<section class="stage"><div class="heading">ROUTE CACHE <span class="hint">miss / hit / invalidate</span></div><div class="cache-flow"><div class="tile request">GET /news</div><div class="arrow">→</div><div class="cache-box">CACHE <b id="cache-state">MISS</b></div><div class="arrow">→</div><div class="tile renderer">RENDER</div></div><div class="caption" id="cache-caption">First request fills the cache</div></section>
.stage{width:min(94vw,780px);height:min(88vh,322px);padding:clamp(12px,3vmin,20px);border:1px solid var(--line);border-radius:16px;background:var(--surface);box-shadow:0 12px 36px #0001;display:flex;flex-direction:column;gap:clamp(7px,2vmin,14px);font:500 clamp(12px,3.5vmin,17px)/1.3 var(--font-sans,system-ui,sans-serif);overflow:hidden}.heading{display:flex;justify-content:space-between;align-items:center;gap:8px;font-weight:750;color:var(--accent)}.hint{color:var(--muted);font-size:clamp(12px,3.2vmin,14px);font-weight:500}.caption{margin-top:auto;color:var(--muted);font-size:clamp(12px,3.2vmin,14px)}.row{display:flex;gap:clamp(5px,1.5vmin,12px);align-items:center}.tile{padding:clamp(6px,1.8vmin,13px);border:1px solid var(--line);border-radius:9px;background:var(--bg);text-align:center;min-width:0}.arrow{color:var(--accent);font-weight:800}.stage [data-on]{transition:background .3s,border-color .3s,opacity .3s,transform .3s}.stage .on{border-color:var(--accent);background:color-mix(in srgb,var(--accent) 14%,var(--surface));color:var(--accent)}.cache-flow{flex:1;display:flex;align-items:center;justify-content:center;gap:clamp(3px,1.3vmin,12px)}.cache-flow .tile,.cache-box{flex:1;max-width:145px;min-width:0;min-height:70px;display:flex;flex-direction:column;align-items:center;justify-content:center}.cache-box{border:2px solid var(--accent);border-radius:9px;background:color-mix(in srgb,var(--accent) 10%,var(--surface));font-weight:700}.cache-box b{color:var(--accent);margin-top:5px}.renderer{opacity:1;transition:opacity .3s}.stage[data-step="1"] .renderer{opacity:.2}.stage[data-step="2"] .cache-box{border-color:var(--accent-3)}.stage small,.stage button,.stage .cards b,.stage .phase b,.stage .pair b,.stage .tree-mini b{font-size:clamp(12px,3.2vmin,14px)!important}
const stage=document.querySelector(".stage"),state=document.getElementById("cache-state"),caption=document.getElementById("cache-caption"),states=["MISS","HIT","PURGE"],notes=["First request fills the cache","Stored response skips rendering","Invalidation forces fresh output"];let step=0;function tick(){stage.dataset.step=String(step);state.textContent=states[step];caption.textContent=notes[step];step=(step+1)%3}tick();let timer=setInterval(tick,1000);stage.addEventListener("pointerdown",()=>{clearInterval(timer);tick()})