Resets and Normalization

Why we need CSS resets and normalization

It’s important for HTML elements to look the same, regardless of which browser is being used to view the web page. Unfortunately, this isn’t true by default due to the way browsers run.

Each browser has its default style sheet that specifies some minimal rules for the elements.

For example, an unstyled <h1> element often has a slightly different amount of padding, depending on which browser is used.

Most of the time, these style defaults are useful. However, there will come a time when a bug occurs in a particular browser because of these differing defaults.

To avoid these inconsistencies, we use CSS resets and normalization.

CSS resets

A CSS reset removes all the browser’s default styles, leaving us to define the styles that we want, according to our needs.

There are multiple types of CSS reset online. The most popular one by far is the Meyer reset:

/* http://meyerweb.com/eric/tools/css/reset/ 
   v2.0 | 20110126
   License: none (public domain)
*/

html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed, 
figure, figcaption, footer, header, hgroup, 
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
	margin: 0;
	padding: 0;
	border: 0;
	font-size: 100%;
	font: inherit;
	vertical-align: baseline;
}

Here, all HTML tags don’t receive a padding, margin, or border. These tags also have an equal font-size value and receive a baseline alignment value.

While it’s great to start a project at a balanced level, CSS resets can be quite messy and have many unnecessary overrides.

There are a few more widely used resets that have come along since the launch of HTML5, such as Richard Clark’s HTML5 Reset, Cleanslate & mini reset to name a few.

Many developers opt for a more minimal approach by simply removing any padding and margins:

* {
  padding: 0;
  margin: 0;
}

Normalization

Normalization is an alternative that’s less aggressive than resets. Instead of removing all the defaults, it only removes browser inconsistencies, and keeps a basic set of defaults in place.

Normalize.css was created to provide this cross-browser consistency. In accordance with the W3CWorld Wide Web Consortium standards, it doesn’t remove styling from elements that are already consistent across browsers.

An example of normalization is provided for you. The code below is heavily commented, so you know exactly what it’s doing:

