/* ==========================================================================
   VISReg Project Page — Adapted from iREPA / paper-layout.css
   ========================================================================== */

/* === CSS CUSTOM PROPERTIES === */
:root {
    --layout-toc-width: 150px;
    --layout-content-width: 720px;
    --layout-side-gap: 256px;

    --bg-page: #ffffff;
    --text-primary: #1a1a1a;
    --text-secondary: #444;
    --text-muted: #666;
    --accent: #2563eb;
    --border-light: #e5e5e5;

    --font-serif: 'Lora', 'Bitstream Charter', Georgia, serif;
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --text-base: 18px;
    --leading-relaxed: 1.75;

    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
}

/* === BASE === */
*, *::before, *::after { box-sizing: border-box; }

body {
    background-color: var(--bg-page);
    font-family: var(--font-serif);
    font-size: var(--text-base);
    line-height: var(--leading-relaxed);
    color: var(--text-primary);
    margin: 0;
    padding: 0;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

img { max-width: 100%; height: auto; display: block; }

/* === TOP NAVIGATION === */
.top-nav {
    background: #fff;
    border-bottom: 1px solid var(--border-light);
    padding: 12px 0;
    position: sticky;
    top: 0;
    z-index: 200;
}

.top-nav-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.top-nav a {
    color: var(--text-primary);
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    font-family: var(--font-sans);
}

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

.top-nav .nav-back i { margin-right: 8px; opacity: 0.5; }

.top-nav .nav-links { display: flex; gap: 20px; }
.top-nav .nav-links a { color: var(--text-muted); font-size: 14px; }

/* === HEADER / HERO === */
.header-wrapper {
    border-bottom: 1px solid #e5e2dd;
    padding: 40px 20px 30px;
}

.central-header {
    max-width: 1000px;
    margin: 0 auto;
}

.title-section {
    text-align: center;
    margin-bottom: 20px;
}

.title-section h1 {
    font-size: 2.2em;
    line-height: 1.2;
    margin: 0 0 0.2em;
    color: var(--text-primary);
}

.title-section h2 {
    font-size: 1.4em;
    line-height: 1.3;
    color: #333;
    margin: 0;
    font-weight: 400;
}

.venue-badge {
    display: inline-block;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    font-family: var(--font-sans);
    font-size: 0.8rem;
    font-weight: 600;
    padding: 4px 14px;
    border-radius: 20px;
    margin-top: 8px;
    letter-spacing: 0.03em;
}

/* Authors */
.authors {
    text-align: center;
    margin: 16px 0 20px;
    line-height: 2.2;
}

.authors a {
    color: var(--text-primary);
    font-size: 1.05rem;
    white-space: nowrap;
}

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

.affiliations {
    font-size: 0.95rem;
    color: var(--text-muted);
    margin-top: 4px;
}

/* TL;DR */
.central-header .tldr-section {
    max-width: 720px;
    margin: 0 auto 24px;
    text-align: left !important;
    font-size: 1.02rem;
    color: var(--text-secondary);
    line-height: 1.7;
    background: #ffffff !important;
    border: 2px solid #c5cad3 !important;
    border-radius: 10px;
    padding: 20px 26px;
    box-shadow: 0 2px 6px rgba(0,0,0,0.08);
}

.central-header .tldr-section p {
    margin: 0;
    text-align: left !important;
}

.tldr-label {
    font-weight: 700;
    color: var(--accent);
    font-family: var(--font-sans);
    font-size: 0.88rem;
    letter-spacing: 0.02em;
    margin-right: 4px;
}

/* Hero: key points + image */
.hero-section {
    display: flex;
    gap: 30px;
    align-items: flex-start;
    margin-top: 20px;
}

.key-points { flex: 1; }

.key-point {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    margin-bottom: 14px;
}

.key-point-icon {
    width: 28px;
    height: 28px;
    flex-shrink: 0;
    margin-top: 2px;
    opacity: 0.8;
}

.key-point-text {
    font-size: 0.95rem;
    line-height: 1.55;
    color: var(--text-secondary);
}

.key-point-text strong { color: var(--accent); }

.hero-media {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero-media img {
    max-width: 100%;
    border-radius: 6px;
}

/* Buttons row */
.button-row {
    display: flex;
    gap: 10px;
    margin-top: 18px;
    flex-wrap: wrap;
}

.button-row a.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    background: #fef3cd;
    color: var(--text-primary);
    border: 1.5px solid #dfc36a;
    border-radius: 50px;
    padding: 8px 20px;
    font-weight: 500;
    font-size: 0.92rem;
    font-family: var(--font-sans);
    text-decoration: none;
    transition: all 0.2s ease;
    box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}

.button-row a.button i {
    font-size: 1.1em;
    line-height: 1;
    vertical-align: middle;
}

