/* ================================================================
   OpenDoc Default Theme — Professional Publication
   Tufte-inspired layout · Dark mode · Margin notes
   ================================================================ */

/* ================================================================
   DESIGN TOKENS — Light Theme
   ================================================================ */

:root {
    /* Typography */
    --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    --font-serif: "Source Serif 4", Georgia, "Times New Roman", serif;
    --font-mono: "JetBrains Mono", "SF Mono", "Fira Code", Menlo, monospace;

    /* Colors — Light */
    --color-bg: #ffffff;
    --color-bg-alt: #f8f9fa;
    --color-surface: #ffffff;
    --color-text: #1a1a2e;
    --color-text-secondary: #4a4a68;
    --color-text-muted: #8b8ba3;
    --color-accent: #3b5bdb;
    --color-accent-hover: #2b4acb;
    --color-accent-soft: rgba(59, 91, 219, 0.08);
    --color-border: #e9ecef;
    --color-border-light: #f1f3f5;
    --color-code-bg: #1e1e2e;
    --color-code-text: #cdd6f4;
    --color-card-shadow: rgba(0, 0, 0, 0.04);
    --color-card-shadow-hover: rgba(0, 0, 0, 0.08);

    /* Margin note variants */
    --mn-note: #5c6bc0;
    --mn-note-bg: rgba(92, 107, 192, 0.06);
    --mn-widget: #00897b;
    --mn-widget-bg: rgba(0, 137, 123, 0.06);
    --mn-deepdive: #7e57c2;
    --mn-deepdive-bg: rgba(126, 87, 194, 0.06);
    --mn-aside: #78909c;
    --mn-aside-bg: rgba(120, 144, 156, 0.06);

    /* Layout */
    --width-body: 640px;
    --width-margin: 260px;
    --width-gap: 40px;
    --width-total: calc(var(--width-body) + var(--width-gap) + var(--width-margin));
    --spacing: 1.5rem;
    --header-height: 56px;

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

    /* Transitions */
    --t-fast: 0.15s ease;
    --t-med: 0.25s ease;
    --t-theme: 0.35s ease;
}

/* ================================================================
   DARK THEME
   ================================================================ */

[data-theme="dark"] {
    --color-bg: #0d1117;
    --color-bg-alt: #161b22;
    --color-surface: #161b22;
    --color-text: #e6edf3;
    --color-text-secondary: #b1bac4;
    --color-text-muted: #7d8590;
    --color-accent: #79a5f2;
    --color-accent-hover: #9bbdf7;
    --color-accent-soft: rgba(121, 165, 242, 0.1);
    --color-border: #21262d;
    --color-border-light: #1c2128;
    --color-code-bg: #161b22;
    --color-code-text: #e6edf3;
    --color-card-shadow: rgba(0, 0, 0, 0.2);
    --color-card-shadow-hover: rgba(0, 0, 0, 0.35);

    --mn-note: #8b9cf7;
    --mn-note-bg: rgba(139, 156, 247, 0.08);
    --mn-widget: #4db6ac;
    --mn-widget-bg: rgba(77, 182, 172, 0.08);
    --mn-deepdive: #b39ddb;
    --mn-deepdive-bg: rgba(179, 157, 219, 0.08);
    --mn-aside: #90a4ae;
    --mn-aside-bg: rgba(144, 164, 174, 0.08);
}

/* ================================================================
   RESET & BASE
   ================================================================ */

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    scroll-behavior: smooth;
    scroll-padding-top: calc(var(--header-height) + 1.5rem);
}

body {
    font-family: var(--font-sans);
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.65;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background var(--t-theme), color var(--t-theme);
}

::selection {
    background: var(--color-accent-soft);
    color: var(--color-text);
}

/* ================================================================
   READING PROGRESS BAR
   ================================================================ */

.reading-progress {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 2px;
    z-index: 1000;
    pointer-events: none;
}

.reading-progress-bar {
    height: 100%;
    width: 0%;
    background: var(--color-accent);
    transition: width 0.08s linear;
}

/* ================================================================
   SITE HEADER
   ================================================================ */

.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    height: var(--header-height);
    border-bottom: 1px solid var(--color-border);
    background: var(--color-bg);
    transition: background var(--t-theme), border-color var(--t-theme);
}

@supports (backdrop-filter: blur(12px)) {
    .site-header {
        background: color-mix(in srgb, var(--color-bg) 85%, transparent);
        backdrop-filter: blur(12px);
    }
}

.site-header nav {
    max-width: var(--width-total);
    margin: 0 auto;
    padding: 0 var(--spacing);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.site-title {
    font-size: 0.9375rem;
    font-weight: 700;
    color: var(--color-text);
    text-decoration: none;
    letter-spacing: -0.02em;
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 1.25rem;
}

.nav-links {
    display: flex;
    gap: 1.25rem;
}

.nav-links a {
    color: var(--color-text-muted);
    text-decoration: none;
    font-size: 0.8125rem;
    font-weight: 500;
    transition: color var(--t-fast);
}

.nav-links a:hover {
    color: var(--color-text);
}

/* Private page lock icon */
.nav-private {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
}

