body{
  margin:0;
  background:#111827;
  font-family:Arial;
  color:white;
}

.container{
  display:flex;
  justify-content:center;
  align-items:center;
  height:100vh;
  padding:20px;
}

.card{
  width:100%;
  max-width:400px;
  background:#1f2937;
  padding:30px;
  border-radius:12px;
}

h1{
  text-align:center;
}

#checkpoint{
  font-size:24px;
  margin:20px 0;
  color:#22c55e;
  text-align:center;
}

input{
  width:100%;
  padding:15px;
  border:none;
  border-radius:8px;
  margin-bottom:20px;
  font-size:16px;
}

button{
  width:100%;
  padding:15px;
  border:none;
  border-radius:8px;
  background:#2563eb;
  color:white;
  font-size:18px;
}

#status{
  margin-top:20px;
  text-align:center;
  font-size:18px;
}