CSS 3 Cheat Sheet

html {
    scroll-behavior: smooth;
}

Click me, the page will scroll smoothly to Getting started

body { counter-reset: section; }
h3::before {
  counter-increment: section; 
  content: "Section." counter(section);
}

ol {
  counter-reset: section;   
  list-marker-type: none;
}
li::before {
  counter-increment: section;
  content: counters(section, ".") " "; 
}

/\* Set "my-counter" to 0 \*/
counter-set: my-counter;

/\* Increment "my-counter" by 1 \*/
counter-increment: my-counter;

/\* Decrement "my-counter" by 1 \*/
counter-increment: my-counter -1;

/\* Reset "my-counter" to 0 \*/
counter-reset: my-counter;

See also: Counter set

Define CSS Variable

:root {
  --first-color: #16f;
  --second-color: #ff7;
}

Variable Usage

#firstParagraph {
  background-color: var(--first-color);
  color: var(--second-color);
}

See also: CSS Variable

#container {
    display: grid;
    align-items: start;
    grid-template-columns: 1fr;
    grid-template-rows: 1fr 1fr 1fr;
    grid-gap: 10px;
}

#grid-container {
    display: grid;
    justify-items: start;
}
.grid-items {
    justify-self: end;
}

The grid items are positioned to the right (end) of the row.

.item {
    grid-area: nav;
}
.grid-container {
    display: grid;
    grid-template-areas:
    'nav nav . .'
    'nav nav . .';
}

#container {
    display: grid;
    justify-items: center;
    grid-template-columns: 1fr;
    grid-template-rows: 1fr 1fr 1fr;
    grid-gap: 10px;
}

.item1 {
    grid-area: 2 / 1 / span 2 / span 3;
}

grid-row-gap: length;

Any legal length value, like px or %. 0 is the default value

CSS syntax:

• grid-row-start: auto|row-line;
• grid-row-end: auto|row-line|span n;

#Example

grid-row-start: 2;
grid-row-end: span 2;

.grid {
    display: grid;
    grid-template-columns: 100px minmax(100px, 500px) 100px; 
}

#grid-container {
    display: inline-grid;
}

CSS syntax:

• grid-row: grid-row-start / grid-row-end;

#Example

.item {
    grid-row: 1 / span 2;
}

#grid-container {
    display: block;
}

/\*The distance between rows is 20px\*/
/\*The distance between columns is 10px\*/
#grid-container {
    display: grid;
    grid-gap: 20px 10px;
}

.grid {
    display: grid;
    width: 100px;
    grid-template-columns: 1fr 60px 1fr;
}

#grid-container {
    display: grid;
    width: 100px;
    grid-template-columns: 20px 20% 60%;
}

.menu > .left  { align-self: flex-start; }
.menu > .right { align-self: flex-end; }

.container {
  align-items: center;
}

Vertically-center all items.

.container {
  display: flex;
}
/\* the 'px' values here are just suggested percentages \*/
.container > .checkbox { flex: 1 0 20px; }
.container > .subject  { flex: 1 0 400px; }
.container > .date     { flex: 1 0 120px; }

This creates columns that have different widths, but size accordingly according to the circumstances.

.container {
  display: flex;
  flex-direction: column;
}
.container > .top {
  flex: 0 0 100px;
}
.container > .content {
  flex: 1 0 auto;
}

A fixed-height top bar and a dynamic-height content area.

.container > .top {
 order: 1;
}
.container > .bottom {
 order: 2;
}

.container {
  display: flex;
  /\* vertical \*/
  align-items: center; 
  /\* horizontal \*/
  justify-content: center;
}

.container {
  display: flex;
}
.container > div {
  width: 100px;
  height: 100px;
  margin: auto;
}

.container > div {

  /\* This: \*/
  flex: 1 0 auto;
  /\* Is equivalent to this: \*/
  flex-grow: 1;
  flex-shrink: 0;
  flex-basis: auto;

  order: 1;

  align-self: flex-start;  /\* left \*/
  margin-left: auto;       /\* right \*/

}

.container {

  display: flex;
  display: inline-flex;

  flex-direction: row;            /\* ltr - default \*/
  flex-direction: row-reverse;    /\* rtl \*/
  flex-direction: column;         /\* top-bottom \*/
  flex-direction: column-reverse; /\* bottom-top \*/

  flex-wrap: nowrap; /\* one-line \*/
  flex-wrap: wrap;   /\* multi-line \*/

  align-items: flex-start; /\* vertical-align to top \*/
  align-items: flex-end;   /\* vertical-align to bottom \*/
  align-items: center;     /\* vertical-align to center \*/
  align-items: stretch;    /\* same height on all (default) \*/

  justify-content: flex-start;    /\* [xxx ] \*/
  justify-content: center;        /\* [ xxx ] \*/
  justify-content: flex-end;      /\* [ xxx] \*/
  justify-content: space-between; /\* [x x x] \*/
  justify-content: space-around;  /\* [ x x x ] \*/
  justify-content: space-evenly;  /\* [ x x x ] \*/