.lock-icon {
    opacity: 0.35;
    flex-shrink: 0;
    vertical-align: middle;
}

/* Theme toggle */
.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 34px;
    height: 34px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background: transparent;
    color: var(--color-text-muted);
    cursor: pointer;
    transition: all var(--t-fast);
}

.theme-toggle:hover {
    color: var(--color-text);
    border-color: var(--color-text-muted);
}

[data-theme="light"] .icon-moon,
[data-theme="dark"] .icon-sun {
    display: none;
}

[data-theme="light"] .icon-sun,
[data-theme="dark"] .icon-moon {
    display: block;
}

/* ================================================================
   MAIN LAYOUT
   ================================================================ */

main {
    max-width: var(--width-total);
    margin: 0 auto;
    padding: 3rem var(--spacing);
    width: 100%;
    flex: 1;
}

/* ================================================================
   POST — HERO HEADER
   ================================================================ */

.post-hero {
    padding: 4rem 0 3rem;
    margin-bottom: 3rem;
    position: relative;
}

/* Animated divider line — spans the full Tufte layout width */
.post-hero::after {
    content: "";
    display: block;
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: min(var(--width-total), calc(100% - 2 * var(--spacing)));
    height: 1px;
    background: linear-gradient(
        90deg,
        transparent 0%,
        var(--color-border) 15%,
        var(--color-accent) 50%,
        var(--color-border) 85%,
        transparent 100%
    );
    opacity: 1;
    transition: opacity 0.5s ease, transform 0.5s ease;
}

/* When scrolled past the hero, the line fades and lifts */
.post-hero.scrolled-past::after {
    opacity: 0;
    transform: translateX(-50%) scaleX(0.3);
}

.post-hero-inner {
    max-width: var(--width-body);
    margin: 0 auto;
    padding: 0 var(--spacing);
}

.post-title {
    font-size: 2.75rem;
    font-weight: 800;
    letter-spacing: -0.035em;
    line-height: 1.15;
    margin: 0.75rem 0 0;
    color: var(--color-text);
}

.post-lead {
    font-family: var(--font-serif);
    font-size: 1.25rem;
    line-height: 1.6;
    color: var(--color-text-secondary);
    margin-top: 1.25rem;
    font-style: italic;
}

.post-meta {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 1.5rem;
    font-size: 0.8125rem;
    color: var(--color-text-muted);
}

.post-author {
    font-weight: 600;
    color: var(--color-text-secondary);
}

.meta-sep {
    opacity: 0.4;
}

.reading-time {
    font-variant-numeric: tabular-nums;
}

.post-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.post-tags a {
    display: inline-block;
    padding: 0.2rem 0.6rem;
    font-size: 0.6875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-accent);
    background: var(--color-accent-soft);
    border-radius: 999px;
    text-decoration: none;
    transition: all var(--t-fast);
}

.post-tags a:hover {
    background: var(--color-accent);
    color: var(--color-bg);
}

/* ================================================================
   POST — TUFTE BODY LAYOUT
   ================================================================ */

.post-body {
    max-width: var(--width-total);
    margin: 0 auto;
    padding: 0 var(--spacing);
}

.tufte-layout {
    position: relative;
}

.tufte-layout > .content {
    max-width: var(--width-body);
}

/* ================================================================
   SCROLL TOC (left gutter on desktop)
   ================================================================ */

.scroll-toc {
    display: none;
}

@media (min-width: 1200px) {
    .scroll-toc {
        display: block;
        position: fixed;
        left: max(1rem, calc((100vw - var(--width-total)) / 2 - 200px));
        top: calc(var(--header-height) + 2rem);
        width: 160px;
    }

    .scroll-toc-inner {
        max-height: calc(100vh - var(--header-height) - 4rem);
        overflow-y: auto;
    }

    .scroll-toc-inner::-webkit-scrollbar {
        width: 0;
    }

    .scroll-toc-label {
        display: block;
        font-size: 0.625rem;
        font-weight: 600;
        text-transform: uppercase;
        letter-spacing: 0.1em;
        color: var(--color-text-muted);
        margin-bottom: 0.75rem;
    }

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

    .scroll-toc .toc a {
        display: block;
        padding: 0.2rem 0 0.2rem 0.75rem;
        font-size: 0.6875rem;
        line-height: 1.5;
        color: var(--color-text-muted);
        text-decoration: none;
        border-left: 1.5px solid transparent;
        transition: all var(--t-fast);
    }

    .scroll-toc .toc a:hover {
        color: var(--color-text-secondary);
    }

    .scroll-toc .toc a.active {
        color: var(--color-accent);
        border-left-color: var(--color-accent);
    }

    .scroll-toc .toc ul ul a {
        padding-left: 1.25rem;
        font-size: 0.625rem;
    }
}

/* ================================================================
   CONTENT TYPOGRAPHY
   ================================================================ */

.content {
    font-family: var(--font-serif);
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--color-text);
}

.content h1, .content h2, .content h3, .content h4, .content h5, .content h6 {
    font-family: var(--font-sans);
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.3;
    color: var(--color-text);
}