/*! normalize.css v8.0.1 | MIT License | github.com/necolas/normalize.css */
/* Document
   ============================================================== */
/**
 * 1. Correct the line height in all browsers.
 * 2. Prevent adjustments of font size after orientation changes in iOS.
 */
html {
  line-height: 1.15; /* 1 */
  -webkit-text-size-adjust: 100%; /* 2 */
}
/* Sections
   ============================================================== */
/**
 * Remove the margin in all browsers.
 */
body {
  margin: 0;
}
/**
 * Render the `main` element consistently in IE.
 */
main {
  display: block;
}
/**
 * Correct the font size and margin on `h1` elements within the `section` and
 * `article` contexts in Chrome, Firefox, and Safari.
 */
h1 {
  font-size: 2em;
  margin: 0.67em 0;
}
/* Grouping content
   ============================================================== */
/**
 * 1. Add the correct box sizing in Firefox.
 * 2. Show the overflow in Edge and IE.
 */
hr {
  box-sizing: content-box; /* 1 */
  height: 0; /* 1 */
  overflow: visible; /* 2 */
}
/**
 * 1. Correct the inheritance and scaling of font size in all browsers.
 * 2. Correct the odd `em` font sizing in all browsers.
 */
pre {
  font-family: monospace, monospace; /* 1 */
  font-size: 1em; /* 2 */
}
/* Text-level semantics
   ============================================================== */
/**
 * Remove the gray background on active links in IE 10.
 */
a {
  background-color: transparent;
}
/**
 * 1. Remove the bottom border in Chrome 57-
 * 2. Add the correct text decoration in Chrome, Edge, IE, Opera, and Safari.
 */
abbr[title] {
  border-bottom: none; /* 1 */
  text-decoration: underline; /* 2 */
  text-decoration: underline dotted; /* 2 */
}
/**
 * Add the correct font weight in Chrome, Edge, and Safari.
 */
b,
strong {
  font-weight: bolder;
}
/**
 * 1. Correct the inheritance and scaling of font size in all browsers.
 * 2. Correct the odd `em` font sizing in all browsers.
 */
code,
kbd,
samp {
  font-family: monospace, monospace; /* 1 */
  font-size: 1em; /* 2 */
}
/**
 * Add the correct font size in all browsers.
 */
small {
  font-size: 80%;
}
/**
 * Prevent `sub` and `sup` elements from affecting the line height in
 * all browsers.
 */
sub,
sup {
  font-size: 75%;
  line-height: 0;
  position: relative;
  vertical-align: baseline;
}
sub {
  bottom: -0.25em;
}
sup {
  top: -0.5em;
}
/* Embedded content
   ============================================================== */
/**
 * Remove the border on images inside links in IE 10.
 */
img {
  border-style: none;
}
/* Forms
   ============================================================== */
/**
 * 1. Change the font styles in all browsers.
 * 2. Remove the margin in Firefox and Safari.
 */
button,
input,
optgroup,
select,
textarea {
  font-family: inherit; /* 1 */
  font-size: 100%; /* 1 */
  line-height: 1.15; /* 1 */
  margin: 0; /* 2 */
}
/**
 * Show the overflow in IE.
 * 1. Show the overflow in Edge.
 */
button,
input { /* 1 */
  overflow: visible;
}
/**
 * Remove the inheritance of text transform in Edge, Firefox, and IE.
 * 1. Remove the inheritance of text transform in Firefox.
 */
button,
select { /* 1 */
  text-transform: none;
}
/**
 * Correct the inability to style clickable types in iOS and Safari.
 */
button,
[type="button"],
[type="reset"],
[type="submit"] {
  -webkit-appearance: button;
}
/**
 * Remove the inner border and padding in Firefox.
 */
button::-moz-focus-inner,
[type="button"]::-moz-focus-inner,
[type="reset"]::-moz-focus-inner,
[type="submit"]::-moz-focus-inner {
  border-style: none;
  padding: 0;
}
/**
 * Restore the focus styles unset by the previous rule.
 */
button:-moz-focusring,
[type="button"]:-moz-focusring,
[type="reset"]:-moz-focusring,
[type="submit"]:-moz-focusring {
  outline: 1px dotted ButtonText;
}
/**
 * Correct the padding in Firefox.
 */
fieldset {
  padding: 0.35em 0.75em 0.625em;
}
/**
 * 1. Correct the text wrapping in Edge and IE.
 * 2. Correct the color inheritance from the `fieldset` elements in IE.
 * 3. Remove the padding, so developers are not caught out when they zero out
 *    `fieldset` elements in all browsers.
 */
legend {
  box-sizing: border-box; /* 1 */
  color: inherit; /* 2 */
  display: table; /* 1 */
  max-width: 100%; /* 1 */
  padding: 0; /* 3 */
  white-space: normal; /* 1 */
}
/**
 * Add the correct vertical alignment in Chrome, Firefox, and Opera.
 */
progress {
  vertical-align: baseline;
}
/**
 * Remove the default vertical scrollbar in IE 10+.
 */
textarea {
  overflow: auto;
}
/**
 * 1. Add the correct box sizing in IE 10.
 * 2. Remove the padding in IE 10.
 */
[type="checkbox"],
[type="radio"] {
  box-sizing: border-box; /* 1 */
  padding: 0; /* 2 */
}
/**
 * Correct the cursor style of increment and decrement buttons in Chrome.
 */
[type="number"]::-webkit-inner-spin-button,
[type="number"]::-webkit-outer-spin-button {
  height: auto;
}
/**
 * 1. Correct the odd appearance in Chrome and Safari.
 * 2. Correct the outline style in Safari.
 */
[type="search"] {
  -webkit-appearance: textfield; /* 1 */
  outline-offset: -2px; /* 2 */
}
/**
 * Remove the inner padding in Chrome and Safari on macOS.
 */
[type="search"]::-webkit-search-decoration {
  -webkit-appearance: none;
}
/**
 * 1. Correct the inability to style clickable types in iOS and Safari.
 * 2. Change font properties to `inherit` in Safari.
 */
::-webkit-file-upload-button {
  -webkit-appearance: button; /* 1 */
  font: inherit; /* 2 */
}
/* Interactive
   ============================================================== */
/*
 * Add the correct display in Edge, IE 10+, and Firefox.
 */
details {
  display: block;
}
/*
 * Add the correct display in all browsers.
 */
summary {
  display: list-item;
}
/* Miscellaneous
   ============================================================== */
/**
 * Add the correct display in IE 10+.
 */
template {
  display: none;
}
/**
 * Add the correct display in IE 10.
 */
[hidden] {
  display: none;
}

Which one?

You can choose either resets or normalization as your go-to solution, the choice is entirely yours! You can also choose a combination of both or even write your own variant.

However, you can never go wrong running normalize CSS with a few resets included as necessary.