app.css

#logo {
    display: flex;
    justify-content: center;
}

#btn {
    color: green;
    height: 30px;
    width: auto;
}

.w1-full{
    display: flex;
    justify-content: center;
}

#img-id{
    display: block;
    margin-left: 40px;
}

#video_elem {
    display: flex;
    justify-content: center;
    align-items: center;
}

#url_input {
    display: flex;
    justify-content: center !important;
    justify-items: center !important;
    /* width: 900px; */
}