Not only can you change the way the platform looks, you can make it look different for different users by preparing many color palettes that will be displayed to users based on information in their profiles. That means that if you want people from different departments or companies see different colors, nothing is stopping you!
First things first, you need to decide which field in user profile will determine the palette. To do that, go to Configuration/Interface settings/Color palette settings.
In "External field ID" field you need to put an ID of a field that will provide information. So, if you want a department to determine the palette, you need to put an ID of a field with the department here. (Fields and their IDs are created in Configuration/Everything else/Custom fields.)
When you choose the field that will provide information, go to "Other color palettes" tab" to create different palettes for different field values.
Click "Add new color palette" to begin creating.
To create a palette, you have to name it - this name will be visible on the list of all the palettes.
The most important part is the ID - it's the value in the field that we chose before. That value determines that users will see this specific palette. So, if we put "A" as an ID, that means that everyone with "A" in their profile (in the chosen field) will see this palette. Basically, people from department A will see different colors than people from department B.
In the next sections you can set the palette - it works just like with settings for the whole platform.