#cover_all{
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vw;
    background-color: rgba(0,0,0,0.5);
    z-index: 200;
}
#ask_back{
    width: 30%;
    height: 20vh;
    position: fixed;
    background-color: white;
    left: 35%;
    top: 40vh;
    z-index: 201;
    box-shadow: 2px 2px 6px black;

}
#ask_back_question{
    padding: 10px;
}
.ask_back_answer{
    position: fixed;
    top: 50vh;
    color: blue;
    cursor: pointer;
    height: 10vh;
    width: 15%;
    z-index: 22;
    line-height: 10vh;
    text-align: center;
}
.ask_back_positive{
    left: 35%;
}
.ask_back_negative{
    left: 50%;
}