https://css-tricks.com/snippets/css/a-guide-to-flexbox/
.container {
display: flex;
}
.child {
flex: 1; // fill remaining space
}
flex-direction: row (default) or column; justify-content: how it aligns along the flex-direction; Think of how text is justified along the direction it flows
align-items: how it aligns perpendicular to the flex-direction