* {
  box-sizing: border-box;
  padding: 0;
  margin: 0;
}

body {
  min-height: 100vh;
  font-family: 'Segoe UI', sans-serif;
  background-color: #000; /* sfondo nero */
  color: #fff; /* testo bianco */
  overflow: hidden;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  padding: 20px;
  position: relative;
  z-index: 1;
}

.calculator {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border-radius: 16px;
  padding: 30px;
  max-width: 400px;
  width: 100%;
  box-shadow: 0 8px 20px rgba(255, 255, 255, 0.1);
  z-index: 1;
  color: white;
}

h2 {
  text-align: center;
  margin-bottom: 20px;
  color: #fff;
}

label {
  display: block;
  margin-top: 15px;
  font-weight: 500;
  color: #eee;
}

input {
  width: 100%;
  padding: 10px;
  margin-top: 5px;
  border: 1px solid #fff;
  border-radius: 8px;
  font-size: 16px;
  background-color: transparent;
  color: #fff;
}

input::placeholder {
  color: #ccc;
}

button {
  margin-top: 25px;
  width: 100%;
  padding: 12px;
  font-size: 16px;
  background-color: #fff;
  color: #000;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  font-weight: bold;
  transition: background 0.3s ease;
}

button:hover {
  background-color: #ddd;
}

#result {
  margin-top: 20px;
  font-size: 18px;
  font-weight: bold;
  text-align: center;
  color: #fff;
}

footer {
  margin-top: 30px;
  text-align: center;
  color: #aaa;
  font-size: 14px;
  z-index: 1;
}

@media screen and (max-width: 500px) {
  .calculator {
    padding: 20px;
  }
  h2 {
    font-size: 20px;
  }
}