}

.container {
  display: flex;
}

.container > div {
  flex: 1 1 auto;
}

.one('webkitAnimationEnd oanimationend msAnimationEnd animationend')

.small-block {
    overflow: scroll;
}

See also: Overflow

div {
    margin: auto;
}

See also: Margin

.invisible-elements {
    visibility: hidden;
}

See also: Visibility

.container {
    box-sizing: border-box;
}

See also: Box-sizing

.block-one {
    margin: 20px;
    padding: 10px;
}

See also: Margin / Padding

.column {
    max-width: 200px;
    width: 500px;
}

See also: max-width / min-width / max-height / min-height

color: inherit;
color: initial;
color: unset;
color: transparent;
color: currentcolor; /\* keyword \*/

color: hsl(30, 100%, 50%, 0.6);
color: hsla(30, 100%, 50%, 0.6);
color: hsl(30 100% 50% / 0.6);
color: hsla(30 100% 50% / 0.6);
color: hsl(30.0 100% 50% / 60%);
color: hsla(30.2 100% 50% / 60%);

color: rgb(34, 12, 64, 0.6);
color: rgba(34, 12, 64, 0.6);
color: rgb(34 12 64 / 0.6);
color: rgba(34 12 64 / 0.3);
color: rgb(34.0 12 64 / 60%);
color: rgba(34.6 12 64 / 30%);

color: #090;
color: #009900;
color: #090a;
color: #009900aa;

color: red;
color: orange;
color: tan;
color: rebeccapurple;

@font-face {
    font-family: 'Glegoo';
    src: url('../Glegoo.woff');
}

/\* Hello \*/
text-transform: capitalize;
/\* HELLO \*/
text-transform: uppercase;
/\* hello \*/
text-transform: lowercase;

font-family: Arial, sans-serif;
font-size: 12pt;
letter-spacing: 0.02em;

#Groups Selector

h1, h2 {
    color: red;
}

#Chaining Selector

h3.section-heading {
    color: blue;
}

#Attribute Selector

div[attribute="SomeValue"] {
    background-color: red;
}

#First Child Selector

p:first-child {
    font-weight: bold;
}

#No Children Selector

.box:empty {
  background: lime;
  height: 80px;
  width: 80px;
}

counter-set: subsection;
counter-increment: subsection;
counter-reset: subsection 0;
:root {
  --bg-color: brown;
}
element {
  background-color: var(--bg-color);
}

See: Dynamic content

#container {
  display: grid;
  grid: repeat(2, 60px) / auto-flow 80px;
}
#container > div {
  background-color: #8ca0ff;
  width: 50px;
  height: 50px;
}

See: Grid Layout

div {
    display: flex;
    justify-content: center;
}
div {
    display: flex;
    justify-content: flex-start;
}

See: Flexbox | Flex Tricks

/\* This is a single line comment \*/
/\* This is a 
 multi-line comment \*/

animation: 300ms linear 0s infinite;
animation: bounce 300ms linear infinite;

See: Animation

.box {
    position: relative;
    top: 20px;
    left: 20px;
}

See also: Position

.page-title {
    font-weight: bold;
    font-size: 30px;
    font-family: "Courier New";
}

See: Fonts

background-color: blue;
background-image: url("nyan-cat.gif");
background-image: url("../image.png");

See: Backgrounds

color: #2a2aff;
color: green;
color: rgb(34, 12, 64, 0.6);
color: hsla(30 100% 50% / 0.6);

See: Colors

h1 { } 
#job-title { }
div.hero { }
div > p { }

See: Selectors

.post-title {
    color: blue !important;
}

Overrides all previous styling rules.

<div class="classname"></div>
<div class="class1 ... classn"></div>

Support multiple classes on one element.

CSS is rich in capabilities and is more than simply laying out pages.

#External stylesheet

<link href="./path/to/stylesheet/style.css" rel="stylesheet" type="text/css">

#Internal stylesheet

<style>
body {
 background-color: linen;
}
</style>

#Inline styles

<h2 style="text-align: center;">Centered text</h2>
<p style="color: blue; font-size: 18px;">Blue, 18-point text</p>