backdrop filter alternative

1main {
2  margin: 100px auto;
3  position: relative;
4  padding: 10px 5px;
5  background: hsla(0, 0%, 100%, .3);
6  font-size: 20px;
7  font-family: 'Lora', serif;
8  line-height: 1.5;
9  border-radius: 10px;
10  width: 60%;
11  box-shadow: 5px 3px 30px black;
12  overflow: hidden;
13}
14
15main::before {
16  content: '';
17  margin: -35px;
18  position: absolute;
19  top: 0;
20  right: 0;
21  bottom: 0;
22  left: 0;
23  filter: blur(20px);
24  z-index: -1;
25}