Alexey

let nodeExternals = require('webpack-node-externals');
...
let serverConfig = {
       externals: [nodeExternals()],
}

function sendAjaxForm(result_form, ajax_form, url) {
    jQuery.ajax({
        url:     url, 
        type:     "POST", 
        dataType: "html", 
        data: jQuery("#"+ajax_form).serialize(),
beforeSend: function() {
        $(placeholder).addClass('loading');
    },
success: function(html){  
    $("#result_form").html(html);  
    	},
    	error: function(response) { 
    		document.getElementById(result_form).innerHTML = "Error.";
    	}
 	});
}

@media screen and (max-width: 550px) {
    .copyrights {
        width: 100%;
    }

    .contacts {
        width: 100%;
    }
}