block.css

html, body {
    height: 100%;
    padding: 0;
    border: 0;
    margin: 0;
}

.menu, .script, .block {
    border: 1px inset #021429;
    border-radius: 7px;
}

h1, h2, h3, h4, h5, h6 {
    text-align: center;
}

h1 {
    margin: 0em;
}

.menu-column {
    width: 24%;
    height: 85%;
    float: left;
    margin-left: 10px;
}

.menu {
    background-color: PeachPuff;
    overflow-y: auto;
}

.menu.over {
    background-color: BurlyWood;
}

.script-column {
    width: 24%;
    height: 85%;
    float: left;
    margin: 0 10px;
}

.script {
    background-color: LightSteelBlue;
    height: 94%;
    overflow-y: auto;
}

.script.over {
    background-color: CadetBlue;
}

.canvas-column {
    width: 46%;
    height: 85%;
    float: right;
    margin-right: 10px;
}

.canvas-placeholder {
    width: 100%;
    height: 85%;
}

.canvas {
    background-color: white;
    position: absolute;
}

.block {
    padding: 5px;
    margin: 10px;
    cursor: move;
}

.block.running {
    outline: 2px solid red;
}

.block.next {
    outline: 2px solid green;
}

.block.dragging {
    opacity: 0.4;
}

.menu .block {
    background-color: Coral;
}

.script .block {
    margin: 5px;
    background-color: DodgerBlue;
}

.block input {
    margin-left: 1em;
    width: 5em;
    margin-bottom: 5px;
}

.container {
    margin: 0 -6px 0 20px;
    padding-bottom: 10px;
    border: 1px inset #021429;
    border-radius: 7px;
    border-right: 0;
    background-color: LightSteelBlue;
    border-radius: 7px 0 0 7px;
}

.menu .container {
    background-color: PeachPuff;
}

.over .container {
    background-color: CadetBlue;
}