/* ================================================
   Mesh Gradient 背景动效备用实现
   当外部库不可用时的CSS动画替代方案
   ================================================ */

/* Mesh Gradient 背景容器 */
.mesh-gradient-bg {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 1;
  background: linear-gradient(135deg, #E8EAF0 0%, #F4F5F9 50%, #FAFBFF 100%);
  overflow: hidden;
}

/* 动态渐变层 */
.mesh-gradient-bg::before,
.mesh-gradient-bg::after {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  border-radius: 50%;
  animation: meshGradientMove 20s ease-in-out infinite;
}

.mesh-gradient-bg::before {
  background: radial-gradient(circle at 30% 30%, rgba(0, 122, 255, 0.25) 0%, transparent 50%);
  animation-delay: 0s;
}

.mesh-gradient-bg::after {
  background: radial-gradient(circle at 70% 70%, rgba(0, 122, 255, 0.2) 0%, transparent 50%);
  animation-delay: -10s;
}

/* 额外的渐变层增加深度 */
.mesh-gradient-bg .gradient-layer-1,
.mesh-gradient-bg .gradient-layer-2,
.mesh-gradient-bg .gradient-layer-3 {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  border-radius: 50%;
  animation: floatGradient 25s ease-in-out infinite;
}

.mesh-gradient-bg .gradient-layer-1 {
  background: radial-gradient(ellipse at 25% 25%, rgba(232, 234, 240, 0.9) 0%, transparent 60%);
  animation-delay: 0s;
}

.mesh-gradient-bg .gradient-layer-2 {
  background: radial-gradient(ellipse at 75% 75%, rgba(244, 245, 249, 0.8) 0%, transparent 60%);
  animation-delay: -8s;
}

.mesh-gradient-bg .gradient-layer-3 {
  background: radial-gradient(ellipse at 50% 50%, rgba(250, 251, 255, 0.85) 0%, transparent 50%);
  animation-delay: -16s;
}

/* 动画关键帧 */
@keyframes meshGradientMove {
  0%, 100% {
    transform: translate(0, 0) rotate(0deg);
    opacity: 0.6;
  }
  25% {
    transform: translate(5%, -3%) rotate(90deg);
    opacity: 0.8;
  }
  50% {
    transform: translate(-2%, 4%) rotate(180deg);
    opacity: 0.7;
  }
  75% {
    transform: translate(-4%, -2%) rotate(270deg);
    opacity: 0.9;
  }
}

@keyframes floatGradient {
  0%, 100% {
    transform: translate(0, 0) scale(1);
    opacity: 0.4;
  }
  33% {
    transform: translate(3%, -2%) scale(1.1);
    opacity: 0.6;
  }
  66% {
    transform: translate(-2%, 3%) scale(0.9);
    opacity: 0.5;
  }
}

/* 响应式调整 */
@media (max-width: 768px) {
  .mesh-gradient-bg::before,
  .mesh-gradient-bg::after {
    animation-duration: 30s; /* 移动端减慢动画 */
  }
  
  .mesh-gradient-bg .gradient-layer-1,
  .mesh-gradient-bg .gradient-layer-2,
  .mesh-gradient-bg .gradient-layer-3 {
    animation-duration: 35s;
  }
}

/* 减少动画模式 */
@media (prefers-reduced-motion: reduce) {
  .mesh-gradient-bg::before,
  .mesh-gradient-bg::after,
  .mesh-gradient-bg .gradient-layer-1,
  .mesh-gradient-bg .gradient-layer-2,
  .mesh-gradient-bg .gradient-layer-3 {
    animation: none;
    opacity: 0.3;
  }
}

/* 高性能模式 */
@media (prefers-reduced-motion: reduce) {
  .mesh-gradient-bg {
    background: linear-gradient(135deg, #E8EAF0 0%, #F4F5F9 50%, #FAFBFF 100%);
  }
  
  .mesh-gradient-bg::before,
  .mesh-gradient-bg::after {
    display: none;
  }
}

/* 硬件加速优化 */
.mesh-gradient-bg,
.mesh-gradient-bg::before,
.mesh-gradient-bg::after,
.mesh-gradient-bg .gradient-layer-1,
.mesh-gradient-bg .gradient-layer-2,
.mesh-gradient-bg .gradient-layer-3 {
  will-change: transform;
  transform: translateZ(0);
}

/* 浏览器兼容性 */
@supports not (animation-name: meshGradientMove) {
  .mesh-gradient-bg {
    background: linear-gradient(135deg, #E8EAF0 0%, #F4F5F9 50%, #FAFBFF 100%);
  }
  
  .mesh-gradient-bg::before,
  .mesh-gradient-bg::after,
  .mesh-gradient-bg .gradient-layer-1,
  .mesh-gradient-bg .gradient-layer-2,
  .mesh-gradient-bg .gradient-layer-3 {
    display: none;
  }
}