Color Changing Border
The border, its tinted fill and the label glide through the color wheel together, one hue at a time. A hue-rotate() filter loop starts from your accent color and works in every browser.
Also known as: css border color animation, rainbow color cycle border, hue shift border.
Color changing
HTML
<div class="bdr-color-changing-border"><span class="bdr-color-changing-border-label">Color changing</span></div>
CSS
.bdr-color-changing-border {
--c: var(--bdr-color, #3b82f6);
font-size: var(--bdr-size, 16px);
position: relative;
display: grid;
place-items: center;
width: 15em;
height: 8.5em;
border-radius: 1em;
font-family: system-ui, sans-serif;
font-weight: 600;
background: color-mix(in srgb, var(--c) 12%, transparent);
animation: bdr-color-changing-border-cycle 6s linear infinite;
}
.bdr-color-changing-border::before {
content: "";
position: absolute;
inset: 0;
padding: 0.2em;
border-radius: inherit;
background: linear-gradient(135deg, var(--c), color-mix(in oklch, var(--c), #a855f7 45%));
-webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
-webkit-mask-composite: xor;
mask: linear-gradient(#000 0 0) content-box exclude, linear-gradient(#000 0 0);
pointer-events: none;
}
.bdr-color-changing-border-label {
color: color-mix(in srgb, var(--c) 70%, currentColor);
}
@keyframes bdr-color-changing-border-cycle {
to { filter: hue-rotate(360deg); }
}
@media (prefers-reduced-motion: reduce) {
.bdr-color-changing-border, .bdr-color-changing-border *, .bdr-color-changing-border::before, .bdr-color-changing-border::after, .bdr-color-changing-border *::before, .bdr-color-changing-border *::after {
animation-duration: 0.01ms !important;
animation-iteration-count: 1 !important;
transition-duration: 0.01ms !important;
}
}Customizing this snippet
- Color: set
--bdr-coloron the element or a parent. Currently previewing#3b82f6. - Base size: set
--bdr-size. Every other dimension is inem, so the whole thing scales together. Currently previewing16px. - Speed: change the duration on the
transitionoranimationshorthand. Staggered delays are relative, so they keep their rhythm. - Reduced motion: the rule at the end of the CSS turns the motion off for people who asked their OS for less of it. Keep it.