docs(video embed): update "Theme" section wording

elements/rh-video-embed/docs/10-style.md

@@ -22,7 +22,7 @@ The video embed element consists of a semitransparent play button with a video t
 
 ## Theme
 
-The video embed element is available in both light and dark themes. It can include either a light or a dark play button, depending on the thumbnail image underneath. If an image is lighter, use a dark play button for accessibility and vice versa. The user is currently responsible for preventing color contrast issues between the video thumbnail and the play button.
+The video embed element is available in both light and dark themes. It can include either a light or a dark play button, depending on the thumbnail image underneath. If an image is lighter, use a dark play button for accessibility and vice versa. The user is currently responsible for setting the play button color and preventing color contrast issues between the button and the video thumbnail.
 
 <div class="grid xs-two-columns">
   <uxdot-example width-adjustment="420px">