css边框轴对称线性渐变
28. border-top: 1px solid;
border-image: -webkit-linear-gradient(90deg, transparent, rgba(48, 160, 255, .5) 50%, transparent) 1;
border-image: linear-gradient(to top right,rgb(15, 223, 223) 20%,rgb(34, 82, 238) 60%,rgb(15, 223, 223)) 20;