Whitelabeling
From Roaring Penguin
To customize your theme go to Setup->Theme Customization. In the Custom CSS properties: box at the bottom of the page, place the following text after clearing the box:
===To turn off the footer banner:
#footer_powered { display: none}
===To disable users ability to change themes:
form.theme-selection { display: none}
===To display your logo on login page
https://emailfilteringservice.net/canit/showtrap.php?&rlm=domain-com
Where domain-com is your realm name.