The Total theme includes built-in settings for altering the default button colors used in the theme either globally or on a per-button basis.
Global Button Color & Border Radius
To change your button color site-wide simply log into WordPress and go to Appearance > Customize > General Theme Options > Links & Buttons to make your adjustments.
Global Button Typography Options
If you want to change the font family, weight, style, transform, line-height and letter spacing of all the buttons on the site you can do this in the Customizer under the Typography > Buttons section.
WPBakery Total Button Module Color
Various modules also have the ability to alter the color of your buttons on a per module basis. For example if you are using any of the Total “grid” modules such as the Portfolio Grid you will see a tab for all the button settings where you can alter the color different from the default site-wide color.