Theme not fitting all screens

I recently built a website for the school district I work for and it looked great on the wide monitors at my desk. The problem is, it looks terrible everywhere else. Some of my coworkers have regular monitors and the title is pushed below the logo and some blocks are cut off. The menu items don’t fit in one row so it pushes one menu heading to the next line below, making it very difficult to get to with the cursor and making the menu section incredibly large and covering up the slider below it. Please note that once you read this, there may not be a slider as I am putting something else in it’s place for the time being. Another issue with the menu is the heading drop-downs get cut off at the end of the screen. I would think they should automatically be pushed over so all the text can be read.
I have checked out the site on my android and there are issues with the title being pushed downwards and looking terrible. I would also think that the sizing would be adjusted to fit all screens.
This theme was highly recommended to me and I was told it was responsive, yet I am not finding that it is. Please help.

The page I need help with: [log in to see the link]