one-pipe-system/src/assets/styles/theme-animation.scss

// 定义基础变量
$bg-animation-color-light: #000;
$bg-animation-color-dark: #fff;
$bg-animation-duration: 0.5s;

html {
  --bg-animation-color: $bg-animation-color-light;

  &.dark {
    --bg-animation-color: $bg-animation-color-dark;
  }

  // View transition styles
  &::view-transition-old(*) {
    animation: none;
  }

  &::view-transition-new(*) {
    animation: clip $bg-animation-duration ease-in;
  }

  &::view-transition-old(root) {
    z-index: 1;
  }

  &::view-transition-new(root) {
    z-index: 9999;
  }

  &.dark {
    &::view-transition-old(*) {
      animation: clip $bg-animation-duration ease-in reverse;
    }

    &::view-transition-new(*) {
      animation: none;
    }

    &::view-transition-old(root) {
      z-index: 9999;
    }

    &::view-transition-new(root) {
      z-index: 1;
    }
  }
}

// 定义动画
@keyframes clip {
  from {
    clip-path: circle(0% at var(--x) var(--y));
  }

  to {
    clip-path: circle(var(--r) at var(--x) var(--y));
  }
}

// body 相关样式
body {
  background-color: var(--bg-animation-color);
}