The theme main color can be changed from app/css/scss/_vars.scss

/* colors */
$templateColor: #333;
$titleColor: #0a0a0a;
$white: #fff;
$hoverColor: #cca300;
$grey:#efefef;

In this file, you will be able to see the variable “$templateColor" which is used in all the site elements. If you will change this variable color code the theme color will be changed.

$templateColor: #333;
$hoverColor: #cca300; 

Also, you can integrate the theme color on your elements like in the following example:

.class {color: #{$templateColor};}

In  app/css/scss/_general.scss  several classes use the color variables:

body {
..
color: $templateColor;
}

a:focus, a:hover {
 color: $hoverColor;
}