body, html {
    margin: 0;
    padding: 0;
    height: 100%;
    font-family: Arial, sans-serif;
}

header {
    background-color: #f0f0f0;
    padding: 10px;
}

main {
    display: flex;
    height: calc(100% - 50px); /* 假设header高度为50px */
}

.toolbar {
    width: 60px;
    background-color: #e0e0e0;
    padding: 10px;
}

#canvas {
    flex-grow: 1;
    background-color: #ffffff;
    min-height: 400px;
    position: relative;
}

.panel {
    width: 200px;
    background-color: #e0e0e0;
    padding: 10px;
}

button {
    display: block;
    width: 100%;
    margin-bottom: 10px;
    padding: 5px;
}

#drawingArea {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
}