body{
background: linear-gradient(135deg,#252c36,#397383);
height:100vh;
display:flex;
justify-content:center;
align-items:center;
font-family:Arial;
}

.signup-container{
width:100%;
max-width:400px;  
}

.card{
border-radius:15px;
}

input{
height:45px;
}

button{
height:45px;
font-size:18px;
}
@media (max-width: 576px) {
  .card { margin: 0 1rem; }
  .signup-container {max-width: 600px;}
}