/* ==========================================================================
   BLOG POST — End2End Diffusion
   Editorial academic warmth. 640px reading column. Tufte sidenotes.
   ========================================================================== */

/* === CSS CUSTOM PROPERTIES === */
:root {
    /* Post layout */
    --post-content-width: 640px;
    --post-toc-width: 150px;
    --post-sidenote-width: 220px;

    /* Post-specific colors (light) */
    --post-bg: #FAFAFA;
    --post-surface: #F5F3EF;
    --post-surface-warm: #FDF8F0;
    --post-text: #1a1a1a;
    --post-text-secondary: #4a4a4a;
    --post-text-muted: #6b6b6b;
    --post-accent: #2563eb;
    --post-accent-hover: #1d4ed8;
    --post-border: #e5e2dd;
    --post-border-light: #f0eee6;
    --post-code-bg: #F9F7F3;
    --post-selection: #2563eb1a;

    /* Badge palette — warm academic mapping */
    --badge-research: #6a9bcc;
    --badge-research-bg: #e8f0f8;
    --badge-result: #788c5d;
    --badge-result-bg: #edf2e8;
    --badge-hypothesis: #7b7a8e;
    --badge-hypothesis-bg: #ededf2;
    --badge-framing: #cc785c;
    --badge-framing-bg: #f5ebe6;
    --badge-note: #d4a27f;
    --badge-note-bg: #f7f0e8;

    /* Typography */
    --post-font-body: 'Lora', Georgia, serif;
    --post-font-ui: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --post-font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
    --post-font-size: 18px;
    --post-line-height: 1.78;

    /* Spacing */
    --post-gap-xs: 0.25rem;
    --post-gap-sm: 0.5rem;
    --post-gap-md: 1rem;
    --post-gap-lg: 1.5rem;
    --post-gap-xl: 2rem;
    --post-gap-2xl: 3rem;
    --post-gap-3xl: 4.5rem;
}

/* Dark mode */
[data-theme="dark"] {
    --post-bg: #0a0a0a;
    --post-surface: #151515;
    --post-surface-warm: #1a1810;
    --post-text: #e8e6dc;
    --post-text-secondary: #b3b0a5;
    --post-text-muted: #8a8880;
    --post-accent: #60a5fa;
    --post-accent-hover: #93c5fd;
    --post-border: #2a2926;
    --post-border-light: #1f1e1b;
    --post-code-bg: #141310;
    --post-selection: #60a5fa1a;

    --badge-research: #7dafd6;
    --badge-research-bg: #1a2a38;
    --badge-result: #96ad7d;
    --badge-result-bg: #1a2518;
    --badge-hypothesis: #9e9db0;
    --badge-hypothesis-bg: #22222e;
    --badge-framing: #d9937d;
    --badge-framing-bg: #2e1f18;
    --badge-note: #dbb89a;
    --badge-note-bg: #2a2018;
}

/* === BASE === */
html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body.post-page {
    background: var(--post-bg);
    color: var(--post-text);
    font-family: var(--post-font-body);
    font-size: var(--post-font-size);
    line-height: var(--post-line-height);
    margin: 0;
    padding: 0;
    transition: background-color 0.3s ease, color 0.3s ease;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body.post-page ::selection {
    background: var(--post-selection);
}

/* === NAVIGATION === */
.post-nav {
    position: sticky;
    top: 0;
    z-index: 200;
    background: var(--post-bg);
    border-bottom: 1px solid var(--post-border);
    font-family: var(--post-font-ui);
    font-size: 0.875rem;
    padding: 0.75rem var(--post-gap-lg);
    display: flex;
    align-items: center;
    justify-content: space-between;
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    background: color-mix(in srgb, var(--post-bg) 85%, transparent);
}

.post-nav-breadcrumb {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--post-text-muted);
    min-width: 0;
}

.post-nav-breadcrumb a {
    color: var(--post-text-muted);
    text-decoration: none;
    transition: color 0.2s ease;
    white-space: nowrap;
}

.post-nav-breadcrumb a:hover {
    color: var(--post-accent);
}

.post-nav-breadcrumb .sep {
    opacity: 0.4;
    user-select: none;
}

.post-nav-breadcrumb .current {
    color: var(--post-text-secondary);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.post-nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-shrink: 0;
}

