.inner-cart-page .woocommerce-shipping-calculator {
    border: 1px solid;
    border-color: #ebebeb;
    padding: 20px 20px 10px 20px;
    width: 100%;
}

@media (min-width: 992px) {
   .inner-cart-page .woocommerce-shipping-calculator {
      width: 100%;
   }
}