The base colors are the default ones for every element of your website. You will need to use this setting to change the color branding of your store, but you can also use custom colors in the section directly if needed.
To access the Bases Colors Settings, click Customize (Themes section on Shopify) > Theme settings > Bases Colors
Play with those setting to modify the most important aspect of your website
Primary accent combination & Secondary accent combination
Preset color combinations
In booster 5.0, you can make 2 presets of colors for your store. If you are customizing one of your sections, you can select in the color combination setting: your primary or secondary combination. This way you can bring consistency to the color of your website.
Let's say your are customizing your button for a CTA. Instead of reselecting the color simply choose between your combination 1 or 2. It is really simple to use.
This color will be used for urgency indicators such as stock left, cart expiry, and alikes.