/* Theme toggle (reuse landing pattern) */
.post-nav .theme-toggle {
    background: none;
    border: none;
    font-size: 1.1rem;
    cursor: pointer;
    color: var(--post-text-muted);
    padding: 0.25rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color 0.2s ease;
    position: relative;
    width: 1.5rem;
    height: 1.5rem;
}

.post-nav .theme-toggle:hover {
    color: var(--post-text);
}

.post-nav .theme-toggle i {
    position: absolute;
    transition: opacity 0.3s ease, transform 0.3s ease;
}

.post-nav .theme-toggle .fa-sun {
    opacity: 1;
    transform: rotate(0deg);
}

.post-nav .theme-toggle .fa-moon {
    opacity: 0;
    transform: rotate(180deg);
}

[data-theme="dark"] .post-nav .theme-toggle .fa-sun {
    opacity: 0;
    transform: rotate(180deg);
}

[data-theme="dark"] .post-nav .theme-toggle .fa-moon {
    opacity: 1;
    transform: rotate(0deg);
}

/* === POST HEADER === */
.post-header {
    max-width: var(--post-content-width);
    margin: 0 auto;
    padding: var(--post-gap-2xl) var(--post-gap-lg) var(--post-gap-lg);
    border-bottom: none;
}

/* Decorative gradient rule — replaces plain border-bottom */
.post-header-rule {
    width: 80px;
    height: 1px;
    margin: var(--post-gap-md) 0;
    background: linear-gradient(
        90deg,
        var(--post-text-muted),
        var(--post-border),
        transparent
    );
}

/* Ornament after author name */
.post-header-ornament {
    display: inline-block;
    margin-left: 0.75rem;
    font-size: 0.85rem;
    color: var(--post-text-muted);
    opacity: 0.45;
    vertical-align: middle;
}

.post-meta {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-family: var(--post-font-ui);
    font-size: 0.8rem;
    color: var(--post-text-muted);
    margin-bottom: var(--post-gap-lg);
    flex-wrap: wrap;
}

.post-number {
    font-family: var(--post-font-mono);
    font-variant-numeric: tabular-nums;
    font-size: 0.8rem;
    letter-spacing: 0.02em;
    color: var(--post-text-muted);
}

.post-meta .dot {
    width: 3px;
    height: 3px;
    border-radius: 50%;
    background: var(--post-text-muted);
    opacity: 0.5;
}

/* Status badges */
/* Status badges — warm academic palette */
.post-status {
    font-family: var(--post-font-ui);
    font-size: 0.6875rem;
    font-weight: 500;
    text-transform: lowercase;
    letter-spacing: 0.02em;
    padding: 2px 8px;
    border-radius: 3px;
    line-height: 1.2;
}

.post-status--research {
    color: var(--badge-research);
    background: var(--badge-research-bg);
}

.post-status--hypothesis {
    color: var(--badge-hypothesis);
    background: var(--badge-hypothesis-bg);
}

.post-status--result {
    color: var(--badge-result);
    background: var(--badge-result-bg);
}

.post-status--framing {
    color: var(--badge-framing);
    background: var(--badge-framing-bg);
}

.post-status--note {
    color: var(--badge-note);
    background: var(--badge-note-bg);
}

.post-date {
    font-variant-numeric: tabular-nums;
}

.post-title {
    font-family: var(--post-font-body);
    font-size: 2.25rem;
    font-weight: 600;
    line-height: 1.25;
    color: var(--post-text);
    margin: 0 0 0.5rem 0;
    text-wrap: balance;
    letter-spacing: -0.015em;
}

.post-subtitle {
    font-family: var(--post-font-body);
    font-size: 1.2rem;
    font-weight: 400;
    font-style: italic;
    line-height: 1.5;
    color: var(--post-text-secondary);
    margin: 0 0 var(--post-gap-lg) 0;
}

.post-author {
    font-family: var(--post-font-ui);
    font-size: 0.9rem;
    color: var(--post-text-secondary);
}

.post-author a {
    color: var(--post-text-secondary);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 0.2s ease, color 0.2s ease;
}

.post-author a:hover {
    color: var(--post-accent);
    border-bottom-color: var(--post-accent);
}

.post-series {
    margin-top: var(--post-gap-md);
    font-family: var(--post-font-ui);
    font-size: 0.8rem;
    color: var(--post-text-muted);
}

.post-series a {
    color: var(--post-accent);
    text-decoration: none;
    font-weight: 500;
}

