修改svg的颜色

<svg
      class="hamburger"
      viewBox="0 0 1024 1024"
      xmlns="http://www.w3.org/2000/svg"
      width="64"
      height="64"
    >
      <path d="M408 442h480c4.4 0 8-3.6 8-8v-56c0-4.4-3.6-8-8-8H408c-4.4 0-8 3.6-8 8v56c0 4.4 3.6 8 8 8zm-8 204c0 4.4 3.6 8 8 8h480c4.4 0 8-3.6 8-8v-56c0-4.4-3.6-8-8-8H408c-4.4 0-8 3.6-8 8v56zm504-486H120c-4.4 0-8 3.6-8 8v56c0 4.4 3.6 8 8 8h784c4.4 0 8-3.6 8-8v-56c0-4.4-3.6-8-8-8zm0 632H120c-4.4 0-8 3.6-8 8v56c0 4.4 3.6 8 8 8h784c4.4 0 8-3.6 8-8v-56c0-4.4-3.6-8-8-8zM142.4 642.1L298.7 519a8.84 8.84 0 0 0 0-13.9L142.4 381.9c-5.8-4.6-14.4-.5-14.4 6.9v246.3a8.9 8.9 0 0 0 14.4 7z" />

.hamburger {
  display: inline-block;
  vertical-align: middle;
  width: 20px;
  height: 20px;
  fill:#fff;
}

只要设置一个fill就好啦