Ripple Border
Rings ripple out from the border and fade, one after another, like a call coming in. Each ring is an outline on a pseudo-element with a growing outline-offset, so it keeps the rounded corners.
Also known as: border pulse animation css, double border ripple, pulse ring border.
Incoming call
HTML
<div class="bdr-ripple-border">Incoming call</div>
CSS
.bdr-ripple-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;
border: 0.12em solid var(--c);
box-sizing: border-box;
background: color-mix(in srgb, var(--c) 8%, #fff);
color: color-mix(in srgb, var(--c) 45%, #111827);
}
.bdr-ripple-border::before,
.bdr-ripple-border::after {
content: "";
position: absolute;
inset: -0.12em;
border-radius: inherit;
outline: 0.12em solid var(--c);
pointer-events: none;
animation: bdr-ripple-border-out 2.4s cubic-bezier(0.2, 0.6, 0.35, 1) infinite;
}
.bdr-ripple-border::after { animation-delay: -1.2s; }
@keyframes bdr-ripple-border-out {
0% { outline-offset: 0; opacity: 1; }
100% { outline-offset: 1.5em; opacity: 0; }
}
@media (prefers-reduced-motion: reduce) {
.bdr-ripple-border, .bdr-ripple-border *, .bdr-ripple-border::before, .bdr-ripple-border::after, .bdr-ripple-border *::before, .bdr-ripple-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.