Circle Bounce Loader
A ball ricochets around the inside of a ring at a constant angle, so its path closes into a faint five-pointed star, and the wall flashes where it hits. The trail is delayed copies.
Also known as: ball bouncing inside circle, circle billiard animation, bouncing ball in a ring.
HTML
<div class="ldr-circle-bounce" role="status" aria-label="Loading">
<svg class="ldr-circle-bounce-star" viewBox="-50 -50 100 100" aria-hidden="true">
<polygon points="0,-38.5 22.6,31.1 -36.6,-11.9 36.6,-11.9 -22.6,31.1" />
</svg>
<span class="ldr-circle-bounce-flash"></span>
<span class="ldr-circle-bounce-ball" style="--k: 0"></span>
<span class="ldr-circle-bounce-ball" style="--k: 1"></span>
<span class="ldr-circle-bounce-ball" style="--k: 2"></span>
<span class="ldr-circle-bounce-ball" style="--k: 3"></span>
<span class="ldr-circle-bounce-ball" style="--k: 4"></span>
</div>CSS
.ldr-circle-bounce {
--s: var(--ldr-size, 48px);
--c: var(--ldr-color, #3b82f6);
position: relative;
width: var(--s);
height: var(--s);
box-sizing: border-box;
border: calc(var(--s) / 24) solid color-mix(in srgb, var(--ldr-color, #3b82f6) 35%, transparent);
border-radius: 50%;
}
.ldr-circle-bounce-star {
position: absolute;
top: calc(var(--s) / -24);
left: calc(var(--s) / -24);
width: var(--s);
height: var(--s);
overflow: visible;
}
.ldr-circle-bounce-star polygon {
fill: none;
stroke: color-mix(in srgb, var(--ldr-color, #3b82f6) 22%, transparent);
stroke-width: 1px;
stroke-linejoin: round;
vector-effect: non-scaling-stroke;
}
/* Steps round the rim by 144deg per bounce, and flares on each one. */
.ldr-circle-bounce-flash {
position: absolute;
inset: 0;
animation: ldr-circle-bounce-step 2s steps(5) infinite;
}
.ldr-circle-bounce-flash::before {
content: "";
position: absolute;
top: calc(var(--s) / -10);
left: calc(50% - var(--s) / 10);
width: calc(var(--s) / 5);
height: calc(var(--s) / 5);
box-sizing: border-box;
border: calc(var(--s) / 30) solid var(--c);
border-radius: 50%;
animation: ldr-circle-bounce-flare 0.4s ease-out infinite;
}
.ldr-circle-bounce-ball {
--d: calc(var(--s) * (0.15 - var(--k) * 0.02));
position: absolute;
top: 50%;
left: 50%;
width: var(--d);
height: var(--d);
margin: calc(var(--d) / -2);
border-radius: 50%;
background: var(--c);
opacity: calc(1 - var(--k) * 0.2);
animation: ldr-circle-bounce-path 2s linear infinite;
animation-delay: calc(var(--k) * 0.04s - 2s);
}
@keyframes ldr-circle-bounce-path {
0% { transform: translate(calc(var(--s) * 0.000), calc(var(--s) * -0.385)); }
20% { transform: translate(calc(var(--s) * 0.226), calc(var(--s) * 0.311)); }
40% { transform: translate(calc(var(--s) * -0.366), calc(var(--s) * -0.119)); }
60% { transform: translate(calc(var(--s) * 0.366), calc(var(--s) * -0.119)); }
80% { transform: translate(calc(var(--s) * -0.226), calc(var(--s) * 0.311)); }
100% { transform: translate(calc(var(--s) * -0.000), calc(var(--s) * -0.385)); }
}
@keyframes ldr-circle-bounce-step {
from { transform: rotate(0deg); }
to { transform: rotate(720deg); }
}
@keyframes ldr-circle-bounce-flare {
from { transform: scale(0.3); opacity: 0.9; }
to { transform: scale(1.3); opacity: 0; }
}
@media (prefers-reduced-motion: reduce) {
.ldr-circle-bounce, .ldr-circle-bounce *, .ldr-circle-bounce::before, .ldr-circle-bounce::after, .ldr-circle-bounce *::before, .ldr-circle-bounce *::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.