.content h1 {
    font-size: 2rem;
    margin: 3rem 0 1rem;
}

.content h2 {
    font-size: 1.5rem;
    margin: 2.75rem 0 0.75rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--color-border-light);
    position: relative;
}

/* Extend the h2 divider line into the right margin on desktop */
@media (min-width: 1101px) {
    .tufte-layout .content h2::after {
        content: "";
        position: absolute;
        bottom: -1px;
        left: 100%;
        width: calc(var(--width-gap) + var(--width-margin));
        height: 1px;
        background: var(--color-border-light);
    }
}

.content h3 {
    font-size: 1.1875rem;
    margin: 2rem 0 0.5rem;
}

.content h4 {
    font-size: 1rem;
    margin: 1.5rem 0 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    font-size: 0.8125rem;
    color: var(--color-text-secondary);
}

.content p {
    margin-bottom: 1.375rem;
}

.content a {
    color: var(--color-accent);
    text-decoration: underline;
    text-decoration-color: color-mix(in srgb, var(--color-accent) 30%, transparent);
    text-underline-offset: 2px;
    transition: text-decoration-color var(--t-fast);
}

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

.content strong {
    font-weight: 600;
    color: var(--color-text);
}

.content em {
    font-style: italic;
}

.content ul, .content ol {
    margin-bottom: 1.375rem;
    padding-left: 1.5rem;
}

.content li {
    margin-bottom: 0.375rem;
}

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

.content hr {
    border: none;
    border-top: 1px solid var(--color-border);
    margin: 3rem 0;
}

/* Blockquotes */
.content blockquote {
    margin: 1.75rem 0;
    padding: 1rem 1.5rem;
    border-left: 3px solid var(--color-accent);
    background: var(--color-bg-alt);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    color: var(--color-text-secondary);
    font-style: italic;
}

.content blockquote p:last-child {
    margin-bottom: 0;
}

/* ================================================================
   CODE BLOCKS
   ================================================================ */

/* Inline code */
.content code {
    font-family: var(--font-mono);
    font-size: 0.84em;
    padding: 0.2em 0.4em;
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: 4px;
    color: var(--color-text);
    word-break: break-word;
}

/* Pygments .highlight wrapper — neutralise its background so our pre controls it */
.content .highlight {
    background: transparent !important;
    margin: 0;
    padding: 0;
}

/* Fenced / block code */
.content pre {
    background: var(--color-code-bg);
    color: var(--color-code-text);
    padding: 0.75rem 1rem;
    border-radius: 6px;
    overflow-x: auto;
    overflow-y: hidden;
    margin: 1.5rem 0;
    line-height: 1.55;
    border: 1px solid rgba(255, 255, 255, 0.06);
    -webkit-overflow-scrolling: touch;
}

[data-theme="dark"] .content pre {
    border-color: rgba(255, 255, 255, 0.04);
}

.content pre code {
    background: none;
    border: none;
    padding: 0;
    font-size: 0.8125rem;
    color: inherit;
    word-break: normal;
}

/* ================================================================
   TABLES
   ================================================================ */

.content table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.75rem 0;
    font-family: var(--font-sans);
    font-size: 0.875rem;
    border-radius: var(--radius-md);
    overflow: hidden;
    border: 1px solid var(--color-border);
}

.content th, .content td {
    padding: 0.625rem 1rem;
    text-align: left;
}

.content th {
    font-weight: 600;
    font-size: 0.6875rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-text-muted);
    background: var(--color-bg-alt);
    border-bottom: 1px solid var(--color-border);
}

.content td {
    border-bottom: 1px solid var(--color-border-light);
}

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

/* ================================================================
   IMAGES & MEDIA
   ================================================================ */

.content img,
.content video {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 2rem auto;
    border-radius: var(--radius-md);
    box-shadow: 0 2px 12px var(--color-card-shadow);
}

/* Image caption: ![alt](url) followed by *caption text* */
.content img + em,
.content p > img + br + em,
.content .media-caption {
    display: block;
    text-align: center;
    font-family: var(--font-sans);
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    margin: -1rem auto 2rem;
    max-width: 80%;
    line-height: 1.5;
}

/* GIF indicator */
.content img[src$=".gif"] {
    box-shadow: 0 2px 12px var(--color-card-shadow);
}

/* Full-bleed images: use alt text containing "full" */
.content img[alt*="full"] {
    max-width: calc(100% + 4rem);
    margin-left: -2rem;
    margin-right: -2rem;
    border-radius: 0;
}

/* ================================================================
   MARGIN NOTES — Text-level Teasers + Breakout Card / Bottom Sheet
   ================================================================ */

/* --- Sidenote block container --- */
.sidenote-block {
    position: relative;
    margin: 0.75rem 0;
    clear: both;
}

/* (Number badge and chevron removed from HTML output) */

/* --- Marginnote panel --- */
.marginnote {
    font-family: var(--font-sans);
    font-size: 0.875rem;
    line-height: 1.6;
    color: var(--color-text-secondary);
}

/* ---- Teaser header (collapsed): bare text link ---- */
.marginnote-header {
    display: flex;
    align-items: baseline;
    gap: 0.4rem;
    cursor: pointer;
    padding: 0.2rem 0;
    background: none;
    border: none;
    border-radius: 0;
    box-shadow: none;
    transition: color var(--t-fast);
    user-select: none;
    font-family: var(--font-sans);
}

