/* 来源：GlassMusicPlayer Ultimate.vue 默认背景（局部炫光流体） */

.gradient-bg {
  --color-bg1: rgb(108, 0, 162);
  --color-bg2: rgb(0, 17, 82);
  --color1: 18, 113, 255;
  --color2: 221, 74, 255;
  --color3: 100, 220, 255;
  --color4: 200, 50, 50;
  --color5: 180, 180, 50;
  --color-interactive: 140, 100, 255;
  --ultimate-anim-factor: 1;
  --ultimate-size-factor: 1;
  --ultimate-follow-lerp: 0.07;
  --ultimate-interactive-scale: 1.1;
  --circle-size: calc(80% * var(--ultimate-size-factor));
  --blending: hard-light;

  width: 100%;
  height: 100%;
  position: absolute;
  overflow: hidden;
  background: linear-gradient(90deg, var(--color-bg1), var(--color-bg2));
  top: 0;
  left: 0;
}

.gradient-bg svg {
  position: fixed;
  top: 0;
  left: 0;
  width: 0;
  height: 0;
}

.gradient-bg .gradients-container {
  filter: url(#goo) blur(40px);
  width: 100%;
  height: 100%;
}

@keyframes ultimate-moveInCircle {
  0% { transform: rotate(0deg); }
  50% { transform: rotate(180deg); }
  100% { transform: rotate(360deg); }
}

@keyframes ultimate-moveVertical {
  0% { transform: translateY(-50%); }
  50% { transform: translateY(50%); }
  100% { transform: translateY(-50%); }
}

@keyframes ultimate-moveHorizontal {
  0% { transform: translateX(-50%) translateY(-10%); }
  50% { transform: translateX(50%) translateY(10%); }
  100% { transform: translateX(-50%) translateY(-10%); }
}

.gradient-bg .g1 {
  position: absolute;
  background: radial-gradient(circle at center, rgba(var(--color1), 0.8) 0, rgba(var(--color1), 0) 50%) no-repeat;
  mix-blend-mode: var(--blending);
  width: var(--circle-size);
  height: var(--circle-size);
  top: calc(50% - var(--circle-size) / 2);
  left: calc(50% - var(--circle-size) / 2);
  transform-origin: center center;
  animation: ultimate-moveVertical calc(30s / var(--ultimate-anim-factor, 1)) ease infinite;
  opacity: 1;
}

.gradient-bg .g2 {
  position: absolute;
  background: radial-gradient(circle at center, rgba(var(--color2), 0.8) 0, rgba(var(--color2), 0) 50%) no-repeat;
  mix-blend-mode: var(--blending);
  width: var(--circle-size);
  height: var(--circle-size);
  top: calc(50% - var(--circle-size) / 2);
  left: calc(50% - var(--circle-size) / 2);
  transform-origin: calc(50% - 400px);
  animation: ultimate-moveInCircle calc(20s / var(--ultimate-anim-factor, 1)) reverse infinite;
  opacity: 1;
}

.gradient-bg .g3 {
  position: absolute;
  background: radial-gradient(circle at center, rgba(var(--color3), 0.8) 0, rgba(var(--color3), 0) 50%) no-repeat;
  mix-blend-mode: var(--blending);
  width: var(--circle-size);
  height: var(--circle-size);
  top: calc(50% - var(--circle-size) / 2 + 200px);
  left: calc(50% - var(--circle-size) / 2 - 500px);
  transform-origin: calc(50% + 400px);
  animation: ultimate-moveInCircle calc(40s / var(--ultimate-anim-factor, 1)) linear infinite;
  opacity: 1;
}

.gradient-bg .g4 {
  position: absolute;
  background: radial-gradient(circle at center, rgba(var(--color4), 0.8) 0, rgba(var(--color4), 0) 50%) no-repeat;
  mix-blend-mode: var(--blending);
  width: var(--circle-size);
  height: var(--circle-size);
  top: calc(50% - var(--circle-size) / 2);
  left: calc(50% - var(--circle-size) / 2);
  transform-origin: calc(50% - 200px);
  animation: ultimate-moveHorizontal calc(40s / var(--ultimate-anim-factor, 1)) ease infinite;
  opacity: 0.7;
}

.gradient-bg .g5 {
  position: absolute;
  background: radial-gradient(circle at center, rgba(var(--color5), 0.8) 0, rgba(var(--color5), 0) 50%) no-repeat;
  mix-blend-mode: var(--blending);
  width: calc(var(--circle-size) * 2);
  height: calc(var(--circle-size) * 2);
  top: calc(50% - var(--circle-size));
  left: calc(50% - var(--circle-size));
  transform-origin: calc(50% - 800px) calc(50% + 200px);
  animation: ultimate-moveInCircle calc(20s / var(--ultimate-anim-factor, 1)) ease infinite;
  opacity: 1;
}

.gradient-bg .interactive {
  position: absolute;
  background: radial-gradient(circle at center, rgba(var(--color-interactive), 0.8) 0, rgba(var(--color-interactive), 0) 50%) no-repeat;
  mix-blend-mode: var(--blending);
  width: calc(100% * var(--ultimate-interactive-scale, 1.1));
  height: calc(100% * var(--ultimate-interactive-scale, 1.1));
  top: -50%;
  left: -50%;
  opacity: 0.7;
  pointer-events: none;
}