Underline Slide Through Link Hover
The resting underline exits to the right while a fresh one enters from the left, and it keeps travelling the same way when you leave. Flipping transform-origin per state does it.
Also known as: underline in left out right, sliding underline hover, underline passes through.
HTML
<a class="hfx-link-underline-slide" href="#">Case studies</a>
CSS
.hfx-link-underline-slide {
--c: var(--hfx-color, #3b82f6);
position: relative;
display: inline-block;
color: var(--c);
font: 600 calc(var(--hfx-size, 16px) * 1.25)/1.3 system-ui, sans-serif;
text-decoration: none;
color: inherit;
padding-bottom: 0.2em;
transition: color 0.3s ease;}
.hfx-link-underline-slide::before,
.hfx-link-underline-slide::after {
content: "";
position: absolute;
left: 0;
right: 0;
bottom: 0;
height: 0.1em;
background: var(--c);
transition: transform 0.35s cubic-bezier(0.65, 0, 0.35, 1);
}
.hfx-link-underline-slide::before {
transform-origin: left;
transition-delay: 0.2s;
}
.hfx-link-underline-slide::after {
transform: scaleX(0);
transform-origin: right;
}
.hfx-link-underline-slide:is(:hover, :focus-visible) { color: var(--c); }
.hfx-link-underline-slide:is(:hover, :focus-visible)::before {
transform: scaleX(0);
transform-origin: right;
transition-delay: 0s;
}
.hfx-link-underline-slide:is(:hover, :focus-visible)::after {
transform: scaleX(1);
transform-origin: left;
transition-delay: 0.2s;
}
@media (prefers-reduced-motion: reduce) {
.hfx-link-underline-slide, .hfx-link-underline-slide *, .hfx-link-underline-slide::before, .hfx-link-underline-slide::after, .hfx-link-underline-slide *::before, .hfx-link-underline-slide *::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.