 document.createElement('canvas');
        offscreenCanvas.width = canvas.width;
        offscreenCanvas.height = canvas.height;
        const offscreenCtx = offscreenCanvas.getContext('2d');

        // 绘制静态元素（轨道线）
        for (const planet of planets) {
            offscreenCtx.beginPath();
            offscreenCtx.arc(sun.x, sun.y, planet.orbit, 0, 2 * Math.PI);
            offscreenCtx.strokeStyle = 'rgba(255, 255, 255, 0.5)';
            offscreenCtx.lineWidth = 1;
            off