.code-fold {
    margin: 22px 0 28px;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    background: #111827;
    overflow: hidden;
}

.code-fold summary {
    cursor: pointer;
    padding: 13px 16px;
    color: #e0e7ff;
    background: #172033;
    font-size: 0.9rem;
    font-weight: 700;
    list-style-position: inside;
}

.code-fold[open] summary { border-bottom: 1px solid #334155; }

.code-fold pre {
    margin: 0;
    padding: 17px 18px 20px;
    overflow-x: auto;
    color: #dbeafe;
    font-size: 0.78rem;
    line-height: 1.62;
    tab-size: 4;
}

.code-fold code {
    padding: 0;
    color: inherit;
    background: transparent;
    border-radius: 0;
    font-size: inherit;
}

.equation-note {
    margin: -10px 0 22px;
    color: var(--text-secondary);
    font-size: 0.88rem;
    line-height: 1.62;
}

.compact-list li { margin-bottom: 5px; }

.contract-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
    margin: 22px 0 27px;
}

.contract-card {
    padding: 16px 17px;
    border: 1px solid var(--border-color);
    border-radius: 11px;
    background: #fbfcfe;
}

.contract-card h3 {
    margin: 0 0 7px;
    font-size: 1rem;
}

.contract-card p {
    margin: 0;
    color: var(--text-secondary);
    font-size: 0.86rem;
    line-height: 1.6;
}

.contract-card .mini-formula {
    display: block;
    margin: 8px 0 7px;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.latex-figure.figure-wide { max-width: 820px; }
.latex-figure.figure-medium { max-width: 700px; }

.reference-group {
    margin: 18px 0;
    padding-top: 4px;
}

.reference-group h3 {
    margin: 0 0 8px;
    font-size: 1rem;
}

.reference-group p { margin-bottom: 8px; }

.plain-summary {
    margin: 24px 0;
    padding: 18px 20px;
    border: 1px solid #c7d2fe;
    border-radius: 12px;
    background: #f5f7ff;
}

.plain-summary strong {
    display: block;
    margin-bottom: 6px;
    color: var(--primary-dark);
}

.plain-summary p:last-child { margin-bottom: 0; }

.symbol-table td:first-child,
.symbol-table th:first-child {
    white-space: nowrap;
    width: 1%;
}

.article-question {
    color: var(--primary-dark);
    font-weight: 700;
}

.colab-callout {
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 14px;
    align-items: center;
    max-width: 720px;
    margin-top: 20px;
    padding: 14px 16px;
    border: 1px solid #f6c26b;
    border-radius: 12px;
    color: var(--text-primary);
    background: #fff9ed;
    text-decoration: none;
    transition: border-color 0.2s, box-shadow 0.2s, transform 0.2s;
}

.colab-callout:hover {
    border-color: #e99a22;
    box-shadow: 0 8px 22px rgba(154, 93, 16, 0.12);
    transform: translateY(-1px);
}

.colab-callout img {
    display: block;
    width: 117px;
    height: auto;
}

.colab-callout span { min-width: 0; }

.colab-callout strong,
.colab-callout small {
    display: block;
}

.colab-callout strong {
    margin-bottom: 3px;
    font-size: 0.94rem;
}

.colab-callout small {
    color: var(--text-secondary);
    font-size: 0.8rem;
    line-height: 1.45;
}

.colab-callout > i {
    color: #d97706;
    font-size: 0.9rem;
}

@media (max-width: 700px) {
    .contract-grid { grid-template-columns: 1fr; }
    .code-fold pre { font-size: 0.7rem; }
    .latex-figure.figure-wide,
    .latex-figure.figure-medium { max-width: 100%; }
    .colab-callout { grid-template-columns: 1fr auto; }
    .colab-callout img { grid-column: 1 / -1; }
}