@keyframes _si{to{opacity:1}}

.legacy-content .lesson {--accent:#414b5a;--accent-deep:#262d38;--accent-soft:rgba(65,75,90,.085)}.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(65,75,90,.22);border-radius:50%;box-shadow:0 0 0 26px rgba(65,75,90,.04),0 0 0 52px rgba(65,75,90,.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(65,75,90,.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(65,75,90,.25);text-align:center;font-size:18px;font-weight:800;line-height:1.8;color:var(--accent-deep)}.legacy-content .visual {background:var(--card);border:1px solid var(--border);border-radius:18px;padding:24px;margin:24px 0;box-shadow:var(--shadow-card)}.legacy-content .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 .source {background:var(--card);border:1px solid var(--border);border-radius:14px;overflow:hidden;margin:24px 0 0;max-width:100%;min-width: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;overflow:auto;max-width:100%}.legacy-content .source code {color:var(--text);font:12.5px/1.85 ui-monospace,SFMono-Regular,Menlo,monospace;background:none;padding:0;white-space:pre;word-break:normal}.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 .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 .exercise {display:grid;grid-template-columns:52px 1fr;gap:18px;background:linear-gradient(135deg,#eff1f5,var(--card));border:1px solid rgba(65,75,90,.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 0 12px;color:var(--sub);font-size:14px;line-height:1.9}.legacy-content .exercise p:last-child {margin:0}.legacy-content .takeaway {margin-top:32px;padding:24px;border-radius:14px;background:var(--accent-soft);border:1px solid rgba(65,75,90,.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:12px 0 0}.legacy-content .cmp-card .cmp-tag {display:inline-block;margin-top:14px;padding:3px 10px;border-radius:999px;font-size:11px;font-weight:700;background:var(--accent-soft);color:var(--accent-deep);border:1px solid rgba(65,75,90,.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(65,75,90,.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-budget {display:flex;align-items:flex-start;gap:12px;flex-wrap:wrap;margin-bottom:20px;padding:16px 18px;border-radius:12px;background:var(--bg);border:1px solid var(--border)}.legacy-content .dm-budget .dm-b-label {font-size:13px;font-weight:700;color:var(--text);padding-top:10px}.legacy-content .dm-budget .dm-b-hint {font-size:12px;color:var(--sub);line-height:1.7;flex:1 1 180px;padding-top:10px}.legacy-content .dm-seg {display:flex;gap:8px;flex-wrap:wrap}.legacy-content .dm-seg button {min-height:44px;padding:10px 16px;border-radius:999px;border:1px solid var(--border);background:var(--card);color:var(--sub);font:600 13px/1 -apple-system,BlinkMacSystemFont,"PingFang SC",sans-serif;cursor:pointer;transition:all .15s cubic-bezier(.4,0,.2,1)}.legacy-content .dm-seg button.on {background:var(--accent);border-color:var(--accent);color:#fff}.legacy-content .dm-cols {display:grid;grid-template-columns:1.05fr .95fr;gap:24px}.legacy-content .dm-col {border:1px solid var(--border);border-radius:12px;background:var(--bg);overflow:hidden;display:flex;flex-direction:column;min-width:0}.