[css-forms-1] Use calc-size in min sizes (#12137)

Author: lukewarlow

css-forms-1/Overview.bs

@@ -892,10 +892,10 @@ input:is([type="color"], [type="button"], [type="reset"], [type="submit"]) {
 
   /* These min-size rules ensure accessibility by following WCAG rules:
    * https://www.w3.org/WAI/WCAG22/Understanding/target-size-minimum.html
-   * The 1.2em is there to make sure that options without text don't change
+   * The 1lh is there to make sure that options without text don't change
    * the block size of the button. */
-  min-block-size: max(24px, 1lh);
-  min-inline-size: 24px;
+  min-block-size: calc-size(auto, max(size, 24px, 1lh));
+  min-inline-size: calc-size(auto, max(size, 24px));
 
   /* box-sizing comes from existing UA styles which happen to
    * already be interoperable. */