css top to bottom animation

1//html code
2<div id="topToBottom"></div>
3
4//css code
5#topToBottom {
6  animation: topToBottom ease 2s;
7  -webkit-animation: topToBottom ease 2s;
8  -moz-animation: topToBottom ease 2s;
9  -o-animation: topToBottom ease 2s;
10  -ms-animation: topToBottom ease 2s;
11}
12@keyframes topToBottom {
13  0% {
14    margin-top: -23%;
15  }
16  100% {
17    margin-top: 0%;
18  }
19}
20
21@-moz-keyframes topToBottom {
22  0% {
23    margin-top: -23%;
24  }
25  100% {
26    margin-top: 0%;
27  }
28}
29
30@-webkit-keyframes topToBottom {
31  0% {
32    margin-top: -23%;
33  }
34  100% {
35    margin-top: 0%;
36  }
37}
38
39@-o-keyframes topToBottom {
40  0% {
41    margin-top: -23%;
42  }
43  100% {
44    margin-top: 0%;
45  }
46}
47
48@-ms-keyframes topToBottom {
49  0% {
50    margin-top: -23%;
51  }
52  100% {
53    margin-top: 0%;
54  }
55}