Fixed link description for CSS property `align-items`
## Helper Classes
-Flexbox makes horizontal and vertical alignment painless, through the CSS properties [`align-content`](https://developer.mozilla.org/en-US/docs/Web/CSS/align-items), [`align-self`](https://developer.mozilla.org/en-US/docs/Web/CSS/align-self), and [`justify-content`](https://developer.mozilla.org/en-US/docs/Web/CSS/justify-content). Foundation includes a handful of classes for these properties, which work with any flexbox-enabled component.
+Flexbox makes horizontal and vertical alignment painless, through the CSS properties [`align-items`](https://developer.mozilla.org/en-US/docs/Web/CSS/align-items), [`align-self`](https://developer.mozilla.org/en-US/docs/Web/CSS/align-self), and [`justify-content`](https://developer.mozilla.org/en-US/docs/Web/CSS/justify-content). Foundation includes a handful of classes for these properties, which work with any flexbox-enabled component.
To understand how these classes work, you need to understand the parent-child relationship created with flexbox. An element with `display: flex` is a *flex parent*, and can horizontally or vertically align its children. All immediate children of the flex parent are *flex children*. A flex child can vertically align itself.