.container {
  --glow-color: #00f0ff;
  --glow-size: 10px;
  
  position: relative;
  padding: 2px;
  border-radius: 0.5rem;
  background: var(--glow-color);
}

.cyan { --glow-color: #00f0ff; }
.pink { --glow-color: #ff00ff; }
.green { --glow-color: #00ff88; }
.purple { --glow-color: #a855f7; }

.rainbow {
  background: linear-gradient(90deg, #00f0ff, #ff00ff, #00ff88, #00f0ff);
  background-size: 300% 100%;
}

.low { --glow-size: 5px; }
.medium { --glow-size: 10px; }
.high { --glow-size: 20px; }

.content {
  position: relative;
  background: hsl(var(--background, 0 0% 4%));
  border-radius: calc(0.5rem - 2px);
  z-index: 1;
}

/* Glow effect */
.container::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border-radius: 0.5rem;
  background: inherit;
  filter: blur(var(--glow-size));
  opacity: 0.7;
  z-index: -1;
}

/* Animation */
.animated {
  animation: glow-pulse 2s ease-in-out infinite;
}

.rainbow.animated {
  animation: glow-pulse 2s ease-in-out infinite, rainbow-border 3s linear infinite;
}

@keyframes glow-pulse {
  0%, 100% { filter: brightness(1); }
  50% { filter: brightness(1.3); }
}

@keyframes rainbow-border {
  0% { background-position: 0% 50%; }
  100% { background-position: 300% 50%; }
}

.container:hover {
  filter: brightness(1.2);
}

.container:hover::before {
  filter: blur(calc(var(--glow-size) * 1.5));
  opacity: 0.9;
}