Selectors are used to target certain elements or groups of elements or even one type of element in its entirety. Selctors can also be given certain criteria that has to be meet to affecte that certain element allowing for element to one thing then another with a few lines of code
ID Selector can only be put on one AND ONLY ONE element and is done like this
#ID h1
Class selctor are use to target a general area and are usually used in div elements and
can be used as many times as needed
.ThisIsAClass
Universal selectors on the other hand target everything in the style sheet making it usfull
to get ride of margin or padding on all elemnts.
* done like this
A few other are the child (h1 > p), adjacent (h2 + div), and the :nth-child() selector.
Display are use to change the orientation of elements in side of the display. they can range from blocks, to grid to flex displays which has there own way of changing how they move to how big the display is. Generally the block is the most use one as it allows you to everything you need in to a easy to move and manipulate diplay
Block is always a good one to use to move generalize elements like text or images.
But both inline and inline block are great if you need thing to line up in one line
some or displays are none with make that element disapper, flex which allows for many different
changes to happen and visibility which with some conditions can make elements be deen of vanish
but still take up the space is was in.
Positioning changes how the element interacts with other element on the page. From making so other element can sit in it to making follow the screen as it moves. Positioning also allows you to move elements around as well so you can move them to just right spot.
Absolute positioning makes it so the element can move into other element without changing
the other element. This can be used to put images ontop of other images or text over said
images
sticky positioning makes it so that after you where supposed to scroll pass an element,
the element will stick to the top of your page and stay on the top of the screen until
you return to is original position.
A few others are the fixed will stay in one place and the content will even go over top of
it as well, and the static which is just the default of all elements.