add centering to div code example

Example 1: css center text

/* To center text, you need to use text-align. */

.centerText {
  text-align: center; /* This puts the text into the center of the 
  screen. */
}

/* There are also other things that you can use in text-align:
left, right, and justify. Left and right make the test align to the
right or left of the screen, while justify makes the text align both
sides by spreading out spaces between some words and squishing others. */

Example 2: center text in div container

text-align: center

Example 3: center element in div

/* html */
<h1>Centering with CSS</h1>

<h3>Text-Align Method</h3>
<div class="blue-square-container">
  <div class="blue-square"></div>
</div>

<h3>Margin Auto Method</h3>
<div class="yellow-square"></div>

<h3>Absolute Positioning Method</h3>
<div class="green-square"></div>

/* css */
h1,
h3 {
  text-align: center;
}

.blue-square-container {
  text-align: center;
}

.blue-square {
  background-color: #0074D9;
  width: 100px;
  height: 100px;
  display: inline-block;
}