.marginnote-header:hover {
    background: none;
    box-shadow: none;
    transform: none;
}

.marginnote-header:hover .marginnote-title {
    color: var(--color-accent);
}

.marginnote-header:active {
    transform: none;
}

.marginnote-label {
    display: none; /* Hidden in teaser — shown in the open card */
}

.marginnote-title {
    font-size: 0.6875rem;
    font-weight: 500;
    color: var(--color-text-muted);
    line-height: 1.5;
    transition: color var(--t-fast);
    text-decoration: none;
}

/* Body — hidden by default */
.marginnote-body {
    display: none;
}

/* Close: backdrop click + Escape key */

/* --- Variant accent colors (used by the open card) --- */
.marginnote--sidenote { --mn-accent: var(--mn-note); }
.marginnote--widget   { --mn-accent: var(--mn-widget); }
.marginnote--deepdive { --mn-accent: var(--mn-deepdive); }
.marginnote--aside    { --mn-accent: var(--mn-aside); }

/* --- Variant label colors (visible in the open card) --- */
.marginnote--sidenote .marginnote-label { color: var(--mn-note); background: var(--mn-note-bg); }
.marginnote--widget .marginnote-label   { color: var(--mn-widget); background: var(--mn-widget-bg); }
.marginnote--deepdive .marginnote-label { color: var(--mn-deepdive); background: var(--mn-deepdive-bg); }
.marginnote--aside .marginnote-label    { color: var(--mn-aside); background: var(--mn-aside-bg); }

/* ================================================================
   BACKDROP OVERLAY (shared desktop + mobile)
   ================================================================ */

.sidenote-backdrop {
    position: fixed;
    inset: 0;
    z-index: 199;
    background: rgba(0, 0, 0, 0.3);
    opacity: 0;
    transition: opacity 0.3s ease;
    pointer-events: none;
}

.sidenote-backdrop.is-visible {
    opacity: 1;
    pointer-events: auto;
}

@supports (backdrop-filter: blur(6px)) {
    .sidenote-backdrop.is-visible {
        backdrop-filter: blur(6px);
    }
}

/* ================================================================
   DESKTOP: Margin Text Teasers + Floating Breakout Card
   ================================================================ */

@media (min-width: 1101px) {

    /* --- Teaser: text links in the right margin --- */
    .sidenote-block {
        float: right;
        clear: right;
        width: var(--width-margin);
        margin-right: calc(-1 * (var(--width-margin) + var(--width-gap)));
        margin-top: 0;
        margin-bottom: 0.25rem;
        margin-left: 1rem;
        padding-left: 0.75rem;
        border-left: 1.5px solid transparent;
        transition: border-color var(--t-fast);
    }

    .sidenote-block:hover {
        border-left-color: var(--color-border);
    }

    .marginnote-header {
        padding: 0.15rem 0;
    }

    .marginnote-title {
        font-size: 0.6875rem;
        line-height: 1.45;
    }

    /* --- Breakout card (open state): clean minimal panel --- */
    .sidenote-block.is-open {
        float: none;
        width: auto;
        margin: 0;
        padding-left: 0;
        border-left: none;
        position: fixed;
        z-index: 200;
        max-height: calc(100vh - var(--header-height) - 3rem);
        overflow-y: auto;
        overscroll-behavior: contain;
    }

    .sidenote-block.is-open .marginnote {
        background: var(--color-bg);
        border: 1px solid var(--color-border);
        border-radius: var(--radius-md);
        box-shadow: 0 8px 32px rgba(0, 0, 0, 0.08);
        animation: breakout-enter 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    }

    [data-theme="dark"] .sidenote-block.is-open .marginnote {
        box-shadow: 0 8px 32px rgba(0, 0, 0, 0.35);
    }

    @keyframes breakout-enter {
        from { opacity: 0; transform: translateY(8px); }
        to   { opacity: 1; transform: translateY(0); }
    }

    /* Header: minimal title bar */
    .sidenote-block.is-open .marginnote-header {
        display: flex;
        align-items: baseline;
        padding: 1rem 1.25rem 0.625rem;
        cursor: default;
        gap: 0.5rem;
        border-bottom: 1px solid var(--color-border-light);
    }

    .sidenote-block.is-open .marginnote-header:hover .marginnote-title {
        color: var(--color-text);
    }

    .sidenote-block.is-open .marginnote-label {
        display: none;
    }

    .sidenote-block.is-open .marginnote-title {
        font-size: 0.875rem;
        font-weight: 600;
        color: var(--color-text);
        flex: 1;
        min-width: 0;
    }

    /* Body */
    .sidenote-block.is-open .marginnote-body {
        display: block;
        padding: 1rem 1.25rem 1.25rem;
    }

    /* Thin scrollbar */
    .sidenote-block.is-open::-webkit-scrollbar {
        width: 3px;
    }

    .sidenote-block.is-open::-webkit-scrollbar-thumb {
        background: var(--color-border);
        border-radius: 2px;
    }
}

