the.com/mobile first
design for the smallest screen first, then let the big screens earn their extra pixels.
means a design and development philosophy where you build the mobile experience before the desktop one, forcing you to prioritize what actually matters.
from coined around 2009 by luke wroblewski, who argued that since mobile constraints force ruthless prioritization, designing for them first makes every version of a product better, not just the phone one.
constraint as featuresmall screens force you to cut the fluff first
google mandategoogle switched to mobile-first indexing in 2018
progressive enhancementdesktop becomes an upgrade, not the default
for instance
google search index — crawls the mobile version of sites as the primary version since 2018
bootstrap framework — shifted to mobile-first grid system starting version 3, 2013
instagram — launched 2010 as phone-only, desktop came years later as an afterthought