Squiggly Underline Animation
A wavy line under one word flows sideways forever, like a playful link or a spelling mark with personality. The SVG wave is wider than the word and slides by exactly one period.
Also known as: wavy underline css, animated wavy line, squiggle underline text.
Make it matter
HTML
<div class="txt-squiggly-underline">Make it <span class="txt-squiggly-underline-word">matter<span class="txt-squiggly-underline-line" aria-hidden="true"><svg viewBox="0 0 200 12"><path d="M0 6 q 5 -6 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0 t 10 0" /></svg></span></span></div>
CSS
.txt-squiggly-underline {
--c: var(--txt-color, #3b82f6);
font-size: var(--txt-size, 32px);
font-family: system-ui, sans-serif;
font-weight: 700;
line-height: 1.2;
white-space: nowrap;}
.txt-squiggly-underline-word {
position: relative;
display: inline-block;
color: var(--c);
}
.txt-squiggly-underline-line {
position: absolute;
left: 0;
right: 0;
bottom: -0.12em;
height: 0.3em;
overflow: hidden;
}
.txt-squiggly-underline-line svg {
display: block;
width: 5em;
height: 0.3em;
fill: none;
stroke: var(--c);
stroke-width: 2.4;
stroke-linecap: round;
animation: txt-squiggly-underline-flow 0.9s linear infinite;
}
/* one period is 20 of the 200 viewBox units: 10% of the svg */
@keyframes txt-squiggly-underline-flow {
to { transform: translateX(-10%); }
}
@media (prefers-reduced-motion: reduce) {
.txt-squiggly-underline, .txt-squiggly-underline *, .txt-squiggly-underline::before, .txt-squiggly-underline::after, .txt-squiggly-underline *::before, .txt-squiggly-underline *::after {
animation-duration: 0.01ms !important;
animation-iteration-count: 1 !important;
transition-duration: 0.01ms !important;
}
}Customizing this snippet
- Color: set
--txt-coloron the element or a parent. Currently previewing#3b82f6. - Font size: set
--txt-size. Every other dimension is inem, so the whole thing scales together. Currently previewing40px. - 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.