.button-row a.button span {
    line-height: 1;
    vertical-align: middle;
}

.button-row a.button:hover {
    background: #fce8a6;
    border-color: #c9a84a;
    box-shadow: 0 3px 8px rgba(0,0,0,0.12);
    text-decoration: none;
}

/* === MAIN CONTENT === */
.content {
    max-width: var(--layout-content-width);
    margin: 0 auto;
    padding: var(--space-xl) 20px;
}

.content h2 {
    font-size: 1.6rem;
    margin: var(--space-2xl) 0 var(--space-lg);
    line-height: 1.3;
}

.content h3 {
    font-size: 1.3rem;
    margin: var(--space-xl) 0 var(--space-md);
    line-height: 1.4;
}

.content p {
    margin: 0 0 var(--space-lg);
    font-size: 1.05rem;
    line-height: 1.8;
}

.content ul, .content ol {
    margin: 0 0 var(--space-lg) var(--space-lg);
}

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

/* === KEY FINDINGS === */
.key-findings {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
    margin: var(--space-xl) 0;
    padding: var(--space-lg);
    background: #f8f9fa;
    border-radius: 8px;
    border: 1px solid var(--border-light);
}

.key-findings-title {
    font-family: var(--font-sans);
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin: 0 0 var(--space-sm);
}

.key-finding {
    display: flex;
    align-items: flex-start;
    gap: 14px;
}

.key-finding-number {
    flex-shrink: 0;
    width: 32px;
    height: 32px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.9rem;
    font-weight: 700;
    font-family: var(--font-sans);
}

.key-finding-text {
    font-size: 0.98rem;
    line-height: 1.6;
    color: var(--text-secondary);
}

.key-finding-text strong { color: var(--text-primary); }

/* === FIGURES === */
figure {
    width: 100%;
    margin: var(--space-xl) 0;
}

figure img {
    width: 80%;
    max-width: 560px;
    margin: 0 auto;
    border-radius: 4px;
}

figcaption {
    font-family: var(--font-sans);
    font-size: 0.88rem;
    color: var(--text-muted);
    margin-top: var(--space-sm);
    line-height: 1.55;
}

/* Figure size variants */
figure.fig-wide img {
    width: 100%;
    max-width: 700px;
}

figure.fig-small img {
    width: 55%;
    max-width: 380px;
}

/* Placeholder images */
.placeholder-img {
    width: 100%;
    background: linear-gradient(135deg, #e8eaf6, #f3e5f5);
    border: 2px dashed #b0b0b0;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #888;
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-style: italic;
    min-height: 200px;
}

.placeholder-img.tall { min-height: 300px; }
.placeholder-img.short { min-height: 150px; }

/* === TABLES === */
.table-wrapper {
    margin: var(--space-xl) 0;
    overflow-x: auto;
}

.table-wrapper table {
    width: 100%;
    border-collapse: collapse;
    font-family: var(--font-sans);
    font-size: 0.88rem;
}

.table-wrapper th {
    background: #f8f9fa;
    font-weight: 600;
    text-align: left;
    padding: 10px 12px;
    border-bottom: 2px solid var(--border-light);
}

.table-wrapper td {
    padding: 8px 12px;
    border-bottom: 1px solid #eee;
}

.table-wrapper tr:hover { background: #fafbfc; }

.table-wrapper .best { font-weight: 700; color: var(--accent); }
.table-wrapper .second { font-weight: 600; text-decoration: underline; }

.table-caption {
    font-family: var(--font-sans);
    font-size: 0.88rem;
    color: var(--text-muted);
    margin-top: 8px;
    line-height: 1.5;
}

/* Real tables */
.table-container {
    margin: var(--space-xl) 0;
    overflow-x: auto;
}

.table-container table {
    width: 100%;
    border-collapse: collapse;
    font-family: var(--font-sans);
    font-size: 0.88rem;
}

.table-container th {
    background: #f8f9fa;
    font-weight: 600;
    text-align: center;
    padding: 10px 14px;
    border-bottom: 2px solid var(--border-light);
}

.table-container th:first-child {
    text-align: left;
}

.table-container td {
    padding: 8px 14px;
    border-bottom: 1px solid #eee;
    text-align: center;
}

.table-container td:first-child {
    text-align: left;
    font-weight: 500;
}

.table-container tr:hover { background: #fafbfc; }

.table-container .highlight-row {
    background: rgba(37, 99, 235, 0.08);
}

.table-container .highlight-row:hover {
    background: rgba(37, 99, 235, 0.12);
}

.table-container .highlight-col {
    background: rgba(37, 99, 235, 0.08);
}

.table-container .fail {
    color: #dc2626;
}

.table-container .fail-row {
    color: var(--text-muted);
}

.table-container .table-caption {
    font-family: var(--font-sans);
    font-size: 0.88rem;
    color: var(--text-muted);
    margin-bottom: 10px;
    line-height: 1.55;
}

