html,body{
    padding: 0px;
    margin: 0px;
    width:  100%;
}

.box_home {
        background-image: url(img/background_img.png);
        background-size: 100%  100%;
}

.box_home_logo {
        display: flex;
        justify-content: center;
}

.box_home_logo_img_w{
        float: right;
        margin-top: 15%;
        width: 50px;
        height: 50px;
}

.box_home_logo_img_m{
        float: right;
        margin-top: 15%;
        width: 100px;
        height: 44px;
}

.box_home_logo_span{
        font-size: 30px;
        color: #FFFFFF;
        font-weight: bold;
        margin-top: 17%;
        margin-left: 2%;
}
.box_home_desc{
        display: flex;
        justify-content: center;
        margin-top: 5%;
}

.box_home_desc_p{
        font-size: 14px;
        text-align: center;
        color: #99b5f1;
}

.box_home_download_box{
        width: 80%;
        margin-left: 10%;
        display: flex;
        justify-content: center;
        margin-top: 10%;
}
.box_home_download_box_item{
        width: 33.3%;
        display: flex;
        justify-content: center;
}
.box_home_download_box_item_img{
    width: 75px;
    height: 60px;
}

.box_home_demo{
    display: flex;
    justify-content: center;
    margin-top: 10%;
}
.box_home_demo_img{
    width: 80%;
    align-self: flex-end;
}
@media only screen and (min-width: 280px) {
    .box_home_logo_img_w_big{
            float: right;
            margin-top: 15%;
            width: 36%;
            height: auto;
    }
    .box_home_logo_img_m{
            float: right;
            margin-top: 18%;
            width: 64px;
            height: 32px;
    }
    .box_home_download_box_item{
            width: 30%;
            display: flex;
            justify-content: center;
    }
    .box_home_download_box_item_img{
            width: 80px;
            height: 30px;
    }
}
@media only screen and (min-width: 540px) {

    .box_home_logo_img_w{
            float: right;
            margin-top: 15%;
            width: 70px;
            height: 70px;
    }
    .box_home_logo_img_m{
            float: right;
            margin-top: 18%;
            width: 76px;
            height: 38px;
    }
    .box_home_logo_span{
            font-size: 40px;
            color: #FFFFFF;
            font-weight: bold;
            margin-top: 17%;
            margin-left: 2%;
    }
    .box_home_desc_p{
            font-size: 18px;
            text-align: center;
            color: #99b5f1;
    }
    .box_home_download_box_item_img{
            width: 100px;
            height: 40px;
    }
}
@media only screen and (min-width: 768px) {
    .box_home_logo_img_w{
            float: right;
            margin-top: 15%;
            width: 90px;
            height: 90px;
    }
    .box_home_logo_img_m{
            float: right;
            margin-top: 18%;
            width: 102px;
            height: 51px;
    }
    .box_home_logo_span{
            font-size: 50px;
            color: #FFFFFF;
            font-weight: bold;
            margin-top: 17%;
            margin-left: 2%;
    }
    .box_home_desc_p{
            font-size: 18px;
            text-align: center;
            color: #99b5f1;
    }
    .box_home_download_box_item_img{
            width: 140px;
            height: 50px;
    }
}
@media only screen and (min-width: 1024px) {
    .box_home_logo_img_w{
            float: right;
            margin-top: 15%;
            width: 150px;
            height: 150px;
    }
    .box_home_logo_img_m{
            float: right;
            margin-top: 19%;
            width: 128px;
            height: 64px;
    }
    .box_home_logo_span{
            font-size: 80px;
            color: #FFFFFF;
            font-weight: bold;
            margin-top: 17%;
            margin-left: 2%;
    }
    .box_home_desc_p{
            font-size: 30px;
            text-align: center;
            color: #99b5f1;
    }
    .box_home_download_box_item_img{
            width: 190px;
            height: 70px;
    }
}