Gooey Button
Blobs of the button's own color bulge out of its edges on hover and keep swelling, joined by stretchy necks like thick liquid. An inline SVG filter blurs the shapes, then sharpens their alpha.
Also known as: liquid button, goo effect css, metaball button.
HTML
<button class="btn-gooey"> <span class="btn-gooey-goo" aria-hidden="true"><i></i><i></i><i></i><i></i><i></i></span> <span class="btn-gooey-label">Get started</span> <svg class="btn-gooey-svg" aria-hidden="true"><filter id="btn-gooey-filter" x="-50%" y="-100%" width="200%" height="300%"><feGaussianBlur in="SourceGraphic" stdDeviation="5"/><feColorMatrix values="1 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 20 -8"/></filter></svg> </button>
CSS
.btn-gooey {
--c: var(--btn-color, #3b82f6);
display: inline-flex;
align-items: center;
justify-content: center;
gap: 0.5em;
font: 600 var(--btn-size, 18px)/1.2 system-ui, sans-serif;
cursor: pointer;
position: relative;
padding: 0.85em 2em;
border: 0;
background: transparent;
color: #fff;}
.btn-gooey-goo {
position: absolute;
inset: 0;
border-radius: 1.5em;
background: var(--c);
filter: url(#btn-gooey-filter);
}
.btn-gooey-goo i {
position: absolute;
width: 1.5em;
height: 1.5em;
border-radius: 50%;
background: var(--c);
transition: translate 0.6s cubic-bezier(0.34, 1.8, 0.64, 1);
}
.btn-gooey-goo i:nth-child(1) { top: 0.1em; left: 12%; }
.btn-gooey-goo i:nth-child(2) { top: 0.2em; left: 52%; width: 1.2em; height: 1.2em; }
.btn-gooey-goo i:nth-child(3) { bottom: 0.1em; left: 28%; }
.btn-gooey-goo i:nth-child(4) { bottom: 0.2em; right: 14%; width: 1.3em; height: 1.3em; }
.btn-gooey-goo i:nth-child(5) { top: 0.3em; right: 0; width: 1.2em; height: 1.2em; }
.btn-gooey-label { position: relative; }
.btn-gooey-svg {
position: absolute;
width: 0;
height: 0;
}
.btn-gooey:is(:hover, :focus-visible) .btn-gooey-goo i { animation: btn-gooey-pulse 1.8s ease-in-out 0.6s infinite; }
.btn-gooey:is(:hover, :focus-visible) .btn-gooey-goo i:nth-child(1) { translate: -0.3em -1.1em; }
.btn-gooey:is(:hover, :focus-visible) .btn-gooey-goo i:nth-child(2) { translate: 0 -1em; transition-delay: 0.06s; animation-duration: 2.2s; }
.btn-gooey:is(:hover, :focus-visible) .btn-gooey-goo i:nth-child(3) { translate: 0 1.15em; transition-delay: 0.03s; animation-duration: 1.6s; }
.btn-gooey:is(:hover, :focus-visible) .btn-gooey-goo i:nth-child(4) { translate: 0.2em 1em; transition-delay: 0.09s; animation-duration: 2s; }
.btn-gooey:is(:hover, :focus-visible) .btn-gooey-goo i:nth-child(5) { translate: 1em -0.2em; transition-delay: 0.12s; animation-duration: 2.4s; }
@keyframes btn-gooey-pulse {
50% { transform: scale(0.5); }
}
@media (prefers-reduced-motion: reduce) {
.btn-gooey, .btn-gooey *, .btn-gooey::before, .btn-gooey::after, .btn-gooey *::before, .btn-gooey *::after {
animation-duration: 0.01ms !important;
animation-iteration-count: 1 !important;
transition-duration: 0.01ms !important;
}
}Customizing this snippet
- Color: set
--btn-coloron the element or a parent. Currently previewing#3b82f6. - Base size: set
--btn-size. Every other dimension is inem, so the whole thing scales together. Currently previewing18px. - 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.