body {
  font-family: Arial, sans-serif;
  background-color: #eef2f3;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
  margin: 0;
}
.container {
  background-color: #fff;
  padding: 2em;
  border-radius: 12px;
  box-shadow: 0 0 10px rgba(0,0,0,0.1);
  width: 300px;
  text-align: center;
}
h1 {
  color: #2c3e50;
}
input {
  width: 100%;
  padding: 0.6em;
  margin: 0.5em 0;
  border-radius: 6px;
  border: 1px solid #ccc;
}
button {
  background-color: #3498db;
  color: white;
  border: none;
  padding: 0.7em;
  width: 100%;
  border-radius: 6px;
  font-size: 1em;
  cursor: pointer;
}
button:hover {
  background-color: #2980b9;
}
#resultado {
  margin-top: 1em;
  font-weight: bold;
}