css (box-shadow) transition on page load

Question

Is there a way to make a transition happen for a box-shadow on page load instead of with a hover or click effect?

The transition I want on page load, or as an event:

.item:hover{
margin:0 auto;
box-shadow: 1px 1px 20px  grey;
transition: 0.7s;
max-width: 940px;
color: dimgrey;
padding-top: 10px;
padding-bottom: 10px;
border-radius: 10px 10px 10px 10px;
}

Answer 1

1. you can name keyframes a name and provide the time you need, I have provided 4sec in the example.
2. It says change the background color from red to yellow and increase the height by 200px and animate this for 4 seconds.

 .item { height: 100px; width: 100px; background-color: blue; animation-name: animate; animation-duration: 4s; border-radius: 10px; } @keyframes animate { from { background-color: red; } to { background-color: yellow; height: 200px; } }

 <div class="item"> </div>