WP Customize API Checkbox change value

Heyo,

I'm once again stuck with my Customizer API. I want a Checkbox to set display:none on an div if it's checked. But insteat of picking the default value that I have set in the add_setting panel, it set's display:1.

my functions.php looks someting like this:

$wp_customize->add_setting('mytheme_setting', array(
    'default' => 'none',
    'transport' => 'refresh',
));

$wp_customize->add_control( new WP_Customize_Control( $wp_customize, 'mytheme_control', array(
    'label' => __('Display This!', 'mytheme'),
    'section' => 'mytheme_section',
    'settings' => 'mytheme_setting',
    'type' => 'checkbox',
)));

and the include looks something like this:

.someclass {
    display: <?php echo get_theme_mod('mytheme_setting'); ?>;
}

Now with this code, if the checkbox is checked it displays 'display:1' and if its not checked, it displays 'display:'. What am I missing?

Thanks in advance!