 Responsive breakpoints from em to px
 Responsive breakpoints from em to px

Should close https://github.com/twbs/bootstrap/issues/18503
lipis/bootstrap,TheFridayInstitute/bootstrap,copperdesign/bootstrap,sealocal/bootstrap,blockstack/blockstack-bootstrap,lemuelbarango/bootstrap,m5o/bootstrap,supergibbs/bootstrap,Hemphill/bootstrap-docs,abvalentine/bootstrap,onenameio/rhythm-bootstrap,lemuelbarango/bootstrap,slavanga/bootstrap,Hemphill/bootstrap-docs,SweetProcess/bootstrap,Delagen/bootstrap,nice-fungal/bootstrap,jipexu/bootstrap,davethegr8/bootstrap,sealocal/bootstrap,SweetProcess/bootstrap,johnajacob/bootstrap,stanwmusic/bootstrap,creativewebjp/bootstrap,edanbarak/bootstrap,9-chirno/chirno,frostbitten/bootstrap,vsn4ik/bootstrap,david-schopf/bootstrap,xt0rted/bootstrap,joblocal/bootstrap,IdanCo/bootstrap,gijsbotje/bootstrap,realcrowd/bootstrap,andresgalante/bootstrap,slavanga/bootstrap,bootstrapbrasil/bootstrap,Delagen/bootstrap,afuno/bootstrap,inway/bootstrap,Lyricalz/bootstrap,yuyokk/bootstrap,supergibbs/bootstrap,tibo66/bootstrap,TheFridayInstitute/bootstrap,igoynawamreh/bootstrap,copperdesign/bootstrap,janseliger/bootstrap,vitaligent/4,NCARB/bootstrap,frostbitten/bootstrap,andresgalante/bootstrap,NCARB/bootstrap,fschumann1211/bootstrap,Hemphill/bootstrap-docs,janseliger/bootstrap,creativewebjp/bootstrap,andresgalante/bootstrap,realcrowd/bootstrap,lipis/bootstrap,9-chirno/chirno,janseliger/bootstrap,seanwu99/bootstrap,tjkohli/bootstrap,NCARB/bootstrap,yuyokk/bootstrap,vitaligent/4,johnajacob/bootstrap,bardiharborow/bootstrap,frostbitten/bootstrap,inway/bootstrap,nice-fungal/bootstrap,jipexu/bootstrap,tibo66/bootstrap,wesamco/bootstrap-rtl,hebbet/bootstrap,jipexu/bootstrap,seanwu99/bootstrap,xt0rted/bootstrap,seanwu99/bootstrap,nice-fungal/bootstrap,supergibbs/bootstrap,hebbet/bootstrap,abvalentine/bootstrap,creativewebjp/bootstrap,Lyricalz/bootstrap,fschumann1211/bootstrap,lipis/bootstrap,zalog/bootstrap,JumpLinkNetwork/bootstrap-backward,bootstrapbrasil/bootstrap,edanbarak/bootstrap,zalog/bootstrap,coliff/bootstrap,Scoutski/bootstrap,joblocal/bootstrap,afuno/bootstrap,Hightrack/bootstrap,bootstrapbrasil/bootstrap,m5o/bootstrap,davethegr8/bootstrap,n054/bootstrap,JumpLinkNetwork/bootstrap-backward,realcrowd/bootstrap,igoynawamreh/bootstrap,lemuelbarango/bootstrap,GerHobbelt/bootstrap,stanwmusic/bootstrap,vsn4ik/bootstrap,davethegr8/bootstrap,creativewebjp/bootstrap,tomlutzenberger/bootstrap,sealocal/bootstrap,david-schopf/bootstrap,bardiharborow/bootstrap,abvalentine/bootstrap,JumpLinkNetwork/bootstrap-backward,onenameio/rhythm-bootstrap,JumpLinkNetwork/bootstrap-backward,hebbet/bootstrap,vsn4ik/bootstrap,peterblazejewicz/bootstrap,xt0rted/bootstrap,IdanCo/bootstrap,n054/bootstrap,gijsbotje/bootstrap,Delagen/bootstrap,IdanCo/bootstrap,lemuelbarango/bootstrap,joblocal/bootstrap,supergibbs/bootstrap,9-chirno/chirno,twbs/bootstrap,Lyricalz/bootstrap,NCARB/bootstrap,janseliger/bootstrap,peterblazejewicz/bootstrap,sealocal/bootstrap,Hightrack/bootstrap,igoynawamreh/bootstrap,tibo66/bootstrap,copperdesign/bootstrap,seanwu99/bootstrap,bardiharborow/bootstrap,Lyricalz/bootstrap,wesamco/bootstrap-rtl,vsn4ik/bootstrap,9-chirno/chirno,gijsbotje/bootstrap,afuno/bootstrap,jipexu/bootstrap,tomlutzenberger/bootstrap,zalog/bootstrap,johnajacob/bootstrap,onenameio/rhythm-bootstrap,Hightrack/bootstrap,slavanga/bootstrap,GerHobbelt/bootstrap,coliff/bootstrap,vitaligent/4,GerHobbelt/bootstrap,wesamco/bootstrap-rtl,stanwmusic/bootstrap,yuyokk/bootstrap,tomlutzenberger/bootstrap,tagliala/bootstrap,fschumann1211/bootstrap,abvalentine/bootstrap,TheFridayInstitute/bootstrap,johnajacob/bootstrap,inway/bootstrap,IdanCo/bootstrap,igoynawamreh/bootstrap,n054/bootstrap,blockstack/blockstack-bootstrap,kvlsrg/bootstrap,SweetProcess/bootstrap,tagliala/bootstrap,xt0rted/bootstrap,tagliala/bootstrap,blockstack/blockstack-bootstrap,joblocal/bootstrap,copperdesign/bootstrap,yuyokk/bootstrap,kvlsrg/bootstrap,bardiharborow/bootstrap,wesamco/bootstrap-rtl,TheFridayInstitute/bootstrap,SweetProcess/bootstrap,tibo66/bootstrap,peterblazejewicz/bootstrap,lipis/bootstrap,stanwmusic/bootstrap,david-schopf/bootstrap,gijsbotje/bootstrap,Hemphill/bootstrap-docs,hebbet/bootstrap,tjkohli/bootstrap,fschumann1211/bootstrap,slavanga/bootstrap,Delagen/bootstrap,davethegr8/bootstrap,Scoutski/bootstrap,edanbarak/bootstrap,andresgalante/bootstrap,Scoutski/bootstrap,n054/bootstrap,frostbitten/bootstrap,twbs/bootstrap,Scoutski/bootstrap,kvlsrg/bootstrap,edanbarak/bootstrap,afuno/bootstrap,realcrowd/bootstrap