Add custom editor color palette

// into functions.php
add_theme_support( 'editor-color-palette', array(
  array(
    'name'  => __( 'Color prime', 'snippress' ),
    'slug'  => 'color-prime',
    'color' => '#535353',
  ),
  array(
    'name'  => __( 'Color second', 'snippress' ),
    'slug'  => 'color-second',
    'color'	=> '#2a3f89',
  ),
  array(			
    'name'  => __( 'Color accent', 'snippress' ),
    'slug'  => 'color-accent',
    'color' => '#EF1851',
  ),
) );
}