Columns are currently a fixed width, unless there are so many columns that they start narrowing.
The reason we chose for this is that iPhone and Mac have very different screen sizes. Having a fixed size one one device will rarely work well on the other. It might work fine on the Mac, but on iPhone it might go off the side of the screen. For this reason, we resize columns to fit the device.
In future, we may make it possible to change the relative widths of columns (eg 30%). We would like to offer more options, but it can quickly become very messy.
We’ll see what we can do.