You can now change size in iOS browsers per website, similar to desktop browsers. Click the "aA" icon at the upper left of the address bar and you'll see "a

You can now change size in iOS browsers per website, similar to desktop browsers. Click the "aA" icon at the upper left of the address bar and you'll see "a 100% A". By clicking the left or right icons, you can change the size percentage. It's very similar to desktop browsers. This relatively new functionality is also very close to where the UI is for "Show Reader View", so it's easy to miss.