文字对齐：中心; 忽略显示：flex元素？

Question

For the following the anchor text isn't centered. If I change the anchor's display from flex to block then the text is centered. Why is this?

Ive only tested on Chrome so far.

<ul>
  <li><a href="#">Link</a></li>
  <li><a href="#">Link</a></li>
  <li><a href="#">Link</a></li>
  <li><a href="#">Link</a></li>
  <li><a href="#">Link</a></li>
  <li><a href="#">Link</a></li>
</ul>



*, *:before, *:after {
  -moz-box-sizing: border-box; 
  -webkit- box-sizing: border-box;   box-sizing: border-box;
 }

ul {
  display: flex;
  flex-flow: row wrap;
  padding: 0;
  width: 40%;
  margin: auto;
  border: 1px solid gold;
}
li {
  list-style-type: none;
}
a {
  background: grey;
  width: 200px;
  border: 1px solid red;
  text-align: center;
  display: flex;
}

http://codepen.io/anon/pen/dgmbH

Answer 1

Note: Before you go ahead to read my answer, I would like you to notify that am not using any of the PROPRIETARY PREFIXES, if it doesn't work for you, its time to update your browser, or try adding the prefixes like -moz or -webkit and see if it works for you.

The correct way to do is to use display: flex; for the ul element and flex-grow on li elements...

ul {
  display: flex;
  padding: 0;
  width: 40%;
  margin: auto;
  border: 1px solid gold;
}

li {
  list-style-type: none;
  flex-grow: 1;
}

Demo

You are using a fixed width on a tag ie width: 200px; and that kills the idea of flex layout, so take that out, and alter your CSS with the one provided by me.

Here, I've used flex-grow with a value of 1 so that each of the li element shares the equal amount of width

---

If you are looking to wrap the cells if they exceed the containers width, than you need to use the following properties on ul element like

ul {
  display: flex;
  padding: 0;
  width: 40%;
  margin: auto;
  border: 1px solid gold;
  flex-direction: row;
  flex-flow: row wrap;
}

Demo (Resize your window to see the effect)

Sample 1, the wrapped element will stretch to full width

---

Sample 2, Elements wrapped equally further

Also note that am using min-width: 100px; on li elements to force wrap in the demonstration

---

As you commented that you wanted three li on each row, than instead of using flex-grow: 1; you need to use flex: 1 1 33%; like

li {
  list-style-type: none;
  flex-grow: 1;
  min-width: 100px;
  flex: 1 1 33.33%;
}

Demo

Sample 3, Equal number of li on each row

Sample 4, Equal number of li on each row even when resized

On further resize, they will accommodate automatically say two in a row and one in a row..