几款效果还不错的loading，纯css编写

1.gif

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

      .loading{
            width: 80px;
            height: 40px;
            margin: 0 auto;
            margin-top:100px;
        }
        .loading span{
            display: inline-block;
            width: 8px;
            height: 100%;
            border-radius: 4px;
            background: lightgreen;
            -webkit-animation: load 1s ease infinite;
        }
        @-webkit-keyframes load{
            0%,100%{
                height: 40px;
                background: lightgreen;
            }
            50%{
                height: 70px;
                margin: -15px 0;
                background: lightblue;
            }
        }
        .loading span:nth-child(2){
            -webkit-animation-delay:0.2s;
        }
        .loading span:nth-child(3){
            -webkit-animation-delay:0.4s;
        }
        .loading span:nth-child(4){
            -webkit-animation-delay:0.6s;
        }
        .loading span:nth-child(5){
            -webkit-animation-delay:0.8s;
        }

2.gif

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

.loading{
            width: 150px;
            height: 4px;
            border-radius: 2px;
            margin: 0 auto;
            margin-top:100px;
            position: relative;
            background: lightgreen;
            -webkit-animation: changeBgColor 1.04s ease-in infinite alternate;
        }
        .loading span{
            display: inline-block;
            width: 16px;
            height: 16px;
            border-radius: 50%;
            background: lightgreen;
            position: absolute;
            margin-top: -7px;
            margin-left:-8px;
            -webkit-animation: changePosition 1.04s ease-in infinite alternate;
        }
        @-webkit-keyframes changeBgColor{
            0%{
                background: lightgreen;
            }
            100%{
                background: lightblue;
            }
        }
        @-webkit-keyframes changePosition{
            0%{
                background: lightgreen;
            }
            100%{
                margin-left: 142px;
                background: lightblue;
            }
        }

3.gif

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

    .loading{
            width: 150px;
            height: 15px;
            margin: 0 auto;
            margin-top:100px;
        }
        .loading span{
            display: inline-block;
            width: 15px;
            height: 100%;
            margin-right: 5px;
            border-radius: 50%;
            background: lightgreen;
            -webkit-animation: load 1.04s ease infinite;
        }
        .loading span:last-child{
            margin-right: 0px; 
        }
        @-webkit-keyframes load{
            0%{
                opacity: 1;
            }
            100%{
                opacity: 0;
            }
        }
        .loading span:nth-child(1){
            -webkit-animation-delay:0.13s;
        }
        .loading span:nth-child(2){
            -webkit-animation-delay:0.26s;
        }
        .loading span:nth-child(3){
            -webkit-animation-delay:0.39s;
        }
        .loading span:nth-child(4){
            -webkit-animation-delay:0.52s;
        }
        .loading span:nth-child(5){
            -webkit-animation-delay:0.65s;
        }

4.gif

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

     .loading{
           width: 150px;
           height: 15px;
           margin: 0 auto;
           margin-top:100px;
       }
       .loading span{
           display: inline-block;
           width: 15px;
           height: 100%;
           margin-right: 5px;
           border-radius: 50%;
           background: lightgreen;
           -webkit-animation: load 1.04s ease infinite;
       }
       .loading span:last-child{
           margin-right: 0px; 
       }
       @-webkit-keyframes load{
           0%{
               opacity: 1;
               -webkit-transform: scale(1.3);
           }
           100%{
               opacity: 0.2;
               -webkit-transform: scale(.3);
           }
       }
       .loading span:nth-child(1){
           -webkit-animation-delay:0.13s;
       }
       .loading span:nth-child(2){
           -webkit-animation-delay:0.26s;
       }
       .loading span:nth-child(3){
           -webkit-animation-delay:0.39s;
       }
       .loading span:nth-child(4){
           -webkit-animation-delay:0.52s;
       }
       .loading span:nth-child(5){
           -webkit-animation-delay:0.65s;
       }

