.article-hero {
            background: linear-gradient(180deg, #0f172a 0%, #16203a 55%, #0f172a 100%);
            padding: 9rem 0 4.5rem;
        }
        .article-hero .eyebrow { display: block; text-align: center; }
        .article-hero h1 {
            font-size: clamp(2.4rem, 3.2vw + 1.2rem, 3.6rem);
            font-weight: 600;
            color: var(--text-heading-on-dark);
            line-height: 1.05;
            text-align: center;
            max-width: 800px;
            margin: 0 auto;
        }
        .article-body { max-width: 720px; margin: 0 auto; }

        /* Editorial family (spec §9): the article card is a reading
           surface — neutral 1px border, level-one elevation, 4px radius */
        .article-card {
            background: var(--bg-card);
            border: 1px solid var(--border-card);
            border-radius: var(--radius-figure);
            padding: 3rem 3.5rem;
            box-shadow: var(--elev-1);
        }
        .article-card h2 {
            font-size: 1.4rem;
            color: var(--text-primary);
            margin: 2rem 0 0.75rem;
            line-height: 1.3;
        }
        .article-card h2:first-child { margin-top: 0; }
        .article-card p, .article-card li {
            color: var(--text-secondary);
            font-size: 1rem;
            line-height: 1.7;
        }
        .article-card ul { padding-left: 1.25rem; }
        .article-card li { margin-bottom: 0.5rem; }

        /* PAGE-04: the related-guide cross reference (editorial line) */
        .article-related {
            border-left: 3px solid var(--accent);
            padding-left: 1rem;
            font-size: 0.95rem;
        }
        .article-related a {
            color: var(--gold-ink);
            font-weight: 600;
            text-decoration: none;
            border-bottom: 1px solid rgba(125, 98, 48, 0.5);
            transition: opacity var(--motion-hover);
        }
        .article-related a:hover { color: var(--gold-ink-hover); }

        /* PAGE-04: the closing proof link */
        .article-proof {
            margin-top: 2rem;
            padding-top: 1.5rem;
            border-top: 1px solid var(--border-card);
        }
        .article-proof a {
            display: inline-flex;
            align-items: center;
            min-height: 44px;
            color: var(--gold-ink);
            font-weight: 600;
            text-decoration: none;
            border-bottom: 1px solid rgba(125, 98, 48, 0.5);
            transition: opacity var(--motion-hover);
        }
        .article-proof a:hover { color: var(--gold-ink-hover); }

        .illustration {
            border-left: 3px solid var(--accent);
            background: rgba(15, 23, 42, 0.03);
            border-radius: 0 var(--radius-figure) var(--radius-figure) 0;
            padding: 1.25rem 1.5rem;
            margin: 1.5rem 0;
        }
        .illustration .label {
            font-size: 0.75rem;
            letter-spacing: 0.08em;
            color: var(--accent);
            font-weight: 600;
            display: block;
            margin-bottom: 0.5rem;
        }
        .back-link {
            display: inline-flex;
            align-items: center;
            min-height: 44px;
            margin-top: 2rem;
            color: var(--gold-ink);
            text-decoration: none;
            font-size: 0.95rem;
        }
        @media (max-width: 768px) {
            .article-card { padding: 2rem 1.5rem; }
            .article-hero h1 { font-size: 2rem; line-height: 1.08; }
        }