Rainbow Border
https://codepen.io/kyktommy/pen/bGBBBZL
- Outside box fill with rainbow gradient background
- Inside box fill with solid background color
/* .box > .inner */
.box {
width: 100px;
height: 100px;
padding: 3px;
box-sizing: border-box;
background-image: linear-gradient(
to bottom right,
#b827fc 0%,
#2c90fc 25%,
#b8fd33 50%,
#fec837 75%,
#fd1892 100%
);
}
.inner {
width: 100%;
height: 100%;
background: black;
}
New css version (safari not supporting)