* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background: #1a1a2e;
    color: #eee;
    font-family: sans-serif;
}

hr {
    border-color: #333;
    margin: 8px 0"
}

#app {
    display: flex;
    height: 100vh;
}

#canvas-container {
    flex: 1;
    position: relative;
}

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

#sidebar {
    width: 220px;
    padding: 16px;
    background: #16213e;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

h2 {
    font-size: 14px;
    color: #aaa;
    margin-bottom: 4px;
}

.group-item {
    padding: 6px 10px;
    border-radius: 4px;
    background: #0f3460;
    cursor: pointer;
    font-size: 13px;
    -webkit-user-select: none;
    user-select: none;
}

.group-item:hover {
    background: #e94560;
}

.group-item.hidden {
    opacity: 0.4;
}

#drop-zone {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    color: #aaa;
    pointer-events: none;
}