:root {
  --logo-size: 44px;
  --logo-halo: rgba(82, 203, 176, 0.32);
  --logo-particle: #52cbb0;
  --logo-particle-dim: rgba(82, 203, 176, 0.38);

  /* 光影系统：用极淡的高光/阴影营造立体感，而非可见边框 */
  --logo-highlight: rgba(255, 255, 255, 0.50);
  --logo-ambient: rgba(11, 87, 56, 0.10);
  --logo-shadow: rgba(6, 47, 33, 0.18);
  --logo-rim: rgba(255, 255, 255, 0.35);
}

/* 容器 */
.brand-logo {
  position: relative;
  width: var(--logo-size);
  height: var(--logo-size);
  display: grid;
  place-items: center;
  flex: 0 0 auto;
}

/* 柔和光晕：呼吸效果 */
.brand-logo__halo {
  position: absolute;
  inset: -18%;
  border-radius: 50%;
  background: radial-gradient(
    circle at 50% 50%,
    var(--logo-halo) 0%,
    rgba(168, 240, 220, 0.10) 45%,
    transparent 72%
  );
  animation: logo-breathe 5s ease-in-out infinite;
  pointer-events: none;
}

@keyframes logo-breathe {
  0%, 100% {
    transform: scale(0.94);
    opacity: 0.55;
  }
  50% {
    transform: scale(1.1);
    opacity: 1;
  }
}

/* 外圈轨道粒子 */
.brand-logo__orbit {
  position: absolute;
  inset: -12%;
  border-radius: 50%;
  animation: logo-orbit 14s linear infinite;
  pointer-events: none;
}

.brand-logo__orbit::before,
.brand-logo__orbit::after {
  content: "";
  position: absolute;
  border-radius: 50%;
  background: var(--logo-particle);
  box-shadow: 0 0 8px var(--logo-particle);
}

.brand-logo__orbit::before {
  width: 4px;
  height: 4px;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  opacity: 0.85;
}

.brand-logo__orbit::after {
  width: 2.5px;
  height: 2.5px;
  bottom: 18%;
  right: 12%;
  background: var(--logo-particle-dim);
  box-shadow: none;
}

@keyframes logo-orbit {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

/* 反向轨道 */
.brand-logo__orbit--reverse {
  animation-direction: reverse;
  animation-duration: 18s;
  inset: -6%;
}

.brand-logo__orbit--reverse::before {
  width: 2.5px;
  height: 2.5px;
  top: auto;
  bottom: 8%;
  left: 22%;
  background: var(--logo-particle-dim);
  box-shadow: none;
}

.brand-logo__orbit--reverse::after {
  width: 3.5px;
  height: 3.5px;
  top: 12%;
  right: 18%;
  background: var(--logo-particle);
  box-shadow: 0 0 6px var(--logo-particle);
}

/* SVG 主体：多层 drop-shadow 模拟自然光影 */
.brand-logo__svg {
  position: relative;
  z-index: 2;
  width: 78%;
  height: 78%;
  overflow: visible;
  animation: logo-float 6s ease-in-out infinite;

  filter:
    /* 左上边缘高光：模拟光线掠过轮廓 */
    drop-shadow(-0.5px -0.5px 0.6px var(--logo-highlight))
    /* 底部主阴影：提供浮起感 */
    drop-shadow(0.5px 1.5px 2px var(--logo-shadow))
    /* 环境柔影：让 logo 与背景柔和分离 */
    drop-shadow(0 4px 8px var(--logo-ambient));
}

@keyframes logo-float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-1.5px); }
}

/* 填充主体：细微呼吸 */
.brand-logo__fill {
  transform-origin: center;
  animation: logo-fill-breathe 5s ease-in-out infinite;
}

@keyframes logo-fill-breathe {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.015); }
}

/* 边缘微光：不是描边，而是极细的高光线 */
.brand-logo__rim {
  fill: none;
  stroke: var(--logo-rim);
  stroke-width: 0.5;
  stroke-linecap: round;
  stroke-linejoin: round;
  opacity: 0.55;
  animation: logo-rim-shimmer 4s ease-in-out infinite;
}

@keyframes logo-rim-shimmer {
  0%, 100% { opacity: 0.40; }
  50% { opacity: 0.65; }
}

/* 悬停加速 */
.brand-logo:hover .brand-logo__halo {
  animation-duration: 3s;
}

.brand-logo:hover .brand-logo__orbit {
  animation-duration: 9s;
}

.brand-logo:hover .brand-logo__orbit--reverse {
  animation-duration: 11s;
}

/* 大尺寸变体（用于登录页 hero） */
.brand-logo--lg {
  --logo-size: 96px;
  --logo-halo: rgba(255, 255, 255, 0.28);
  --logo-particle: #ffffff;
  --logo-particle-dim: rgba(255, 255, 255, 0.5);
  --logo-highlight: rgba(255, 255, 255, 0.65);
  --logo-ambient: rgba(6, 47, 33, 0.16);
  --logo-shadow: rgba(2, 24, 16, 0.24);
  --logo-rim: rgba(255, 255, 255, 0.55);
}

.brand-logo--lg .brand-logo__svg {
  filter:
    drop-shadow(-1px -1px 1px var(--logo-highlight))
    drop-shadow(1px 2px 3px var(--logo-shadow))
    drop-shadow(0 6px 14px var(--logo-ambient));
}

.brand-logo--lg .brand-logo__orbit::before {
  width: 7px;
  height: 7px;
}

.brand-logo--lg .brand-logo__orbit::after {
  width: 4.5px;
  height: 4.5px;
}

.brand-logo--lg .brand-logo__orbit--reverse::before,
.brand-logo--lg .brand-logo__orbit--reverse::after {
  width: 5px;
  height: 5px;
}

.brand-logo--lg .brand-logo__rim {
  stroke-width: 0.75;
}

/* 减少动效偏好 */
@media (prefers-reduced-motion: reduce) {
  .brand-logo__halo,
  .brand-logo__orbit,
  .brand-logo__orbit--reverse,
  .brand-logo__svg,
  .brand-logo__fill,
  .brand-logo__rim {
    animation: none;
  }
  .brand-logo__halo {
    opacity: 0.7;
    transform: scale(1);
  }
  .brand-logo__rim {
    opacity: 0.55;
  }
}