Folding Zigzag Loader
A straight line folds up into a tight zigzag from both ends toward the middle, like a carpenter's ruler, then springs flat again. Each joint is a nested bar that rotates relative to its parent.
Also known as: zigzag line animation, folding ruler loader, accordion line loader.
HTML
<div class="ldr-zigzag-fold" role="status" aria-label="Loading"> <i><span><span><span></span></span></span></i> <i><span><span><span></span></span></span></i> </div>
CSS
.ldr-zigzag-fold {
--s: var(--ldr-size, 48px);
--c: var(--ldr-color, #3b82f6);
--w: calc(var(--s) / 3);
--t: calc(var(--s) / 10);
position: relative;
width: calc(var(--s) * 1.7);
height: var(--s);
}
.ldr-zigzag-fold i {
position: absolute;
top: 50%;
left: 50%;
animation: ldr-zigzag-fold-lift 2.2s cubic-bezier(0.65, 0, 0.35, 1) infinite;
}
.ldr-zigzag-fold i + i { scale: -1 1; }
.ldr-zigzag-fold span {
position: absolute;
top: calc(var(--t) / -2);
left: calc(var(--t) / -2);
width: var(--w);
height: var(--t);
border-radius: var(--s);
background: var(--c);
transform-origin: calc(var(--t) / 2) 50%;
animation: ldr-zigzag-fold-a 2.2s cubic-bezier(0.65, 0, 0.35, 1) infinite;
}
.ldr-zigzag-fold span span {
top: 0;
left: calc(100% - var(--t));
background: color-mix(in srgb, var(--ldr-color, #3b82f6) 50%, transparent);
animation-name: ldr-zigzag-fold-b;
}
.ldr-zigzag-fold span span span {
background: var(--c);
animation-name: ldr-zigzag-fold-c;
}
@keyframes ldr-zigzag-fold-a {
0%, 12%, 100% { transform: rotate(0deg); }
45%, 62% { transform: rotate(70deg); animation-timing-function: cubic-bezier(0.34, 1.4, 0.64, 1); }
}
@keyframes ldr-zigzag-fold-b {
0%, 12%, 100% { transform: rotate(0deg); }
45%, 62% { transform: rotate(-140deg); animation-timing-function: cubic-bezier(0.34, 1.4, 0.64, 1); }
}
@keyframes ldr-zigzag-fold-c {
0%, 12%, 100% { transform: rotate(0deg); }
45%, 62% { transform: rotate(140deg); animation-timing-function: cubic-bezier(0.34, 1.4, 0.64, 1); }
}
@keyframes ldr-zigzag-fold-lift {
0%, 12%, 100% { transform: translateY(0); }
45%, 62% { transform: translateY(calc((var(--w) - var(--t)) * -0.47)); animation-timing-function: cubic-bezier(0.34, 1.4, 0.64, 1); }
}
@media (prefers-reduced-motion: reduce) {
.ldr-zigzag-fold, .ldr-zigzag-fold *, .ldr-zigzag-fold::before, .ldr-zigzag-fold::after, .ldr-zigzag-fold *::before, .ldr-zigzag-fold *::after {
animation-duration: 3s;
}
}Customizing this loader
- Color: set
--ldr-coloron the element or a parent. Currently previewing#3b82f6. - Size: set
--ldr-size. Every dimension in the snippet is derived from it. Currently previewing64px. - Speed: change the duration on the
animationshorthand. Delays on the children are relative, so they keep their rhythm. - Accessibility: the root carries
role="status"and anaria-labelso screen readers announce the wait. The reduced-motion rule at the end slows the animation for users who asked for less motion.