Horizontal autoscaling

<div class="stage" data-phase="0"><div class="title">LOAD → REPLICAS</div><div class="meter"><div class="fill"></div><span>requests</span></div><div class="row replicas"><div class="panel">P1</div><div class="panel">P2</div><div class="panel extra">P3</div><div class="panel extra">P4</div></div><div class="sub">target utilization controls count</div></div>

.stage{width:min(94vw,760px);height:min(88vh,330px);padding:clamp(9px,2.6vmin,20px);border:1px solid var(--line);border-radius:14px;background:var(--surface);font:600 clamp(12px,2.5vmin,16px)/1.3 "Pretendard Variable",Pretendard,-apple-system,BlinkMacSystemFont,"Apple SD Gothic Neo",sans-serif;display:flex;flex-direction:column;gap:clamp(6px,1.7vmin,12px);overflow:hidden;position:relative}.stage *{min-width:0}.stage .title{color:var(--accent);font-weight:800}.stage .sub{color:var(--muted)}.stage .row{display:flex;align-items:center;gap:clamp(5px,1.6vmin,12px)}.stage .panel{border:1px solid var(--line);border-radius:8px;background:var(--bg);padding:clamp(6px,1.6vmin,12px)}.stage .mono{font-family:ui-monospace,SFMono-Regular,monospace;font-size:clamp(12px,2.5vmin,15px)}.stage .grow{flex:1}.stage .on{color:var(--accent)}.meter{height:clamp(28px,7vmin,48px);border:1px solid var(--line);border-radius:7px;position:relative;overflow:hidden}.meter span{position:absolute;left:9px;top:50%;transform:translateY(-50%)}.fill{width:30%;height:100%;background:color-mix(in srgb,var(--accent) 36%,var(--surface));transition:width .4s}.replicas{flex:1;justify-content:center}.replicas .panel{flex:1;text-align:center;max-width:120px}.extra{color:var(--muted);border-style:dashed!important;transform:scale(.9);transition:transform .4s,background .4s}.stage[data-phase="1"] .fill{width:90%;background:color-mix(in srgb,var(--accent-3) 45%,var(--surface))}.stage[data-phase="2"] .fill{width:55%}.stage[data-phase="2"] .extra{transform:scale(1);border-color:var(--accent)!important;background:color-mix(in srgb,var(--accent) 15%,var(--surface))}

const stage=document.querySelector('.stage');let phase=0;function advance(){phase=(phase+1)%3;stage.dataset.phase=String(phase)}const timer=setInterval(advance,1200);stage.addEventListener('pointerdown',()=>{clearInterval(timer);advance()})