<!DOCTYPE html>
<html>
<body style="text-align:center;font-family:Arial">
<h1>🔢 Desafio dos Decimais</h1>
<h2 id="t">⏱️ 5:00</h2>
<p id="q">Quanto é 2,5 + 1,5?</p>
<input id="a" type="number" step="0.1">
<button onclick="responder()">RESPONDER</button>
<p id="msg"></p>

<script>
let tempo=300;
let timer=setInterval(()=>{
 tempo--;
 document.getElementById("t").innerText="⏱️ "+Math.floor(tempo/60)+":"+String(tempo%60).padStart(2,"0");
 if(tempo<=0){clearInterval(timer);document.body.innerHTML="<h1>⏰ TEMPO ESGOTADO!</h1>"}
},1000);

function responder(){
 if(document.getElementById("a").value=="4")
   document.body.innerHTML="<h1>🏆 VITÓRIA!</h1><p>Parabéns! 🎉</p>";
 else
   document.getElementById("msg").innerText="❌ Resposta errada!";
}
</script>
</body>
</html>