@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,.22);border-radius:50%;box-shadow:0 0 0 26px rgba(77,107,254,.04),0 0 0 52px rgba(77,107,254,.025)}.legacy-content .lesson>p {font-size:15px;line-height:2;margin:0 0 20px}.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: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 .q-tag {display:inline-block;padding:5px 14px;border-radius:999px;background:var(--accent-soft);color:var(--accent-deep);font-size:13px;font-weight:800;margin:28px 0 14px}.legacy-content .key-line {margin:32px 0;padding:24px;border-radius:14px;background:var(--accent-soft);border:1px solid rgba(77,107,254,.25);text-align:center;font-size:18px;font-weight:800;line-height:1.8;color:var(--accent-deep)}.legacy-content .codemode-visual {background:var(--card);border:1px solid var(--border);border-radius:18px;padding:24px;margin:24px 0;box-shadow:var(--shadow-card)}.legacy-content .codemode-visual svg {width:100%;height:auto;display:block}.legacy-content .visual-caption {font-size:12.5px;color:var(--sub);text-align:center;margin-top:12px;line-height:1.7}.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:24px 0 0}.legacy-content .source-head {display:flex;justify-content:space-between;gap:12px;padding:12px 18px;background:var(--accent-soft);color:var(--accent-deep);font:12px ui-monospace,SFMono-Regular,Menlo,monospace}.legacy-content .source pre {margin:0;padding:20px}.legacy-content .source pre {overflow:auto}.legacy-content .source code {color:var(--text);font:12.5px/1.75 ui-monospace,SFMono-Regular,Menlo,monospace;background:none;padding:0}.legacy-content .cm {color:#9ca3af}.legacy-content .snapshot {margin:14px 0 0;padding:14px 18px;border:1px solid var(--border);border-radius:8px;background:var(--bg);font-size:12px;line-height:1.8;color:var(--sub)}.legacy-content .snapshot code {color:var(--text);background:rgba(0,0,0,.05)}.legacy-content .doc-quote {margin:24px 0;padding:22px 24px;border:1px solid rgba(77,107,254,.25);border-radius:12px;background:linear-gradient(135deg,var(--accent-soft),var(--card))}.legacy-content .doc-quote p {margin:0;font-size:14px;line-height:1.9;color:var(--text)}.legacy-content .doc-quote .doc-src {display:block;margin-top:10px;font:11.5px ui-monospace,SFMono-Regular,Menlo,monospace;color:var(--accent-deep)}.legacy-content .exercise {display:grid;grid-template-columns:52px 1fr;gap:18px;background:linear-gradient(135deg,#eef1ff,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 10px;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,.25);color:var(--text);display:flex;gap:14px;font-size: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 .compare {display:grid;grid-template-columns:1fr;gap:20px;margin-top:14px}.legacy-content .cmp-card {background:var(--card);border:1px solid var(--border);border-radius:12px;padding:24px;box-shadow:var(--shadow-card)}.legacy-content .cmp-card h4 {margin:0;font-size:15px;color:var(--text);display:flex;align-items:center;gap:8px}.legacy-content .cmp-card h4 svg {color:var(--accent)}.legacy-content .cmp-card p {font-size:14px;line-height:1.9;color:var(--sub);margin:10px 0 0}.legacy-content .cmp-card .cmp-tag {display:inline-block;margin-top:12px;padding:3px 10px;border-radius:999px;font-size:11px;font-weight:700;background:var(--accent-soft);color:var(--accent-deep);border:1px solid rgba(77,107,254,.25)}.legacy-content .demo {background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:28px;box-shadow:var(--shadow-card)}.legacy-content .demo-top {display:flex;justify-content:space-between;align-items:center;gap:14px;flex-wrap:wrap;margin-bottom:20px}.legacy-content .demo-title {font-size:14px;font-weight:700;color:var(--text)}.legacy-content .demo-ctrl {display:flex;gap:12px;flex-wrap:wrap}.legacy-content .demo-ctrl button {display:inline-flex;align-items:center;justify-content:center;gap:7px;padding:10px 20px;min-height:44px;min-width:44px;border:1px solid rgba(77,107,254,.35);border-radius:999px;background:var(--accent-soft);color:var(--accent-deep);font:600 14px/1 -apple-system,BlinkMacSystemFont,"PingFang SC",sans-serif;cursor:pointer;transition:filter .15s}.legacy-content .demo-ctrl button:active {filter:brightness(.92)}.legacy-content .dm-cols {display:grid;grid-template-columns:1fr 1fr;gap:24px}.legacy-content .dm-col {border:1px solid var(--border);border-radius:12px;background:var(--bg);overflow:hidden;display:flex;flex-direction:column}.legacy-content .dm-head {padding:14px 16px;background:var(--card);border-bottom:1px solid