5.gif

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

      .loading{
            width: 150px;
            height: 15px;
            margin: 0 auto;
            position: relative;
            margin-top:100px;
        }
        .loading span{
            position: absolute;
            width: 15px;
            height: 100%;
            border-radius: 50%;
            background: lightgreen;
            -webkit-animation: load 1.04s ease-in infinite alternate;
        }
        @-webkit-keyframes load{
            0%{
                opacity: 1;
                -webkit-transform: translate(0px);
            }
            100%{
                opacity: 0.2;
                -webkit-transform: translate(150px);
            }
        }
        .loading span:nth-child(1){
            -webkit-animation-delay:0.13s;
        }
        .loading span:nth-child(2){
            -webkit-animation-delay:0.26s;
        }
        .loading span:nth-child(3){
            -webkit-animation-delay:0.39s;
        }
        .loading span:nth-child(4){
            -webkit-animation-delay:0.52s;
        }
        .loading span:nth-child(5){
            -webkit-animation-delay:0.65s;
        }

6.gif

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

.loading{
            width: 150px;
            height: 15px;
            margin: 0 auto;
            margin-top:100px;
            text-align: center;
        }
        .loading span{
            display: inline-block;
            width: 15px;
            height: 100%;
            margin-right: 5px;
            background: lightgreen;
            -webkit-animation: load 1.04s ease infinite;
        }
        .loading span:last-child{
            margin-right: 0px; 
        }
        @-webkit-keyframes load{
            0%{
                opacity: 1;
            }
            100%{
                opacity: 0;
            }
        }
        .loading span:nth-child(1){
            -webkit-animation-delay:0.13s;
        }
        .loading span:nth-child(2){
            -webkit-animation-delay:0.26s;
        }
        .loading span:nth-child(3){
            -webkit-animation-delay:0.39s;
        }
        .loading span:nth-child(4){
            -webkit-animation-delay:0.52s;
        }
        .loading span:nth-child(5){
            -webkit-animation-delay:0.65s;
        }

7.gif

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

.loading{
            width: 150px;
            height: 15px;
            margin: 0 auto;
            margin-top:100px;
        }
        .loading span{
            display: inline-block;
            width: 15px;
            height: 100%;
            margin-right: 5px;
            background: lightgreen;
            -webkit-transform-origin: right bottom;
            -webkit-animation: load 1s ease infinite;
        }
        .loading span:last-child{
            margin-right: 0px; 
        }
        @-webkit-keyframes load{
            0%{
                opacity: 1;
            }
            100%{
                opacity: 0;
                -webkit-transform: rotate(90deg);
            }
        }
        .loading span:nth-child(1){
            -webkit-animation-delay:0.13s;
        }
        .loading span:nth-child(2){
            -webkit-animation-delay:0.26s;
        }
        .loading span:nth-child(3){
            -webkit-animation-delay:0.39s;
        }
        .loading span:nth-child(4){
            -webkit-animation-delay:0.52s;
        }
        .loading span:nth-child(5){
            -webkit-animation-delay:0.65s;
        }

8.gif

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

.loading{
            width: 150px;
            height: 15px;
            margin: 0 auto;
            margin-top:100px;
        }
        .loading span{
            display: inline-block;
            width: 15px;
            height: 100%;
            margin-right: 5px;
            background: lightgreen;
            -webkit-transform-origin: right bottom;
            -webkit-animation: load 1s ease infinite;
        }
        .loading span:last-child{
            margin-right: 0px; 
        }
        @-webkit-keyframes load{
            0%{
                opacity: 1;
                -webkit-transform: scale(1);
            }
            100%{
                opacity: 0;
                -webkit-transform: rotate(90deg) scale(.3);
            }
        }
        .loading span:nth-child(1){
            -webkit-animation-delay:0.13s;
        }
        .loading span:nth-child(2){
            -webkit-animation-delay:0.26s;
        }
        .loading span:nth-child(3){
            -webkit-animation-delay:0.39s;
        }
        .loading span:nth-child(4){
            -webkit-animation-delay:0.52s;
        }
        .loading span:nth-child(5){
            -webkit-animation-delay:0.65s;
        }

