Theme Loading Into Dashboard

I’m experiencing the exact same problem, and it makes using the editor very difficult. I can only assume that it is a bug with one of the newer versions of WordPress in certain scenarios / configurations.

Until it gets fixed properly my workaround is to wrap my enqueue statements in an if statement for !is_admin().

For example, in your case:

function myyogawebsite_scripts() {
    if(!is_admin()) {
        wp_enqueue_style( 'foundation-normalize', get_template_directory_uri() . '/css/normalize.css' );
        wp_enqueue_style( 'foundation-min-css', get_template_directory_uri() . '/css/foundation.min.css' );

        // WordPress Core
        wp_enqueue_style( 'wordpress-core-css', get_template_directory_uri() . '/css/wp-core.css' );

        // Load our main stylesheet.
        wp_enqueue_style( 'myyogawebsite-style', get_template_directory_uri() . '/style.css' );

        wp_enqueue_script( 'foundation-jquery', get_template_directory_uri() . '/js/jquery.js', null, null, false);

        wp_enqueue_script( 'foundation-modernizr', get_template_directory_uri() . '/js/modernizr.js', null, null, true);
        wp_enqueue_script( 'foundation-min-js', get_template_directory_uri() . '/js/foundation.min.js', array('foundation-jquery'), null, true);
    }
}
add_action( 'wp_enqueue_scripts', 'myyogawebsite_scripts' );

See how that works for you. What version of WordPress are you using, and what platform is your website hosted on (eg. Linux, Windows). I’m on WP4.0 on Windows.