.post-series a:hover {
    text-decoration: underline;
}

/* === CONTENT LAYOUT === */
.post-layout {
    max-width: var(--post-content-width);
    margin: 0 auto;
    padding: var(--post-gap-2xl) var(--post-gap-lg);
}

body.post-page {
    overflow-x: hidden;
}

/* === TABLE OF CONTENTS (Fixed Left) === */
.post-toc {
    display: none;
}

@media (min-width: 1200px) {
    .post-toc {
        display: block;
        position: fixed;
        left: max(24px, calc(50% - var(--post-content-width) / 2 - var(--post-toc-width) - 60px));
        top: 80px;
        width: var(--post-toc-width);
        max-height: calc(100vh - 120px);
        overflow-y: auto;
        font-family: var(--post-font-ui);
        font-size: 0.78rem;
        line-height: 1.5;
        overscroll-behavior: contain;
    }

    .post-toc::-webkit-scrollbar {
        width: 0;
    }
}

.post-toc h4 {
    font-size: 0.65rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--post-text-muted);
    margin: 0 0 var(--post-gap-md) 0;
    padding-bottom: var(--post-gap-sm);
    border-bottom: 1px solid var(--post-border);
}

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

.post-toc li {
    margin-bottom: 0.4rem;
}

.post-toc li.toc-h3 {
    padding-left: 0.75rem;
}

.post-toc a {
    color: var(--post-text-muted);
    text-decoration: none;
    display: block;
    padding: 2px 0;
    transition: color 0.15s ease;
}

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

.post-toc a.active {
    color: var(--post-accent);
    font-weight: 600;
}

/* === MAIN ARTICLE CONTENT === */
.post-content {
    width: 100%;
}

/* Headings */
.post-content h2 {
    font-family: var(--post-font-body);
    font-size: 1.55rem;
    font-weight: 600;
    line-height: 1.3;
    color: var(--post-text);
    margin: var(--post-gap-3xl) 0 var(--post-gap-lg) 0;
    letter-spacing: -0.01em;
    padding-top: var(--post-gap-md);
}

.post-content h2:first-child {
    margin-top: 0;
}

.post-content h3 {
    font-family: var(--post-font-ui);
    font-size: 1.15rem;
    font-weight: 600;
    line-height: 1.35;
    color: var(--post-text);
    margin: var(--post-gap-xl) 0 var(--post-gap-md) 0;
}

/* Paragraphs */
.post-content p {
    margin: 0 0 var(--post-gap-lg) 0;
    font-size: 1.0625rem;
    color: var(--post-text-secondary);
    hanging-punctuation: first;
    text-wrap: pretty;
}

/* Lead paragraph (first paragraph, emphasized) */
.post-content .lead {
    font-size: 1.15rem;
    line-height: 1.85;
    color: var(--post-text);
}

/* Drop cap on lead paragraph */
.post-content .lead::first-letter {
    float: left;
    font-family: var(--post-font-body);
    font-size: 3.8em;
    font-weight: 400;
    line-height: 0.8;
    margin-right: 0.08em;
    margin-top: 0.05em;
    color: var(--post-accent);
}

/* Links */
.post-content a {
    color: var(--post-accent);
    text-decoration: none;
    border-bottom: 1px solid color-mix(in srgb, var(--post-accent) 30%, transparent);
    transition: border-color 0.2s ease;
}

.post-content a:hover {
    border-bottom-color: var(--post-accent);
}

/* Lists */
.post-content ul,
.post-content ol {
    margin: 0 0 var(--post-gap-lg) 0;
    padding-left: 1.5rem;
    font-size: 1.05rem;
    color: var(--post-text-secondary);
}

.post-content li {
    margin-bottom: var(--post-gap-sm);
}

.post-content li::marker {
    color: var(--post-text-muted);
}

/* Blockquotes */
.post-content blockquote {
    margin: var(--post-gap-xl) 0;
    padding: var(--post-gap-md) var(--post-gap-lg);
    border-left: 3px solid var(--post-accent);
    background: var(--post-surface-warm);
    border-radius: 0 4px 4px 0;
    font-style: italic;
    color: var(--post-text-secondary);
}

.post-content blockquote p {
    margin: 0;
    color: inherit;
}

.post-content blockquote cite {
    display: block;
    margin-top: var(--post-gap-sm);
    font-style: normal;
    font-family: var(--post-font-ui);
    font-size: 0.85rem;
    color: var(--post-text-muted);
}

