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diff --git a/css.html.markdown b/css.html.markdown index 8ee4f4b9..5dae06ca 100644 --- a/css.html.markdown +++ b/css.html.markdown @@ -7,16 +7,23 @@ contributors: - ["Connor Shea", "https://github.com/connorshea"] - ["Deepanshu Utkarsh", "https://github.com/duci9y"] - ["Tyler Mumford", "https://tylermumford.com"] + filename: learncss.css --- -Web pages are built with HTML, which specifies the content of a page. CSS (Cascading Style Sheets) is a separate language which specifies a page's **appearance**. +Web pages are built with HTML, which specifies the content of a page. +CSS (Cascading Style Sheets) is a separate language which specifies +a page's **appearance**. -CSS code is made of static *rules*. Each rule takes one or more *selectors* and gives specific *values* to a number of visual *properties*. Those properties are then applied to the page elements indicated by the selectors. +CSS code is made of static *rules*. Each rule takes one or more *selectors* and +gives specific *values* to a number of visual *properties*. Those properties are +then applied to the page elements indicated by the selectors. -This guide has been written with CSS 2 in mind, which is extended by the new features of CSS 3. +This guide has been written with CSS 2 in mind, which is extended by the new +features of CSS 3. -**NOTE:** Because CSS produces visual results, in order to learn it, you need to try everything in a CSS playground like [dabblet](http://dabblet.com/). +**NOTE:** Because CSS produces visual results, in order to learn it, you need to +try everything in a CSS playground like [dabblet](http://dabblet.com/). The main focus of this article is on the syntax and some general tips. ## Syntax @@ -66,7 +73,7 @@ div { } [otherAttr~='foo'] { } [otherAttr~='bar'] { } -/* or contains a value in a dash-separated list, ie, "-" (U+002D) */ +/* or contains a value in a dash-separated list, e.g., "-" (U+002D) */ [otherAttr|='en'] { font-size:smaller; } @@ -113,7 +120,8 @@ selector:first-child {} /* any element that is the last child of its parent */ selector:last-child {} -/* Just like pseudo classes, pseudo elements allow you to style certain parts of a document */ +/* Just like pseudo classes, pseudo elements allow you to style certain parts of + a document */ /* matches a virtual first child of the selected element */ selector::before {} @@ -132,9 +140,9 @@ selector::after {} #################### */ selector { - + /* Units of length can be absolute or relative. */ - + /* Relative units */ width: 50%; /* percentage of parent element width */ font-size: 2em; /* multiples of element's original font-size */ @@ -143,14 +151,14 @@ selector { font-size: 2vh; /* or its height */ font-size: 2vmin; /* whichever of a vh or a vw is smaller */ font-size: 2vmax; /* or greater */ - + /* Absolute units */ width: 200px; /* pixels */ font-size: 20pt; /* points */ width: 5cm; /* centimeters */ min-width: 50mm; /* millimeters */ max-width: 5in; /* inches */ - + /* Colors */ color: #F6E; /* short hex format */ color: #FF66EE; /* long hex format */ @@ -161,10 +169,10 @@ selector { color: transparent; /* equivalent to setting the alpha to 0 */ color: hsl(0, 100%, 50%); /* as hsl percentages (CSS 3) */ color: hsla(0, 100%, 50%, 0.3); /* as hsl percentages with alpha */ - + /* Images as backgrounds of elements */ background-image: url(/img-path/img.jpg); /* quotes inside url() optional */ - + /* Fonts */ font-family: Arial; /* if the font family name has a space, it must be quoted */ @@ -195,7 +203,13 @@ Save a CSS stylesheet with the extension `.css`. ## Precedence or Cascade -An element may be targeted by multiple selectors and may have a property set on it in more than once. In these cases, one of the rules takes precedence over others. Rules with a more specific selector take precedence over a less specific one, and a rule occuring later in the stylesheet overwrites a previous one. +An element may be targeted by multiple selectors and may have a property set on +it in more than once. In these cases, one of the rules takes precedence over +others. Rules with a more specific selector take precedence over a less specific +one, and a rule occurring later in the stylesheet overwrites a previous one +(which also means that if two different linked stylesheets contain rules for an +element and if the rules are of the same specificity, then order of linking +would take precedence and the sheet linked latest would govern styling) . This process is called cascading, hence the name Cascading Style Sheets. @@ -224,18 +238,25 @@ and the following markup: <p style='/*F*/ property:value;' class='class1 class2' attr='value' /> ``` -The precedence of style is as follows. Remember, the precedence is for each **property**, not for the entire block. +The precedence of style is as follows. Remember, the precedence is for each +**property**, not for the entire block. -* `E` has the highest precedence because of the keyword `!important`. It is recommended that you avoid its usage. +* `E` has the highest precedence because of the keyword `!important`. It is +recommended that you avoid its usage. * `F` is next, because it is an inline style. -* `A` is next, because it is more "specific" than anything else. It has 3 specifiers: The name of the element `p`, its class `class1`, an attribute `attr='value'`. -* `C` is next, even though it has the same specificity as `B`. This is because it appears after `B`. +* `A` is next, because it is more "specific" than anything else. It has 3 + specifiers: The name of the element `p`, its class `class1`, an attribute + `attr='value'`. +* `C` is next, even though it has the same specificity as `B`. + This is because it appears after `B`. * `B` is next. * `D` is the last one. ## Compatibility -Most of the features in CSS 2 (and many in CSS 3) are available across all browsers and devices. But it's always good practice to check before using a new feature. +Most of the features in CSS 2 (and many in CSS 3) are available across all +browsers and devices. But it's always good practice to check before using +a new feature. ## Resources |