body {
  font-family: Arial, sans-serif;
  background: #f3f3f3;
  margin: 0;
  padding: 0;
}
#app {
  max-width: 500px;
  margin: 40px auto;
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 1px 6px rgba(0,0,0,0.15);
  padding: 30px 40px;
}
input, button, select {
  margin: 8px 0;
  padding: 8px;
  width: 100%;
  box-sizing: border-box;
}
.historial {
  margin-top: 20px;
  background: #f9f9f9;
  border-radius: 6px;
  padding: 10px;
}
button {
  background: #1976d2;
  color: #fff;
  border: none;
  border-radius: 4px;
  cursor: pointer;
}
button:hover {
  background: #1259a7;
}