/* T-070 root fix: refactored from Bootstrap accordion (.accordion-button +
           collapse JS) to HTML5 <details>/<summary> native — no JS dependency.
           Selectors changed: .accordion-button → summary.citation-header;
           .accordion-button:not(.collapsed) → .citation-modern[open] summary;
           .accordion-body → .citation-body. Visual identical. */
        .citation-modern {
            background: linear-gradient(135deg, var(--bg-subtle) 0%, var(--bg-muted) 100%);
            border-radius: 16px;
            overflow: hidden;
            box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
            border: 1px solid rgba(255, 255, 255, 0.8);
        }

        .citation-modern .citation-header {
            background: linear-gradient(135deg, #255869 0%, #002937 100%);
            color: var(--text-on-navy, #fff);
            font-weight: 600;
            font-size: 1rem;
            padding: 16px 20px;
            cursor: pointer;
            list-style: none;
            display: flex;
            align-items: center;
            justify-content: space-between;
            letter-spacing: 0.5px;
            user-select: none;
            transition: background 0.2s ease;
        }

        /* Hide native disclosure markers across browsers */
        .citation-modern .citation-header::-webkit-details-marker { display: none; }
        .citation-modern .citation-header::marker { display: none; content: ''; font-size: 0; }
        .citation-modern > summary { list-style: none; }

        .citation-modern .citation-arrow {
            width: 20px;
            height: 20px;
            color: var(--text-on-navy, #fff);
            transition: transform 0.3s ease;
            margin-inline-start: 10px;
        }

        /* Native [open] selector replaces JS-driven .collapsed toggle */
        .citation-modern[open] .citation-arrow {
            transform: rotate(180deg);
        }

        .citation-modern .citation-header:focus-visible {
            outline: 2px solid var(--teal-light, #12A09E);
            outline-offset: -2px;
        }

        .citation-modern .citation-body {
            padding: 20px 24px;
            background: rgba(255, 255, 255, 0.6);
            backdrop-filter: blur(10px);
        }

        .citation-modern .citation-global-text {
            font-size: 0.93rem;
            color: #374151;
            line-height: 1.75;
            margin-bottom: 16px;
            padding-bottom: 16px;
            border-bottom: 1px solid rgba(102, 126, 234, 0.15);
        }

        .citation-modern .citation-sources-content {
            font-size: 0.92rem;
            color: #4b5563;
            line-height: 1.75;
        }

        .citation-modern .citation-sources-content a {
            color: #255869;
            text-decoration: underline;
            word-break: break-all;
        }

        .citation-modern .citation-sources-content a:hover {
            color: #002937;
        }

        @media (max-width: 768px) {
            .citation-modern .citation-header { padding: 14px 18px; font-size: 0.95rem; }
            .citation-modern .citation-body { padding: 16px 18px; }
        }

        @media (max-width: 480px) {
            .citation-modern .citation-body { padding: 14px 16px; }
            .citation-modern .citation-header { padding: 14px 16px; font-size: 0.9rem; }
            .citation-modern .citation-sources-content { font-size: 13px; }
        }