Update src/content/pages/guidelines.mdx

Co-authored-by: Nikoś <[email protected]>

Author: cmaureir

src/content/pages/guidelines.mdx

@@ -34,7 +34,7 @@ are:
 * Try not to cram too much on one slide. There are no hard and fast rules about how many slides to
   have in a talk, as long as the slides naturally flow with your spoken narrative and don’t overwhelm
   your audience with information.
-* The resolution of the projectors is 1920x1080px, so be mindful in case your
+* The resolution of the projectors is 1080p (1920 × 1080 pixels), so be mindful in case your
   computer has a different one, like a 4k screen, so you can test that before.
 
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