9.gif

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

.loadEffect{
            width: 100px;
            height: 100px;
            position: relative;
            margin: 0 auto;
            margin-top:100px;
        }
        .loadEffect span{
            display: inline-block;
            width: 16px;
            height: 16px;
            border-radius: 50%;
            background: lightgreen;
            position: absolute;
            -webkit-animation: load 1.04s ease infinite;
        }
        @-webkit-keyframes load{
            0%{
                opacity: 1;
            }
            100%{
                opacity: 0.2;
            }
        }
        .loadEffect span:nth-child(1){
            left: 0;
            top: 50%;
            margin-top:-8px;
            -webkit-animation-delay:0.13s;
        }
        .loadEffect span:nth-child(2){
            left: 14px;
            top: 14px;
            -webkit-animation-delay:0.26s;
        }
        .loadEffect span:nth-child(3){
            left: 50%;
            top: 0;
            margin-left: -8px;
            -webkit-animation-delay:0.39s;
        }
        .loadEffect span:nth-child(4){
            top: 14px;
            right:14px;
            -webkit-animation-delay:0.52s;
        }
        .loadEffect span:nth-child(5){
            right: 0;
            top: 50%;
            margin-top:-8px;
            -webkit-animation-delay:0.65s;
        }
        .loadEffect span:nth-child(6){
            right: 14px;
            bottom:14px;
            -webkit-animation-delay:0.78s;
        }
        .loadEffect span:nth-child(7){
            bottom: 0;
            left: 50%;
            margin-left: -8px;
            -webkit-animation-delay:0.91s;
        }
        .loadEffect span:nth-child(8){
            bottom: 14px;
            left: 14px;
            -webkit-animation-delay:1.04s;
        }

10.gif

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

.loadEffect{
            width: 100px;
            height: 100px;
            position: relative;
            margin: 0 auto;
            margin-top:100px;
        }
        .loadEffect span{
            display: inline-block;
            width: 20px;
            height: 20px;
            border-radius: 50%;
            background: lightgreen;
            position: absolute;
            -webkit-animation: load 1.04s ease infinite;
        }
        @-webkit-keyframes load{
            0%{
                -webkit-transform: scale(1.2);
                opacity: 1;
            }
            100%{
                -webkit-transform: scale(.3);
                opacity: 0.5;
            }
        }
        .loadEffect span:nth-child(1){
            left: 0;
            top: 50%;
            margin-top:-10px;
            -webkit-animation-delay:0.13s;
        }
        .loadEffect span:nth-child(2){
            left: 14px;
            top: 14px;
            -webkit-animation-delay:0.26s;
        }
        .loadEffect span:nth-child(3){
            left: 50%;
            top: 0;
            margin-left: -10px;
            -webkit-animation-delay:0.39s;
        }
        .loadEffect span:nth-child(4){
            top: 14px;
            right:14px;
            -webkit-animation-delay:0.52s;
        }
        .loadEffect span:nth-child(5){
            right: 0;
            top: 50%;
            margin-top:-10px;
            -webkit-animation-delay:0.65s;
        }
        .loadEffect span:nth-child(6){
            right: 14px;
            bottom:14px;
            -webkit-animation-delay:0.78s;
        }
        .loadEffect span:nth-child(7){
            bottom: 0;
            left: 50%;
            margin-left: -10px;
            -webkit-animation-delay:0.91s;
        }
        .loadEffect span:nth-child(8){
            bottom: 14px;
            left: 14px;
            -webkit-animation-delay:1.04s;
        }

