@keyframes _si{to{opacity:1}}

.legacy-content .lesson-header {position:relative;overflow:hidden}.legacy-content .lesson-header:after {content:"";position:absolute;right:-70px;top:-70px;width:220px;height:220px;border:1px solid rgba(77,107,254,.24);border-radius:50%;box-shadow:0 0 0 26px rgba(77,107,254,.05),0 0 0 52px rgba(77,107,254,.028)}.legacy-content .sec-label {margin:56px 0 20px}.legacy-content .objective {display:grid;grid-template-columns:auto 1fr;gap:16px;align-items:center;background:linear-gradient(135deg,var(--accent-soft),rgba(255,255,255,.75));border:1px solid rgba(77,107,254,.28);border-radius:var(--radius);padding:24px;margin:24px 0 32px}.legacy-content .objective svg {color:var(--accent)}.legacy-content .objective b {display:block;color:var(--accent);margin-bottom:6px}.legacy-content .objective span {font-size:14px;line-height:1.9;color:var(--text)}.legacy-content .prose {font-size:15px;line-height:2;color:var(--text);margin:0 0 20px}.legacy-content .ask {font-size:15px;font-weight:800;color:var(--accent-deep);margin:32px 0 12px;display:flex;align-items:center;gap:8px}.legacy-content .ask svg {flex:none;color:var(--accent)}.legacy-content .src-note {font-size:12px;color:var(--sub);line-height:1.8;margin:0 0 20px}.legacy-content .src-note code {color:var(--sub)}.legacy-content .stress {margin:32px auto;padding:24px;max-width:640px;border-radius:14px;background:var(--accent-soft);border:1px solid rgba(77,107,254,.25);color:var(--accent-deep);font-size:18px;font-weight:800;text-align:center;line-height:1.8}.legacy-content .core-visual {background:var(--card);border:1px solid var(--border);border-radius:18px;padding:24px;box-shadow:var(--shadow-card);margin:24px 0}.legacy-content .core-visual svg {width:100%;height:auto;display:block}.legacy-content .visual-caption {font-size:12px;color:var(--sub);text-align:center;margin-top:12px}.legacy-content .paths {display:grid;grid-template-columns:1fr 1fr;gap:20px;margin:24px 0}.legacy-content .path-card {background:var(--card);border:1px solid var(--border);border-radius:14px;padding:24px;box-shadow:var(--shadow-card)}.legacy-content .path-card p {font-size:14px;line-height:1.9;color:var(--sub);margin:12px 0 0}.legacy-content .vs-head {display:flex;align-items:center;gap:8px;font-weight:800;color:var(--text)}.legacy-content .vs-head svg {color:var(--accent);flex:none}.legacy-content .exercise {display:grid;grid-template-columns:52px 1fr;gap:18px;background:linear-gradient(135deg,#f0f3ff,var(--card));border:1px solid rgba(77,107,254,.3);border-radius:14px;padding:24px;margin-top:16px}.legacy-content .exercise-num {width:46px;height:46px;border-radius:12px;background:var(--accent);color:white;display:grid;place-items:center;font-weight:900}.legacy-content .exercise h3 {margin:0 0 10px;color:var(--text);font-size:16px}.legacy-content .exercise p {margin:0 0 10px;color:var(--sub);font-size:14px;line-height:1.9}.legacy-content .exercise p:last-child {margin-bottom:0}.legacy-content .takeaway {margin-top:32px;padding:24px;border-radius:14px;background:var(--accent-soft);border:1px solid rgba(77,107,254,.25);color:var(--text);display:flex;gap:14px;line-height:1.9;font-size:14px}.legacy-content .takeaway svg {flex:0 0 auto;color:var(--accent)}.legacy-content .takeaway b {color:var(--accent-deep)}.legacy-content .demo {background:var(--card);border:1px solid var(--border);border-radius:18px;padding:24px;box-shadow:var(--shadow-card)}.legacy-content .demo-hint {font-size:13px;color:var(--sub);line-height:1.9;margin:0 0 20px}.legacy-content .demo-hint code {color:var(--accent-deep)}.legacy-content .demo-bar {display:flex;justify-content:space-between;align-items:center;gap:14px;flex-wrap:wrap;margin-bottom:20px}.legacy-content .demo-scenarios, .legacy-content .demo-ctrl {display:flex;gap:12px;flex-wrap:wrap}.legacy-content .demo button {display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:44px;padding:8px 16px;border-radius:10px;border:1px solid var(--border);background:var(--bg);color:var(--text);font:600 13px/1.2 -apple-system,BlinkMacSystemFont,"PingFang SC",sans-serif;cursor:pointer;transition:background .2s,border-color .2s,color .2s}.legacy-content .demo button.active {background:var(--accent);border-color:var(--accent);color:#fff}.legacy-content .demo button svg {flex:none}.legacy-content .demo-stage {display:grid;grid-template-columns:1.05fr 1fr;gap:20px;align-items:start}.legacy-content .codepane {border:1px solid