If your browser supports display: grid and shape-outside: circle(), the text and border will be red.
.box { border: 4px solid blue; color: blue; } @supports (display: grid) and (shape-outside: circle()) { .box { border: 4px solid red; color: red; } }
<div class="box"> If your browser supports display: grid and shape-outside: circle(), the text and border will be red. </div>