11.gif

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

.loading{
            width: 80px;
            height: 40px;
            margin: 0 auto;
            margin-top:100px;
        }
        .loading span{
            display: inline-block;
            width: 8px;
            height: 100%;
            border-radius: 4px;
            background: lightgreen;
            -webkit-animation: load 1.04s ease infinite;
        }
        @-webkit-keyframes load{
            0%,100%{
                height: 40px;
                background: lightgreen;
            }
            50%{
                height: 60px;
                margin-top: -20px;
                background: lightblue;
            }
        }
        .loading span:nth-child(2){
            -webkit-animation-delay:0.13s;
        }
        .loading span:nth-child(3){
            -webkit-animation-delay:0.26s;
        }
        .loading span:nth-child(4){
            -webkit-animation-delay:0.39s;
        }
        .loading span:nth-child(5){
            -webkit-animation-delay:0.52s;
        }

12.gif

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

.loading{
            width: 80px;
            height: 80px;
            border-radius: 50%;
            margin: 0 auto;
            margin-top:100px;
            position: relative;
            border:5px solid lightgreen;
            -webkit-animation: turn 2s linear infinite;
        }
        .loading span{
            display: inline-block;
            width: 30px;
            height: 30px;
            border-radius: 50%;
            background: lightgreen;
            position: absolute;
            left: 50%;
            margin-top: -15px;
            margin-left: -15px;
            -webkit-animation: changeBgColor 2s linear infinite;
        }
        @-webkit-keyframes changeBgColor{
            0%{
                background: lightgreen;
            }
            100%{
                background: lightblue;
            }
        }
        @-webkit-keyframes turn{
            0%{
                -webkit-transform: rotate(0deg);
                border-color: lightgreen;
            }
            100%{
                -webkit-transform: rotate(360deg);
                border-color: lightblue;
            }
        }

13.gif

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

.loading{
            width: 150px;
            height: 15px;
            margin: 0 auto;
            margin-top:100px;
            text-align: center;
        }
        .loading span{
            display: inline-block;
            width: 15px;
            height: 100%;
            margin-right: 5px;
            background: lightgreen;
            -webkit-animation: load 1.04s ease infinite;
        }
        .loading span:last-child{
            margin-right: 0px; 
        }
        @-webkit-keyframes load{
            0%{
                opacity: 1;
                -webkit-transform: scale(1.2);
            }
            100%{
                opacity: .2;
                -webkit-transform: scale(.2);
            }
        }
        .loading span:nth-child(1){
            -webkit-animation-delay:0.13s;
        }
        .loading span:nth-child(2){
            -webkit-animation-delay:0.26s;
        }
        .loading span:nth-child(3){
            -webkit-animation-delay:0.39s;
        }
        .loading span:nth-child(4){
            -webkit-animation-delay:0.52s;
        }
        .loading span:nth-child(5){
            -webkit-animation-delay:0.65s;
        }

15.gif

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

.loading{
            width: 150px;
            height: 8px;
            border-radius: 4px;
            margin: 0 auto;
            margin-top:100px;
            position: relative;
            background: lightblue;
            overflow: hidden;
        }
        .loading span{
            display:block;
            width: 100%;
            height: 100%;
            border-radius: 3px;
            background: lightgreen;
            -webkit-animation: changePosition 4s linear infinite;
        }
        @-webkit-keyframes changePosition{
            0%{
                -webkit-transform: translate(-150px);
            }
            50%{
                -webkit-transform: translate(0);
            }
            100%{
                -webkit-transform: translate(150px);
            }
        }

