Bug with running landing page, wont Run changes to work


Wondered If anyone could give some advice or assist with this issue.

So I’m building my landing page using HTML and CSS. Everything worked fine yesterday. I go back to working on it this evening, however when I make changes or add new content to my css/HTML these changes are no longer being made, when I press “RUN” no new content is added.

Is this a glitch or a bug? Please help!

Thanks for taking the time to read this, appreciate any assistance.