refactor: revert media query range notation (#1072)

Media queries range syntax not supported by Safari for iOS under 16.4

See also:
- https://caniuse.com/?search=media-queries

This reverts commit 1682ce9d7c.

_sass/addon/syntax.scss

@@ -240,7 +240,7 @@ div {
   }
 }
 
-@media all and (width >= 576px) {
+@media all and (min-width: 576px) {
   div[class^='language-'] {
     .post-content > & {
       @include ml-mr(0);