/* 机制图复用现有主题，表格按手机宽度排版。 */
.c4-mechanism{margin:18px 0;padding:18px;background:var(--bg);border:1px solid var(--line);border-radius:10px}.c4-mechanism figcaption{display:flex;flex-wrap:wrap;gap:8px;justify-content:space-between;margin-bottom:18px;font-size:14px}.c4-mechanism figcaption span{font-size:11px;color:var(--sub)}.c4-table-wrap{overflow-x:auto}.c4-mechanism table{border-collapse:collapse;width:100%;font-size:14px;font-variant-numeric:tabular-nums}.c4-mechanism th,.c4-mechanism td{padding:12px 8px;text-align:left;border-bottom:1px solid var(--line);overflow-wrap:anywhere}.c4-mechanism th{color:var(--accent-deep);font-size:12px}.c4-mechanism tbody tr:last-child td{border-bottom:0}.c4-mechanism p{font-size:12px;color:var(--sub);margin-bottom:0}.c4-visual-title{font-size:15px;margin:22px 0 10px}[data-course="chapter4"] .c2-frame{min-height:530px}[data-course="chapter4"] .c2-frame .figure{margin:14px 0}[data-course="chapter4"] .c2-transcript h3{font-size:20px}.sr-only{position:absolute;width:1px;height:1px;padding:0;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}@media(max-width:600px){.c4-mechanism{padding:12px}.c4-mechanism th,.c4-mechanism td{padding:10px 5px;font-size:12px}[data-course="chapter4"] .c2-frame{min-height:610px}}