How to make alignment along the length - the center?

Question

css

This is an offline page of the site. It is not possible to align the layer along the length. On phone/tablet, content is not centered in relation to length. Here is a screenshot and here is the site onehub.ru. Highlighted in red as it should be. If anyone knows, throw off the code and styles how to fix it.

Answer 1

html {
    min-height: 100%;
}
body {
    min-height: 100vh;
    display: flex;
}
.main {
    margin: auto;
}