body, html {
    margin: 0;
    padding: 0;
    min-height: 100vh;
    min-width: 320px;
    overflow: hidden;
}
body {
    background-color: #2a303c;
}
.main {
    text-align: center;
    min-height: 100vh;
    background-image: url(../img/bg-phones.png);
    background-size: cover;
    background-position: center center;
}

#container {
    perspective: 30px;
  }
  
#inner {
    display: inline-block;
    transition: transform 0.5s;
    -webkit-transition: transform 0.5s;
}
img {
    max-width: 100%;
    max-height: 100%;
}
a {
    outline: none;
    text-decoration: none;
}
.central {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    text-align: center;
    padding: 0 15px;
    min-height: 100vh;
}
.left, .right {
    width: 50%;
    height: 100%;
}
.left {
    display: flex;
    justify-content: stretch;
    align-items: stretch;
    flex-direction: column;
}
.right {
    flex-direction: column;
}
.logo {
    max-width: 350px;
    text-align: center;
    margin-left: auto;
    margin-right: auto;
}
.btns {
    margin: 40px 0;
}
.qr-code {
    background-color: #fff;
    padding: 10px;
    border-radius: 15px;
    max-width: 180px;
}
.btns-btn {
    display: inline-block;
    position: relative;
    margin: 10px 15px;
    max-width: 180px;
}
.btns-btn:hover .qr-code {
    opacity: 1;
    visibility: visible;
}
.qr-code {
    opacity: 0;
    visibility: hidden;
    position: absolute;
    top: 105%;
    left: 0;
    z-index: 1;
    transition: all .25s ease-in-out;
}

.socials-btn {
    display: inline-flex;
    margin: 0 15px;
    max-width: 64px;
    opacity: .6;
    transition: opacity .25s ease-in-out;
}
.socials-btn:hover {
    opacity: 1;
}

@media only screen and (max-width: 768px) {
    .central {
        flex-direction: column;
        padding: 30px 15px;
    }
    .logo {
        margin-top: 40px;
        max-width: 300px;
    }
    .left, .right {
        width: 100%;
        height: auto;
    }
    .right {
        max-width: 70%;
        justify-self: center;
    }
    .main {
        background-image: url(../img/bg-phones-mobile.png);
        display: flex;
        align-items: center;
        justify-content: center;    
    }
    .btns {
        margin: 40px 0;
    }
    .btns-btn {
        margin: 10px 5px;
    }
    .socials-btn {
        max-width: 64px;
        margin: 0 10px;
    }
    .qr-code {
        display: none;
    }
}

@media only screen and (max-width: 480px) {
    .socials-btn {
        max-width: 64px;
        margin: 0 10px;
    }
    .qr-code {
        display: none;
    }
}