WP Customizer - custom text line

function themedemo_customize($wp_customize)
{

    $wp_customize->add_section( 'themedemo_demo_settings', array(
        'title'          => 'Indstillinger',
        'priority'       => 35,
    ) );

    $wp_customize->add_setting( 'headline-1', array(
        'default'        => 'default_value',
    ) );

    $wp_customize->add_control( 'headline-1', array(
        'label'   => 'Header line 1',
        'section' => 'themedemo_demo_settings',
        'type'    => 'text',
    ) );
   }

<?php echo get_theme_mod( 'headline-1', 'default_value' ); ?>