It took a little longer than some other products, but the recently renamed Keep Notes Android app was updated in line with Google's new Material Theme last week. The same new stylings are now starting to roll out to Keep on the web, and it looks much cleaner than before.
"Too much white space" has often been the complaint with Google's recent design refreshes and the new Keep continues this trend. The same principles apply as with the Android app — the yellow header is now white, the gray background is now white, and Google's Product Sans is used for headers with Roboto for body text.
The way things used to be.
The slide-out menu on the left side now has the rounded yellow identifier for what's in focus, and the iconography has been updated to include Google's new hollowed out versions. The general rounding of everything continues, and the settings cog has been moved to the top right corner of the header bar.
Out with the old (above) and in with the new (below).
There are no changes to functionality — this is very much just a fresh lick of paint. One of my accounts has the new design but the other doesn't, so don't panic if you don't have it yet. It'll roll out to you in due course.