var(--border);display:flex;justify-content:space-between;align-items:center;gap:10px;flex-wrap:wrap}.legacy-content .dm-head .dm-name {font-size:13px;font-weight:800;color:var(--text)}.legacy-content .dm-meter {display:flex;gap:16px;font-size:11px;font-weight:600;color:var(--sub);text-align:right}.legacy-content .dm-meter b {display:block;color:var(--accent-deep);font-size:22px;line-height:1.15;font-variant-numeric:tabular-nums}.legacy-content .dm-stream {padding:16px;display:flex;flex-direction:column;gap:12px;min-height:300px}.legacy-content .dm-i {display:none}.legacy-content .dm-i.on {display:block;animation:dmin .3s ease}@keyframes dmin{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}.legacy-content .dm-bubble {background:var(--card);border:1px solid rgba(77,107,254,.3);border-radius:10px;padding:11px 14px;font-size:12.5px;line-height:1.7;color:var(--text)}.legacy-content .dm-bubble .dm-role {display:block;font-size:10.5px;font-weight:800;letter-spacing:.5px;color:var(--accent);margin-bottom:4px}.legacy-content .dm-tool {background:var(--accent-soft);border:1px solid rgba(77,107,254,.3);border-radius:10px;padding:10px 14px;font:11.5px/1.7 ui-monospace,SFMono-Regular,Menlo,monospace;color:var(--accent-deep)}.legacy-content .dm-result {background:var(--card);border:1px dashed var(--border);border-radius:10px;padding:10px 14px;font-size:12px;line-height:1.7;color:var(--sub)}.legacy-content .dm-done {border:1px solid rgba(22,163,74,.4);background:rgba(22,163,74,.07);border-radius:10px;padding:10px 14px;font-size:12px;font-weight:700;color:var(--success)}.legacy-content .dm-i.cur .dm-bubble, .legacy-content .dm-i.cur .dm-tool, .legacy-content .dm-i.cur .dm-result {box-shadow:0 0 0 2px rgba(77,107,254,.35)}.legacy-content .dm-code {background:var(--card);border:1px solid rgba(77,107,254,.3);border-radius:10px;padding:14px 16px;overflow-x:auto}.legacy-content .dm-code .cl {display:none;font:11.5px/1.8 ui-monospace,SFMono-Regular,Menlo,monospace;color:var(--text);white-space:pre}.legacy-content .dm-code .cl.on {display:block}.legacy-content .dm-code .cl.hl {background:rgba(77,107,254,.16);border-radius:3px}.legacy-content .dm-code-tag {font-size:10.5px;font-weight:700;color:var(--sub);margin-bottom:8px}.legacy-content .dm-sandbox {border:2px dashed rgba(77,107,254,.55);border-radius:12px;padding:12px 14px;background:rgba(77,107,254,.05)}.legacy-content .dm-sandbox .dm-sb-label {font-size:10.5px;font-weight:800;letter-spacing:.5px;color:var(--accent-deep);margin-bottom:10px;display:flex;align-items:center;gap:6px}.legacy-content .dm-chip {display:none;margin-top:8px;padding:9px 12px;border-radius:8px;background:var(--card);border:1px solid var(--border);font:11.5px/1.6 ui-monospace,SFMono-Regular,Menlo,monospace;color:var(--text)}.legacy-content .dm-chip.on {display:block;animation:dmin .3s ease}.legacy-content .dm-chip.cur {border-color:var(--accent);box-shadow:0 0 0 2px rgba(77,107,254,.3)}.legacy-content .dm-chip .dm-note {display:block;font:600 10.5px/1.5 -apple-system,BlinkMacSystemFont,"PingFang SC",sans-serif;color:var(--sub);margin-top:3px}.legacy-content .dm-caption {margin-top:20px;min-height:56px;display:flex;align-items:center;gap:12px;padding:16px 18px;border-radius:10px;background:var(--accent-soft);border:1px solid rgba(77,107,254,.22);font-size:14px;line-height:1.8;color:var(--text)}.legacy-content .dm-caption svg {flex:0 0 auto;color:var(--accent)}.legacy-content .dm-summary {display:none;margin-top:20px;border:1px solid rgba(77,107,254,.3);border-radius:12px;background:linear-gradient(135deg,var(--accent-soft),var(--card));padding:20px 22px}.legacy-content .dm-summary.on {display:flex;flex-direction:column;gap:14px;animation:dmin .4s ease}.legacy-content .dm-summary .dm-s {font-size:13px;line-height:1.8;color:var(--sub)}.legacy-content .dm-summary .dm-s b {display:block;font-size:13.5px;color:var(--accent-deep);margin-bottom:2px}.legacy-content .demo-caption {font-size:11.5px;color:var(--sub);margin-top:14px;line-height:1.7}@media(max-width:760px){.legacy-content .compare {grid-template-columns:1fr}.legacy-content .dm-cols {grid-template-columns:1fr}.legacy-content .source-head {flex-direction:column}.legacy-content .codemode-visual {padding:14px}.legacy-content .objective {grid-template-columns:1fr}.legacy-content .lesson-header:after {display:none}.legacy-content .dm-stream {min-height:0}.legacy-content .demo {padding:18px}.legacy-content .demo-ctrl {width:100%}.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)}