Front-end daily combat: # 2 video demonstrates how to rotate a rectangle loader special effects with pure CSS creation

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https://codepen.io/zhang-ou/pen/vjLQMM

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https://scrimba.com/c/cJMkwH9

Source code download

Please download from github.

https://github.com/comehope/front-end-daily-challenges/tree/master/002-rectangular-rotating-loader-animation

Code Reading

Define dom, a span of three containers comprising:

<div class="loader">
    <span></span>
    <span></span>
    <span></span>
</div>

Centered:

html, body {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: black;
}

Sized containers:

.loader {
    width: 150px;
    height: 150px;
    position: relative;
}

Set the border style rectangle:

.loader span {
    position: absolute;
    box-sizing: border-box;
    border: 10px solid dimgray;
    border-radius: 2px;
}

Provided with three rectangular dimensions:

.loader span:nth-child(1) {
    width: 100%;
    height: 100%;
}

.loader span:nth-child(2) {
    width: 70%;
    height: 70%;
    margin: 15%;
}

.loader span:nth-child(3) {
    width: 40%;
    height: 40%;
    margin: 30%;
}

Drawing the upper left and lower right of the pseudo trim elements:

.loader span::before,
.loader span::after {
    content: '';
    position: absolute;
    width: 10px;
    height: 50%;
    background-color: gold;
}

.loader span::before {
    top: -10px;
    left: -10px;
}

.loader span::after {
    bottom: -10px;
    right: -10px;
}

Custom animation effects:

@keyframes rotating {
    from {
        transform: rotateY(0deg);
    }

    to {
        transform: rotateY(360deg);
    }
}

The animation is applied to the three rectangles:

.loader span {
    animation: rotating linear infinite;
}

.loader span:nth-child(1) {
    animation-duration: 4s;
}

.loader span:nth-child(2) {
    animation-duration: 2s;
}

.loader span:nth-child(3) {
    animation-duration: 1s;
}

Finally, the rectangle is provided at three stacking order:

.loader span:nth-child(1) {
    z-index: 3;
}

.loader span:nth-child(2) {
    z-index: 2;
}

.loader span:nth-child(3) {
    z-index: 1;
}

We're done!

Knowledge Point

• @keyframes https://developer.mozilla.org/en-US/docs/Web/CSS/@keyframes
• animation-duration https://developer.mozilla.org/en-US/docs/Web/CSS/animation-duration
• rotateY https://developer.mozilla.org/en-US/docs/Web/CSS/transform-function/rotateY
• nth-child https://developer.mozilla.org/en-US/docs/Web/CSS/:nth-child
• z-index https://developer.mozilla.org/en-US/docs/Web/CSS/z-index
• ::before https://developer.mozilla.org/en-US/docs/Web/CSS/::before
• ::after https://developer.mozilla.org/en-US/docs/Web/CSS/::after