There are no major syntax errors or obvious deviations from the standard template code. The most noticeable difference is:

The original version uses !important to override the styles. You might consider removing it since this can lead to less predictable behavior across devices and different versions of browsers.

However, if you're not using any vendor-specific prefixes (e.g., -webkit-, -moz-) already then that doesn't seem critical right now based on the knowledge cutoff provided - but it's good practice to use them consistently!

Optimization suggestion: Ensure padding values adhere exactly to CSS grid alignment principles rather than being rounded; otherwise elements inside an element with grid-template-columns:auto * 300px; like .page-content could become unevenly spaced. Consider adding a media query when screen size > 640px to adjust the layout accordingly.