선택적 상향·하향 구매

<div class="trade"><div class="shop"><div class="option" id="basic">BASIC <strong>$5</strong></div><div class="traveler" id="traveler">SHOPPER</div><div class="option" id="premium">PREMIUM <strong>$9</strong></div></div><button id="proof">SHOW VALUE PROOF</button><div class="reason" id="reason">No clear advantage shown</div></div>

.trade{width:min(90%,540px);font:900 clamp(10px,max(2vmin,1vw),15px)/1.2 sans-serif;text-align:center}.shop{display:flex;justify-content:space-between;align-items:center;gap:5px;min-height:clamp(80px,24vmin,145px)}.option{flex:1;border:2px solid var(--line);background:var(--surface);padding:clamp(9px,3vmin,20px) 3px;transition:.35s}.option strong{display:block;font-size:clamp(19px,5vmin,36px)}.option.on{border-color:var(--accent);box-shadow:0 6px 0 var(--accent)}.traveler{font-size:clamp(10px,max(1.8vmin,1vw),12px);background:var(--accent-2);color:#211b19;border-radius:50%;width:clamp(48px,14vmin,90px);height:clamp(48px,14vmin,90px);display:grid;place-items:center;transition:transform .35s}.traveler.move{transform:translateX(14px)}button{margin-top:12px;background:var(--accent);color:white;border:0;padding:8px 12px;font:inherit;cursor:pointer}.reason{color:var(--muted);margin-top:8px}@media(min-width:700px){body>:first-child{transform:scale(1.25);transform-origin:center}}

let on=false;const btn=document.querySelector('#proof');function draw(){document.querySelector('#basic').classList.toggle('on',!on);document.querySelector('#premium').classList.toggle('on',on);document.querySelector('#traveler').classList.toggle('move',on);document.querySelector('#reason').textContent=on?'Proven durability + convenience':'No clear advantage shown';btn.textContent=on?'HIDE VALUE PROOF':'SHOW VALUE PROOF'}btn.onclick=()=>{on=!on;draw()};draw();setTimeout(()=>{on=true;draw()},650);setTimeout(()=>{on=false;draw()},2600);