Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in HTML or XML (including XML dialects such as SVG, MathML or XHTML).
— developer.mozilla.org/en-US/docs/Web/CSS
TODO 
.header{
    backround: linear-gradient(rgba(0,0,0,0.5), rgba(0,0,0,0.5)),
    url("./big.jpeg")center/cover no-repeat fixed;
}

text-indent: 50px

opacity
backround-repeat: round

static, relative, fixed, absolute

::before
::after
p::before{ content: "hello "; display: block;}

/* Descendent child selectors */
div h1 {} | div > h1 {}

p::first-line {} | p::first-letter

p:hover
div:hover {
    backround: coral;
}

Transform:transition()
display: inline-block;
transform: translate(px, px)
transform: scale( $num, $num)
transform: rotateX|Y|Z($(num)deg)
transform: skew(40deg, 60deg)


transition-property: backround;
transition-duration: 4s;
transition-delay: 4s;
transition: {property} {lenght} {delay
transition: all 4s function 5s;
}

transition-timig-function: ease | linear | ease-in | ease-out | ease-in-out

@keyframes  move {
    0%{
        transform: translateX
    }
    50%{
        transform: translateX
    }
}
.div {
    animation-name: move;
    animation-duration: 10s;
    animation-iteration-count: 2;
    animation: move duration count;
    animation: move 5s infinite;
}

animation-fill-mode: forwards;

background-image: url("../pictures/industry-839254_1920.jpg");
display: grid;
grid-template-columns: 3fr 1fr 6fr 1fr;

Inspirations

Selectors

:root pseudo-class

Universal_selectors * { style properties }

Text

font-size property

line-height property

color property

hwb (hue whiteness blackness) functional notation

<angle> data type

overflow-wrap property

word-break property

white-space property

Import Google Font
@import url('https://fonts.googleapis.com/css2?family=Lexend&display=swap');

body {
    font-family: 'Lexend', sans-serif;
}

Custom Properties (Variables)

Margin Padding Border

This property can be used to set a margin on all four sides of an element. Margins create extra space around an element, unlike padding, which creates extra space within an element.
— developer.mozilla.org/en-US/docs/Web/CSS/margin

Position property

Display property

Data Types

<length> data type

Rules

@import rule

Media rule

@media screen and (min-aspect-ratio: 1/1) {
    ...
}
@media (orientation: portrait) {
    ...
}