body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #0e0e0e;
  color: #fff;
}
.app {
  max-width: 420px;
  margin: auto;
  padding: 15px;
}
header {
  text-align: center;
}
button {
  width: 100%;
  padding: 12px;
  background: #00e0ff;
  border: none;
  border-radius: 6px;
  font-weight: bold;
  cursor: pointer;
}
.card {
  background: #1b1b1b;
  padding: 15px;
  border-radius: 10px;
  margin-bottom: 15px;
}
input, select {
  width: 100%;
  padding: 10px;
  border-radius: 6px;
  border: none;
  margin-top: 8px;
}