The problem with em-based font sizing is that the font size compounds. A list within a list isn't 14px, it's 20px. Go another level deeper and it's 27px!
The rem unit is relative to the root—or the html—element. That means that we can define a single font size on the html element and define all rem units to be a percentage of that.
html { font-size: 62.5%; }
body { font-size: 1.4rem; } /* =14px */
h1 { font-size: 2.4rem; } /* =24px */
We can specify the fall-back using px, if you don't mind users of older versions of Internet Explorer still being unable to resize the text (well, there's still page zoom in IE7 and IE8). To do so, we specify the font-size using px units first and then define it again using rem units.
html { font-size: 62.5%; }
body { font-size: 14px; font-size: 1.4rem; } /* =14px */
h1 { font-size: 24px; font-size: 2.4rem; } /* =24px */
A 5 minute microslot on how to make sure the browser you want gets the CSS that you want it to have! Exclude IE6 and earlier from seeing your CSS3, and specify styles for mobiles and IE versions.
The easy way to use CSS2.1 to solve difficult cross-browser layout issues: CSS tables solve all the problems encountered when using absolute positioning or floats to create multi-column layouts in modern browsers. Specifying the value table for the display property of an element allows you to display the element and its descendants as though they're table elements. The main benefit of CSS table-based layouts is the ability to easily define the boundaries of a cell so that we can add backgrounds and so on to it-without the semantic problems of marking up non-tabular content as a HTML table in the document.
CSS has brought us many capabilities in terms of typography and the web, but we always seem to be limited to the same 4-5 typefaces over and over again. There is an inherant problem, if the font you specify isn't on the viewers computer it won't render in that font. So as designers and developers we end up selecting the ones that we can safely assume is available on most computers today. So most pages use Arial, Helvetica, or Georgia as their typefaces… and the world of the web remains slightly more bland.
The pointer-events property allows authors to control whether or when an element may be the target of user pointing device (pointer, e.g. mouse) events. This property is used to specify under which circumstance (if any) a pointer event should go "through" an element and target whatever is "underneath" that element instead. This also applies to other "hit testing" behaviors such as dynamic pseudo-classes (:hover, :active, :focus), hyperlinks, and Document.elementFromPoint().
It is possible to output rules in your CSS which allow tools to locate the source of the rule.
Either specify the option dumpLineNumbers as above or add !dumpLineNumbers:mediaQuery to the url.
In case, you find the need to change the DNS server for your entire network on your router or set it individually on a PC or other device then have a look on this tutorial.