style guide CSS example

example.css

/* single-line comment */
.block {
  --block-box-shadow: rgba(160, 20, 88, 0.2);
  --block-inner-shadow: rgba(189, 20, 90, 1);

  display: flex;
  align-items: baseline;
  justify-content: space-between;
  position: relative;
  top: 0;
  left: calc(calc(1em * 2) / 3);
  height: 100px;
  margin: -16px auto;
  padding: 8px 16px;

  /* comment empty-line before */
  box-shadow: 0 2px 16px 0 var(--block-box-shadow);
  opacity: 0.5;

  font-family: 'Avenir Next', sans-serif;
  font-weight: 600;
  line-height: 1.4;
  text-align: left;
  transition: box-shadow 0.12s ease-in;
  z-index: 2;
}

/* selector and value lists comma */
.block:hover,
.block:focus {
  box-shadow:
    0 2px 16px 0 var(--block-box-shadow),
    inset 0 -2px 0 4px var(--block-inner-shadow);
}

/* selector attribute brackets space inside */
[target='_blank'] {
  font-size: 16px;
  font-size: 1rem;
  text-decoration: underline;
}

[class*='col'] {
  /* block no empty, ignore comments  */
}

/* at-rule name space after */

@charset 'UTF-8';

@import url(x.css);
@import url(y.css);

@font-face {
    font-family: 'foo';
    src: url("/fonts/OpenSans-Regular-webfont.woff2") format("woff2"),
         url("/fonts/OpenSans-Regular-webfont.woff") format("woff"); 
    font-style: normal;
    font-display: swap;
}

@keyframes name {
  from {
    top: 10px;
  }
  to {
    top: 20px;
  }
}

@keyframes name2 {
  0% {
    top: 10px;
  }
  100% {
    top: 20px;
  }
}

@media screen and (min-width: 700px) {
  .class {
    property: value;
  }
}

@media screen and (min-width: 700px) {
  .class {
    property: value;
  }
}

@supports {
  @media {}

  @media {}
}