/* ================================================================
   MOBILE/TABLET: Inline Text Teasers + Bottom Sheet
   ================================================================ */

@media (max-width: 1100px) {

    /* --- Teaser: inline text link with subtle left border --- */
    .sidenote-block {
        margin: 0.75rem 0;
        padding-left: 0.75rem;
        border-left: 1.5px solid var(--color-border-light);
    }

    .marginnote-title {
        font-size: 0.75rem;
    }

    /* --- Bottom sheet (open state): clean minimal panel --- */
    .sidenote-block.is-open {
        position: fixed;
        bottom: 0;
        left: 0;
        right: 0;
        top: auto;
        margin: 0;
        padding-left: 0;
        border-left: none;
        z-index: 200;
        border-radius: var(--radius-md) var(--radius-md) 0 0;
        background: var(--color-bg);
        box-shadow: 0 -4px 24px rgba(0, 0, 0, 0.1);
        max-height: 85vh;
        overflow-y: auto;
        overscroll-behavior: contain;
        animation: sheet-enter 0.3s cubic-bezier(0.16, 1, 0.3, 1);
        border-top: 1px solid var(--color-border);
    }

    [data-theme="dark"] .sidenote-block.is-open {
        box-shadow: 0 -4px 24px rgba(0, 0, 0, 0.4);
    }

    @keyframes sheet-enter {
        from { transform: translateY(100%); }
        to   { transform: translateY(0); }
    }

    /* Drag handle */
    .sidenote-block.is-open::before {
        content: "";
        display: block;
        width: 32px;
        height: 3px;
        border-radius: 2px;
        background: var(--color-border);
        margin: 0.625rem auto 0;
    }

    /* Header: minimal title bar */
    .sidenote-block.is-open .marginnote-header {
        display: flex;
        align-items: baseline;
        padding: 0.625rem 1.25rem 0.5rem;
        cursor: default;
        gap: 0.5rem;
        border-bottom: 1px solid var(--color-border-light);
    }

    .sidenote-block.is-open .marginnote-header:hover .marginnote-title {
        color: var(--color-text);
    }

    .sidenote-block.is-open .marginnote-label {
        display: none;
    }

    .sidenote-block.is-open .marginnote-title {
        font-size: 0.875rem;
        font-weight: 600;
        color: var(--color-text);
        flex: 1;
        min-width: 0;
    }

    .sidenote-block.is-open .marginnote-body {
        display: block;
        padding: 1rem 1.25rem 1.25rem;
    }
}

/* ================================================================
   MARGIN NOTE — Inner Content Styles (shared)
   ================================================================ */

.marginnote-body p {
    margin-bottom: 0.625rem;
    font-family: var(--font-sans);
    font-size: 0.875rem;
    line-height: 1.65;
}

.marginnote-body p:last-child {
    margin-bottom: 0;
}

.marginnote-body img {
    max-width: 100%;
    border-radius: var(--radius-sm);
    margin: 0.75rem 0;
    box-shadow: none;
}

.marginnote-body table {
    font-size: 0.8125rem;
    width: 100%;
}

.marginnote-body pre {
    font-size: 0.8125rem;
    padding: 1rem;
    overflow-x: auto;
    border-radius: var(--radius-md);
}

.marginnote-body ul, .marginnote-body ol {
    padding-left: 1.25rem;
    margin-bottom: 0.625rem;
}

.marginnote-body li {
    margin-bottom: 0.25rem;
    font-size: 0.875rem;
}

.marginnote-body code {
    font-size: 0.8125rem;
}

.marginnote-body strong {
    color: var(--color-text);
}

.marginnote-body h1,
.marginnote-body h2,
.marginnote-body h3,
.marginnote-body h4 {
    font-family: var(--font-sans);
    color: var(--color-text);
    font-weight: 600;
    margin: 1rem 0 0.5rem;
}

/* Divider inside notes */
.marginnote-body hr {
    border: none;
    border-top: 1px solid var(--color-border-light);
    margin: 1rem 0;
}

/* ================================================================
   WIDGET INTERACTIVE ELEMENTS
   Theme-aware button/input styling for embedded widgets
   ================================================================ */

.marginnote-body button,
.sidenote-block button {
    font-family: var(--font-sans);
    font-size: 0.8125rem;
    padding: 0.4rem 0.85rem;
    border: 1px solid var(--color-border);
    border-radius: 999px;
    background: var(--color-bg-alt);
    color: var(--color-text);
    cursor: pointer;
    transition: all var(--t-fast);
}

.marginnote-body button:hover,
.sidenote-block button:hover {
    background: var(--color-accent-soft);
    border-color: var(--color-accent);
    color: var(--color-accent);
}

.marginnote-body button:active,
.sidenote-block button:active {
    transform: scale(0.97);
}

.marginnote-body input[type="range"],
.sidenote-block input[type="range"] {
    accent-color: var(--color-accent);
    width: 100%;
}

.marginnote-body canvas,
.sidenote-block canvas {
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-border);
    background: var(--color-code-bg);
}

/* No body scroll lock — the card/sheet is independently scrollable
   via overflow-y: auto + overscroll-behavior: contain on .sidenote-block.is-open */

