 class Ribbon {
        constructor() {
            this.numPoints = 50 + Math.floor(Math.random() * 30); // 组成彩带路径的点数
            this.points = [];
            this.baseY = height * (0.2 + Math.random() * 0.6);
            this.amplitude = height * (0.05 + Math.random() * 0.15);
            this.frequency = 0.002 + Math.random() * 0.003;
            this.phase = Math.random() * Math.PI * 2;
            this.thickness = 20 + Math.random() * 30; // 彩带厚度
            this.speed = 0.5 