16.gif

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

.loadEffect{
            width: 100px;
            height: 100px;
            position: relative;
            margin: 0 auto;
            margin-top:100px;
        }
        .loadEffect span{
            display: inline-block;
            width: 30px;
            height: 10px;
            border-top-left-radius: 5px;
            border-bottom-left-radius: 5px;
            background: lightgreen;
            position: absolute;
            -webkit-animation: load 1.04s ease infinite;
        }
        @-webkit-keyframes load{
            0%{
                opacity: 1;
            }
            100%{
                opacity: 0.2;
            }
        }
        .loadEffect span:nth-child(1){
            left: 0;
            top: 50%;
            margin-top:-5px;
            -webkit-animation-delay:0.13s;
        }
        .loadEffect span:nth-child(2){
            left: 10px;
            top: 20px;
            -webkit-transform: rotate(45deg);
            -webkit-animation-delay:0.26s;
        }
        .loadEffect span:nth-child(3){
            left: 50%;
            top: 10px;
            margin-left: -15px;
            -webkit-transform: rotate(90deg);
            -webkit-animation-delay:0.39s;
        }
        .loadEffect span:nth-child(4){
            top: 20px;
            right:10px;
            -webkit-transform: rotate(135deg);
            -webkit-animation-delay:0.52s;
        }
        .loadEffect span:nth-child(5){
            right: 0;
            top: 50%;
            margin-top:-5px;
            -webkit-transform: rotate(180deg);
            -webkit-animation-delay:0.65s;
        }
        .loadEffect span:nth-child(6){
            right: 10px;
            bottom:20px;
            -webkit-transform: rotate(225deg);
            -webkit-animation-delay:0.78s;
        }
        .loadEffect span:nth-child(7){
            bottom: 10px;
            left: 50%;
            margin-left: -15px;
            -webkit-transform: rotate(270deg);
            -webkit-animation-delay:0.91s;
        }
        .loadEffect span:nth-child(8){
            bottom: 20px;
            left: 10px;
            -webkit-transform: rotate(315deg);
            -webkit-animation-delay:1.04s;
        }

17.gif

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

.loadEffect {
            width: 100px;
            height: 100px;
            margin: 0 auto;
            margin-top:100px;
            position: relative;
        }
        .loadEffect div{
            width: 100%;
            height: 100%;
            position: absolute;
            -webkit-animation: load 2.08s linear infinite;
        }
        .loadEffect div span{
            display: inline-block;
            width: 20px;
            height: 20px;
            border-radius: 50%;
            background: lightgreen;
            position: absolute;
            left: 50%;
            margin-top: -10px;
            margin-left: -10px;
        }
        @-webkit-keyframes load{
            0%{
                -webkit-transform: rotate(0deg);
            }
            10%{
                -webkit-transform: rotate(45deg);
            }
            50%{
                opacity: 1;
                -webkit-transform: rotate(160deg);
            }
            62%{
                opacity: 0;
            }
            65%{
                opacity: 0;
                -webkit-transform: rotate(200deg);
            }
            90%{
                -webkit-transform: rotate(340deg);
            }
            100%{
                -webkit-transform: rotate(360deg);
            }

        }
        .loadEffect div:nth-child(1){
            -webkit-animation-delay:0.2s;
        }
        .loadEffect div:nth-child(2){
            -webkit-animation-delay:0.4s;
        }
        .loadEffect div:nth-child(3){
            -webkit-animation-delay:0.6s;
        }
        .loadEffect div:nth-child(4){
            -webkit-animation-delay:0.8s;
        }

18.gif

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

.loading{
            width: 60px;
            height: 60px;
            margin: 0 auto;
            margin-top:100px;
            position: relative;
            -webkit-animation: load 3s linear infinite;
        }
        .loading div{
            width: 100%;
            height: 100%;
            position: absolute;
        }
        .loading span{
            display: inline-block;
            width: 20px;
            height: 20px;
            border-radius: 50%;
            background: #99CC66;
            position: absolute;
            left: 50%;
            margin-top: -10px;
            margin-left: -10px;
            -webkit-animation: changeBgColor 3s ease infinite;
        }
        @-webkit-keyframes load{
            0%{
                -webkit-transform: rotate(0deg);
            }
            33.3%{
                -webkit-transform: rotate(120deg);
            }
            66.6%{
                -webkit-transform: rotate(240deg);
            }
            100%{
                -webkit-transform: rotate(360deg);
            }
        }
        @-webkit-keyframes changeBgColor{
            0%,100%{
                background: #99CC66;
            }
            33.3%{
                background: #FFFF66;
            }
            66.6%{
                background: #FF6666;
            }
        }
        .loading div:nth-child(2){
            -webkit-transform: rotate(120deg);
        }
        .loading div:nth-child(3){
            -webkit-transform: rotate(240deg);
        }
        .loading div:nth-child(2) span{
            -webkit-animation-delay: 1s;
        }
        .loading div:nth-child(3) span{
            -webkit-animation-delay: 2s;
        }

