Pure CSS saving/loading dots animation

Inspired by the Instapaper iOS Saving Overlay I opened CodePen and built the saving dots animation with CSS and tweaked the animation a little bit. The result looks like that:

See the Pen Saving dots animation by Martin Wolf (@martinwolf) on CodePen.

Let me explain how it works. First the HTML:

<p class="saving">Saving<span>.</span><span>.</span><span>.</span></p>

Each dot is wrapped in a span element and the whole thing will be controller by the .saving class. To make the magic happen we need some CSS:

@keyframes blink {
    /**
     * At the start of the animation the dot
     * has an opacity of .2
     */
    0% {
      opacity: .2;
    }
    /**
     * At 20% the dot is fully visible and
     * then fades out slowly
     */
    20% {
      opacity: 1;
    }
    /**
     * Until it reaches an opacity of .2 and
     * the animation can start again
     */
    100% {
      opacity: .2;
    }
}

.saving span {
    /**
     * Use the blink animation, which is defined above
     */
    animation-name: blink;
    /**
     * The animation should take 1.4 seconds
     */
    animation-duration: 1.4s;
    /**
     * It will repeat itself forever
     */
    animation-iteration-count: infinite;
    /**
     * This makes sure that the starting style (opacity: .2)
     * of the animation is applied before the animation starts.
     * Otherwise we would see a short flash or would have
     * to set the default styling of the dots to the same
     * as the animation. Same applies for the ending styles.
     */
    animation-fill-mode: both;
}

.saving span:nth-child(2) {
    /**
     * Starts the animation of the third dot
     * with a delay of .2s, otherwise all dots
     * would animate at the same time
     */
    animation-delay: .2s;
}

.saving span:nth-child(3) {
    /**
     * Starts the animation of the third dot
     * with a delay of .4s, otherwise all dots
     * would animate at the same time
     */
    animation-delay: .4s;
}

This is only the minimal required code for making the animation work, no visual styles for formatting the text. In the CodePen example above I increased the font-size of the dots to make it look better.