Why are all of the tables small instead of 100% width? [Screenshot Included]

[Alex C.]

I've been working on a new theme and this hasn't ever happened on previous themes I've created but the tables have somehow randomly shrunk... I've manually fixed some of them but I would like to know why they have done this and how I can fix all of them easily. Here's the picture:



I'd appreciate any help!

[Jason L.]

.tborder { width: 100%; }

[Alex C.]

Ah, thank you so much Jason, I appreciate it.