.ebill-wrapper {
  max-width: 500px;
  margin: 40px auto;
  padding: 20px;
  background: #f9f9f9;
  border-radius: 10px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
  font-family: sans-serif;
}
.ebill-wrapper h2 {
  text-align: center;
  color: #2c3e50;
}
.ebill-wrapper label, .ebill-wrapper select, .ebill-wrapper input, .ebill-wrapper button {
  width: 100%;
  display: block;
  margin-top: 10px;
}
#result {
  margin-top: 20px;
  text-align: center;
  font-weight: bold;
  font-size: 18px;
}