Help with customized header and background color?

[takarai_karin]

I'm using the Summer layout, and would like some help, please.

Journal you are trying to modify: takarai-karin

Account Level (basic, plus, paid): Plus

What are you trying to accomplish?

• Is it possible for me to change the header's image?
  
• Is it possible to change the background color from the current white to preferably light grey, since it's kinder to the eyes?
  
  I'm opening everything in ?style=mine now, and while my layout is still preferable than LJ's default, the whiteness can still be a bit tiring.