Space two items in a flexbox with the left and right edges aligned with the outer container.

style.css

.flex-container {
	padding: 0;
	display: -ms-flexbox;
	display: -webkit-flex;
	display: flex;
	-webkit-flex-direction: row;
	-ms-flex-direction: row;
	flex-direction: row;
	-webkit-flex-wrap: nowrap;
	-ms-flex-wrap: nowrap;
	flex-wrap: nowrap;
	-webkit-justify-content: center;
	-ms-flex-pack: center;
	justify-content: center;
	-webkit-align-content: stretch;
	-ms-flex-line-pack: stretch;
	align-content: stretch;
	-webkit-align-items: stretch;
	-ms-flex-align: stretch;
	align-items: stretch;
	}
.flex-half-left {
	width: 49%;
	padding-right: 1%;
	-webkit-order: 0;
	-ms-flex-order: 0;
	order: 0;
	-webkit-flex: 0 1 auto;
	-ms-flex: 0 1 auto;
	flex: 0 1 auto;
	-webkit-align-self: auto;
	-ms-flex-item-align: auto;
	align-self: auto;
}
.flex-half-right {
	width: 49%;
	padding-left: 1%;
	text-align: right;
	-webkit-order: 1;
	-ms-flex-order: 1;
	order: 1;
	-webkit-flex: 0 1 auto;
	-ms-flex: 0 1 auto;
	flex: 0 1 auto;
	-webkit-align-self: auto;
	-ms-flex-item-align: auto;
	align-self: auto;
}