Curtain Drop Button
A pleated curtain drops from the top, bounces twice off the bottom edge and settles. The bounce is a linear() easing curve, and the folds are one repeating gradient.
Also known as: curtain fill hover, roller blind button, drop down fill.
HTML
<button class="hfx-curtain-drop">Watch the demo</button>
CSS
.hfx-curtain-drop {
--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 0.2s ease 0.15s;
}
.hfx-curtain-drop::before {
content: "";
position: absolute;
inset: -40% 0 0;
z-index: -1;
background:
linear-gradient(to top, color-mix(in srgb, #000 18%, var(--c)) 0 0.14em, transparent 0),
repeating-linear-gradient(90deg, color-mix(in srgb, #fff 10%, transparent), color-mix(in srgb, #000 10%, transparent) 0.7em, color-mix(in srgb, #fff 10%, transparent) 1.4em),
var(--c);
transform: translateY(-100%);
transition: transform 0.35s cubic-bezier(0.5, 0, 0.75, 0);
}
.hfx-curtain-drop:is(:hover, :focus-visible) {
background-color: var(--c); /* hides the hairline where the fill meets the border */
color: #fff;
transition: color 0.2s ease 0.2s, background-color 0s 0.8s;
}
.hfx-curtain-drop:is(:hover, :focus-visible)::before {
transform: translateY(0);
transition: transform 0.8s linear(0, 0.06 8.75%, 0.25 17.5%, 0.56 26.25%, 1 35%, 0.925 41%, 0.9 47%, 0.925 53%, 1 59%, 0.98 65%, 1 71%);
}
@media (prefers-reduced-motion: reduce) {
.hfx-curtain-drop, .hfx-curtain-drop *, .hfx-curtain-drop::before, .hfx-curtain-drop::after, .hfx-curtain-drop *::before, .hfx-curtain-drop *::after {
animation-duration: 0.01ms !important;
animation-iteration-count: 1 !important;
transition-duration: 0.01ms !important;
}
}Customizing this snippet
- Color: set
--hfx-coloron the element or a parent. Currently previewing#3b82f6. - Base size: set
--hfx-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.