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 {font-size:11px;font-weight:600;color:var(--sub)}.legacy-content .dm-meter b {color:var(--accent-deep);font-variant-numeric:tabular-nums}.legacy-content .dm-meter.warn {color:var(--danger);font-weight:700}.legacy-content .dm-meter.hold {color:var(--accent-deep);font-weight:700}.legacy-content .dm-meter.ok {color:var(--success);font-weight:700}.legacy-content #dm-lamp {transition:opacity .4s cubic-bezier(.4,0,.2,1)}.legacy-content #dm-hist-n {display:inline-flex;flex-direction:column;align-items:flex-end;font-variant-numeric:tabular-nums}.legacy-content #dm-hist-n:after {content:"";display:block;height:3px;width:28px;margin-top:5px;border-radius:99px;background:currentColor;transform:scaleX(var(--hist-bar,0));transform-origin:left center;transition:transform .5s cubic-bezier(.25,1,.5,1)}.legacy-content .dm-body {padding:18px;display:flex;flex-direction:column;gap:10px;min-height:320px}.legacy-content .dm-ly {display:flex;align-items:flex-start;gap:12px;padding:12px;border-radius:10px;border:1px solid var(--border);background:var(--card);opacity:1;transform:scale(1);transition:all .35s cubic-bezier(.4,0,.2,1)}.legacy-content .dm-ly em {flex:0 0 28px;width:28px;height:28px;border-radius:8px;background:var(--bg);color:var(--faint);display:grid;place-items:center;font:800 12px/1 -apple-system,BlinkMacSystemFont,"PingFang SC",sans-serif}.legacy-content .dm-ly b {display:block;font-size:13px;color:var(--text);margin-bottom:2px}.legacy-content .dm-ly span {display:block;font-size:12px;line-height:1.7;color:var(--sub)}.legacy-content .dm-ly .tag {display:inline-block;max-height:0;overflow:hidden;opacity:0;margin-top:0;padding:0 8px;border-radius:999px;font-size:11px;font-weight:700;background:rgba(220,38,38,.08);color:var(--danger);transition:max-height .4s cubic-bezier(.25,1,.5,1),opacity .35s cubic-bezier(.4,0,.2,1),margin .4s cubic-bezier(.25,1,.5,1),padding .4s cubic-bezier(.25,1,.5,1)}.legacy-content #dm-layers.is-live .dm-ly {opacity:.4;transform:scale(.98)}.legacy-content #dm-layers.is-live .dm-ly.on {opacity:1;transform:scale(1)}.legacy-content #dm-layers.is-live .dm-ly.done {opacity:.55;transform:scale(.98)}.legacy-content .dm-ly.on {background:var(--accent-soft);border-color:rgba(65,75,90,.4)}.legacy-content .dm-ly.on em {background:var(--accent);color:#fff}.legacy-content .dm-ly.on b, .legacy-content .dm-ly.on span {color:var(--accent-deep)}.legacy-content .dm-ly.irrev.on {background:rgba(220,38,38,.06);border-color:rgba(220,38,38,.35)}.legacy-content .dm-ly.irrev.on em {background:var(--danger);color:#fff}.legacy-content .dm-ly.irrev.on .tag {max-height:28px;opacity:1;margin-top:6px;padding:2px 8px}.legacy-content .dm-ly.firing {animation:fireGlow .8s cubic-bezier(.25,1,.5,1)}.legacy-content .dm-ly .tag.pop {animation:flashPop .8s cubic-bezier(.25,1,.5,1)}.legacy-content .dm-hist {position:relative;display:flex;flex-direction:column;gap:10px}.legacy-content .dm-h {padding:12px 14px;border-radius:9px;border:1px solid var(--border);background:var(--card);transition:transform .4s cubic-bezier(.25,1,.5,1),opacity .35s cubic-bezier(.4,0,.2,1)}.legacy-content .dm-h b {display:block;font-size:12.5px;color:var(--accent-deep);margin-bottom:4px}.legacy-content .dm-h span {display:block;font-size:12px;line-height:1.7;color:var(--sub)}.legacy-content .dm-h.keep {border-color:rgba(22,163,74,.35);background:rgba(22,163,74,.07)}.legacy-content .dm-h.abort {border-color:rgba(217,119,6,.35);background:rgba(217,119,6,.07)}.legacy-content .dm-h.mark {border-color:rgba(65,75,90,.4);background:var(--accent-soft)}.legacy-content .dm-h.bg {border-style:dashed}.legacy-content .dm-h.is-enter {opacity:0;transform:translateY(8px)}.legacy-content .dm-h.is-enter.in {opacity:1;transform:none;transition:opacity .35s cubic-bezier(.4,0,.2,1),transform .35s cubic-bezier(.4,0,.2,1)}.legacy-content .dm-h.pop {animation:flashPop .8s cubic-bezier(.25,1,.5,1)}.legacy-content .dm-ghost {position:absolute;z-index:2;pointer-events:none;margin:0;transition:all .4s cubic-bezier(.25,1,.5,1)}.legacy-content .dm-ghost.fly {opacity:0;transform:translateY(-18px) scale(.9)}.legacy-content .dm-empty {padding:36px 12px;text-align:center;font-size:13px;color:var(--faint);line-height:1.8}.legacy-content .dm-trace {margin-top:24px;border:1px solid var(--border);border-radius:12px;background:var(--bg);overflow:hidden}.legacy-content .dm-trace-tag {padding:12px 18px;background:var(--card);border-bottom:1px solid var(--border);font-size:12px;font-weight:700;color:var(--sub)}.legacy-content .dm-trace ol {margin:0;padding:10px 0;list-style:none}.legacy-content .dm-trace li {display:flex;justify-content:space-between;gap:16px;padding:9px 18px;font-size:12.5px;line-height:1.7;color:var(--sub);opacity:1;transform:scale(1);transition:background .35s cubic-bezier(.4,0,.2,1),opacity .35s cubic-bezier(.4,0,.2,1),transform .35s cubic-bezier(.4,0,.2,1)}.legacy-content #dm-trace.is-live li {opacity:.4;transform:scale(.98)}.legacy-content #dm-trace.is-live li.on {opacity:1;transform:scale(1);background:var(--accent-soft);color:var(--accent-deep);font-weight:600}.legacy-content .dm-trace li.on {background:var(--accent-soft);color:var(--accent-deep);font-weight:600}.legacy-content .dm-trace li.firing {animation:fireGlow .8s cubic-bezier(.25,1,.5,1)}.legacy-content .dm-trace li span.ln {flex:0 0 auto;font:11px ui-monospace,SFMono-Regular,Menlo,monospace;color:var(--faint)}.legacy-content .dm-trace li.on span.ln {color:var(--accent-deep)}.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(65,75,90,.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-caption-text {transition:opacity .3s cubic-bezier(.4,0,.2,1)}.legacy-content .dm-summary {display:flex;flex-direction:column;gap:14px;max-height:0;overflow:hidden;opacity:0;margin-top:0;padding:0 22px;border:1px solid transparent;border-radius:12px;background:linear-gradient(135deg,var(--accent-soft),var(--card));transition:max-height .5s cubic-bezier(.25,1,.5,1),opacity .4s cubic-bezier(.4,0,.2,1),margin .4s cubic-bezier(.25,1,.5,1),padding .4s cubic-bezier(.25,1,.5,1)}.legacy-content .dm-summary.on {max-height:560px;opacity:1;margin-top:20px;padding:20px 22px;border-color:rgba(65,75,90,.3)}.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}@keyframes flashPop{0%{transform:scale(.8)}30%{transform:scale(1.15)}100%{transform:scale(1)}}@keyframes fireGlow{0%{box-shadow:0 0 0 0 rgba(65,75,90,.3)}50%{box-shadow:0 0 20px 6px rgba(65,75,90,.2)}100%{box-shadow:none}}@media(prefers-reduced-motion:reduce){.legacy-content .demo, .legacy-content .demo * {transition-duration:0s!important;animation-duration:0s!important}}@media(max-width:760px){.legacy-content .lesson {overflow-x:hidden}.legacy-content .compare {grid-template-columns:1fr}.legacy-content .dm-cols {grid-template-columns:1fr}.legacy-content .objective {grid-template-columns:1fr}.legacy-content .lesson-header:after {display:none}.legacy-content .demo {padding:18px}.legacy-content .demo-ctrl {width:100%}.legacy-content .demo-ctrl button {flex:1}.legacy-content .dm-body {min-height:0}.legacy-content .visual {padding:14px}.legacy-content .dm-trace li {flex-direction:column;gap:4px}.legacy-content .dm-budget .dm-b-label {padding-top:0}.legacy-content .source, .legacy-content .demo, .legacy-content .visual, .legacy-content .cmp-card {max-width:100%;min-width:0}.legacy-content .source pre {overflow-x:auto}.legacy-content .lesson code {overflow-wrap:anywhere;word-break:break-word}}

.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)}