^^CSS selectors.

CSS rule

selector {
property:value;
}

CSS selector

selector is a pattern used to select the elements to style.

struttura: is the first part of a CSS Rule, quella prima di { }
funzione: seleziona un tipo elementi di un documento html, referred to as the subjects of the selector.

Selector	Description
	Simple selectors
p	tag name	selector
#carbon	id	selector
.chimica	class	selector
span.chimica	to specify which HTML elements select
h1, h2, p	To group selectors, separate each selector with a comma.
	Combinator selectors
div p elm elm	descendant selector (space) selects all elements that are descendants of a specified element. es: all p elements inside a div element
div > p elm > elm	child selector (>)selects all elements that are the children of a specified element es: all p elements children of a div element
div + p elm + elm	immediately after selector (+) selects all elements that are immediately after of a specified element. es: all p elements immediately after a div element
div ~ p elm ~ elm	siblings_after selector (~) selects all sibling elements after of a specified element. es: all siblings p elements after a div element

w3/Level 3 Selectors specification

w3schools/css_selectors

MDN Mozilla Developers Network

Selectors, in particolare Types of selectors.

Piu' in generale, il modulo cui appartiene questo capitolo >>>

element.className.

# (hash character) select id

to select an element with a specific id, write a hash (#) character, followed by the id of the element.

<style> #myHeader { background-color: lightblue; color: black; } </style>

<h1 id="myHeader">My Header</h1>

CSS element+element Selector

Syntax

element + element {
css declarations;
}

select the element after (not inside) the first specified element.

Es Hover over a <span> element to show a <div> element (like a tooltip)

span:hover + div { display: block; }