Schema Validation

<div class="viz"><h3>REQUEST SCHEMA</h3><div class="row"><div class="box code" id="input">quantity: 2</div><span class="arrow">→</span><div class="box">quantity<br>number ≥ 1</div><span class="arrow">→</span><div class="box" id="out">PASS</div></div><div class="muted" id="why">valid field</div></div>

.viz{width:94%;height:88%;max-width:960px;padding:clamp(10px,2vmin,18px);border:1px solid var(--line);border-radius:14px;background:var(--surface);font:600 clamp(12px,1.35vw,16px)/1.35 var(--font-sans,system-ui,sans-serif);display:flex;flex-direction:column;gap:clamp(7px,1.8vmin,13px);overflow:hidden}.viz h3{margin:0;color:var(--accent);font:700 clamp(12px,1.35vw,16px)/1.2 var(--font-sans,system-ui,sans-serif);letter-spacing:.04em}.viz .row{display:flex;align-items:center;justify-content:center;gap:clamp(5px,1.4vmin,12px);flex:1;min-height:0}.viz .box{padding:clamp(5px,1.5vmin,12px);border:1px solid var(--line);border-radius:9px;background:var(--bg);text-align:center}.viz .muted{color:var(--muted)}.viz .accent{color:var(--accent)}.viz .code{font-family:ui-monospace,monospace}.viz .pill{padding:3px 7px;border:1px solid var(--line);border-radius:99px;white-space:nowrap}.viz .active{border-color:var(--accent);background:color-mix(in srgb,var(--accent) 12%,var(--surface))}.viz .arrow{color:var(--accent);font:700 18px ui-monospace,monospace}#out{min-width:18%;border-color:var(--accent)}#out.bad{border-color:var(--accent-3);color:var(--accent-3)}

let invalid=false;function draw(){invalid=!invalid;document.getElementById('input').textContent=invalid?'quantity: "two"':'quantity: 2';const out=document.getElementById('out');out.textContent=invalid?'ERROR':'PASS';out.classList.toggle('bad',invalid);document.getElementById('why').textContent=invalid?'quantity must be a number':'valid field'}draw();setInterval(draw,1600)