Basics
For controlling "cellpadding" in CSS, you can simply use padding on table cells. E.g. for 10px of "cellpadding":
td {
padding: 10px;
}
For "cellspacing", you can apply the border-spacing CSS property to your table. E.g. for 10px of "cellspacing":
table {
border-spacing: 10px;
border-collapse: separate;
}
This property will even allow separate horizontal and vertical spacing, something you couldn't do with old-school "cellspacing".
Issues in IE ≤ 7
This will work in almost all popular browsers except for Internet Explorer up through Internet Explorer 7, where you're almost out of luck. I say "almost" because these browsers still support the border-collapse property, which merges the borders of adjoining table cells. If you're trying to eliminate cellspacing (that is, cellspacing="0") then border-collapse:collapse should have the same effect: no space between table cells. This support is buggy, though, as it does not override an existing cellspacing HTML attribute on the table element.
In short: for non-Internet Explorer 5-7 browsers, border-spacing handles you. For Internet Explorer, if your situation is just right (you want 0 cellspacing and your table doesn't have it defined already), you can use border-collapse:collapse.
table {
border-spacing: 0;
border-collapse: collapse;
}
Note: For a great overview of CSS properties that one can apply to tables and for which browsers, see this fantastic Quirksmode page.
Below is the best all-around solution I could build to vertically and horizontally center a fixed-width, flexible height content box. It was tested and worked for recent versions of Firefox, Opera, Chrome, and Safari.
.outer {
display: table;
position: absolute;
top: 0;
left: 0;
height: 100%;
width: 100%;
}
.middle {
display: table-cell;
vertical-align: middle;
}
.inner {
margin-left: auto;
margin-right: auto;
width: 400px;
/* Whatever width you want */
}
<div class="outer">
<div class="middle">
<div class="inner">
<h1>The Content</h1>
<p>Once upon a midnight dreary...</p>
</div>
</div>
</div>
View A Working Example With Dynamic Content
I built in some dynamic content to test the flexibility and would love to know if anyone sees any problems with it. It should work well for centered overlays also -- lightbox, pop-up, etc.
Best Answer
It means, essentially, what it says; that 'this is important, ignore subsequent rules, and any usual specificity issues, apply this rule!'
In normal use a rule defined in an external stylesheet is overruled by a style defined in the
headof the document, which, in turn, is overruled by an in-line style within the element itself (assuming equal specificity of the selectors). Defining a rule with the!important'attribute' (?) discards the normal concerns as regards the 'later' rule overriding the 'earlier' ones.Also, ordinarily, a more specific rule will override a less-specific rule. So:
Is normally overruled by:
As the latter selector is more specific (and it doesn't, normally, matter where the more-specific selector is found (in the
heador the external stylesheet) it will still override the less-specific selector (in-line style attributes will always override the 'more-', or the 'less-', specific selector as it's always more specific.If, however, you add
!importantto the less-specific selector's CSS declaration, it will have priority.Using
!importanthas its purposes (though I struggle to think of them), but it's much like using a nuclear explosion to stop the foxes killing your chickens; yes, the foxes will be killed, but so will the chickens. And the neighbourhood.It also makes debugging your CSS a nightmare (from personal, empirical, experience).