Try refreshing your browser with Ctrl-F5, or by clearing your cache.
If you are unsure on how to clear your browser cache, you can find more information
here.
If this does not help, updating your browser or trying a different browser may improve things for you.
It also possible its a screen resize problem. To rectify this please use CTRL+0 on a PC or CMD+0 on a Macbook. It is not always possible to work out whether the screen has zoomed in or out from looking so this will reset the zoom to 100%.