I’m Kayla, and I live in CSS land. I ship real sites for small clients, and I tinker late at night. I care a lot about motion. It should feel smooth. It should also be kind. If you’re after the full, step-by-step breakdown, I published a deeper dive on checking CSS animations.
Here’s how I check animation in CSS, what tools I reach for, and a few real things that went wrong on me (and how I fixed them). I used all of these on my own projects: a coffee cart homepage, a local soccer club site, and a tiny shop page. Different vibes, same motion rules.
One of those client gigs actually took me briefly to France—Lyon, to be exact. If you’re ever in that city and want to blend a little people-watching research with after-work fun, the local dating directory at Plan Cul Lyon is a quick way to see what’s happening around town and could even double as real-world sample data for list-style CSS animations. Back in the U.S., Knoxville has its own vibrant dating index; grabbing a handful of headline/thumbnail pairs from this Sugar Baby Knoxville listing lets me throw diverse real-world content at my animation tests, and it’s genuinely useful if you’re curious about what the modern Southern matchmaking scene looks like.
The first tool I open: Chrome DevTools Animation panel
When an animation looks off, I open the Animation panel in Chrome. I scrub the timeline and slow it to 25%. If it snaps at 30% or stalls near the end, I’ll see it there. The colors make it easy to spot weird easing.
For a richer overview of the tooling and mental models behind UI motion, I always keep the excellent web.dev animations guide bookmarked.
On my 2018 MacBook Air, I had a card flip that felt sticky. The panel showed a tiny jump at 60%. Turns out I had a bad keyframe.
Bad version:
.card {
animation: flip 800ms ease-in-out both;
}
@keyframes flip {
0% { transform: rotateY(0); }
60% { transform: rotateY(178deg); } /* tiny gap caused a snap */
100% { transform: rotateY(180deg); }
}
Fixed:
@keyframes flip {
0% { transform: rotateY(0); }
60% { transform: rotateY(180deg); }
100% { transform: rotateY(180deg); }
}
I also use the Performance panel for frames. If the FPS drops under 55 on my older Android, I rethink the motion.
Need a quick move? Animate.css is my fast helper
When I need a simple entrance, I use Animate.css. It’s a set of class names. I used it for a “sale” banner on a small shop.
Example:
<h2 class="animate__animated animate__fadeInUp animate__faster">
Fall Sale — 30% off beans
</h2>
It just works. The little catch? It can feel same-y if you use it everywhere. And the file can feel big if you import the whole thing. I now import only what I need.
For navigation samples, CSS Menu Tools lets me grab lightweight menu animations that plug right into my styles. For time-boxed promos, I even wired up a tiny CSS-only timer; here’s what I learned about countdown animations if you’d like to try one.
Designing from scratch: Animista saves time
When I want a custom feel, I use Animista. I play with sliders, test the easing, and copy the CSS. I used it to make a soft “wiggle” on an “Add to cart” button. It sounds silly. It sold more mugs.
.btn-add {
animation: wiggle 600ms ease-out 1 both;
}
@keyframes wiggle {
0% { transform: scale(1) rotate(0); }
30% { transform: scale(1.07) rotate(1deg); }
60% { transform: scale(0.98) rotate(-1deg); }
100% { transform: scale(1) rotate(0); }
}
Pro: It’s fast and fun. Con: The exported names can get long if you don’t rename them. Need something more organic? I explored morphing blobs and this approach finally worked for me.
Linting that saves me from typos: stylelint plus a plugin
I’ve shipped a typo in an animation name. Twice. stylelint caught it later. I use stylelint with a rule that flags unknown keyframes. It yells when I write this:
.box {
animation: fadein 300ms ease-out both; /* oops: should be fade-in */
}
@keyframes fade-in {
from { opacity: 0; transform: translateY(4px); }
to { opacity: 1; transform: translateY(0); }
}
Fix:
.box {
animation: fade-in 300ms ease-out both;
}
It’s boring, but it saves me hours.
Performance check: transforms over layout
I used to animate left and top. Bad idea. It triggers layout and paint on many setups. On my client’s Chromebook, it stuttered.
If you need a refresher on why these properties are expensive (and how to squeeze more speed out of your CSS overall), LogRocket has a clear rundown of best practices for improving CSS performance.
Bad:
.bad-move {
position: relative;
animation: slide 600ms ease-out;
}
@keyframes slide {
from { left: 0; }
to { left: 200px; }
}
Better:
.good-move {
will-change: transform; /* hint */
animation: slideX 600ms ease-out;
}
@keyframes slideX {
from { transform: translateX(0); }
to { transform: translateX(200px); }
}
I measured again with the FPS meter. No more drops. You know what? That one change did more than any micro-tweak. The same switch to transforms paid off again when I built a CSS scroll indicator for a long article—the bar felt buttery once I swapped left for translateX.
Little things that make motion feel real
- Use fill-mode both when you want the final state to stick.
- Shorten long fades. 300–500ms feels nice for UI. Long can feel sleepy.
- Easing matters. Ease-out feels quick but gentle. Linear looks robotic (which is fine for spinners).
- For sprite steps, use steps(). It looks crisp.
Sprite example:
.icon-run {
width: 64px; height: 64px;
background: url(run-sprite.png) 0 0 no-repeat;
animation: run 800ms steps(12) infinite;
}
@keyframes run {
from { background-position: 0 0; }
to { background-position: -768px 0; } /* 12 frames * 64px */
}
While we’re talking about polish, a subtle loading shimmer can keep users engaged; I broke down what works (and what doesn’t) in my test of the CSS shimmer effect.
Accessibility: respect reduced motion
A friend gets motion sick. So I test motion with reduced settings. I keep the feel but cut the spin.
@media (prefers-reduced-motion: reduce) {
* {
animation: none !important;
transition: none !important;
}
}
@media (prefers-reduced-motion: no-preference) {
.toast {
animation: fade-in 260ms ease-out both;
}
}
Sometimes I won’t kill all motion. I just swap in a soft fade. That still feels calm.
Real bug I hit, and the fix
On the soccer site, a shadow pulse on a badge tanked frames. It looked cool on my iPhone 12, but not on a basic Android.
Original:
.badge {
animation: glow 2s ease-in-out infinite;
}
@keyframes glow {
0%, 100% { box-shadow: 0 0 0 rgba(0,0,0,0); }
50% { box-shadow: 0 0 40px rgba(0,0,0,0.35); }
}
Fix: I faked it with a pseudo element and opacity. Much lighter.
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