Use this code...
.component-content .pagination ul li a, .component-content .pagination ul li span {
line-height: normal ;
}
To create a custom CSS compatible with Gantry 5 please read this
http://docs.gantry.org/gantry5/tutorials/adding-a-custom-style-sheet
.
Remember to recompile CSS from base outline too.
NOTE: you have an error in your existing custom.scss file... see screenshot.
Regards, Mark.