* {
        margin: 0;
        padding: 0;
        box-sizing: border-box;
        font-family: Arial, sans-serif;
      }

      section {
        display: flex;
        justify-content: center;
        align-items: center;
        width: 100%;
        min-height: 64vh;
        background-color: antiquewhite;
        padding: 12px;
      }

      .calculator {
        background: #fff;
        padding: 25px;
        border-radius: 12px;
        box-shadow: 0 0 15px rgba(0, 0, 0, 0.15);
        width: 100%;
        max-width: 400px;
      }

      h3 {
        text-align: center;
        margin-bottom: 20px;
      }

      form {
        display: flex;
        flex-direction: column;
        gap: 12px;
        font-size: 16px;
      }

      input {
        padding: 10px;
        font-size: 16px;
        border-radius: 6px;
        border: 1px solid #ccc;
      }

      button {
        padding: 12px;
        font-size: 18px;
        border-radius: 6px;
        border: none;
        background-color: #007bff;
        color: #fff;
        cursor: pointer;
        margin-top: 10px;
      }

      button:hover {
        background-color: #0056b3;
      }

      .result {
        margin-top: 15px;
        padding: 15px;
        border-radius: 12px;
        color: green;
        background: #fefcfc;
        display: none;
        font-size: 16px;
      }

      .error {
        color: red;
      }