Mesh Gradient Border: CSS Border Animation

Mesh Gradient Border

Soft blobs of color wander around the frame and melt into each other, like a mesh gradient in motion. Three radial gradients ride two registered @property percentages instead of rotating.

Also known as: mesh gradient border css, fluid gradient border, lava lamp border.

Mesh gradient

Color Base size 16px Dark background Hold hover state

HTML

<div class="bdr-mesh-gradient-border">Mesh gradient</div>

CSS

@property --bdr-mesh-gradient-border-x {
  syntax: "<percentage>";
  inherits: false;
  initial-value: 0%;
}
@property --bdr-mesh-gradient-border-y {
  syntax: "<percentage>";
  inherits: false;
  initial-value: 0%;
}
.bdr-mesh-gradient-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;
  --x: var(--bdr-mesh-gradient-border-x);
  --y: var(--bdr-mesh-gradient-border-y);
  box-sizing: border-box;
  border: 0.26em solid transparent;
  background:
    linear-gradient(#fff, #fff) padding-box,
    radial-gradient(circle at var(--x) var(--y), color-mix(in oklch, var(--c), #ec4899 85%), transparent 55%) border-box,
    radial-gradient(circle at calc(100% - var(--x)) calc(100% - var(--y)), color-mix(in oklch, var(--c), #22d3ee 80%), transparent 55%) border-box,
    radial-gradient(circle at var(--y) calc(100% - var(--x)), color-mix(in oklch, var(--c), #facc15 85%), transparent 50%) border-box,
    linear-gradient(var(--c), var(--c)) border-box;
  color: #111827;
  animation: bdr-mesh-gradient-border-drift 8s cubic-bezier(0.45, 0, 0.55, 1) infinite;
}
@keyframes bdr-mesh-gradient-border-drift {
  0%, 100% { --bdr-mesh-gradient-border-x: 10%; --bdr-mesh-gradient-border-y: 15%; }
  25%      { --bdr-mesh-gradient-border-x: 90%; --bdr-mesh-gradient-border-y: 25%; }
  50%      { --bdr-mesh-gradient-border-x: 80%; --bdr-mesh-gradient-border-y: 90%; }
  75%      { --bdr-mesh-gradient-border-x: 15%; --bdr-mesh-gradient-border-y: 80%; }
}

@media (prefers-reduced-motion: reduce) {
  .bdr-mesh-gradient-border, .bdr-mesh-gradient-border *, .bdr-mesh-gradient-border::before, .bdr-mesh-gradient-border::after, .bdr-mesh-gradient-border *::before, .bdr-mesh-gradient-border *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

Customizing this snippet

Color: set --bdr-color on the element or a parent. Currently previewing #3b82f6.
Base size: set --bdr-size. Every other dimension is in em, so the whole thing scales together. Currently previewing 16px.
Speed: change the duration on the transition or animation shorthand. 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.

Mesh Gradient Border

HTML

CSS

Customizing this snippet

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