#main1, #main2 {
    width: 350px;
    height: 300px;
    display: inline-block;
}
#main3 {
    width: 650px;
    height: 300px;
    margin: 5px auto;
}

.tab-btn {
    padding: 5px;
    margin: 0 8px;
    border: 1px solid #5470C6;
    background: #fff;
    color: #5470C6;
    border-radius: 4px;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.2s;
}
.tab-btn.active, .tab-btn:focus {
    background: #5470C6;
    color: #fff;
    border: 1.5px solid #27408B;
    outline: none;
}
.box_relative {
position: absolute;
right: 60px;
top: 30px;
z-index: 99;
}
@media (max-width: 450px) {
    #main3 {
        width: 100% !important;
        height: 250px !important;
    }
    .box_relative {
        display: none;
    }
}