/* 第二章后半段：文字材料 + 重绘图表 */
.da-source-material {
    margin-top: 16px;
    padding: 16px 18px;
    border: 1px solid #e2e5e9;
    border-radius: 14px;
    background: #fbfcfd;
    color: #2f343b;
    line-height: 1.85;
}
.da-source-material-label {
    margin-bottom: 8px;
    color: #667085;
    font-size: 13px;
    font-weight: 700;
}
.da-source-material-text { font-size: 15px; }
.da-question-stem {
    margin-top: 14px;
    padding: 14px 16px;
    border-radius: 12px;
    background: #f5f7fa;
    color: #20242a;
    font-size: 16px;
    line-height: 1.7;
}
.da-question-stem strong { margin-right: 6px; }
@media (max-width: 600px) {
    .da-source-material { padding: 12px; }
    .da-source-material-text, .da-question-stem { font-size: 14px; }
}