Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in HTML or XML. CSS describes how elements should be rendered on screen, on paper, in speech, or on other media.
A CSS rule consists of a selector and a declaration block:
selector {
  property: value;
}
Example:
p {
  color: red;
}
Selectors are used to target the HTML elements you want to style.
*)element)#id).class)[attribute]):pseudo-class)::pseudo-element)selector1, selector2)Colors can be defined using names, HEX values, RGB, RGBA, HSL, and HSLA.
color: red; /* Name */
color: #ff0000; /* HEX */
color: rgb(255, 0, 0); /* RGB */
color: rgba(255, 0, 0, 0.5); /* RGBA */
color: hsl(0, 100%, 50%); /* HSL */
color: hsla(0, 100%, 50%, 0.5); /* HSLA */
background-colorbackground-imagebackground-repeatbackground-attachmentbackground-positionbackground-sizebackgroundbody {
  background-color: lightblue;
  background-image: url('background.jpg');
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-position: center;
  background-size: cover;
}
borderborder-widthborder-styleborder-colorborder-radiusdiv {
  border: 2px solid black;
  border-radius: 10px;
}
Margins are used to create space around elements, outside of any defined borders.
margin-topmargin-rightmargin-bottommargin-leftmargindiv {
  margin: 20px;
}
Padding is used to create space around an element’s content, inside of any defined borders.
padding-toppadding-rightpadding-bottompadding-leftpaddingdiv {
  padding: 20px;
}
heightwidthmax-heightmax-widthmin-heightmin-widthdiv {
  height: 100px;
  width: 100px;
}
The CSS box model describes the rectangular boxes that are generated for elements in the document tree and laid out according to the visual formatting model.
contentpaddingbordermargindiv {
  width: 300px;
  padding: 10px;
  border: 5px solid black;
  margin: 20px;
}
colortext-aligntext-decorationtext-transformtext-indentletter-spacingline-heighttext-shadowword-spacingp {
  color: blue;
  text-align: center;
  text-decoration: underline;
  text-transform: uppercase;
  letter-spacing: 2px;
  line-height: 1.5;
}
font-familyfont-stylefont-sizefont-weightfont-variantfontp {
  font-family: Arial, sans-serif;
  font-size: 16px;
  font-weight: bold;
  font-style: italic;
}
Icons can be added using various icon libraries like Font Awesome.
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.3/css/all.min.css">
<i class="fas fa-camera"></i>
a:linka:visiteda:hovera:activea:link {
  color: blue;
}
a:visited {
  color: purple;
}
a:hover {
  color: red;
}
a:active {
  color: orange;
}
list-style-typelist-style-positionlist-style-imagelist-styleul {
  list-style-type: square;
  list-style-position: inside;
}
border-collapseborder-spacingcaption-sideempty-cellstable-layouttable {
  border-collapse: collapse;
}
td, th {
  border: 1px solid black;
  padding: 8px;
}
noneblockinlineinline-blockflexgriddiv {
  display: block;
}
staticrelativeabsolutefixedstickydiv {
  position: absolute;
  top: 50px;
  left: 100px;
}
The z-index property specifies the stack order of an element.
div {
  position: absolute;
  z-index: 1;
}
visiblehiddenscrollautodiv {
  overflow: scroll;
}
leftrightnoneleftrightbothnonediv {
  float: left;
}
div.clear {
  clear: both;
}
Flexbox is a layout model that provides a more efficient way to lay out, align, and distribute space among items in a container.
display: flex;flex-directionjustify-contentalign-itemsalign-contentflex-wrapflex-growflex-shrinkflex-basisflexorder.container {
  display: flex;
  flex-direction: row;
  justify-content: center;
  align-items: center;
}
CSS Grid Layout is a two-dimensional layout system for the web.
display: grid;grid-template-columnsgrid-template-rowsgrid-gapgrid-columngrid-rowgrid-area.container {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-gap: 10px;
}
Media queries are used to apply different styles for different devices or screen sizes.
@media screen and (max-width: 600px) {
  body
 {
    background-color: lightblue;
  }
}
CSS transitions allow you to change property values smoothly (over a given duration).
transition-propertytransition-durationtransition-timing-functiontransition-delaytransitiondiv {
  transition: width 2s;
}
div:hover {
  width: 200px;
}
CSS animations allow you to animate transitions from one CSS style configuration to another.
@keyframesanimation-nameanimation-durationanimation-timing-functionanimation-delayanimation-iteration-countanimation-directionanimation@keyframes example {
  from {background-color: red;}
  to {background-color: yellow;}
}
div {
  animation-name: example;
  animation-duration: 4s;
}
CSS transforms allow you to rotate, scale, skew, or translate an element.
transformtransform-origindiv {
  transform: rotate(45deg);
}
Pseudo-classes are used to define the special state of an element.
a:hover {
  color: red;
}
Pseudo-elements are used to style specified parts of an element.
p::first-line {
  color: blue;
}
CSS variables are entities defined by CSS authors that contain specific values to be reused throughout a document.
:root {
  --main-color: blue;
}
p {
  color: var(--main-color);
}
CSS has several built-in functions, such as calc(), var(), rgb(), hsl(), and others.
div {
  width: calc(100% - 50px);
}
Responsive design makes web pages render well on a variety of devices and window or screen sizes.
img {
  max-width: 100%;
  height: auto;
}
@media screen and (max-width: 600px) {
  .container {
    flex-direction: column;
  }
}
This tutorial provides a comprehensive overview of CSS, from basic concepts to advanced techniques. By mastering these topics, you’ll be able to create visually appealing and responsive web pages.
https://youtu.be/ESnrn1kAD4E?si=Z2gX5J0jf7CiBQbI