Customizer Options for Categories

I have a bunch of categories which I’ve managed to appear as icons with background colours on the posts list. I would like the option to customise these css styles in my theme customizer so it is easier to change later for other users rather than rummaging around in the CSS.

I tried adding the following code to my functions.php, code that I’ve found whilst trying to read tutorials online:

/*Customizer Code HERE*/
add_action('customize_register', 'category_1_customizer');
function category_1_customizer($wp_customize){
$wp_customize->add_section('category_1_definition', array(
  'title'          => 'Edit Category 1 Styles'
 ));
$wp_customize->add_setting('background_color', array(
 'default'        => '#adfd46',
 ));
$wp_customize->add_control( new WP_Customize_Color_Control( $wp_customize, 'background_color', array(
 'label'   => 'Change Background Colour',
  'section' => 'category_1_definition',
 'settings'   => 'background_color',
)));

$wp_customize->add_setting('category_icon');
$wp_customize->add_control(new WP_Customize_Upload_Control($wp_customize,'category_icon',array(
 'label'      => __('Category Icon', 'invest'),
 'section'    => 'category_1_definition',
 'settings'   => 'category_icon',
 )));

}

function invest_customize_css()
{
    ?>
         <style type="text/css">
             .corporate .sticky-category, .corporate .bottom-category { background:url(<?php echo get_theme_mod('category_icon'); ?>) no-repeat <?php echo get_theme_mod('background_colour', '#adfd46'); ?>; }
         </style>
    <?php
}
add_action( 'customize_register', 'category_1_customizer');

The style I want changing is the following:

.corporate .sticky-category, .corporate .bottom-category {
	height: 80px;
	width: 80px;
	background:url(/wp-content/uploads/2016/05/category-1.png) no-repeat #adfd46;
	background-position:50% 50%;
	float:left;
	background-size:50px 50px;
	margin-top:247px;
}

The Customizer options appear in the Customizer but nothing happens when I change a background colour, so there is something apparent I’m doing wrong but I cannot find a tutorial online to help me with this.