var(--border);border-radius:14px;background:var(--bg);padding:18px}.legacy-content .cp-title {font:700 12px/1.6 -apple-system,BlinkMacSystemFont,"PingFang SC",sans-serif;color:var(--sub);margin-bottom:12px;letter-spacing:.04em}.legacy-content .cp-group {margin-bottom:14px}.legacy-content .cp-group:last-child {margin-bottom:0}.legacy-content .cp-label {font:700 10.5px/1.4 ui-monospace,Menlo,monospace;color:var(--accent);margin:0 0 5px 4px;letter-spacing:.08em}.legacy-content .cl {display:flex;justify-content:space-between;gap:10px;padding:6px 9px;border-radius:6px;color:var(--text);font:12.5px/1.65 ui-monospace,Menlo,monospace;transition:background .25s,color .25s}.legacy-content .cl .ln {color:var(--sub);flex:none;user-select:none}.legacy-content .cl.on {background:rgba(77,107,254,.15);color:var(--accent-deep);font-weight:700}.legacy-content .cl.on .ln {color:var(--accent-deep)}.legacy-content .chamber {position:relative;height:320px;border:2px solid rgba(77,107,254,.3);border-radius:14px;background:var(--bg);overflow:hidden;transition:border-color .3s,box-shadow .3s}.legacy-content .chamber.boom {border-color:var(--danger);box-shadow:0 0 0 3px rgba(220,38,38,.14)}.legacy-content .chamber.ok {border-color:var(--success);box-shadow:0 0 0 3px rgba(22,163,74,.14)}.legacy-content .chamber.shake {animation:dcshk .5s ease}@keyframes dcshk{0%,100%{transform:translateX(0)}25%{transform:translateX(-6px)}50%{transform:translateX(6px)}75%{transform:translateX(-3px)}}.legacy-content .th-line {position:absolute;left:0;right:0;bottom:80%;height:2px;background:repeating-linear-gradient(90deg,var(--accent) 0 9px,transparent 9px 15px);z-index:2;pointer-events:none}.legacy-content .th-line span {position:absolute;right:6px;top:-20px;font:700 11px/1 ui-monospace,Menlo,monospace;color:var(--accent-deep)}.legacy-content .blocks {position:absolute;left:8px;right:8px;bottom:8px;display:flex;flex-direction:column-reverse;gap:3px;z-index:1}.legacy-content .blk {border-radius:6px;flex:none;display:flex;align-items:center;padding:0 8px;font:600 10px/1 ui-monospace,Menlo,monospace;color:#fff;overflow:hidden;transition:height .45s ease,opacity .45s ease,margin .45s ease}.legacy-content .blk.u {background:rgba(77,107,254,.8)}.legacy-content .blk.a {background:rgba(77,107,254,.55)}.legacy-content .blk.t {background:rgba(77,107,254,.18);color:var(--accent-deep)}.legacy-content .blk.huge {background:rgba(220,38,38,.12);border:1px solid rgba(220,38,38,.5);color:var(--danger)}.legacy-content .blk.sum {background:linear-gradient(135deg,var(--accent-deep),var(--accent));font-weight:800}.legacy-content .blk.fold {height:0!important;opacity:0;margin:0;padding-top:0;padding-bottom:0}.legacy-content .err-banner {position:absolute;top:10px;left:10px;right:10px;background:rgba(220,38,38,.08);border:1px solid rgba(220,38,38,.4);color:var(--danger);font:700 11px/1.5 ui-monospace,Menlo,monospace;padding:6px 10px;border-radius:8px;opacity:0;transition:opacity .3s;z-index:3;text-align:center;pointer-events:none}.legacy-content .err-banner.show {opacity:1}.legacy-content .gauge {display:flex;justify-content:space-between;align-items:center;margin-top:14px;font-size:13px;color:var(--sub);flex-wrap:wrap;gap:12px}.legacy-content .gauge .gen b {display:inline-block;color:var(--accent-deep);font:800 16px/1 ui-monospace,Menlo,monospace;margin-left:4px}.legacy-content .gauge .gen b.pop {animation:dcpop .4s ease}@keyframes dcpop{50%{transform:scale(1.5);color:var(--accent)}}.legacy-content .verdict {display:inline-flex;align-items:center;gap:6px;font-weight:700;min-height:22px}.legacy-content .verdict.yes {color:var(--success)}.legacy-content .verdict.no {color:var(--danger)}.legacy-content .dc-status {margin-top:14px;min-height:76px;padding:14px 16px;border-radius:10px;background:var(--bg);border:1px solid var(--border);font-size:14px;color:var(--text);line-height:1.8}.legacy-content .demo-note {font-size:12px;color:var(--sub);margin-top:20px;line-height:1.8}@media(max-width:760px){.legacy-content .paths {grid-template-columns:1fr}.legacy-content .demo-stage {grid-template-columns:1fr}.legacy-content .chamber {height:260px}.legacy-content .objective {grid-template-columns:1fr}.legacy-content .lesson-header:after {display:none}.legacy-content .core-visual {padding:16px}.legacy-content .demo-bar {flex-direction:column;align-items:stretch}.legacy-content .demo button {flex:1}.legacy-content .stress {font-size:16px;padding:20px}}

.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)}