/* Placeholder table */
.placeholder-table {
    width: 100%;
    background: #f8f9fa;
    border: 2px dashed #b0b0b0;
    border-radius: 8px;
    padding: 30px;
    text-align: center;
    color: #888;
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-style: italic;
    margin: var(--space-xl) 0;
}

/* === CODE BLOCK === */
.code-block {
    background: #1e1e2e;
    color: #cdd6f4;
    border-radius: 8px;
    padding: 20px 24px;
    overflow-x: auto;
    font-family: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
    font-size: 0.85rem;
    line-height: 1.65;
    margin: var(--space-xl) 0;
}

.code-block pre {
    margin: 0;
    padding: 0;
    background: none;
    font-family: inherit;
    font-size: inherit;
    line-height: inherit;
    white-space: pre;
}

.code-block code {
    font-family: inherit;
    font-size: inherit;
    background: none;
    padding: 0;
}

.code-block .comment { color: #6c7086; }
.code-block .keyword { color: #cba6f7; }
.code-block .function { color: #89b4fa; }
.code-block .string { color: #a6e3a1; }
.code-block .number { color: #fab387; }
.code-block .operator { color: #89dceb; }

.code-title {
    font-family: var(--font-sans);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

/* === BIBTEX === */
.bibtex-section {
    margin: var(--space-2xl) 0;
}

.bibtex-container {
    position: relative;
    background: #f5f5f5;
    border-radius: 8px;
    border: 1px solid var(--border-light);
    padding: 20px;
    overflow-x: auto;
}

.bibtex-container pre {
    margin: 0;
    font-family: 'JetBrains Mono', 'Fira Code', monospace;
    font-size: 0.82rem;
    line-height: 1.6;
    color: var(--text-secondary);
    white-space: pre-wrap;
    word-break: break-word;
}

.copy-btn {
    position: absolute;
    top: 12px;
    right: 12px;
    background: #fff;
    border: 1px solid #ddd;
    border-radius: 6px;
    padding: 6px 14px;
    font-size: 0.8rem;
    font-family: var(--font-sans);
    cursor: pointer;
    transition: all 0.2s;
    color: var(--text-secondary);
}

.copy-btn:hover { background: #f0f0f0; border-color: #bbb; }
.copy-btn.copied { background: #d4edda; border-color: #a3d9b1; color: #155724; }

/* === STICKY TOC === */
.toc-container {
    display: none;
}

@media (min-width: 1200px) {
    .toc-container {
        display: block;
        position: fixed;
        left: calc(50% - var(--layout-content-width)/2 - var(--layout-toc-width) - var(--layout-side-gap));
        top: 120px;
        width: var(--layout-toc-width);
        font-family: var(--font-sans);
        font-size: 0.85rem;
        line-height: 1.5;
        opacity: 0;
        transition: opacity 0.3s ease;
        z-index: 100;
    }

    .toc-container.visible { opacity: 1; }

    .toc-container h4 {
        font-size: 0.75rem;
        font-weight: 600;
        text-transform: uppercase;
        letter-spacing: 0.05em;
        color: var(--text-primary);
        margin: 0 0 12px;
    }

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

    .toc-container li { margin-bottom: 8px; }

    .toc-container a {
        color: var(--text-muted);
        text-decoration: none;
        transition: color 0.2s ease;
    }

    .toc-container a:hover { color: var(--accent); }
    .toc-container a.active { color: var(--accent); font-weight: 500; }
}

/* === SCROLL OFFSET FOR STICKY NAV === */
section[id] {
    scroll-margin-top: 80px;
}

/* === SECTION DIVIDERS === */
.section-divider {
    border: none;
    border-top: 1px solid var(--border-light);
    margin: var(--space-2xl) 0;
}

/* === FOOTER === */
.page-footer {
    border-top: 1px solid var(--border-light);
    padding: 24px 20px;
    text-align: center;
    font-family: var(--font-sans);
    font-size: 0.85rem;
    color: var(--text-muted);
}

.page-footer a { color: var(--text-muted); }
.page-footer a:hover { color: var(--accent); }

/* === RESPONSIVE === */
@media (max-width: 900px) {
    .hero-section {
        flex-direction: column;
    }

    .hero-media {
        max-width: 90%;
        margin: 0 auto;
    }
}

@media (max-width: 640px) {
    :root { --text-base: 16px; }

    .header-wrapper { padding: 24px 16px 20px; }

    .title-section h1 { font-size: 1.6em; }
    .title-section h2 { font-size: 1.1em; }

    .content { padding: var(--space-lg) 16px; }
    .content h2 { font-size: 1.3rem; }
    .content h3 { font-size: 1.1rem; }
    .content p { font-size: 0.95rem; }

    .key-findings { padding: var(--space-md); }

    .button-row a.button { padding: 6px 14px; font-size: 0.85rem; }
}