/* ================================================================
   PAGE ARTICLE (non-post pages)
   ================================================================ */

.page-article {
    max-width: var(--width-body);
    margin: 0 auto;
}

.page-article h1 {
    font-size: 2.25rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    margin-bottom: 2rem;
}

/* ================================================================
   COLLECTION INDEX
   ================================================================ */

.collection-index {
    max-width: var(--width-body);
    margin: 0 auto;
}

/* Grid layout needs wider container for multi-column cards */
.collection-index:has(.layout-grid) {
    max-width: var(--width-total);
}

.collection-header {
    margin-bottom: 3rem;
}

.collection-header h1 {
    font-size: 2.25rem;
    font-weight: 800;
    letter-spacing: -0.03em;
}

.collection-subtitle {
    color: var(--color-text-muted);
    font-size: 1.0625rem;
    margin-top: 0.5rem;
}

/* ── Timeline layout (default — chronological list) ───────────── */

.layout-timeline {
    display: flex;
    flex-direction: column;
    gap: 0;
}

/* ── Grid layout (responsive cards) ───────────────────────────── */

.layout-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

a.grid-card {
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    background: var(--color-surface);
    text-decoration: none;
    color: inherit;
    transition: all var(--t-med);
}

a.grid-card:hover {
    border-color: var(--color-accent);
    box-shadow: 0 4px 20px var(--color-card-shadow-hover);
    transform: translateY(-2px);
}

.grid-card-title {
    font-size: 1.125rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.3;
    color: var(--color-text);
    margin: 0;
}

.grid-card-excerpt {
    color: var(--color-text-secondary);
    font-family: var(--font-serif);
    font-size: 0.875rem;
    line-height: 1.6;
    margin-top: 0.625rem;
    flex: 1;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.grid-card-footer {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-top: 1rem;
    padding-top: 0.75rem;
    border-top: 1px solid var(--color-border-light);
    font-size: 0.75rem;
    color: var(--color-text-muted);
}

.grid-card-tags {
    display: flex;
    gap: 0.375rem;
    flex-wrap: wrap;
}

.grid-tag {
    font-size: 0.625rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-accent);
    background: var(--color-accent-soft);
    padding: 0.1rem 0.4rem;
    border-radius: 999px;
}

/* ── Minimal layout (dense title list) ────────────────────────── */

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

.layout-minimal li {
    display: flex;
    align-items: baseline;
    gap: 1rem;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--color-border-light);
}

.layout-minimal li:last-child {
    border-bottom: none;
}

.layout-minimal time {
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    min-width: 6.5rem;
    flex-shrink: 0;
}

.layout-minimal a {
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--color-text);
    text-decoration: none;
    transition: color var(--t-fast);
}

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

a.post-card {
    display: block;
    padding: 1.75rem 1.5rem;
    margin: 0 -1.5rem;
    border-radius: var(--radius-lg);
    text-decoration: none;
    color: inherit;
    transition: all var(--t-med);
}

a.post-card:hover {
    background: var(--color-bg-alt);
    box-shadow: 0 2px 16px var(--color-card-shadow-hover);
    transform: translateY(-1px);
}

.post-card h2 {
    font-size: 1.375rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin: 0.5rem 0 0;
    line-height: 1.3;
    color: var(--color-text);
}

.post-card-meta {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 0.75rem;
    color: var(--color-text-muted);
}

.post-card-tags span {
    font-size: 0.625rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-accent);
    background: var(--color-accent-soft);
    padding: 0.1rem 0.4rem;
    border-radius: 999px;
}

.post-card-excerpt {
    color: var(--color-text-secondary);
    font-family: var(--font-serif);
    font-size: 0.9375rem;
    line-height: 1.6;
    margin-top: 0.5rem;
}

.post-card-read {
    display: inline-block;
    margin-top: 0.75rem;
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--color-accent);
}

.empty-state {
    color: var(--color-text-muted);
    font-style: italic;
}

/* ================================================================
   ARCHIVE
   ================================================================ */

.archive-year h2 {
    font-size: 1.125rem;
    margin-bottom: 0.75rem;
    color: var(--color-text-muted);
    font-weight: 600;
    border: none;
    padding-bottom: 0;
}

.archive-year ul {
    list-style: none;
    padding: 0;
    margin-bottom: 2rem;
}

.archive-year li {
    display: flex;
    gap: 1rem;
    padding: 0.375rem 0;
}

.archive-year time {
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    min-width: 4rem;
}

/* Post list simple (tags, archive) */
.post-list-simple {
    list-style: none;
    padding: 0;
}

.post-list-simple li {
    display: flex;
    gap: 1rem;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--color-border-light);
}

.post-list-simple time {
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    min-width: 6rem;
}

/* Tags index */
.tag-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: 0.625rem;
}

.tag-item {
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    padding: 0.4rem 0.8rem;
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: 999px;
    font-size: 0.8125rem;
    color: var(--color-text);
    text-decoration: none;
    transition: all var(--t-fast);
}

