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

      img {
            max-width: 100%;
            display: inline block;
      }
        body {
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100svh;
            width: 100svw;
        }
        
        #calcUtility {
              display: grid;
              grid-template-columns: autofit;
              position: relative;
        }
        
       
        #calcUtility span {
              position: absolute;
              top: 0.25rem;
              left: 15%;
              padding-block-start: 1rem;
              text-align: center;
              color: gold;
              font-weight: 700;
              letter-spacing: 0.2rem;
              text-shadow: 0 0 0.15rem rebeccapurple;
        }

        #calculator {
            font-family: Arial, sans-serif;
            background-color: aquamarine;
            border-radius: 1rem;
            max-width: 31.25rem;
            overflow: hidden;
            border: 0.5rem inset gold;
            outline: 0.5rem ridge purple;
        }

        #display {
            width: 100%;
            padding-inline: 1.25rem;
            padding-block: 1rem;
            font-size: 5rem;
            text-align: left;
            font-weight: 700;
            border: 0.2rem inset gold;
            border-radius: 1rem 1rem 0 0;
            outline: 0.2rem ridge purple;
            background-color: bisque;
            color: dodgerblue;
            text-shadow: 0 0.1rem 0.2rem rebeccapurple;
        }

        #keys {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 1.25rem;
            padding-inline: 1.5rem;
            padding-block: 1.5rem;
            max-width: 100%;
            border-radius: 0 0 1rem 1rem;
        }

        button {
            max-width: 6.25rem;
            max-height: 6.25rem;
            border-radius: .5rem;
            border: 0.2rem groove gold;
            outline: 0.2rem ridge purple;
            outline-offset: 0.1rem;
            background-color: hsla(210, 68%, 70%, 0.3);
            padding-inline: 0.25rem;
            padding-block: 0.25rem;
            text-align: center;
            vertical-align: middle;
            font-size: clamp(2rem, 2.5rem, 3rem);
            font-weight: 700;
            color: gold;
            text-shadow: 0 0.1rem 0.2rem purple;
            cursor: pointer;
            transition: all 500ms ease-in-out;
        }

        button:hover {
            border: 0.2rem groove purple;
            outline: 0.2rem ridge gold;
            outline-offset: 0.1rem;
            background-color: hsla(290, 69%, 70%, 0.3);
            color: purple;
            text-shadow: 0 0.1rem 0.2rem gold;
        }

        .clear {
            max-width: 100%;
            padding-inline: 0.5rem;
            grid-column: span 3;
        }