Use `@font-family-base` for headings font-family variable
Use `@font-family-base` for headings font-family variable

BS3 commit 1b89a63a48f0bfd6ba024f1cf573c03a42aa5ef2

ztx1491/todc-bootstrap,mozillo/todc-bootstrap,up2vs/todc-bootstrap,2947721120/todc-bootstrap,2947721120/googlebt4,todc/todc-bootstrap,todc/todc-bootstrap,todc/todc-bootstrap,aaroncnhk/todc-bootstrap