body {
  font-family: Arial, sans-serif;
  background: #0f172a;
  color: white;
  margin: 0;
}

.hero {
  text-align: center;
  padding: 60px;
}

.calculator {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  padding: 40px;
}

.form, .results {
  background: #1e293b;
  padding: 25px;
  border-radius: 10px;
}

input {
  width: 100%;
  padding: 12px;
  margin-bottom: 15px;
}

button {
  padding: 12px;
  background: #22c55e;
  border: none;
  color: white;
  cursor: pointer;
}

.results {
  opacity: 0;
  transition: 0.5s;
}

.results.show {
  opacity: 1;
}

.result-box {
  background: #0f172a;
  padding: 20px;
  border-radius: 10px;
  margin-bottom: 15px;
  text-align: center;
  border: 1px solid #334155;
}

.error {
  color: red;
}

@media (max-width: 768px) {
  .calculator {
    grid-template-columns: 1fr;
  }
}