Update ·
More room on your phone
On a phone, Home, the Library and Versions now use the full width, and Create keeps the prompt at the bottom of the screen.

Kuro on a phone used to leave a lot of the screen empty. Pictures sat inside wide margins, and a widescreen video in the Library was drawn as a small thumbnail in one of two columns.
Home, the Library and Versions
Home’s recipes now run almost edge to edge. In the Library, a widescreen picture or video takes the full width of the screen, so you can see what you made without opening it. When you open an item, its Versions tab uses the whole screen too.
Create
The prompt now sits at the bottom of the screen, where your thumb already is. It is taller, so there is room to write, and the + for adding a picture sits next to Create. The recipes for what you are making are just below the headline: scroll up and they slide behind the prompt.
Nothing changes on a computer.