彩虹

image.png

 <div class="loader">
        <div class="loader-inner">
            <div class="loader-line-wrap">
                <div class="loader-line"></div>
            </div>
            <div class="loader-line-wrap">
                <div class="loader-line"></div>
            </div>
            <div class="loader-line-wrap">
                <div class="loader-line"></div>
            </div>
            <div class="loader-line-wrap">
                <div class="loader-line"></div>
            </div>
            <div class="loader-line-wrap">
                <div class="loader-line"></div>
            </div>
        </div>
    </div>

.loader {
    background: #000;
    background: radial-gradient(#222, #000);
    bottom: 0;
    left: 0;
    overflow: hidden;
    position: fixed;
    right: 0;
    top: 0;
    z-index: 99999;
}

.loader-inner {
    bottom: 0;
    height: 60px;
    left: 0;
    margin: auto;
    position: absolute;
    right: 0;
    top: 0;
    width: 100px;
}

.loader-line-wrap {
    animation: 
        spin 2000ms cubic-bezier(.175, .885, .32, 1.275) infinite
    ;
    box-sizing: border-box;
    height: 50px;
    left: 0;
    overflow: hidden;
    position: absolute;
    top: 0;
    transform-origin: 50% 100%;
    width: 100px;
}
.loader-line {
    border: 4px solid transparent;
    border-radius: 100%;
    box-sizing: border-box;
    height: 100px;
    left: 0;
    margin: 0 auto;
    position: absolute;
    right: 0;
    top: 0;
    width: 100px;
}
.loader-line-wrap:nth-child(1) { animation-delay: -50ms; }
.loader-line-wrap:nth-child(2) { animation-delay: -100ms; }
.loader-line-wrap:nth-child(3) { animation-delay: -150ms; }
.loader-line-wrap:nth-child(4) { animation-delay: -200ms; }
.loader-line-wrap:nth-child(5) { animation-delay: -250ms; }

.loader-line-wrap:nth-child(1) .loader-line {
    border-color: hsl(0, 80%, 60%);
    height: 90px;
    width: 90px;
    top: 7px;
}
.loader-line-wrap:nth-child(2) .loader-line {
    border-color: hsl(60, 80%, 60%);
    height: 76px;
    width: 76px;
    top: 14px;
}
.loader-line-wrap:nth-child(3) .loader-line {
    border-color: hsl(120, 80%, 60%);
    height: 62px;
    width: 62px;
    top: 21px;
}
.loader-line-wrap:nth-child(4) .loader-line {
    border-color: hsl(180, 80%, 60%);
    height: 48px;
    width: 48px;
    top: 28px;
}
.loader-line-wrap:nth-child(5) .loader-line {
    border-color: hsl(240, 80%, 60%);
    height: 34px;
    width: 34px;
    top: 35px;
}

@keyframes spin {
    0%, 15% {
        transform: rotate(0);
    }
    100% {
        transform: rotate(360deg);
    }
}

image.png

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


$colors:
  hsla(337, 84, 48, 0.75)
  hsla(160, 50, 48, 0.75)
  hsla(190, 61, 65, 0.75)
  hsla( 41, 82, 52, 0.75);
$size: 2.5em;
$thickness: 0.5em;

// Calculated variables.
$lat: ($size - $thickness) / 2;
$offset: $lat - $thickness;

