You can add this at the end of your global.css and it works in Niara and Community default to get basic responsive shopping cart.
This is extracted from very old original prestashop 1.6 bootstrap theme with minimal edits to fit Niara and Community theme.
@media (max-width: 767px) {
#order-detail-content #cart_summary table, #order-detail-content #cart_summary thead, #order-detail-content #cart_summary tbody, #order-detail-content #cart_summary th, #order-detail-content #cart_summary td, #order-detail-content #cart_summary tr {
display: block; }
#order-detail-content #cart_summary thead tr {
position: absolute;
top: -9999px;
left: -9999px; }
#order-detail-content #cart_summary tr {
border-bottom: 1px solid #cccccc;
padding-bottom: 7px;
overflow: hidden;
position: relative; }
#order-detail-content #cart_summary td {
border: none;
position: relative;
float: left;
white-space: normal;
padding: 7px; }
#order-detail-content #cart_summary td.cart_product {
text-align: left; }
#order-detail-content #cart_summary td.cart_avail {
display: none; }
#order-detail-content #cart_summary td.cart_unit {
width: 33%;
text-align: left;
min-height: 70px;
clear: both; }
#order-detail-content #cart_summary td.cart_unit .price {
text-align: left; }
#order-detail-content #cart_summary td.cart_quantity {
width: 33%;
min-height: 70px;
border-left: 1px solid #cccccc;
border-right: 1px solid #cccccc; }
#order-detail-content #cart_summary td.cart_quantity div {
display: block; }
#order-detail-content #cart_summary td.cart_quantity > .form-control {
display: inline; }
#order-detail-content #cart_summary td.cart_quantity > .cart_quantity_button a {
margin-right: 0px;
float: none; }
#order-detail-content #cart_summary td.cart_total {
width: 33%;
min-height: 70px;
text-align: right; }
#order-detail-content #cart_summary td.cart_delete {
position: absolute;
right: 0px;
top: 0px; }
#order-detail-content #cart_summary td.cart_delete:before {
content: '' !important; }
#order-detail-content #cart_summary td div {
display: inline; }
#order-detail-content #cart_summary td:before {
content: attr(data-title);
font-weight: bold;
display: block; }
#order-detail-content #cart_summary tfoot td {
float: none;
width: 100%; }
#order-detail-content #cart_summary tfoot td:before {
display: inline; }
#order-detail-content #cart_summary tfoot tr .text-right, #order-detail-content #cart_summary tfoot tr tbody td.cart_unit, #order-detail-content #cart_summary tbody tfoot tr td.cart_unit, #order-detail-content #cart_summary tfoot tr tbody td.cart_total, #order-detail-content #cart_summary tbody tfoot tr td.cart_total, #order-detail-content #cart_summary tfoot tr .price {
display: block;
float: left;
width: 50%; } }
@media (max-width: 768px) {
#order-detail-content #cart_summary tbody td .price {
text-align: center; }
#order-detail-content #cart_summary tbody td.cart_description {
width: calc(100% - 130px); }
.cart_voucher {
vertical-align: top !important; }
.cart_voucher h4 {
font: 600 18px/22px "Open Sans", sans-serif;
color: #555454;
text-transform: uppercase;
padding: 7px 0 10px 0; }
.cart_voucher .title-offers {
color: #333;
font-weight: bold;
margin-bottom: 6px; }
.cart_voucher fieldset {
margin-bottom: 10px; }
.cart_voucher fieldset #discount_name {
float: left;
width: 219px;
margin-right: 11px; }
.cart_voucher #display_cart_vouchers span {
font-weight: bold;
cursor: pointer;
color: #777; }
.cart_voucher #display_cart_vouchers span:hover {
color: #515151; }
}