/* ============================================================================
   research-article.css — shared framework for functionSPACE research articles
   ----------------------------------------------------------------------------
   Single source of truth for the styling of every article under /research/<slug>/.
   Load it AFTER /assets/site.css (which provides the design tokens, the fixed
   nav, and the global scroll-padding-top anchor offset):

       <link rel="stylesheet" href="/assets/site.css" />
       <link rel="stylesheet" href="/assets/research-article.css" />

   The anchor-offset fix that keeps section headings clear of the fixed nav lives
   in site.css (`html { scroll-padding-top: calc(var(--nav-height) + 24px) }`),
   so any page using #hash TOC navigation inherits it — do NOT re-add per-element
   scroll-margin here.

   Start a new article from /research/_template/index.html.
   ========================================================================== */

:root {
    --max-w: 1200px;
    --sidebar-w: 220px;
}

main { flex: 1; }

/* ── HERO IMAGE ── */
.hero-art {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 0 48px;
}
.hero-art-frame {
    aspect-ratio: 16 / 7;
    width: 100%;
    overflow: hidden;
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    background: var(--color-surface);
}
.hero-art-frame img {
    width: 100%; height: 100%;
    object-fit: cover;
    display: block;
}
@media (max-width: 768px) {
    .hero-art { padding: 0 24px; }
    .hero-art-frame { aspect-ratio: 4 / 3; }
}
@media (max-width: 480px) {
    .hero-art { padding: 0 16px; }
}

/* Article figure with real image */
.figure-image {
    margin: 0;
    background: #fff;
    border-radius: var(--radius-md);
    overflow: hidden;
    border: 1px solid var(--color-border);
}
.figure-image img {
    display: block;
    width: 100%;
    height: auto;
}

/* ── BACK LINK ── */
.back-bar {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: calc(var(--nav-height) + 36px) 48px 0;
}
.back-link {
    display: inline-flex; align-items: center; gap: 6px;
    font-family: var(--font-mono);
    font-size: 11px; font-weight: 600;
    letter-spacing: .08em; text-transform: uppercase;
    color: var(--color-text-tertiary);
    transition: color .15s;
}
.back-link:hover { color: var(--color-text); }
.back-link svg { transform: rotate(180deg); }

/* ── PAGE HEADER ── */
.page-header {
    border-bottom: 1px solid var(--color-border);
    padding: 28px 48px 48px;
}
.page-header-inner { max-width: var(--max-w); margin: 0 auto; }
.page-eyebrow {
    font-family: var(--font-mono);
    font-size: 11px; font-weight: 700;
    letter-spacing: .1em; text-transform: uppercase;
    color: var(--color-accent);
    margin-bottom: 14px;
}
.page-title {
    font-family: var(--font-heading);
    font-size: clamp(30px, 4.4vw, 50px);
    font-weight: 400; line-height: 1.08;
    letter-spacing: -.02em;
    color: var(--color-text);
    margin-bottom: 18px;
    max-width: 880px;
}
.page-lead {
    font-size: 16px; color: var(--color-text-tertiary);
    line-height: 1.65; max-width: 760px;
    margin-bottom: 24px;
}
.page-lead strong { color: var(--color-text-secondary); font-weight: 600; }
.meta-row {
    display: flex; flex-wrap: wrap;
    gap: 24px;
    font-family: var(--font-mono);
    font-size: 11px; font-weight: 600;
    letter-spacing: .08em; text-transform: uppercase;
    color: var(--color-text-muted);
}
.meta-row .meta-item span { color: var(--color-text-secondary); }
.meta-row a { color: var(--color-accent); }

/* ── LAYOUT ── */
.article-layout {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 0 48px 96px;
    display: grid;
    grid-template-columns: var(--sidebar-w) 1fr;
    gap: 64px;
    align-items: start;
}

/* ── SIDEBAR ── */
.sidebar {
    position: sticky;
    top: 88px;
    padding-top: 48px;
}
.sidebar-label {
    font-family: var(--font-mono);
    font-size: 10px; font-weight: 700;
    letter-spacing: .12em; text-transform: uppercase;
    color: var(--color-text-muted);
    margin-bottom: 10px;
    padding: 0 10px;
}
.sidebar-nav { display: flex; flex-direction: column; gap: 0; }
.sidebar-link {
    display: block;
    font-size: 13px; color: var(--color-text-tertiary);
    padding: 6px 10px;
    border-radius: var(--radius-sm);
    transition: color .12s, background .12s;
    border-left: 2px solid transparent;
    line-height: 1.4;
}
.sidebar-link:hover { color: var(--color-text-secondary); background: var(--color-surface); }
.sidebar-link.active {
    color: var(--color-accent);
    background: var(--color-accent-subtle);
    border-left-color: var(--color-accent);
}

/* ── CONTENT ── */
.content { padding-top: 48px; min-width: 0; }

.doc-section { margin-bottom: 64px; }
.doc-section:last-child { margin-bottom: 0; }

