body.single-product #content {
      width: 100%;
}
body,
button,
input,
select,
textarea {
    font-size: 18px;
}
.main-navigation li a {
    font-size: 23px;
}

#billing_postcode,
#shipping_postcode,
input[name="billing_postcode"],
input[name="shipping_postcode"] {
    width: 100% !important;
    max-width: 100% !important;
    min-width: 200px !important;
    height: auto !important;
    display: block !important;
    box-sizing: border-box !important;
}

.woocommerce-cart .shipping-calculator-form input,
.woocommerce-cart .shipping-calculator-form select {
    width: 100% !important;
    max-width: 100% !important;
    box-sizing: border-box !important;
}

.woocommerce-cart .shipping-calculator-form p {
    display: block !important;
    width: 100% !important;
}