.bdimg{ border:50px solid; border-image:radial-gradient(at 50% 50%,transparent 14%,purple 15% 19%,blue 20% 24%,lightblue 25% 29%,green 30% 34%,yellow 35% 39%,orange 40% 44%,red 45% 49%,transparent 50%) 49%; } お疲れ様です‍♀️ 目に見える効果…