body,
html {
    min-height: 100%;
    margin: 0;
    padding: 0;
}
.container{
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    height: 80vh;
}
.logo{
    margin: 80px 0;
    width: 50%;
}
.app-buttons {
    margin: 0;
    padding: 0;
    text-align: center;
}
.app-buttons li {
    flex: 0 0 20%;
    list-style: none;
    display: inline-block;
    padding: 10px;
}
.app-buttons li img {
    height: 100px;
    cursor: pointer;
}