CSS block-size

The block-size CSS property defines the size of the block-level element. It determines the height of the element in the inline direction. This property can be specified using different units such as pixels, percentages, and ems.

Let's see how the block-size property works with some examples:

<div style="block-size: 100px; background-color: lightblue;">
    This is a block-level element with a block-size of 100px.
</div>

Result:

This is a block-level element with a block-size of 100px.

In the example above, the block-size property is set to 100px, so the height of the block-level element is 100 pixels.

Now let's see another example with a percentage value:

<div style="height:200px">
<div style="block-size: 50%; background-color: lightgreen;color:black;">
    This is a block-level element with a block-size of 50%.
  </div>
  </div>

Result:

This is a block-level element with a block-size of 50%.

In this example, the block-size property is set to 50%, which makes the height of the block-level element half the height of its containing element.

Lastly, let's take a look at an example using the em unit:

<div style="block-size: 2em; background-color: lightcoral;color:black;">
    This is a block-level element with a block-size of 2em.
</div>

Result:

This is a block-level element with a block-size of 2em.

In this last example, the block-size property is set to 2em, where 1em is equal to the font-size of the element. So, the height of the block-level element is twice the font-size of the element.