Strangler fig pattern

<div class="scene"><div class="title">GRADUAL TRAFFIC MIGRATION</div><div class="split"><div id="legacy">LEGACY <b id="oldPct">80%</b></div><div id="modern">NEW <b id="newPct">20%</b></div></div><div class="row route"><div class="tile">ROUTER</div><span>→</span><div class="tile" id="route">catalog → new</div></div></div>

.scene{width:min(94vw,760px);height:min(86vh,320px);padding:clamp(10px,2.5vmin,18px);border:1px solid var(--line);border-radius:14px;background:var(--surface);color:var(--fg);font:500 clamp(11px,1.3vw,16px)/1.25 "Pretendard Variable",Pretendard,-apple-system,sans-serif;display:flex;flex-direction:column;gap:clamp(7px,1.6vmin,12px);overflow:hidden}.scene *{box-sizing:border-box}.title{font-weight:750;color:var(--accent)}.muted{color:var(--muted)}.mono{font-family:ui-monospace,monospace}.row{display:flex;align-items:center;justify-content:center;gap:clamp(5px,1.4vmin,12px);flex:1;min-height:0}.tile{border:1px solid var(--line);border-radius:8px;background:var(--bg);padding:clamp(6px,1.6vmin,12px);text-align:center;min-width:0}.on{border-color:var(--accent)!important;background:color-mix(in srgb,var(--accent) 12%,var(--surface))!important}.pulse{animation:pulse 1.6s infinite alternate}@keyframes pulse{to{border-color:var(--accent);transform:translateY(-3px)}}.split{display:flex;height:36%;min-height:42px;border-radius:8px;overflow:hidden;border:1px solid var(--line)}.split div{display:flex;align-items:center;justify-content:center;gap:5px;white-space:nowrap;transition:width .6s}.split #legacy{background:var(--line)}.split #modern{background:var(--accent);color:var(--bg)}.route{justify-content:flex-start}.route span{color:var(--accent)}

let n=1;function tick(){const newer=n*20,old=100-newer;document.getElementById('legacy').style.width=old+'%';document.getElementById('modern').style.width=newer+'%';document.getElementById('oldPct').textContent=old+'%';document.getElementById('newPct').textContent=newer+'%';document.getElementById('route').textContent=['catalog','profile','checkout','search'][n-1]+' → new';n=n%4+1}tick();setInterval(tick,1100)