body {
    margin: 0;
    padding: 0;
    overflow: hidden;
}

.menu {
    position: fixed;
    top: 4px;
    left: calc(50% - 80px);
    z-index: 10000;
    background-color: #000000ee;
    color: #fff;
    border-radius: 4px;
    font-size: 12px;
    font-weight: bold;
    opacity: 1.0;
    user-select: none;
}

.label {
    display: inline-block;
    padding: 2px 8px;    
    border-radius: 4px;
    background-color: #000000ee;
    cursor: pointer;
}

.label:hover {
    background-color: #1d976e;
}

#canvas {
    width: 100%;
    height: auto;
    display: block;
}