body{
  font-family:Arial, sans-serif;
  background:#f4f6f8;
  display:flex;
  align-items:center;
  justify-content:center;
  min-height:100vh;
  margin:0
}
.box{
  background:#fff;
  padding:30px;
  border-radius:12px;
  width:100%;
  max-width:360px;
  box-shadow:0 10px 30px rgba(0,0,0,.15)
}
h1{
  margin-top:0;
  text-align:center
}
label{
  display:block;
  margin-top:15px;
  font-weight:bold
}
input{
  width:100%;
  box-sizing:border-box;
  padding:10px;
  margin-top:6px;
  border-radius:6px;
  border:1px solid #ccc;
  font-size:15px
}
button{
  width:100%;
  box-sizing:border-box;
  margin-top:25px;
  padding:12px;
  background:#1f6f54;
  color:#fff;
  border:none;
  border-radius:6px;
  font-size:16px;
  font-weight:bold;
  cursor:pointer
}
.error{
  margin-top:15px;
  color:#c0392b;
  text-align:center;
  font-weight:bold
}