.RM_botbox{ display: inline-block; position: fixed; z-index: 9999; bottom: 50px; right: 20px; text-align: right;}
.RM_botbox iframe{ width: 100vw; max-width: 640px; height: 50vh; border-radius: 20px; box-shadow: 3px 3px 6px rgba(0,0,0,.3); display: none;}
.RM_botbox.on iframe{ display: block;}
.RM_botbox a.serve{ display: inline-block; width: 50px; height: 50px; background-size: cover; background-position: center; border-radius: 50%; border: 3px solid #999; box-shadow: 3px 3px 6px rgba(0,0,0,.3);  cursor: pointer; position: relative; transition: .5s; overflow: hidden;}
.RM_botbox.on a.serve{margin-top: 20px;}
.RM_botbox a.serve::after{ content: ''; width: 100%; height: 100%; position: absolute; top: 0; left: 0; display: inline-block; background-image: url('https://bot.realmedia.tw/UI/Images/down.svg'); background-color: #FFF; background-size: contain; background-position: center; opacity: 0; transition: .5s;}
.RM_botbox.on a.serve::after{ opacity: 1;}
@media screen and (max-width: 640px) {
    .RM_botbox{right: 10px; bottom: 30px;}
    .RM_botbox iframe{ width: calc(100vw - 20px); height: 75vh;}
}