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

.tag-count {
    font-size: 0.6875rem;
    color: var(--color-text-muted);
}

.back-link {
    margin-top: 2rem;
}

.back-link a {
    font-size: 0.875rem;
    color: var(--color-text-muted);
    text-decoration: none;
}

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

/* ================================================================
   CODE COPY BUTTON
   ================================================================ */

.code-block-wrapper {
    position: relative;
}

.copy-btn {
    position: absolute;
    top: 0.6rem;
    right: 0.6rem;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    padding: 0;
    border: none;
    border-radius: 4px;
    background: transparent;
    color: rgba(255, 255, 255, 0.25);
    cursor: pointer;
    transition: color 0.15s ease, background 0.15s ease;
    opacity: 0;
    z-index: 2;
}

.code-block-wrapper:hover .copy-btn,
.code-tabs:hover .copy-btn {
    opacity: 1;
}

.copy-btn:hover {
    background: rgba(255, 255, 255, 0.08);
    color: rgba(255, 255, 255, 0.7);
}

.copy-btn.copied {
    color: #4ade80;
    background: rgba(74, 222, 128, 0.08);
    opacity: 1;
}

/* ================================================================
   TABBED CODE BLOCKS
   ================================================================ */

.code-tabs {
    margin: 1.5rem 0;
    border-radius: 6px;
    overflow: hidden;
    background: var(--color-code-bg);
    border: 1px solid rgba(255, 255, 255, 0.06);
}

[data-theme="dark"] .code-tabs {
    border-color: rgba(255, 255, 255, 0.04);
}

/* Tab navigation bar */
.code-tabs-nav {
    display: flex;
    gap: 0;
    background: rgba(0, 0, 0, 0.15);
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    padding: 0 0.125rem;
}

.code-tabs-nav::-webkit-scrollbar {
    display: none;
}

/* Individual tab button */
.code-tab {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.375rem 0.75rem;
    font-family: var(--font-mono);
    font-size: 0.7rem;
    font-weight: 400;
    letter-spacing: 0.01em;
    color: rgba(255, 255, 255, 0.4);
    background: none;
    border: none;
    border-bottom: 2px solid transparent;
    cursor: pointer;
    white-space: nowrap;
    transition: color 0.15s ease, border-color 0.15s ease;
    margin-bottom: -1px;
}

.code-tab:hover {
    color: rgba(255, 255, 255, 0.75);
}

.code-tab.active {
    color: rgba(255, 255, 255, 0.9);
    border-bottom-color: var(--color-accent);
}

/* Tab content panels */
.code-tab-panel {
    display: none;
}

.code-tab-panel.active {
    display: block;
}

/* Code blocks inside tabs — seamless with the container */
.code-tab-panel pre {
    margin: 0;
    border: none;
    border-radius: 0;
    background: transparent;
    padding: 0.625rem 1rem;
}

.code-tab-panel .highlight {
    margin: 0;
    padding: 0;
    background: transparent !important;
}

/* ================================================================
   LATEX MATH (KaTeX) — Academic Paper Quality
   ================================================================ */

/* --- Inline math ------------------------------------------------ */
/* Blend seamlessly with body text (Source Serif is our body serif) */
.katex {
    font-size: 1em;
}

/* KaTeX colours follow the page theme */
.katex .base {
    color: var(--color-text);
}

/* --- Display equations ------------------------------------------ */
/* Centred with generous vertical breathing room, like a real paper */
.math-display {
    position: relative;
    margin: 1.75rem 0;
    padding: 0.25rem 0;
    text-align: center;
    overflow-x: auto;
    overflow-y: hidden;
    -webkit-overflow-scrolling: touch;
}

/* Kill KaTeX's own display margins — we handle spacing ourselves */
.math-display .katex-display {
    margin: 0;
    padding: 0;
}

/* Display equations slightly larger than surrounding text */
.math-display .katex {
    font-size: 1.1em;
}

/* --- Equation numbering ----------------------------------------- */
/* If data-equation-number is set, show it right-aligned */
.math-display[data-equation-number]::after {
    content: "(" attr(data-equation-number) ")";
    position: absolute;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    font-family: var(--font-serif);
    font-size: 0.9rem;
    color: var(--color-text-secondary);
}

/* --- Scrollable overflow for wide equations --------------------- */
.katex-display {
    overflow-x: auto;
    overflow-y: hidden;
    padding: 0.125rem 0;
}

/* --- Theorem / Definition / Proof environments ------------------ */
/* Academic-style blocks for formal mathematical writing */
.theorem, .definition, .lemma, .proposition, .corollary, .remark, .proof {
    margin: 1.75rem 0;
    padding: 1rem 1.25rem;
    border-left: 3px solid var(--color-border);
    background: transparent;
}

.theorem-head, .definition-head, .lemma-head, .proposition-head,
.corollary-head, .remark-head, .proof-head {
    font-weight: 600;
    font-family: var(--font-sans);
    font-size: 0.875rem;
    letter-spacing: 0.02em;
    text-transform: uppercase;
    margin-bottom: 0.5rem;
    color: var(--color-text-secondary);
}

