@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 .lesson .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:18px 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 .facts {display:grid;grid-template-columns:1fr;gap:20px;margin-top:20px}.legacy-content .fact {background:var(--card);border:1px solid var(--border);border-radius:12px;padding:24px;box-shadow:var(--shadow-card)}.legacy-content .fact code {color:var(--accent);font-weight:800}.legacy-content .fact p {font-size:14px;line-height:1.9;color:var(--sub);margin:8px 0 0}.legacy-content .prose {font-size:15px;line-height:2;color:var(--text);margin:0 0 20px}.legacy-content .src-note {font-size:12.5px;color:var(--sub);line-height:1.8;margin:-8px 0 20px}.legacy-content .src-note code {font-size:11.5px}.legacy-content .source {background:var(--card);border:1px solid var(--border);border-radius:14px;overflow:hidden;margin-top:12px;box-shadow:var(--shadow-card)}.legacy-content .source-head {display:flex;justify-content:space-between;gap:12px;padding:10px 16px;background:var(--accent-soft);color:var(--accent-deep);font:12px ui-monospace,SFMono-Regular,Menlo,monospace}.legacy-content .source pre {margin:0;padding:18px;overflow:auto}.legacy-content .source code {color:var(--text);font:12.5px/1.68 ui-monospace,SFMono-Regular,Menlo,monospace}.legacy-content .kw {color:#3450d4}.legacy-content .ty {color:#7c3aed}.legacy-content .fn {color:#0891b2}.legacy-content .cm {color:#9ca3af}.legacy-content .str {color:#16a34a}.legacy-content .snapshot {margin-top:14px;padding:13px 16px;border:1px solid var(--border);border-radius:8px;background:var(--bg);font-size:12px;line-height:1.7;color:var(--sub)}.legacy-content .snapshot code {color:var(--text)}.legacy-content .doc-quote {margin-top:12px;background:var(--card);border:1px solid var(--border);border-radius:12px;padding:16px 18px;box-shadow:var(--shadow-card)}.legacy-content .doc-quote .dq-path {font:700 11px/1.5 ui-monospace,SFMono-Regular,Menlo,monospace;color:var(--accent);overflow-wrap:anywhere;margin-bottom:8px}.legacy-content .doc-quote blockquote {margin:0;font-size:14px;line-height:1.9;color:var(--text)}.legacy-content .exercise {display:grid;grid-template-columns:52px 1fr;gap:16px;background:linear-gradient(135deg,#f0f3ff,var(--card));border:1px solid rgba(77,107,254,.3);border-radius:14px;padding:24px;margin-top:12px}.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 8px;color:var(--text);font-size:16px}.legacy-content .exercise p {margin:0;color:var(--sub);font-size:14px;line-height:1.9}.legacy-content .takeaway {margin-top:32px;padding:24px;border-radius:14px;background:var(--accent-soft);border:1px solid rgba(77,107,254,.28);color:var(--text);display:flex;gap:14px;line-height:1.9}.legacy-content .takeaway svg {flex:0 0 auto;color:var(--accent)}.legacy-content .takeaway b {color:var(--accent-deep)}.legacy-content .layers {display:grid;grid-template-columns:1fr 1fr;gap:20px;margin-top:14px}.legacy-content .layer-card {background:var(--card);border:1px solid var(--border);border-radius:14px;padding:24px;box-shadow:var(--shadow-card)}.legacy-content .layer-card:last-child {grid-column:1/-1}.legacy-content .layer-card strong {color:var(--accent)}.legacy-content .layer-card p {font-size:14px;line-height:1.9;color:var(--sub);margin:8px 0 0}.legacy-content .compare-head {display:flex;align-items:center;gap:8px;font-weight:800;color:var(--text);margin:16px 0 8px}.legacy-content .compare-head svg {color:var(--accent)}.legacy-content .demo {background:var(--card);border:1px solid rgba(77,107,254,.25);border-radius:18px;padding:28px;box-shadow:0 14px 40px rgba(77,107,254,.10)}.legacy-content .demo-bar {display:flex;justify-content:space-between;align-items:center;gap:10px;flex-wrap:wrap;margin-bottom:14px}.legacy-content .demo-tabs, .legacy-content .demo-ctrl {display:flex;gap:8px;flex-wrap:wrap}.legacy-content .demo button {display:inline-flex;align-items:center;justify-content:center;gap:7px;min-height:46px;padding:9px 15px;border-radius:11px;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}.legacy-content .demo button.active, .legacy-content .demo button.primary {background:var(--accent);border-color:var(--accent);color:#fff}.legacy-content .demo-ctrl button {border-color:rgba(77,107,254,.35);background:var(--accent-soft);color:var(--accent-deep);font-weight:700}.legacy-content .demo-ctrl button.primary {background:var(--accent);color:#fff}.legacy-content .world-stage {background:var(--bg);border:1px solid var(--border);border-radius:14px;padding:10px}.legacy-content .world-stage svg {width:100%;height:auto;display:block}.legacy-content .ws-line {stroke:rgba(77,107,254,.45);stroke-width:2;transition:stroke .35s}.legacy-content .ws-line.ok {stroke:#16a34a;stroke-width:3}.legacy-content .ws-line.bad {stroke:#dc2626;stroke-dasharray:5 4;stroke-width:3}.legacy-content .ws-box {fill:#fff;stroke:rgba(0,0,0,.10)}.legacy-content .ws-box.seam {stroke:rgba(77,107,254,.5);stroke-width:2}.legacy-content .ws-box.hl {stroke:var(--accent);stroke-width:2.5}.legacy-content #dw-worldgroup {transition:opacity .4s}.legacy-content .decoder {display:none;background:var(--bg);border:1px solid var(--border);border-radius:14px;padding:14px}.legacy-content .decoder.show {display:block}.legacy-content .dec-stderr {background:var(--card);border:1px solid var(--border);border-radius:10px;padding:10px 14px;font:12.5px/1.7 ui-monospace,Menlo,monospace;color:var(--text);margin-bottom:12px;overflow-wrap:anywhere}.legacy-content .dec-flow {display:grid;grid-template-columns:1fr 28px 1fr 28px 1fr;gap:0;align-items:center}.legacy-content .dec-node {background:var(--card);border:1.5px solid var(--border);border-radius:12px;padding:12px 10px;text-align:center;min-height:80px;display:flex;flex-direction:column;justify-content:center;transition:border-color .3s,background .3s}.legacy-content .dec-node b {font-size:13px;color:var(--text)}.legacy-content .dec-node span {font-size:11px;color:var(--sub);margin-top:3px;line-height:1.5}.legacy-content .dec-node.on {border-color:var(--accent);background:var(--accent-soft)}.legacy-content .dec-node.hit {border-color:var(--amber);background:rgba(217,119,6,.07)}.legacy-content .dec-node.deny {border-color:var(--danger);background:rgba(220,38,38,.06)}.legacy-content .dec-node.pass {border-color:var(--success);background:rgba(22,163,74,.07)}.legacy-content .dec-arrow {text-align:center;color:rgba(77,107,254,.6)}.legacy-content .dec-scen {display:flex;gap:8px;flex-wrap:wrap;margin-bottom:12px}.legacy-content .demo-caption {margin-top:14px;padding:16px 18px;background:var(--bg);border:1px solid var(--border);border-radius:10px;font-size:14px;line-height:1.8;color:var(--text);min-height:52px}.legacy-content .demo-note {font-size:12px;color:var(--sub);margin-top:12px;line-height:1.7}.legacy-content .ws-counter {margin-top:10px;font:700 13px/1.4 ui-monospace,Menlo,monospace;color:var(--accent-deep);min-height:20px}.legacy-content .ws-counter.bad {color:var(--danger)}@media(max-width:760px){.legacy-content .facts {grid-template-columns:1fr}.legacy-content .layers {grid-template-columns:1fr}.legacy-content .dec-flow {grid-template-columns:1fr}.legacy-content .dec-arrow {transform:rotate(90deg);padding:2px 0}.legacy-content .objective {grid-template-columns:1fr}.legacy-content .exercise {grid-template-columns:1fr}.legacy-content .lesson-header:after {display:none}.legacy-content .source-head {flex-direction:column;gap:2px}.legacy-content .demo-bar {flex-direction:column;align-items:stretch}.legacy-content .demo-ctrl button {flex:1}}

.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)}