Useful CSS Snippets For Your Core Stylesheet

Hopefully, you are using CSS to stylise and layout your site. If you are not, you should move away from inline styles and start using CSS. The benefits are well worth the time to learn CSS.

Furthermore, if you are not using a CSS pre-processor, you should skill-up and learn one. There are many like SASS, LESS and Stylus. My personal preference is SASS, but my current job requires LESS so I am living in a world between both. They are both quite similar, but I expect SASS is gaining market share. Just look at the latest version of Bootstrap. They have moved their LESS core to SASS. I think that says a lot.

Here are some useful "template" CSS snippets for you to add to your core CSS file. When I say core, I mean a default CSS file that you can port between projects. This file simply does layout, global styles and mixins.

Feel free to add your own examples in the comments.

/*	CSS Resets	*/
html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, abbr, acronym, address, big, cite, code, del, dfn, em, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, b, u, i, center, dl, dt, dd, ol, ul, li, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td, article, aside, canvas, details, embed, figure, figcaption, footer, header, hgroup, menu, nav, output, ruby, section, summary, time, mark, audio, video {
  margin: 0;
  padding: 0;
  border: 0;
  font-size: 100%;
  font: inherit;
  vertical-align: baseline;
  outline: none;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}
html { height: 101%; }
body { font-size: 62.5%; line-height: 1; font-family: Arial, Tahoma, sans-serif; }
 
article, aside, details, figcaption, figure, footer, header, hgroup, menu, nav, section { display: block; }
ol, ul { list-style: none; }
 
blockquote, q { quotes: none; }
blockquote:before, blockquote:after, q:before, q:after { content: ''; content: none; }
strong { font-weight: bold; } 
 
table { border-collapse: collapse; border-spacing: 0; }
img { border: 0; max-width: 100%; }
 
p { font-size: 1.2em; line-height: 1.0em; color: #333; }

/*	Clear Fix	*/
.clearfix:before, .container:after { content: ""; display: table; }
.clearfix:after { clear: both; }
 
	/* IE 6/7 */
.clearfix { zoom: 1; }

/*	Default H1-H5 Headers	*/
h1,h2,h3,h4,h5{
    color: #005a9c;
}
h1{
    font-size: 2.6em;
    line-height: 2.45em;
}
h2{
    font-size: 2.1em;
    line-height: 1.9em;
}
h3{
    font-size: 1.8em;
    line-height: 1.65em;
}
h4{
    font-size: 1.65em;
    line-height: 1.4em;
}
h5{
    font-size: 1.4em;
    line-height: 1.25em;
}


/*	Cross-Browser Transparency	*/
.transparent {
    filter: alpha(opacity=50); /* internet explorer */
    -khtml-opacity: 0.5;      /* khtml, old safari */
    -moz-opacity: 0.5;       /* mozilla, netscape */
    opacity: 0.5;           /* fx, safari, opera */
}

/*	CSS Blockquote Template	*/
blockquote {
    background: #f9f9f9;
    border-left: 10px solid #ccc;
    margin: 1.5em 10px;
    padding: .5em 10px;
    quotes: "\201C""\201D""\2018""\2019";
}
blockquote:before {
    color: #ccc;
    content: open-quote;
    font-size: 4em;
    line-height: .1em;
    margin-right: .25em;
    vertical-align: -.4em;
}
blockquote p {
    display: inline;
}

/*	Individual Rounded Corners	*/
#container {
    -webkit-border-radius: 4px 3px 6px 10px;
    -moz-border-radius: 4px 3px 6px 10px;
    -o-border-radius: 4px 3px 6px 10px;
    border-radius: 4px 3px 6px 10px;
}
 
/* alternative syntax broken into each line */
#container {
    -webkit-border-top-left-radius: 4px;
    -webkit-border-top-right-radius: 3px;
    -webkit-border-bottom-right-radius: 6px;
    -webkit-border-bottom-left-radius: 10px;
     
    -moz-border-radius-topleft: 4px;
    -moz-border-radius-topright: 3px;
    -moz-border-radius-bottomright: 6px;
    -moz-border-radius-bottomleft: 10px;
}

