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

Support multiple classes on one element.

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

Overrides all previous styling rules.

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

See: Selectors

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

See: Colors

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

See: Backgrounds

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

See: Fonts

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

See also: Position

animation: 300ms linear 0s infinite;

animation: bounce 300ms linear infinite;

See: Animation

/* This is a single line comment */

/* This is a 
   multi-line comment */

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

See: Flexbox | Flex Tricks

#container {
  display: grid;
  grid: repeat(2, 60px) / auto-flow 80px;
}

#container > div {
  background-color: #8ca0ff;
  width: 50px;
  height: 50px;
}

See: Grid Layout

counter-set: subsection;
counter-increment: subsection;
counter-reset: subsection 0;

:root {
  --bg-color: brown;
}
element {
  background-color: var(--bg-color);
}

See: Dynamic content

See also: Type / Class / ID / Universal selectors

See also: Adjacent / Sibling / Child selectors

See also: Attribute selectors

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

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

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

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

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: 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: inherit;
color: initial;
color: unset;
color: transparent;

color: currentcolor; /* keyword */

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

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

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

See also: Margin / Padding

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

See also: Box-sizing

.invisible-elements {
    visibility: hidden;
}

See also: Visibility

div {
    margin: auto;
}

See also: Margin

.small-block {
    overflow: scroll;
}

See also: Overflow

.container {
  display: flex;
}

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

.container {
  display: flex;

  /* vertical */
  align-items: center; 

  /* horizontal */
  justify-content: center;
}

.container > .top {
 order: 1;
}

.container > .bottom {
 order: 2;
}

.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 {
  align-items: center;
}

Vertically-center all items.

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

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

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

#grid-container {
    display: block;
}

CSS syntax:

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

#Example

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

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

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

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-row-gap: length;

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

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

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

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

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

.grid-items {
    justify-self: end;
}

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

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

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

/* 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

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, ".") " "; 
}

html {
    scroll-behavior: smooth;
}

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