example-two-column-address.css

/* Main layout: arrange all my address fields in 2 columns */
#pmpro_form_fieldset-my-address .pmpro_form_fields {
	display: flex !important;
	flex-wrap: wrap !important;
	flex-direction: row !important;
	gap: 20px;
}

/* Each field gets half-width column */
#pmpro_form_fieldset-my-address .pmpro_form_field {
	flex: 1 1 calc(50% - 20px) !important;
	max-width: calc(50% - 20px) !important;
	box-sizing: border-box !important;
}

/* Mobile responsive stacking */
@media (max-width: 640px) {
	#pmpro_form_fieldset-my-address .pmpro_form_field {
		flex: 1 1 100% !important;
		max-width: 100% !important;
	}
}