Staircase Fill Button: CSS Hover Effect

Staircase Fill Button

Four bars rise one after another and lock together into a solid fill, then drop in reverse order when you leave. The stagger is a --i index per bar feeding transition-delay.

Also known as: staggered bars fill, step fill hover, stair step button.

Color Base size 16px Dark background Hold hover state

HTML

<button class="hfx-staircase-fill">
  <span class="hfx-staircase-fill-steps" aria-hidden="true"><i style="--i: 0"></i><i style="--i: 1"></i><i style="--i: 2"></i><i style="--i: 3"></i></span>
  Browse catalog
</button>

CSS

.hfx-staircase-fill {
  --c: var(--hfx-color, #3b82f6);
  position: relative;
  isolation: isolate;
  overflow: hidden;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  padding: 0.75em 1.75em;
  border-radius: 0.5em;
  font: 600 var(--hfx-size, 16px)/1.2 system-ui, sans-serif;
  white-space: nowrap;
  cursor: pointer;
  border: 2px solid var(--c);
  background: transparent;
  color: var(--c);
  transition: color 0.25s ease 0.25s;
}
.hfx-staircase-fill-steps {
  position: absolute;
  inset: 0;
  z-index: -1;
  display: flex;
}
.hfx-staircase-fill-steps i {
  flex: 1;
  margin-right: -1px;
  background: var(--c);
  transform: translateY(101%);
  transition: transform 0.35s cubic-bezier(0.65, 0, 0.35, 1) calc((3 - var(--i)) * 0.05s);
}
.hfx-staircase-fill:is(:hover, :focus-visible) {
  background-color: var(--c); /* hides the hairline where the fill meets the border */
  color: #fff;
  transition: color 0.25s ease 0.25s, background-color 0s 0.6s;
}
.hfx-staircase-fill:is(:hover, :focus-visible) .hfx-staircase-fill-steps i {
  transform: translateY(0);
  transition-delay: calc(var(--i) * 0.07s);
}

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

Tailwind CSS version

The same effect using Tailwind utility classes. No custom CSS or config needed.

<button class="group relative isolate overflow-hidden rounded-lg border-2 border-blue-500 px-7 py-3 font-semibold text-blue-500 transition-colors delay-150 duration-300 hover:text-white">
  <span class="absolute inset-0 -z-10 flex" aria-hidden="true">
    <span class="flex-1 translate-y-full bg-blue-500 transition-transform duration-300 ease-in-out group-hover:translate-y-0"></span>
    <span class="flex-1 translate-y-full bg-blue-500 transition-transform duration-300 ease-in-out group-hover:translate-y-0 group-hover:delay-75"></span>
    <span class="flex-1 translate-y-full bg-blue-500 transition-transform duration-300 ease-in-out group-hover:translate-y-0 group-hover:delay-150"></span>
    <span class="flex-1 translate-y-full bg-blue-500 transition-transform duration-300 ease-in-out group-hover:translate-y-0 group-hover:delay-200"></span>
  </span>
  Browse catalog
</button>

Customizing this snippet

Color: set --hfx-color on the element or a parent. Currently previewing #3b82f6.
Base size: set --hfx-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.

Staircase Fill Button

HTML

CSS

Tailwind CSS version

Customizing this snippet

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