body {
  font-family: Arial, sans-serif;
  background: #f4f4f4;
  padding: 20px;
}
.container {
  max-width: 800px;
  margin: auto;
  background: white;
  padding: 20px;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
}
h1 {
  text-align: center;
}
.card {
  margin: 20px 0;
  padding: 15px;
  background: #f9f9f9;
  border-radius: 8px;
}
label {
  display: block;
  margin-bottom: 10px;
}
input, select {
  width: 100%;
  padding: 8px;
  margin-top: 5px;
}
button {
  width: 100%;
  padding: 12px;
  font-size: 16px;
  background-color: #28a745;
  color: white;
  border: none;
  border-radius: 6px;
  cursor: pointer;
}
button:hover {
  background-color: #218838;
}
.result {
  margin-top: 20px;
  padding: 15px;
  background: #eef;
  border-radius: 8px;
  text-align: center;
}
.presets {
  text-align: center;
  margin-bottom: 20px;
}
.presets button {
  margin: 0 5px;
  padding: 10px 20px;
  background: #007bff;
  color: white;
  border: none;
  border-radius: 6px;
}