*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
.big{
    display: flex;
    justify-content: center;
    align-items: center;

}
.welcome{
    margin-top: 50px;
    padding: 25px;
    box-shadow: 0 0 10px black;
    width: 500px;
    height: 400;
    border-radius: 10px;
}