.section-title {
    font-family: var(--font-heading);
    font-size: clamp(22px, 2.8vw, 30px);
    font-weight: 400; line-height: 1.18;
    letter-spacing: -.015em;
    color: var(--color-text);
    margin-bottom: 22px;
}
.section-divider {
    border: none; border-top: 1px solid var(--color-border);
    margin-bottom: 64px;
}

/* Body prose */
.prose p {
    font-size: 16px; color: var(--color-text-secondary);
    line-height: 1.75; margin-bottom: 18px;
}
.prose p:last-child { margin-bottom: 0; }
.prose strong { color: var(--color-text); font-weight: 600; }
.prose em { color: var(--color-text); font-style: italic; }
.prose a { color: var(--color-accent); border-bottom: 1px solid var(--color-accent-bdr); }
.prose a:hover { color: var(--color-accent-hover); }
.prose code {
    font-family: var(--font-mono);
    font-size: 13px;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: 1px 5px;
}

/* ── LISTS ── */
.bullet-list { list-style: none; padding-left: 0; margin-bottom: 18px; }
.bullet-list li {
    font-size: 16px; color: var(--color-text-secondary);
    line-height: 1.75; margin-bottom: 10px;
    padding-left: 18px; position: relative;
}
.bullet-list li::before {
    content: "—"; position: absolute; left: 0;
    color: var(--color-text-muted);
}
.bullet-list li strong { color: var(--color-text); font-weight: 600; }

.findings-list { list-style: none; padding-left: 0; margin: 0; counter-reset: findings; }
.findings-list li {
    font-size: 16px; color: var(--color-text-secondary);
    line-height: 1.75; margin-bottom: 16px;
    padding-left: 30px; position: relative;
}
.findings-list li strong { color: var(--color-text); font-weight: 600; }
.findings-list li::before {
    counter-increment: findings;
    content: counter(findings);
    position: absolute; left: 0; top: 1px;
    font-family: var(--font-mono);
    font-size: 12px; font-weight: 700;
    color: var(--color-accent);
}

/* ── TABLE ── */
.data-table-wrap {
    margin: 22px 0 28px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow-x: auto;
    background: var(--color-surface);
    -webkit-overflow-scrolling: touch;
}
.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 13.5px;
    font-family: var(--font-sans);
    min-width: 480px;
}
.data-table th, .data-table td {
    padding: 12px 16px;
    text-align: left;
    border-bottom: 1px solid var(--color-border);
    white-space: nowrap;
}
.data-table thead th {
    font-family: var(--font-mono);
    font-size: 10.5px; font-weight: 700;
    letter-spacing: .08em; text-transform: uppercase;
    color: var(--color-text-muted);
    background: var(--color-surface-alt);
}
.data-table tbody tr:last-child td { border-bottom: none; }
.data-table tbody td {
    color: var(--color-text-secondary);
}
.data-table tbody td:first-child {
    color: var(--color-text);
    font-weight: 500;
}
.data-table tbody td.num,
.data-table tbody td.numeric { font-variant-numeric: tabular-nums; }
.data-table tbody tr:hover td { background: var(--color-surface-alt); }
.data-table tbody tr.total-row td {
    font-weight: 700;
    color: var(--color-text);
    background: var(--color-surface-alt);
}
.data-table caption {
    caption-side: top;
    padding: 14px 16px;
    font-family: var(--font-mono);
    font-size: 10.5px; font-weight: 700;
    letter-spacing: .08em; text-transform: uppercase;
    color: var(--color-text-muted);
    text-align: left;
    border-bottom: 1px solid var(--color-border);
    background: var(--color-surface-alt);
}

/* ── FIGURE / CHART PLACEHOLDER ── */
.figure {
    margin: 24px 0 28px;
    border: 1px dashed var(--color-border);
    border-radius: var(--radius-lg);
    padding: 18px;
    background: var(--color-surface);
}
.figure-placeholder {
    display: flex; align-items: center; justify-content: center;
    min-height: 220px;
    border-radius: var(--radius-md);
    background: repeating-linear-gradient(
        45deg,
        var(--color-surface) 0,
        var(--color-surface) 12px,
        var(--color-surface-alt) 12px,
        var(--color-surface-alt) 24px
    );
    color: var(--color-text-muted);
    font-family: var(--font-mono);
    font-size: 11px; font-weight: 600;
    letter-spacing: .08em; text-transform: uppercase;
}
.figure-caption {
    margin-top: 14px;
    font-size: 13px; color: var(--color-text-tertiary);
    line-height: 1.6;
}
.figure-caption strong { color: var(--color-text-secondary); font-weight: 600; }

/* ── CALLOUT ── */
.callout {
    background: var(--color-accent-subtle);
    border: 1px solid var(--color-accent-bdr);
    border-radius: var(--radius-md);
    padding: 18px 22px;
    margin: 24px 0;
}
.callout-label {
    font-family: var(--font-mono);
    font-size: 10px; font-weight: 700;
    letter-spacing: .1em; text-transform: uppercase;
    color: var(--color-accent);
    margin-bottom: 6px;
}
.callout p {
    font-size: 14.5px; color: var(--color-text-secondary);
    line-height: 1.7; margin: 0;
}
.callout p strong { color: var(--color-text); font-weight: 600; }

