You can customize the overall look and feel of your knowledge base by simply updating the header color and logo to your brand's assets. To change this, you'll need to find the "Custom Header and Footer" option under your brand's customizable settings.
Go to "Settings" > "Brands" > "See all settings" > "Custom Header and Footer".
You'll need to enter something like this in the header. Just replace the capital letters with your assets.
<div style="padding: 20px 0px; background: #HEXCODE"> <div class="container"> <a href="SITE URL"><img src="LOGO URL" style="height: 40px" /></a> </div> </div>