/* Horizontal rules */
.post-content hr {
    border: none;
    height: 1px;
    background: var(--post-border);
    margin: var(--post-gap-2xl) 0;
}

/* Decorative section break */
.post-content hr.section-break {
    background: none;
    text-align: center;
    margin: var(--post-gap-3xl) 0;
}

.post-content hr.section-break::after {
    content: '* * *';
    color: var(--post-text-muted);
    font-size: 0.85rem;
    letter-spacing: 0.5em;
}

/* === SIDENOTES (Tufte-style) === */

/* Sidenote reference number in text */
.sidenote-ref {
    font-size: 0.7em;
    vertical-align: super;
    line-height: 0;
    color: var(--post-accent);
    cursor: pointer;
    font-family: var(--post-font-ui);
    font-weight: 600;
}

/* Mobile default: inline callout */
.sidenote {
    display: block;
    font-family: var(--post-font-ui);
    font-size: 0.84rem;
    line-height: 1.55;
    color: var(--post-text-muted);
    margin: var(--post-gap-md) 0;
    padding: var(--post-gap-sm) var(--post-gap-md);
    border-left: 2px solid var(--post-border);
    background: var(--post-surface);
    border-radius: 0 4px 4px 0;
}

.sidenote-number {
    font-weight: 600;
    color: var(--post-accent);
    margin-right: 0.3em;
    font-size: 0.75rem;
}

/* Desktop: right margin sidenotes — only when viewport has room */
@media (min-width: 1100px) {
    .post-content {
        position: relative;
    }

    .sidenote {
        position: absolute;
        right: calc(-1 * var(--post-sidenote-width) - 32px);
        width: var(--post-sidenote-width);
        margin: 0;
        padding: 0;
        background: none;
        border-left: 1px solid var(--post-border);
        border-radius: 0;
        padding-left: var(--post-gap-md);
        font-size: 0.8rem;
    }
}

/* === FIGURES === */
.post-content figure {
    margin: var(--post-gap-2xl) 0;
    padding: 0;
}

.post-content figure img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 4px;
}

.post-content figcaption {
    font-family: var(--post-font-ui);
    font-size: 0.85rem;
    line-height: 1.5;
    color: var(--post-text-muted);
    margin-top: var(--post-gap-sm);
    padding-top: var(--post-gap-sm);
    border-top: 1px solid var(--post-border-light);
}

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

/* Wide figure — breaks out of content column */
.post-content figure.figure-wide {
    width: calc(100% + 160px);
    margin-left: -80px;
    margin-right: -80px;
}

@media (max-width: 900px) {
    .post-content figure.figure-wide {
        width: 100%;
        margin-left: 0;
        margin-right: 0;
    }
}

/* === CODE === */

/* Inline code */
.post-content code {
    font-family: var(--post-font-mono);
    font-size: 0.88em;
    background: var(--post-code-bg);
    padding: 0.1em 0.35em;
    border-radius: 3px;
    color: var(--post-text);
    border: 1px solid var(--post-border-light);
}

/* Code blocks */
.post-content pre {
    margin: var(--post-gap-xl) 0;
    padding: var(--post-gap-lg);
    background: var(--post-code-bg);
    border: 1px solid var(--post-border);
    border-radius: 6px;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    position: relative;
}

.post-content pre code {
    background: none;
    border: none;
    padding: 0;
    font-size: 0.84rem;
    line-height: 1.6;
    color: var(--post-text-secondary);
}

/* Code language label */
.code-label {
    position: absolute;
    top: 0;
    right: 0;
    font-family: var(--post-font-ui);
    font-size: 0.65rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--post-text-muted);
    padding: 0.3em 0.7em;
    background: var(--post-border-light);
    border-radius: 0 6px 0 4px;
}

/* === CALLOUT BOXES === */
.post-callout {
    margin: var(--post-gap-xl) 0;
    padding: var(--post-gap-lg);
    border-radius: 6px;
    font-size: 0.95rem;
}

.post-callout-label {
    font-family: var(--post-font-ui);
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-bottom: var(--post-gap-sm);
}

.post-callout--finding {
    background: var(--post-surface-warm);
    border-left: 3px solid var(--post-accent);
}

.post-callout--finding .post-callout-label {
    color: var(--post-accent);
}

.post-callout--note {
    background: var(--post-surface);
    border: 1px solid var(--post-border);
}

