* {
        box-sizing: border-box;
      }

      body {
        background-color: #f2f2f2;
        font-family: "Helvetica", sans-serif;
      }

      .container {
        background-color: white;
        max-width: 600px;
        margin: 100px auto;
        padding: 20px;
        box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
        border-radius: 10px;
      }

      h1 {
        margin-top: 0;
        text-align: center;
      }

      input {
        padding: 10px;
        border: 1px solid #ccc;
        border-radius: 4px;
        margin: 10px 0;
        width: 100%;
      }

      button {
        background-color: #4caf50;
        color: white;
        padding: 10px;
        border: none;
        cursor: pointer;
        margin: 10px 0;
        width: 100%;
        font-size: 18px;
        text-transform: uppercase;
        transition: background-color 0.2s ease;
      }

      button:hover {
        background-color: #45a049;
      }

      #total {
        font-size: 24px;
        font-weight: bold;
        margin-top: 10px;
      }