.mixer {
    height: calc(100% + 20px);
    position: relative;
}
#mixer {
    position: relative;
}
.plus {
    position: absolute;
    left: 25px;
    bottom: -25px;
}
.plus .horizontal {
    position: absolute;
    background-color: black;
    width: 36px;
    height: 10px;
    top: 13px;
    left: 0px;
}
.plus .vertical {
    position: absolute;
    background-color: black;
    width: 10px;
    height: 36px;
    left: 13px;
}
.keyboard-module {
    height: 175px;
    border: 2px solid white;
    background-color: grey;
    position: relative;
}
.keyboard-module .module-body {
    width: 100%;
    display: inline-block;
    position: absolute;
    left: 250px;
    height: 100%;
}
.keyboard-module .module-body .set {
    display: inline-block;
    min-width: 1px;
    height: 100%;
    border: 2px solid blue;
    position: absolute;
}
.keyboard-module .module-mixer {
    display: inline-block;
    width: 250px;
    height: 100%;
    background-color: green;
    border-right: 2px solid white;
    text-align: center;
    padding: 20px;
    position: relative;
}
.pull-top {
    position: absolute;
    top: 0px;
    left: calc(50% - 8px);
}
.pull-top .top {
    display: block;
    height: 1px;
    border-top: 2px solid black;
    margin: 1em 0;
    padding: 0;
    position: absolute;
    top: -10px;
    width: 16px;
}
.pull-top .bot {
    display: block;
    height: 1px;
    border-top: 2px solid black;
    margin: 1em 0;
    padding: 0;
    position: absolute;
    top: -6px;
    width: 16px;
}
.pull-bottom {
    position: absolute;
    bottom: 14px;
    left: calc(50% - 8px);
}
.pull-bottom .top {
    display: block;
    height: 1px;
    border-top: 2px solid black;
    margin: 1em 0;
    padding: 0;
    position: absolute;
    top: -10px;
    width: 16px;
}
.pull-bottom .bot {
    display: block;
    height: 1px;
    border-top: 2px solid black;
    margin: 1em 0;
    padding: 0;
    position: absolute;
    top: -6px;
    width: 16px;
}
.module-mixer .vol-box {
    max-width: 80%;
    display: inline-block;
}
.module-mixer .select-box {
    display: inline-block;
    min-width: 150px;
}
.module-mixer .select-box .instbox {
    background: blue;
}