update bold

Author: tcaldwell-x

overview.mdx

@@ -29,7 +29,7 @@ import { Button } from '/snippets/button.mdx';
       <img src="/logo/grok.svg" alt="Grok logo" style={{ width: '100%' }} />
     </div>
     <div style={{ position: 'relative', zIndex: 1 }}>
-      Pay only for what you use. Plus, earn free xAI API credits when you purchase X API credits!
+      Pay only for what you use. Plus, <span style={{fontWeight: 500, color: 'rgba(255,255,255,0.75)'}}>earn free xAI API credits</span> when you purchase X API credits!
       <br /><br />
       <Button href="/x-api/getting-started/pricing">Learn more</Button>
     </div>