22. Grid Layout 1

Layout a 3x3 grid and place A to I in column-first order.

1. set gap in rows and columns of 10px
2. container size is already set.

<div class="container">  <div class="item a">A</div>  <div class="item b">B</div>  <div class="item c">C</div>  <div class="item d">D</div>  <div class="item e">E</div>  <div class="item f">F</div>  <div class="item g">G</div>  <div class="item h">H</div>  <div class="item i">I</div></div>