/* ── NOTE (limitations, byline) ── */
.note {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: 18px 22px;
    margin: 16px 0;
}
.note p {
    font-size: 14px; color: var(--color-text-tertiary);
    line-height: 1.65; margin: 0;
}
.note p + p { margin-top: 10px; }
.note strong { color: var(--color-text-secondary); font-weight: 600; }
.note a { color: var(--color-accent); }
.note code {
    font-family: var(--font-mono); font-size: 12.5px;
    background: var(--color-surface-alt);
    border-radius: var(--radius-sm); padding: 1px 5px;
}

/* ── SUBHEAD ── */
.sub-heading {
    font-family: var(--font-sans);
    font-size: 13px; font-weight: 700;
    letter-spacing: .04em; text-transform: uppercase;
    color: var(--color-text-tertiary);
    margin: 32px 0 14px;
}
.sub-heading:first-child { margin-top: 0; }

/* ── BYLINE ── */
.byline {
    margin-top: 56px;
    padding: 20px 24px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background: var(--color-surface);
    font-size: 14px;
    color: var(--color-text-tertiary);
    line-height: 1.7;
}
.byline strong { color: var(--color-text-secondary); font-weight: 600; }
.byline a { color: var(--color-accent); }

/* ── RELATED RESEARCH ── */
.related-section {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 48px 48px 96px;
    border-top: 1px solid var(--color-border);
}
.related-eyebrow {
    font-family: var(--font-mono);
    font-size: 11px; font-weight: 700;
    letter-spacing: .1em; text-transform: uppercase;
    color: var(--color-accent);
    margin-bottom: 10px;
}
.related-title {
    font-family: var(--font-heading);
    font-size: clamp(24px, 3vw, 32px);
    font-weight: 400; line-height: 1.15;
    color: var(--color-text);
    margin-bottom: 8px;
}
.related-lead {
    font-size: 15px; color: var(--color-text-tertiary);
    margin-bottom: 28px;
}
.related-grid {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 16px;
}
.related-card {
    display: flex; flex-direction: column;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 22px;
    transition: border-color .15s, background .15s;
}
.related-card:hover {
    border-color: var(--color-accent-bdr);
    background: var(--color-accent-subtle);
}
.related-tag {
    font-family: var(--font-mono);
    font-size: 10px; font-weight: 700;
    letter-spacing: .1em; text-transform: uppercase;
    color: var(--color-accent);
    margin-bottom: 12px;
}
.related-card-title {
    font-family: var(--font-heading);
    font-size: 18px; font-weight: 400;
    line-height: 1.25;
    color: var(--color-text);
    margin-bottom: 10px;
}
.related-card-desc {
    font-size: 13.5px; color: var(--color-text-tertiary);
    line-height: 1.6;
    margin-bottom: 14px;
}
.related-date {
    margin-top: auto;
    font-family: var(--font-mono);
    font-size: 10.5px; font-weight: 600;
    letter-spacing: .08em; text-transform: uppercase;
    color: var(--color-text-muted);
}

/* ── MOBILE TOC ── */
.mobile-toc {
    display: none;
    overflow-x: auto;
    gap: 6px;
    padding: 14px 16px;
    border-bottom: 1px solid var(--color-border);
    background: var(--color-surface);
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
}
.mobile-toc::-webkit-scrollbar { display: none; }
.mobile-toc a {
    display: inline-block;
    white-space: nowrap;
    font-family: var(--font-mono);
    font-size: 11px; font-weight: 600;
    letter-spacing: .04em;
    color: var(--color-text-tertiary);
    padding: 4px 10px;
    border: 1px solid var(--color-border);
    border-radius: 20px;
    transition: color .12s, border-color .12s;
}
.mobile-toc a:hover, .mobile-toc a.active {
    color: var(--color-accent);
    border-color: var(--color-accent-bdr);
}

/* ── RESPONSIVE ── */
@media (max-width: 900px) {
    .related-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 860px) {
    .article-layout { grid-template-columns: 1fr; }
    .sidebar { display: none; }
    .mobile-toc { display: flex; }
    .related-grid { grid-template-columns: 1fr; }
}
@media (max-width: 768px) {
    .back-bar { padding: calc(var(--nav-height) + 24px) 24px 0; }
    .page-header { padding: 22px 24px 36px; }
    .article-layout { padding: 0 24px 72px; }
    .related-section { padding: 36px 24px 72px; }
    .data-table th, .data-table td { padding: 10px 12px; font-size: 13px; }
}
@media (max-width: 480px) {
    .back-bar { padding: calc(var(--nav-height) + 20px) 16px 0; }
    .page-header { padding: 18px 16px 28px; }
    .article-layout { padding: 0 16px 56px; }
    .related-section { padding: 28px 16px 56px; }
    .meta-row { gap: 14px; }
}