Some CSS not working

Hi there lovely WMPU Dev folks! Some of the CSS on my site has stopped working. I suspect the WP update itself has caused this. I have deactivated all the plugins and turned them back on one by one but no luck. I can't update WP myself because of my host. They insist on doing it. I'm thinking they updated it, didn't tell me and I didn't notice the errors until I went to make plugin updates. I could be wrong but that's my thought, anyway.

Here are the issues:
If you look at the menu, I had the text set at a much smaller size and it should be regular regular, not bolded. Here's the corresponding code:??
.et-fixed-header #top-menu li a
{?font-size: 16px !important;
font-weight: 300;

If you scroll down the home page, the number counter is much smaller than it was before the update. Here's the code that isn't being read correctly that is currently in the CSS box of my theme. Here's the corresponding code:??
#as58 .stat .number, #as58 .stat .fa {?font-size: 100px !important;?}
??I took a screenshot encompassing both these areas illustrating what I've said. It's the first attachment below.

If you scroll down even further,  you'll see that the events are stacked on top of the other. They were once next to one another, four across. I can't get this code to work anymore:
div#sf_widget_event-3 {?width: 100%;?margin: 0;?}?.event-item {? width: 22.5%;?    float: left;?    margin-right: 3%;?}?.event-item:last-child {?margin-right: 0;?}

I've attached a screenshot of what it should look like. It should be the second uploaded.

I have also installed the WPMU Dev Dashboard and granted support access. Let me know what you'd like me to try! I'd love to know what's wrong and help with the fix.

Many thanks to you all!