fix: update style

Author: gera2ld

content/pages/index.mdx

@@ -1,8 +1,8 @@
 <ProjectInfo title="Violentmonkey" subtitle="An open source userscript manager." />
 
-<div class="home-buttons" data-ga-category="home-buttons">
-  <a href="get-it/" class="button-primary" data-ga-label="get-started">Get Started</a>
-  <a href="https://github.com/violentmonkey/violentmonkey" class="button-gray" target="_blank" rel="noopener noreferrer" data-ga-label="github">GitHub</a>
+<div class="flex items-center justify-center gap-2 mt-8 mb-20" data-ga-category="home-buttons">
+  <a role="button" href="get-it/" class="button button-primary" data-ga-label="get-started">Get Started</a>
+  <a role="button" href="https://github.com/violentmonkey/violentmonkey" class="button button-secondary" target="_blank" rel="noopener noreferrer" data-ga-label="github">GitHub</a>
 </div>
 
 Violentmonkey provides userscripts support for browsers.