@keyframes _si{from{opacity:0}to{opacity:1}}

.legacy-content .lesson-header .kicker {color:var(--ct)}.legacy-content .chips {display:flex;flex-wrap:wrap;gap:8px;margin-top:14px}.legacy-content .chip {padding:6px 14px;border-radius:999px;background:var(--ct-soft);color:var(--ct-deep);font-size:13px;font-weight:700}.legacy-content .desc {font-size:15px;color:var(--sub);line-height:1.8}.legacy-content .desc b, .legacy-content .quote-card b {color:var(--ct-deep)}.legacy-content .quote-card {background:var(--ct-soft);border:1.5px solid var(--ct-line);border-radius:14px;padding:18px 22px;font-size:16px;line-height:1.8}.legacy-content .fig-wrap {margin-top:14px;background:var(--card);border:1.5px solid var(--border);border-radius:14px;padding:10px;box-shadow:var(--shadow-card)}.legacy-content .fig-wrap img {width:100%;border-radius:8px;display:block}.legacy-content .fig-cap {font-size:12.5px;color:var(--sub);padding:8px 6px 4px;line-height:1.6}.legacy-content .steps {display:flex;flex-direction:column;gap:10px;margin-top:14px}.legacy-content .step {display:flex;gap:14px;align-items:flex-start;background:var(--card);border:1.5px solid var(--border);border-radius:12px;padding:14px 17px;box-shadow:var(--shadow-card)}.legacy-content .step-num {width:28px;height:28px;border-radius:9px;background:var(--ct-soft);color:var(--ct-deep);display:flex;align-items:center;justify-content:center;font-weight:800;font-size:13px;flex-shrink:0;margin-top:2px}.legacy-content .step p {font-size:14px;color:var(--sub);line-height:1.75;margin:0}.legacy-content .step p b {color:var(--ct-deep)}.legacy-content .tbl {width:100%;border-collapse:collapse;margin-top:14px;font-size:13.5px;background:var(--card);border-radius:12px;overflow:hidden;box-shadow:var(--shadow-card)}.legacy-content .tbl th {background:var(--ct-soft);color:var(--ct-deep);font-weight:800;text-align:left;padding:11px 14px;font-size:13px}.legacy-content .tbl td {padding:11px 14px;border-top:1px solid var(--border);color:var(--sub);line-height:1.65;vertical-align:top}.legacy-content .tbl td b {color:var(--ct-deep)}.legacy-content .tbl td.warn {color:var(--warn);font-weight:800}.legacy-content .tbl-wrap {overflow-x:auto}.legacy-content .tk-demo {background:var(--card);border:1.5px solid var(--border);border-radius:14px;padding:20px 22px;margin-top:14px;box-shadow:var(--shadow-card)}.legacy-content .tk-row {display:flex;flex-wrap:wrap;gap:9px}.legacy-content .tk-btn {padding:10px 16px;border-radius:10px;border:1.5px solid var(--border);background:var(--card);cursor:pointer;font-family:inherit;font-size:13.5px;font-weight:700;color:var(--text);transition:all .18s;min-height:42px}.legacy-content .tk-btn.on {border-color:var(--ct);background:var(--ct-soft);color:var(--ct-deep)}.legacy-content .tk-stage {margin-top:16px;min-height:120px}.legacy-content .tk-text {font-size:15px;font-weight:700;color:var(--text);margin-bottom:12px;word-break:break-all}.legacy-content .tk-bars {display:flex;flex-direction:column;gap:10px}.legacy-content .tkb {display:flex;align-items:center;gap:10px}.legacy-content .tkb .n {font-size:12.5px;font-weight:700;color:var(--sub);width:110px;flex-shrink:0}.legacy-content .tkb .t {flex:1;height:24px;background:rgba(0,0,0,.045);border-radius:7px;overflow:hidden}.legacy-content .tkb .f {height:100%;border-radius:7px;transition:width .3s;display:flex;align-items:center;justify-content:flex-end;padding-right:8px;font-size:12px;font-weight:800;color:#fff;min-width:60px}.legacy-content .tkb.en .f {background:#2563eb}.legacy-content .tkb.zh .f {background:var(--warn)}.legacy-content .tk-note {margin-top:12px;font-size:13.5px;color:var(--sub);line-height:1.75}.legacy-content .tk-note b {color:var(--ct-deep)}.legacy-content .takeaways {display:flex;flex-direction:column;gap:10px;margin-top:12px}.legacy-content .tk-item {display:flex;gap:12px;align-items:flex-start;background:var(--card);border:1.5px solid var(--border);border-radius:12px;padding:14px 16px;box-shadow:var(--shadow-card)}.legacy-content .tk-ic {width:22px;height:22px;border-radius:7px;background:var(--ct-soft);color:var(--ct);display:flex;align-items:center;justify-content:center;flex-shrink:0;font-weight:800;font-size:13px;margin-top:1px}.legacy-content .tk-item p {font-size:14px;line-height:1.75;color:var(--text);margin:0}.legacy-content .tk-item p b {color:var(--ct-deep)}.legacy-content .src-note {margin-top:28px;font-size:13px;color:var(--sub);line-height:1.85}.legacy-content .src-note b {color:var(--text)}

.legacy-content .xa-tldr {margin:18px 0 4px;padding:14px 18px;background:rgba(0,102,255,0.04);border:1px solid rgba(0,102,255,0.16);border-radius:10px}.legacy-content .xa-tldr .xa-tldr-tag {display:block;font-size:11px;font-weight:800;letter-spacing:1px;color:var(--accent,#0066ff);margin-bottom:6px}.legacy-content .xa-tldr p {margin:0;font-size:15px;line-height:1.8;color:var(--text,#1f2937)}