th: var(--box-size);
        height: var(--box-size);
        border-radius: calc((var(--box-size) / 4) - 4px);
        box-sizing: border-box;

        background-color: black;
      }
      .box.outline {
        background-color: bisque;
        border: 8px solid black;
      }
      .box.outline.dashed {
        background-color: darkkhaki;
        border-style: dashed;
      }
      .box.outline.double {
        background-color: darkseagreen;
        border-style: double;
      }
      .box.outer {
  