Opacity
Control the opacity of elements.
The opacity property sets the opacity level for an element. The opacity level describes the transparency level, where 1 is not transparent at all, .5 is 50% visible, and 0 is completely transparent.
100%
75%
50%
25%
<!-- Opacity -->
<div class="opacity-100">...</div>
<div class="opacity-75">...</div>
<div class="opacity-50">...</div>
<div class="opacity-25">...</div>