.post-callout--note .post-callout-label {
    color: var(--post-text-muted);
}

/* === MATH (KaTeX overrides) === */
.post-content .katex-display {
    margin: var(--post-gap-xl) 0;
    overflow-x: auto;
    overflow-y: hidden;
    padding: var(--post-gap-sm) 0;
}

/* === TABLES === */
.post-content table {
    width: 100%;
    border-collapse: collapse;
    font-family: var(--post-font-ui);
    font-size: 0.9rem;
    margin: var(--post-gap-xl) 0;
}

.post-content th {
    text-align: left;
    font-weight: 600;
    color: var(--post-text);
    padding: var(--post-gap-sm) var(--post-gap-md);
    border-bottom: 2px solid var(--post-text);
}

.post-content td {
    padding: var(--post-gap-sm) var(--post-gap-md);
    border-bottom: 1px solid var(--post-border);
    color: var(--post-text-secondary);
}

/* === POST FOOTER === */
.post-footer {
    max-width: var(--post-content-width);
    margin: 0 auto;
    padding: var(--post-gap-xl) var(--post-gap-lg) var(--post-gap-3xl);
    border-top: 1px solid var(--post-border);
}

.post-footer-nav {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    font-family: var(--post-font-ui);
    font-size: 0.85rem;
    gap: var(--post-gap-xl);
}

.post-footer-link {
    color: var(--post-text-muted);
    text-decoration: none;
    transition: color 0.2s ease;
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
    max-width: 50%;
}

.post-footer-link:hover {
    color: var(--post-accent);
}

.post-footer-link .label {
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--post-text-muted);
}

.post-footer-link .title {
    color: var(--post-text-secondary);
    transition: color 0.2s ease;
}

.post-footer-link:hover .title {
    color: var(--post-accent);
}

.post-footer-link--next {
    text-align: right;
    margin-left: auto;
}

.post-footer-back {
    text-align: center;
    margin-top: var(--post-gap-2xl);
}

.post-footer-back a {
    font-family: var(--post-font-ui);
    font-size: 0.8rem;
    color: var(--post-text-muted);
    text-decoration: none;
    letter-spacing: 0.03em;
    transition: color 0.2s ease;
}

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

/* === RESPONSIVE === */

/* Tablet: hide TOC, center content */
@media (max-width: 1199px) {
    .post-toc {
        display: none;
    }

    .post-layout {
        max-width: var(--post-content-width);
    }
}

/* Mobile */
@media (max-width: 767px) {
    .post-header {
        padding: var(--post-gap-2xl) var(--post-gap-md) var(--post-gap-lg);
    }

    .post-title {
        font-size: 1.65rem;
    }

    .post-subtitle {
        font-size: 1.05rem;
    }

    .post-content .lead::first-letter {
        font-size: 3em;
    }

    .post-layout {
        padding: var(--post-gap-xl) var(--post-gap-md);
    }

    .post-content p,
    .post-content li {
        font-size: 1rem;
    }

    .post-content h2 {
        font-size: 1.35rem;
    }

    .post-content h3 {
        font-size: 1.05rem;
    }

    .post-footer {
        padding: var(--post-gap-lg) var(--post-gap-md) var(--post-gap-2xl);
    }

    .post-footer-nav {
        flex-direction: column;
        gap: var(--post-gap-lg);
    }

    .post-footer-link {
        max-width: 100%;
    }

    .post-footer-link--next {
        text-align: left;
        margin-left: 0;
    }

    .post-nav-breadcrumb .current {
        max-width: 120px;
    }
}

/* Small mobile */
@media (max-width: 400px) {
    .post-title {
        font-size: 1.45rem;
    }

    body.post-page {
        font-size: 16px;
    }
}

/* === PRINT === */
@media print {
    .post-nav,
    .post-toc,
    .post-footer-nav {
        display: none;
    }

    body.post-page {
        font-size: 11pt;
        color: #000;
        background: #fff;
    }

    .post-content a {
        color: #000;
        border-bottom: none;
    }

    .post-content a::after {
        content: ' (' attr(href) ')';
        font-size: 0.8em;
        color: #666;
    }

    .sidenote {
        font-size: 0.8em;
        border-left: 1px solid #ccc;
        padding-left: 0.5em;
        margin: 0.5em 0;
    }
}