CSS Gradient Border Generator

.gradient-border {
  position: relative;
  background: #18181b;
  border-radius: 12px;
  padding: 3px;
}

.gradient-border::before {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: 12px;
  padding: 3px;
  background: linear-gradient(90deg, #a855f7 0%, #3b82f6 50%, #06b6d4 100%);
  -webkit-mask: 
    linear-gradient(#fff 0 0) content-box, 
    linear-gradient(#fff 0 0);
  mask: 
    linear-gradient(#fff 0 0) content-box, 
    linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
}

.gradient-border-content {
  background: #18181b;
  border-radius: 9px;
  padding: 1rem;
}