body {
  margin: 0;
  font-family: sans-serif;
  background: #111;
  color: #fff;
}

.app {
  padding: 20px;
  max-width: 500px;
  margin: auto;
}

h1 {
  text-align: center;
}

button {
  width: 100%;
  padding: 15px;
  font-size: 18px;
  margin-bottom: 20px;
  background: #9f2dbc;
  border: none;
  border-radius: 10px;
  color: #000;
}

.control {
  margin-bottom: 20px;
}

label {
  display: block;
  margin-bottom: 5px;
}

input[type="range"] {
  width: 100%;
}

select {
  width: 100%;
  padding: 10px;
  border-radius: 8px;
}