/* ==========================================================================
   Design System Variables
   ========================================================================== */
:root {
    /* Base Theme */
    --c-primary: #511c75;
    --c-accent: #e68d4e;
    --c-highlight: #529e78;

    /* Color Palette - Light Theme */
    --c-bg: color-mix(in srgb, var(--c-primary) 24%, #f2f3f5);
    --c-text: #472340;
    --c-text-contrast: #130202;
    --c-highlight-bg: color-mix(in srgb, var(--c-highlight) 20%, #487083);

    /* Typography */
    --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'Cascadia Code', Consolas, 'Courier New', monospace;

    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 2.25rem;

    --leading-tight: 1.25;
    --leading-snug: 1.375;
    --leading-normal: 1.6;
    --leading-relaxed: 1.75;

    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-12: 3rem;
    --space-16: 4rem;

    /* Layout */
    --layout-max-width: 800px;
    --header-height: 4.5rem;

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

    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);

    color-scheme: light;
}

@media (prefers-color-scheme: dark) {
    :root {
        /* Color Palette - Dark Theme */
        --c-bg: color-mix(in srgb, var(--c-primary) 12%, #221325);
        --c-text: #94a3b8;
        --c-text-contrast: #d0d6dd;
        --c-highlight-bg: color-mix(in srgb, var(--c-highlight) 20%, #0f172a);

        color-scheme: dark;
    }
}

/* ==========================================================================
   Reset
   ========================================================================== */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-sans);
    line-height: var(--leading-normal);
    color: var(--c-text);
    background: var(--c-bg);
    transition: background-color var(--transition-fast), color var(--transition-fast);
}

/* ==========================================================================
   Layout
   ========================================================================== */
.inner {
    width: min(var(--layout-max-width), calc(100% - var(--space-8)));
    margin: 0 auto;
}

/* ==========================================================================
   Header
   ========================================================================== */
.site-header {
    border-bottom: 1px solid color-mix(in srgb, var(--c-accent) 20%, transparent);
    background: var(--c-bg);
    position: sticky;
    top: 0;
    z-index: 10;
    backdrop-filter: blur(8px);
    background: color-mix(in srgb, var(--c-bg) 85%, transparent);
}

.site-header .inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: var(--header-height);
}

.brand {
    color: var(--c-accent);
    text-decoration: none;
    font-weight: 700;
    font-family: var(--font-mono);
    font-size: var(--text-lg);
    letter-spacing: 0.03em;
    transition: opacity var(--transition-fast);
}

.brand:hover {
    opacity: 0.8;
}

.brand::first-letter {
    color: var(--c-accent);
}

nav .nav-link {
    margin-left: var(--space-6);
    color: var(--c-text);
    font-size: var(--text-base);
    font-weight: 500;
    letter-spacing: 0.05em;
    transition: color var(--transition-fast);
}

nav .nav-link:hover {
    color: var(--c-accent);
}

/* ==========================================================================
   ToC Dropdown
   ========================================================================== */
.toc-dropdown {
    position: relative;
    margin-left: var(--space-4);
    display: inline-block;
}

.toc-dropdown summary {
    color: var(--c-text);
    font-size: var(--text-base);
    font-weight: 500;
    letter-spacing: 0.05em;
    cursor: pointer;
    list-style: none;
    user-select: none;
    display: flex;
    align-items: center;
    gap: var(--space-1);
    transition: color var(--transition-fast);
}

.toc-chevron {
    display: inline-block;
    font-size: 0.9em;
    transition: transform var(--transition-fast);
}

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

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

.toc-dropdown summary:hover {
    color: var(--c-accent);
}

.toc-menu {
    position: absolute;
    right: 0;
    top: calc(100% + var(--space-2));
    background: var(--c-bg);
    border: 1px solid color-mix(in srgb, var(--c-accent) 20%, transparent);
    border-radius: var(--radius-md);
    min-width: 260px;
    max-height: 70vh;
    overflow-y: auto;
    z-index: 20;
    display: flex;
    flex-direction: column;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    padding: var(--space-2) 0;
}

.toc-item {
    display: block;
    padding: var(--space-2) var(--space-4);
    color: var(--c-text);
    font-size: var(--text-sm);
    text-decoration: none;
    font-family: var(--font-sans);
    transition: all var(--transition-fast);
}

.toc-item:hover {
    color: var(--c-accent);
    background: var(--c-highlight-bg);
}

.toc-h1 {
    padding-left: var(--space-4);
    font-weight: 600;
    color: var(--c-text-contrast);
}

.toc-h2 {
    padding-left: calc(var(--space-4) + var(--space-4));
}

.toc-h3 {
    padding-left: calc(var(--space-4) + var(--space-8));
    font-size: 0.8rem;
}

/* ==========================================================================
   Heading Anchors
   ========================================================================== */
.md-heading-anchor {
    opacity: 0;
    margin-left: var(--space-2);
    font-size: 0.75em;
    color: var(--c-accent);
    text-decoration: none;
    font-family: var(--font-mono);
    font-weight: normal;
    vertical-align: middle;
    transition: opacity var(--transition-fast);
}

h1:hover .md-heading-anchor,
h2:hover .md-heading-anchor,
h3:hover .md-heading-anchor,
h4:hover .md-heading-anchor,
h5:hover .md-heading-anchor,
h6:hover .md-heading-anchor,
.block-heading:hover .md-heading-anchor {
    opacity: 1;
}

