
}

.dark-mode img:not([data-no-invert]) {
    filter: invert(1) hue-rotate(180deg);
}

figure {
    margin: var(--space-lg) 0;
}

figcaption {
    text-align: center;
    font-size: 0.875rem;
    color: var(--color-text-muted);
    margin-top: var(--space-sm);
    font-style: italic;
}

/* Footer */
.site-footer {
    border-top: 1px solid var(--color-border);
    padding: var(--space-lg) 0;
    text-align: center;
    font-family: var(--font-sans);
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

.site-footer a {
    color: var(--color-text-muted);
}

/* Sidenotes */
.sidenote-ref {
    vertical-align: super;
    font-size: 0.75em;
    font-weight: 600;
    cursor: pointer;
    user-select: none;
    padding: 0 0.125em;
}

.sidenote {
    float: right;
    clear: right;
    margin-right: calc(-1 * (var(--sidenote-width) + var(--sidenote-gap)));
    width: var(--sidenote-width);
    font-size: 0.875rem;
    line-height: 1.4;
    color: var(--color-text-muted);
    position: relative;
}

.sidenote-number {
    font-weight: 600;
}

/* Mobile sidenotes */
@media (max-width: 1400px) {
    .sidenote {
        float: none;
        margin: var(--space-sm) 0;
        width: 100%;
        background-color: var(--color-bg-alt);
        padding: var(--space-sm);
        border-radius: 2px;
        display: none;
    }
    
    .sidenote.active {
        display: block;
    }
}

/* Responsive adjustments */
@media (max-width: 768px) {
    :root {
        --font-size-base: 16px;
    }
    
    h1 { font-size: 2rem; }
    h2 { font-size: 1.5rem; }
    h3 { font-size: 1.25rem; }
    
    .nav-links {
        gap: var(--space-md);
    }
    
    .experiment-grid {
        grid-template-columns: 1fr;
    }
}

/* Print styles */
@media print {
    .site-nav,
    .site-footer,
    .theme-toggle {
        display: none;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.5;
        color: #000;
        background: #fff;
    }
    
    a {
        color: #000;
        text-decoration: underline;
    }
    
    .sidenote {
        float: none;
        margin: 0.5em 0;
        width: 100%;
        font-size: 10pt;
        page-break-inside: avoid;
    }
    
    h1, h2, h3, h4, h5, h6 {
        page-break-after: avoid;
    }
    
    blockquote, figure, table {
        page-break-inside: avoid;
    }
}

/* Utility classes */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.fade-in {
    animation: fadeIn var(--transition-speed) ease-in;
}