CSS Animation Example: The Pulse

"The Pulse" is a soft, radiating glow effect commonly used for Call-to-Action (CTA) buttons to draw the user's eye.

This effect is achieved by animating the transform and box-shadow properties using @keyframes. Over the course of the animation, the button scales up slightly, while a colored shadow expands outward and fades away.

Here is the code to create the Pulse animation.

<!doctype html>
<title>Example</title>
<style>
body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    font-family: sans-serif;
    background-color: #f0f0f0;
}

.pulse-button {
    background-color: #007bff;
    color: white;
    border: none;
    padding: 15px 30px;
    font-size: 1.2rem;
    border-radius: 5px;
    cursor: pointer;
    box-shadow: 0 0 0 0 rgba(0, 123, 255, 0.7);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% {
        transform: scale(0.95);
        box-shadow: 0 0 0 0 rgba(0, 123, 255, 0.7);
    }
    
    70% {
        transform: scale(1);
        box-shadow: 0 0 0 15px rgba(0, 123, 255, 0);
    }
    
    100% {
        transform: scale(0.95);
        box-shadow: 0 0 0 0 rgba(0, 123, 255, 0);
    }
}

/* Accessibility: Disable animation for users who prefer reduced motion */
@media (prefers-reduced-motion: reduce) {
    .pulse-button {
        animation: none;
    }
}
</style>
<button class="pulse-button">Click Me</button>

View Output

Accessibility Considerations

Animations that draw attention can be distracting or even problematic for users with vestibular disorders. It's a best practice to respect the user's system preferences regarding motion. You can use the prefers-reduced-motion media query to detect if the user has requested that the system minimize the amount of non-essential motion it uses. Users generally set this preference via their operating system settings or a browser extension, and you can mimic this setting for testing purposes via your browser's Developer Tools.

Here we completely disable the animation for those users.


@media (prefers-reduced-motion: reduce) {
    .pulse-button {
        animation: none;
    }
}