/*	General Media Queries	*/
	/* variables */
$screen-xs: 320px;
$screen-sm: 768px;
$screen-md: 1024px;
$screen-lg: 1224px;
$screen-xl: 1824px;

/* Smartphones (portrait and landscape) ----------- */
@media only screen
and (min-device-width : $screen-xs) and (max-device-width : 480px) {
  /* Styles */
}
 
	/* Smartphones (landscape) ----------- */
@media only screen and (min-width : $screen-xs + 1) {

}
 
	/* Smartphones (portrait) ----------- */
@media only screen and (max-width : $screen-xs) {

}
 
	/* iPads (portrait and landscape) ----------- */
@media only screen and (min-device-width : $screen-sm) and (max-device-width : $screen-md) {

}
 
	/* iPads (landscape) ----------- */
@media only screen and (min-device-width : $screen-sm) and (max-device-width : $screen-md) and (orientation : landscape) {

}
 
	/* iPads (portrait) ----------- */
@media only screen and (min-device-width : $screen-sm) and (max-device-width : $screen-md) and (orientation : portrait) {

}
 
	/* Desktops and laptops ----------- */
@media only screen and (min-width : $screen-lg) {

}
 
	/* Large screens ----------- */
@media only screen and (min-width : $screen-xl) {

}
 
	/* iPhone 4 ----------- */
@media only screen and (-webkit-min-device-pixel-ratio:1.5), only screen and (min-device-pixel-ratio:1.5) {

}

/*	Modern Font Stacks	*/
	/* Times New Roman-based serif */
font-family: Cambria, "Hoefler Text", Utopia, "Liberation Serif", "Nimbus Roman No9 L Regular", Times, "Times New Roman", serif;
 
	/* A modern Georgia-based serif */
font-family: Constantia, "Lucida Bright", Lucidabright, "Lucida Serif", Lucida, "DejaVu Serif," "Bitstream Vera Serif", "Liberation Serif", Georgia, serif;
 
	/* A more traditional Garamond-based serif */
font-family: "Palatino Linotype", Palatino, Palladio, "URW Palladio L", "Book Antiqua", Baskerville, "Bookman Old Style", "Bitstream Charter", "Nimbus Roman No9 L", Garamond, "Apple Garamond", "ITC Garamond Narrow", "New Century Schoolbook", "Century Schoolbook", "Century Schoolbook L", Georgia, serif;
 
	/* The Helvetica/Arial-based sans serif */
font-family: Frutiger, "Frutiger Linotype", Univers, Calibri, "Gill Sans", "Gill Sans MT", "Myriad Pro", Myriad, "DejaVu Sans Condensed", "Liberation Sans", "Nimbus Sans L", Tahoma, Geneva, "Helvetica Neue", Helvetica, Arial, sans-serif;
 
	/* The Verdana-based sans serif */
font-family: Corbel, "Lucida Grande", "Lucida Sans Unicode", "Lucida Sans", "DejaVu Sans", "Bitstream Vera Sans", "Liberation Sans", Verdana, "Verdana Ref", sans-serif;
 
	/* The Trebuchet-based sans serif */
font-family: "Segoe UI", Candara, "Bitstream Vera Sans", "DejaVu Sans", "Bitstream Vera Sans", "Trebuchet MS", Verdana, "Verdana Ref", sans-serif;
 
	/* The heavier "Impact" sans serif */
font-family: Impact, Haettenschweiler, "Franklin Gothic Bold", Charcoal, "Helvetica Inserat", "Bitstream Vera Sans Bold", "Arial Black", sans-serif;
 
	/* The monospace */
font-family: Consolas, "Andale Mono WT", "Andale Mono", "Lucida Console", "Lucida Sans Typewriter", "DejaVu Sans Mono", "Bitstream Vera Sans Mono", "Liberation Mono", "Nimbus Mono L", Monaco, "Courier New", Courier, monospace;


/*	Custom Text Selection	*/
::selection { background: #e2eae2; }
::-moz-selection { background: #e2eae2; }
::-webkit-selection { background: #e2eae2; }

