KNACSS/sass/base/_reset.scss

/* ----------------------------- */
/* ==Reset                       */
/* ----------------------------- */


/**
 * disable animations styles when reduced motion is enabled
 */

@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition: none !important;
  }
}

/**
 * 1. switch to border-box model for all elements
 * 2. avoid min-width: auto and min-height: auto on flex and grid children
 */

*,
*::before,
*::after {
  box-sizing: border-box; /* 1 */
  min-width: 0; /* 2 */
  min-height: 0; /* 2 */
}

/**
 * 1. remove the grey highlight on links in iOS 
 * 2. prevent orientation font changes in iOS
 * 3. set base font-size to equiv "10px", which is adapted to rem unit
 */

html {
  -webkit-tap-highlight-color: transparent; /* 1 */
  -webkit-text-size-adjust: 100%; /* 2 */
  font-size: calc(1em * 0.625); /* 3 */
}

/* Body */
body {
  margin: 0;
  @include font-size(base);
  background-color: $background-base;
  color: $color-base;
  font-family: $font-family-base;
  line-height: $line-height-base;
}

/* Links */
a {
  color: $link-color;
  text-decoration: $link-decoration;

  &:focus,
  &:hover,
  &:active {
    color: $link-color-hover;
    text-decoration: $link-decoration-hover;
  }
}

/* Headings */
h1, .h1-like {
  @include font-size(h1);
  @if variable_exists(font-family-headings) and $font-family-headings != $font-family-base{
    font-family: $font-family-headings;
  }
  font-weight: $weight-medium;
}

h2, .h2-like {
  @include font-size(h2);
  @if variable_exists(font-family-headings) and $font-family-headings != $font-family-base{
    font-family: $font-family-headings;
  }
  font-weight: $weight-medium;
}

h3, .h3-like {
  @include font-size(h3);
  font-weight: $weight-medium;
}

h4, .h4-like {
  @include font-size(h4);
  font-weight: $weight-medium;
}

h5, .h5-like {
  @include font-size(h5);
  font-weight: $weight-medium;
}

h6, .h6-like {
  @include font-size(h6);
  font-weight: $weight-medium;
}

/* Vertical rythm */
h1,
h2,
h3,
h4,
h5,
h6,
dd {
  margin-top: 0;
  margin-bottom: $headings-margin-bottom;
}

p,
address,
ol,
ul,
dl,
blockquote,
pre {
  margin-top: 0;
  margin-bottom: $paragraph-margin-bottom;
}

/* Avoid margins on nested elements */
li p,
li .p-like,
li ul,
li ol,
ol ol,
ul ul {
  margin-top: 0;
  margin-bottom: 0;
}

/* Styling elements */
a,
area,
button,
[role="button"],
.btn,
.button,
[type="button"]
input:not([type="range"]),
label,
select,
summary,
textarea {
  -ms-touch-action: manipulation;
      touch-action: manipulation;
}

img,
table,
td,
blockquote,
code,
pre,
textarea,
input,
video,
svg {
  max-width: 100%;
}

img {
  height: auto;
  vertical-align: middle;
  border-style: none;
}

svg:not(:root) {
  overflow: hidden;
}

ul,
ol {
  padding-left: 2em;
}

b,
strong {
  font-weight: bolder;
}

em,
.italic,
address,
cite,
i,
var {
  font-style: italic;
}

pre,
code,
kbd,
samp {
  font-family: monospace, monospace;
  font-size: 1em;
  white-space: pre-wrap;
  line-height: normal;
}

pre {
  overflow: auto;
  -ms-overflow-style: scrollbar;
  tab-size: 2;
}

code,
kbd,
mark {
  border-radius: 2px;
}

kbd {
  padding: 0 2px;
  border: 1px solid #999;
}

code {
  padding: 2px 4px;
  background: rgba(0, 0, 0, 0.04);
  color: #b11;
}

pre code {
  padding: 0;
  background: none;
  color: inherit;
  border-radius: 0;
}

mark {
  padding: 2px 4px;
}

sup,
sub {
  vertical-align: 0;
}

sup {
  bottom: 1ex;
}

sub {
  top: 0.5ex;
}

blockquote {
  position: relative;
  padding-left: 3em;
  min-height: 2em;
}

blockquote::before {
  content: "\201C";
  position: absolute;
  left: 0;
  top: 0;
  font-family: georgia, serif;
  font-size: 5em;
  height: .4em;
  line-height: .9;
  color: $quote-color;
}

blockquote > footer {
  margin-top: .75em;
  font-size: 0.9em;
  color: rgba(0, 0, 0, .7);

  &::before {
    content: "\2014 \0020";
  }
}

q {
  font-style: normal;
}

q,
.q {
  quotes: "“" "”" "‘" "’";

  &:lang(fr) {
    quotes: "«\00a0" "\00a0»" "“" "”";
  }
}

hr {
  display: block;
  clear: both;
  height: 1px;
  margin: 1em 0 2em;
  padding: 0;
  border: 0;
  color: #ccc;
  background-color: #ccc;
}

blockquote,
figure {
  margin-left: 0;
  margin-right: 0;
}