/* ==========================================================================
   Typography & Prose
   ========================================================================== */
h1,
h2,
h3,
h4,
h5,
h6,
.block-heading {
    font-family: var(--font-sans);
    font-weight: 700;
    color: var(--c-text-contrast);
    line-height: var(--leading-tight);
    scroll-margin-top: calc(var(--header-height) + var(--space-4));
}

h1 {
    font-size: var(--text-2xl);
    margin: var(--space-4) 0 var(--space-2);
    letter-spacing: -0.01em;
}

h2 {
    font-size: var(--text-xl);
    margin: var(--space-4) 0 var(--space-2);
}

h3 {
    font-size: var(--text-lg);
    margin: var(--space-3) 0 var(--space-1);
}

/* Make bold and italic bright */
strong,
b {
    color: var(--c-text-contrast);
    font-weight: 700;
}

em,
i,
.block-quote {
    color: var(--c-text-contrast);
    font-style: italic;
}

/* Links */
a {
    color: var(--c-highlight);
    text-decoration: none;
    transition: color var(--transition-fast), filter var(--transition-fast);
}

a:hover {
    filter: brightness(0.8);
    text-decoration: underline;
}

@media (prefers-color-scheme: dark) {
    a:hover {
        filter: brightness(1.2);
    }
}

/* Markdown Markers */
.md-marker {
    color: var(--c-accent);
    font-family: var(--font-mono);
    font-style: normal;
    font-weight: normal;
}

/* Prose blocks */
.prose p,
.block-paragraph {
    margin: var(--space-3) 0;
    color: var(--c-text);
    text-align: justify;
}

.prose ul,
.prose ol,
.block-list {
    margin: var(--space-3) 0;
    color: var(--c-text);
}

ul.block-list,
ol.block-list,
.block-list {
    list-style: none;
    padding-left: 0;
}

.block-list li {
    margin: var(--space-2) 0;
    position: relative;
    padding-left: var(--space-6);
    text-align: justify;
}

.block-list li>.md-marker {
    position: absolute;
    left: 0;
    top: 0;
}

/* Blockquote */
.block-quote {
    border-left: 4px solid var(--c-accent);
    margin: var(--space-2) 0;
    padding: var(--space-2) var(--space-3) var(--space-2) 0;
    background: var(--c-highlight-bg);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    color: var(--c-text-contrast);
    font-style: italic;
}

.block-quote p {
    margin: var(--space-1) 0;
}

.block-quote p:first-child {
    margin-top: 0;
}

.block-quote p:last-child {
    margin-bottom: 0;
}

.md-blockquote-line {
    display: block;
}

/* Code Blocks */
.block-code {
    background: var(--c-highlight-bg);
    border: 1px solid color-mix(in srgb, var(--c-accent) 20%, transparent);
    padding: var(--space-3);
    border-radius: var(--radius-md);
    margin: var(--space-4) 0;
    overflow-x: auto;
}

.inline-code {
    font-family: var(--font-mono);
    font-size: 0.9em;
    background: var(--c-highlight-bg);
    color: var(--c-accent);
    padding: 0.2em 0.4em;
    border-radius: var(--radius-sm);
    border: 1px solid color-mix(in srgb, var(--c-accent) 20%, transparent);
}

.block-code code {
    font-family: var(--font-mono);
    color: var(--c-text);
    font-size: var(--text-sm);
    line-height: var(--leading-relaxed);
}

/* Math */
.inline-math {
    font-family: var(--font-mono);
    font-style: italic;
    color: var(--c-accent);
}

.block-math {
    font-family: var(--font-mono);
    font-style: italic;
    color: var(--c-accent);
    overflow-x: auto;
    padding: var(--space-3);
    background: var(--c-highlight-bg);
    border-radius: var(--radius-md);
    margin: var(--space-4) 0;
    white-space: pre;
    border: 1px solid color-mix(in srgb, var(--c-accent) 20%, transparent);
}

/* Horizontal Rule */
.block-hr {
    display: flex;
    align-items: center;
}

hr {
    all: unset;
    display: block;
    flex: 1;
    border-top: 1px solid var(--c-accent);
    margin: 0;
}

.block-hr>hr {
    margin: 0 0 0 var(--space-4);
}

/* Article List */
.article-list {
    list-style: none;
    padding: 0;
    margin: var(--space-4) 0;
}

.article-list li {
    margin: var(--space-2) 0;
    display: flex;
    justify-content: space-between;
    align-items: baseline;
}

.article-list a {
    font-size: var(--text-base);
    font-weight: 500;
}

.meta {
    color: var(--c-text);
    font-size: var(--text-sm);
    font-family: var(--font-mono);
}

.year-group {
    margin: var(--space-6) 0 var(--space-3);
}

.year-label {
    font-size: var(--text-sm);
    font-weight: 600;
    letter-spacing: 0.1em;
    color: var(--c-text);
    margin-bottom: var(--space-4);
}

.page-tree,
.page-tree-children {
    list-style: none;
    padding-left: 0;
    margin: 0;
}

.page-tree-children {
    padding-left: var(--space-4);
    margin-top: var(--space-2);
    border-left: 1px solid color-mix(in srgb, var(--c-accent) 20%, transparent);
    margin-left: var(--space-2);
}

.page-tree li {
    margin: var(--space-3) 0;
}

.page-tree-group {
    font-weight: 600;
    color: var(--c-text-contrast);
}