Increasing the AMP CSS limit
Whether your style is a professional journalist website or bohemian ecommerce emails, AMP now gives you more room to show it. The AMP maximum allowable CSS limit has been raised to 75kB – a 50% increase! This is the biggest, and, well, only change to the CSS cap in the near half-decade lifespan on the AMP project, and affects both AMP powered websites and AMP for Email.
AMP had the 50kB limit with the best intentions – a forcing function to encourage strong CSS hygiene. Over the years, we’ve received a lot of feedback on the CSS allotment, and we hear you! Fitting experiences that meet higher-than-ever user expectations within a maintainable 50kB limit is difficult.
This was no hasty change – we investigated many different possibilities, including automatic AMP cache level minification, migrating to a percentage-of-used-selector based limit, or even a dynamic limit based on document complexity. Ultimately, raising the limit was the option that best fit AMP developer’s needs.
So the good news is that you now have 75kB of CSS available on each AMP powered webpage and AMP email. Even better news: you don’t have to change a thing on your existing AMP experiences! Since the AMP library is evergreen, this limit will automatically roll out to any and every AMP powered site soon.
The AMP team is thrilled to see what new possibilities this change will open up for all developers, and can’t wait to see what’s dreamed up. You can join the community to share what you make, or just follow along with all AMP updates, on the Slack channel, twitter, or by sign up for our newsletter.
Crystal Lambert, Technically a Writer, Google, AMP Project
Patrick Kettner, Developer Cheerleader, Google, AMP Project