2015 LX CVT poor gas mileage

I have a 2015 LX CVT with about 140k miles. Gradually over the past few months, my gas mileage has gotten worse and worse. Now I'm regularly getting below 30mpg for mixed city/highway driving, the kind of driving that I would have gotten 35-38 mpg a couple of years ago.

The gauge that displays bars that show what mpg I'm getting right at the moment seems to be working fine... Like I am often getting long stretches on the highway where it's over 45mpg on the gauge but it doesn't seem to nudge the overall average gas mileage when it's sitting at 26-27mpg.

Anyone else have this issue and possible solutions?