CSS3 keyframe animation timing functions

by Emanuele del Grande

HTML

<div class="logo">
    <span>CSS</span> <span>Easings</span>
    <div>CSS easing functions</div>
</div>

<div class="bars">
    <div id="div1">linear</div>
    <div id="div2">ease</div>
    <div id="div3">ease-in</div>
    <div id="div4">ease-out</div>
    <div id="div5">ease-in-out</div>
</div>

CSS

@import url(https://fonts.googleapis.com/css2?family=Inter:wght@100;200;300;400;500;600;700;800;900&display=swap);

:root {
  --font-color: #444;
  --font-family: Inter, Roboto, Arial, Helvetica;
  --font-size: 14px;
  --font-weight: 300;
  --letter-spacing: -0.5px;
  --main-color: #607f8b; /* #4ae */
  --inner-border-width: 1px;
  --border-color: #ddd;
  --v-padding: 10px;
}


/* GENERIC STYLE */
*, *:before, *:after { margin; 0; padding: 0; box-sizing: border-box; outline: none; }
html, body {
    font: 14px var(--font-family); color: var(--font-color); line-height: 1.4em;
    font-weight: var(--font-weight); letter-spacing: var(--letter-spacing);
}
.logo { font: 42px var(--font-family); margin: 0; padding: 10px 0 0 20px; font-weight: 800; letter-spacing: -3px; white-space: nowrap; }
.logo span:first-child {
    position: relative; top: 0; left: 0; padding: 0 13px 0 10px; color: var(--main-color); background: var(--main-color); color: #fff;
    clip-path: ellipse(100% 125% at 100% 50%); z-index: 1;
}
.logo span:nth-child(2) { position: relative;top: 0; left: 0; margin: 0 0 0 -13px; background: transparent; z-index: 2; }

.logo div { font: 12px var(--font-family); padding: 0 0 0 70px; letter-spacing: -0.5px; }


/* EASING FUNCTIONS BAR STYLES */
@-webkit-keyframes width {
    0%, 100% { width: 160px; }
    50% { width: 350px; }
}
@-moz-keyframes width {
    0%, 100% { width: 160px; }
    50% { width: 350px; }
}
@-o-keyframes width {
    0%, 100% { width: 160px; }
    50% { width: 350px; }
}
.bars div { width: 160px; height: 30px; margin: 10px 0; padding: 0 0 0 20px;
    border-bottom: 15px solid rgba(0, 0, 0, 0.4); line-height: 30px; vertical-align: middle;
    color: white; font-size: 18px;
    background: var(--main-color);
    -webkit-animation: width 2s infinite;
       -moz-animation: width 2s infinite;
         -o-animation: width 2s infinite;
}

#div1 { animation-timing-function: linear; }
#div2 { animation-timing-function: ease; }
#div3 {...