html,
body {
    margin: 0;
    height: 100%;
    overflow: hidden;
}
canvas {
    display: block;
    background: #fff;
}
#controls {
    position: fixed;
    top: 10px;
    left: 10px;
    background: rgba(255, 255, 255, 0.9);
    padding: 8px;
    border-radius: 8px;
    z-index: 10;
    font-family: sans-serif;
}
label {
    margin-right: 8px;
}
#modeSwitcher {
    position: fixed;
    top: 278px;
    left: 11px;
    z-index: 100;
    background: #4db6e2;
    border-radius: 16px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    padding: 8px 16px;
    user-select: none;
    cursor: grab;
    font-family: sans-serif;
    display: flex;
    align-items: center;
    gap: 10px;
}
.switch {
    position: relative;
    display: inline-block;
    width: 48px;
    height: 24px;
}
.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}
.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #eee;
    border-radius: 12px;
    border: 1px solid #ccc;
    transition: .2s;
}
.slider:before {
    position: absolute;
    content: "";
    height: 20px;
    width: 20px;
    left: 2px;
    bottom: 2px;
    background-color: #fff;
    border-radius: 50%;
    transition: .2s;
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.12);
}
input:checked+.slider {
    background-color: #fff;
}
input:checked+.slider:before {
    transform: translateX(24px);
}