.theorem       { border-left-color: var(--color-accent); }
.definition    { border-left-color: #e67e22; }
.lemma         { border-left-color: #27ae60; }
.proposition   { border-left-color: #8e44ad; }
.proof         { border-left-color: var(--color-text-muted); }
.proof-head    { font-style: italic; text-transform: none; }

/* QED symbol at end of proof */
.proof-qed {
    text-align: right;
    margin-top: 0.5rem;
    color: var(--color-text-muted);
}

.proof-qed::after {
    content: "\25A0"; /* ■ */
    font-size: 0.7rem;
}

/* ================================================================
   FOOTER
   ================================================================ */

footer {
    border-top: 1px solid var(--color-border);
    padding: 2rem var(--spacing);
    background: var(--color-bg);
    transition: background var(--t-theme), border-color var(--t-theme);
}

.footer-inner {
    max-width: var(--width-body);
    margin: 0 auto;
    text-align: center;
    color: var(--color-text-muted);
    font-size: 0.75rem;
}

footer a {
    color: var(--color-text-muted);
    text-decoration: underline;
    text-decoration-color: color-mix(in srgb, var(--color-text-muted) 30%, transparent);
    text-underline-offset: 2px;
}

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

/* ================================================================
   GENERIC LINKS (outside .content)
   ================================================================ */

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color var(--t-fast);
}

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

/* ================================================================
   RESPONSIVE
   ================================================================ */

@media (max-width: 768px) {
    .site-header nav {
        padding: 0 1rem;
    }

    .nav-links {
        gap: 0.75rem;
    }

    .nav-links a {
        font-size: 0.75rem;
    }

    main {
        padding: 2rem 1rem;
    }

    .post-hero {
        padding: 2.5rem 0 2rem;
    }

    .post-hero-inner {
        padding: 0 1rem;
    }

    .post-title {
        font-size: 1.875rem;
    }

    .post-lead {
        font-size: 1.0625rem;
    }

    .post-body {
        padding: 0 1rem;
    }

    .content {
        font-size: 1.0625rem;
    }

    .content h2 {
        font-size: 1.3125rem;
    }

    .content img[alt*="full"] {
        max-width: calc(100% + 2rem);
        margin-left: -1rem;
        margin-right: -1rem;
    }

    a.post-card {
        margin: 0 -1rem;
        padding: 1.25rem 1rem;
    }
}

@media (max-width: 480px) {
    .post-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.25rem;
    }

    .meta-sep {
        display: none;
    }
}

/* ── TERMINAL WIDGET ────────────────────────────────────────── */
/* Usage: <div class="opendoc-terminal" data-mode="shell"></div>   */

.opendoc-terminal {
    position: relative;
    width: 100%;
    height: 400px;
    display: flex;
    flex-direction: column;
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid var(--color-border);
    background: var(--color-code-bg, #0d1117);
    margin: 1.5rem 0;
}

.opendoc-terminal-toolbar {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.4rem 0.75rem;
    background: rgba(0, 0, 0, 0.2);
    border-bottom: 1px solid var(--color-border);
    font-size: 0.8125rem;
    font-family: var(--font-mono, 'JetBrains Mono', 'Fira Code', monospace);
    flex-shrink: 0;
}

.opendoc-terminal-status {
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.opendoc-terminal-status::before {
    content: "";
    display: inline-block;
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: #7d8590;
    transition: background 0.2s ease;
}

.opendoc-terminal-status[data-status="connecting"]         { color: #d29922; }
.opendoc-terminal-status[data-status="connecting"]::before { background: #d29922; }
.opendoc-terminal-status[data-status="connected"]          { color: #3fb950; }
.opendoc-terminal-status[data-status="connected"]::before  { background: #3fb950; }
.opendoc-terminal-status[data-status="disconnected"]          { color: #f85149; }
.opendoc-terminal-status[data-status="disconnected"]::before  { background: #f85149; }
.opendoc-terminal-status[data-status="error"]          { color: #f85149; }
.opendoc-terminal-status[data-status="error"]::before  { background: #f85149; }

.opendoc-terminal-mode {
    color: var(--color-muted, #7d8590);
    font-size: 0.6875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.opendoc-terminal-reconnect {
    margin-left: auto;
    padding: 0.2rem 0.5rem;
    font-size: 0.6875rem;
    font-family: inherit;
    background: rgba(121, 165, 242, 0.08);
    color: var(--color-accent, #79a5f2);
    border: 1px solid rgba(121, 165, 242, 0.2);
    border-radius: 4px;
    cursor: pointer;
    transition: background 0.15s ease, border-color 0.15s ease;
}

.opendoc-terminal-reconnect:hover {
    background: rgba(121, 165, 242, 0.18);
    border-color: rgba(121, 165, 242, 0.45);
}

.opendoc-terminal-screen {
    flex: 1;
    min-height: 0;
    padding: 0.25rem;
}

.opendoc-terminal-screen .xterm {
    height: 100%;
}

.opendoc-terminal-screen .xterm-viewport {
    overflow-y: auto;
}

/* Mobile */
@media (max-width: 768px) {
    .opendoc-terminal {
        margin-left: -1rem;
        margin-right: -1rem;
        border-radius: 0;
        border-left: none;
        border-right: none;
    }
}