*{
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: Arial, sans-serif;
}

body{
  min-height: 100vh;
  background: #101828; /* plain color */
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.container{
  width: 100%;
  max-width: 420px;
  background: #ffffff;
  padding: 24px;
  border-radius: 14px;
  box-shadow: 0 12px 30px rgba(0,0,0,0.25);
  text-align: center;
}

h1{
  font-size: 1.6rem;
  color: #101828;
  margin-bottom: 6px;
}

.subtitle{
  color: #475467;
  font-size: 0.95rem;
  margin-bottom: 18px;
}

.row{
  display: flex;
  gap: 12px;
}

input{
  width: 100%;
  padding: 12px;
  border: 1px solid #d0d5dd;
  border-radius: 10px;
  font-size: 1rem;
  text-align: center;
  outline: none;
}

input:focus{
  border-color: #2563eb;
}

button{
  width: 100%;
  margin-top: 12px;
  padding: 12px;
  background: #2563eb; /* plain color */
  color: #fff;
  border: 0;
  border-radius: 10px;
  font-size: 1rem;
  cursor: pointer;
}

button:hover{
  background: #1d4ed8;
}

.genaratedNumber{
  display: block;
  margin-top: 18px;
  padding: 16px;
  border-radius: 12px;
  background: #f2f4f7;
  font-size: 2.4rem;
  font-weight: 700;
  color: #101828;
}

/* Mobile spacing */
@media (max-width: 480px){
  h1{ font-size: 1.4rem; }
  .row{ flex-direction: column; }
}