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These are my notes while taking the The Complete Web Developer Zero to Mastery course by Andrei Neagoie on ZTM Academy.

CSS Tricks

CSS, Cascading Style Sheet, is used to describe how elements should be rendered to users.

CSS can be implemented in several ways. Inline styling, inside the style tag of an HTML document, or in an external stylesheet.

Identify Elements

There are multiple ways to tell the browser how to "find" the elements you want to style.

Here are some examples.

Element Names

Just using an HTML elements tag name is one of the simplest ways to add styling to an element. An example is:

div { *styles for all div tags go here* }
p {*styles for paragraph tags go here* }

Class Selector

Classes are probably the most common selector given to elements, because they are reusable.
You can have one css style for a certain class and give it to as many elements as you want.

<div class="my-div">Style the div tag by applying the class "my-div" to it.</div>

Then, in the css styles to use a class, you start it with a period and then the name of the class:

.my-div { *styles for class my-div go here* }

ID Selector

IDs should only be given to a single element in the HTML and are the most specific of the simple selectors.

<div id="this-div">Style the div tag by applying the id "this-div" to it.</div>

Then, in the css styles to use an id, you start it with a hash (#) and then the name of the id:

#this-div { *styles for class my-div go here* }


CSS selectors tell the browser which HTML element you want to style.

There are 5 types of selectors.

  1. 1. Simple selectors (element name, class, or id)
div {*styles*} .my-div {*styles*} #this-div {*styles*}
  1. 2. Combination selectors (relationship between multiple elements)
 .my-div p {*styles only paragraphs with a parent container with a class of my-div*}
  1. 3. Pseudo-class selectors (state of an element)
a:hover {*styles the anchor link when it is hovered over*} li:nth-child(even) {*styles every other list element*}
  1. 4. Pseudo-elements selectors (a piece of an element)
h1::before {content: "-"; *styles before the h1 with a -*} h1::after{content: "-"; *styles after the h1 with a -*}
  1. 5. Attribute selectors (an element with an attribute)


If there are conflicting selectors in your CSS, the browser follows some standards to choose which rule to use. This is called specificity.

There are 4 categories that define the level of specificity for selectors ranging from most specific to least specific.

  1. 1. Inline styles
  2. 2. IDs
  3. 3. Classes, attributes, and pseudo-classes
  4. 4. Elements and pseudo-elements

CSS Grid vs Flexbox

Should I use Flexbox or Grid? - Both, stop thinking of them as separate layout methods as if they were frameworks. Think about the pattern you need for the layout. CSS Grid Layout is a two-dimensional system, meaning it can handle both columns and rows, unlike flexbox which is a one-dimensional system (either in a column or a row, not both). Flexbox layouts are content-first and works well when distributing space and aligning content. Grid is layout-first and works well on large scale layouts that aren't linear. It allows you to define areas and the relationship between them. If you only need to define a layout as a row or a column, then you probably need flexbox. If you want to define a grid and fit content into it in two dimensions — you need the grid.

Where to learn and practice Flexbox and Grid


What the FLEXBOX?! by Wes Bos
Flexbox Froggy
Flexbox Defense
A Complete Guide to Flexbox by CSS Tricks


CSS Grid by Wes Bos
CSS Grid Garden
Grid by Example by Rachel Andrew
A Complete Guide to Grid by CSS Tricks