Custom Design Object

All fields:

• screen_name_color (string) [optional]
• text_color (string) [optional]
• link_color (string) [optional]
• sidebar_border_color (string) [optional]
• sidebar_color (string) [optional]
• background_color (string) [optional]
• background_image (string) [optional]
• text_color (string) [optional]
• background_position (string) [optional]
• background_repeat (string) [optional]
• background_attachment (string) [optional]
• background_size (string) [optional]