.gas-spring-calculator {
  background: #f4f9ff;
  border: 1px solid #dbe9f6;
  border-radius: 12px;
  padding: 20px;
  max-width: 400px;
  margin: auto;
  font-family: 'Segoe UI', sans-serif;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.gas-spring-calculator h2 {
  text-align: center;
  color: #0077cc;
}

.gas-spring-calculator label {
  display: block;
  margin: 10px 0 5px;
  font-weight: 500;
}

.gas-spring-calculator input[type="number"] {
  width: 100%;
  padding: 8px;
  border: 1px solid #ccddee;
  border-radius: 6px;
}

.gas-spring-calculator input[type="checkbox"] {
  margin-right: 6px;
}

.buttons {
  display: flex;
  justify-content: space-between;
  margin-top: 15px;
}

.buttons button {
  flex: 1;
  margin-right: 10px;
  background: #0077cc;
  color: white;
  border: none;
  padding: 10px;
  border-radius: 8px;
  cursor: pointer;
  font-weight: bold;
  transition: background 0.3s ease;
}

.buttons button:last-child {
  background: #4db6ac;
  margin-right: 0;
}

.buttons button:hover {
  background: #005fa3;
}

#result {
  margin-top: 20px;
  font-weight: bold;
  color: #333;
}