To change the color please open the _variables.scss file from /assets/scss/normalize/_variables.scss

You will get the following variables there,

$primary:    #404459 !default;
$secondary:  #3F51B5 !default;
$success:    #fdcb6e !default;
$warning:    #d63031;
$info:      #eeeeee;
$dark:      #2d3436;
$light:      #ffffff;
$danger:      #63646a;

$color-1 : #6c5ce7;
$color-2 : #0984e3;
$color-3 : #ff7675;
$color-4 : #fdcb6e;
$color-5 : #e84393;
$color-6 : #00b894;

Now change the color code from there.