.flex-container {
	display: -webkit-flex;
	display: flex;
}
.flex-nav {
	margin: 2px;
	border: 1px solid #444;
	padding: 10px;
	width: 200px;

}
.flex-spalte {
	margin: 2px;
	border: 1px solid #444;
	padding: 10px;
	flex:1; /*alle gleich breit */
}

.sp4 {
	flex:4;	/* oder flex-grow: 4 */
}

figure img {
	width: 100%;
	height: auto;
}

.flex-spalte figure {
	margin:0;
	width: 100%;	
}