Repository not displaying the same on colleagues computer

I have recently done an update on my repository, and have been informed by my colleagues that they are having issues viewing the css formatting correctly. When I view it on my computer through the GitHub Pages it looks great, but when my colleagues view it on their end it’s not displaying correctly. This is relating to the h1 heading in the projectideas.html file, it should be displayed side by side not one word offset and above the other. can someone help me?

Can you share screenshots?