Gradient Border Card

<div class="gb-card"><div class="gb-card-inner"><h3>Premium</h3><p>Renkli sınır animasyonlu kart.</p></div></div>

.gb-card {
  position: relative;
  width: 260px;
  padding: 2px;
  border-radius: 18px;
  background: conic-gradient(from 0deg, #7c3aed, #ec4899, #f59e0b, #22d3ee, #7c3aed);
  animation: gb-rot 6s linear infinite;
}
.gb-card-inner {
  background: #0a0a14;
  border-radius: 16px;
  padding: 24px;
  color: #fff;
  font-family: system-ui, sans-serif;
}
.gb-card-inner h3 {
  margin: 0 0 8px;
  font-size: 18px;
  background: linear-gradient(135deg, #a78bfa, #ec4899);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.gb-card-inner p {
  margin: 0;
  font-size: 13px;
  color: rgba(255,255,255,0.65);
}
@keyframes gb-rot { to { filter: hue-rotate(360deg); } }