The layout for the view that shows a single world clock needs to improved: the time should be vertically centred against the image, and it needs to scale as the window size is changed.

Guidance can be found here:

https://github.com/gnome-design-team/gnome-mockups/raw/master/clocks/layout-clock-alignment.png

https://github.com/gnome-design-team/gnome-mockups/raw/master/clocks/layout-clock-scaling.png

(Note that the numbers in these images are suggestions only - you can use your own judgement!)