.loader {
  position: relative;
  width: $size;
  height: $size;
  transform: rotate(165deg);
  
  &:before,
  &:after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    display: block;
    width: $thickness;
    height: $thickness;
    border-radius: $thickness / 2;
    transform: translate(-50%, -50%);
  }
  
  &:before {
    animation: before 2s infinite;
  }
  
  &:after {
    animation: after 2s infinite;
  }
}

@keyframes before {
  0% {
    width: $thickness;
    box-shadow:
      $lat (-$offset) nth($colors, 1),
      (-$lat) $offset nth($colors, 3);
  }
  35% {
    width: $size;
    box-shadow:
      0 (-$offset) nth($colors, 1),
      0   $offset  nth($colors, 3);
  }
  70% {
    width: $thickness;
    box-shadow:
      (-$lat) (-$offset) nth($colors, 1),
      $lat $offset nth($colors, 3);
  }
  100% {
    box-shadow:
      $lat (-$offset) nth($colors, 1),
      (-$lat) $offset nth($colors, 3);
  }
}

@keyframes after {
  0% {
    height: $thickness;
    box-shadow:
      $offset $lat nth($colors, 2),
      (-$offset) (-$lat) nth($colors, 4);
  }
  35% {
    height: $size;
    box-shadow:
        $offset  0 nth($colors, 2),
      (-$offset) 0 nth($colors, 4);
  }
  70% {
    height: $thickness;
    box-shadow:
      $offset (-$lat) nth($colors, 2),
      (-$offset) $lat nth($colors, 4);
  }
  100% {
    box-shadow:
      $offset $lat nth($colors, 2),
      (-$offset) (-$lat) nth($colors, 4);
  }
}



/**
 * Attempt to center the whole thing!
 */

html,
body {
  height: 100%;
}

.loader {
  position: absolute;
  top: calc(50% - #{$size / 2});
  left: calc(50% - #{$size / 2});
}

image.png

<figure>
    <div class="dot white"></div>
    <div class="dot"></div>
    <div class="dot"></div>
    <div class="dot"></div>
    <div class="dot"></div>
</figure>

body { background: #222; }
figure { 
  position: absolute;
  margin: auto;
  top: 0; bottom: 0; left: 0; right: 0;
  width: 6.250em; height: 6.250em;
  animation: rotate 2.4s linear infinite;
}
.white { 
  top: 0; bottom: 0; left: 0; right: 0; 
  background: white; 
  animation: flash 2.4s linear infinite;
  opacity: 0;
}
.dot {
  position: absolute;
  margin: auto;
  width: 2.4em; height: 2.4em;
  border-radius: 100%;
  transition: all 1s ease;
}
.dot:nth-child(2) { top: 0; bottom: 0; left: 0; background: #FF4444; animation: dotsY 2.4s linear infinite; }
.dot:nth-child(3) { left: 0; right: 0; top: 0; background: #FFBB33; animation: dotsX 2.4s linear infinite; }
.dot:nth-child(4) { top: 0; bottom: 0; right: 0; background: #99CC00; animation: dotsY 2.4s linear infinite; }
.dot:nth-child(5) { left: 0; right: 0; bottom: 0; background: #33B5E5; animation: dotsX 2.4s linear infinite; }

@keyframes rotate {
  0% { transform: rotate( 0 ); }
  10% { width: 6.250em; height: 6.250em; }
  66% { width: 2.4em; height: 2.4em; }
  100%{ transform: rotate(360deg); width: 6.250em; height: 6.250em; }
}

@keyframes dotsY {
  66% { opacity: .1; width: 2.4em; }
  77%{ opacity: 1; width: 0; }
}
@keyframes dotsX {
  66% { opacity: .1; height: 2.4em;}
  77%{ opacity: 1; height: 0; }
}

@keyframes flash {
  33% { opacity: 0; border-radius: 0%; }
  55%{ opacity: .6; border-radius: 100%; }
  66%{ opacity: 0; }
}