Hello sarahdc,
It can be done by css. Follow below steps:
1. Login as admin and go on theme customizer Dashboard >> Apperance >> Customize or Click on Custimze link on top bar from front-end.
2. Navigate Additional CSS and put below css into textarea then click on Save & Publish button.
.last {
display:none !important;
}
.one_fourth {
width: 28.33% !important;
}
If Additional CSS Option is not shown then put css code into your current theme’s style.css located wp-content/themes/colorway/ folder.
Note : All Changes you done in style.css or other file are gone when you update theme. So prefer Child Theme.
Hope this will helps you.