/*	Hiding H1 Text for Logo	*/
h1.logo {
    text-indent: -9999px;
    margin: 0 auto;
    width: 320px;
    height: 85px;
    background: transparent url("images/logo.png") no-repeat scroll;
}

/*	Polaroid Image Border	*/
img.polaroid {
    background:#000; /*Change this to a background image or remove*/
    border:solid #fff;
    border-width:6px 6px 20px 6px;
    box-shadow:1px 1px 5px #333; /* Standard blur at 5px. Increase for more depth */
    -webkit-box-shadow:1px 1px 5px #333;
    -moz-box-shadow:1px 1px 5px #333;
    height:200px; /*Set to height of your image or desired div*/
    width:200px; /*Set to width of your image or desired div*/
}

/*	Anchor Link Pseudo Classes	*/
a:link { color: blue; }
a:visited { color: purple; }
a:hover { color: red; }
a:active { color: yellow; }

/*	Fullscreen Backgrounds with CSS3	*/
html { 
    background: url('images/bg.jpg') no-repeat center center fixed; 
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}

/*	Vertically Centered Content	*/
.container {
    min-height: 6.5em;
    display: table-cell;
    vertical-align: middle;
}

/*	CSS3 Gradients Template	*/
#colorbox {
    background: #629721;
    background-image: -webkit-gradient(linear, left top, left bottom, from(#83b842), to(#629721));
    background-image: -webkit-linear-gradient(top, #83b842, #629721);
    background-image: -moz-linear-gradient(top, #83b842, #629721);
    background-image: -ms-linear-gradient(top, #83b842, #629721);
    background-image: -o-linear-gradient(top, #83b842, #629721);
    background-image: linear-gradient(top, #83b842, #629721);
}

/*	@font-face Template	*/
@font-face {
    font-family: 'MyWebFont';
    src: url('webfont.eot'); /* IE9 Compat Modes */
    src: url('webfont.eot?#iefix') format('embedded-opentype'), /* IE6-IE8 */
    url('webfont.woff') format('woff'), /* Modern Browsers */
    url('webfont.ttf')  format('truetype'), /* Safari, Android, iOS */
    url('webfont.svg#svgFontName') format('svg'); /* Legacy iOS */
}
body {
    font-family: 'MyWebFont', Arial, sans-serif;
}

/*	Inner CSS3 Box Shadow	*/
#mydiv { 
    -moz-box-shadow: inset 2px 0 4px #000;
    -webkit-box-shadow: inset 2px 0 4px #000;
    box-shadow: inset 2px 0 4px #000;
}

/*	Outer CSS3 Box Shadow	*/
#mydiv { 
    -webkit-box-shadow: 0 2px 2px -2px rgba(0, 0, 0, 0.52);
    -moz-box-shadow: 0 2px 2px -2px rgba(0, 0, 0, 0.52);
    box-shadow: 0 2px 2px -2px rgba(0, 0, 0, 0.52);
}

/*	Triangular List Bullets	*/
ul.triangular {
    margin: 0.75em 0;
    padding: 0 1em;
    list-style: none;

	li:before { 
		content: "";
		border-color: transparent #111;
		border-style: solid;
		border-width: 0.35em 0 0.35em 0.45em;
		display: block;
		height: 0;
		width: 0;
		left: -1em;
		top: 0.9em;
		position: relative;
	}
}

/*	CSS3 Column Text	*/
#columns-3 {
    text-align: justify;
    -moz-column-count: 3;
    -moz-column-gap: 12px;
    -moz-column-rule: 1px solid #c4c8cc;
    -webkit-column-count: 3;
    -webkit-column-gap: 12px;
    -webkit-column-rule: 1px solid #c4c8cc;
}

/*	CSS Fixed Footer	*/
#footer.fixed {
    position: fixed;
    left: 0px;
    bottom: 0px;
    height: 30px;
    width: 100%;
    background: #444;
}
  
	/* IE 6 */
* html #footer.fixed {
    position: absolute;
    top: expression((0-(footer.offsetHeight)+(document.documentElement.clientHeight ? document.documentElement.clientHeight : document.body.clientHeight)+(ignoreMe = document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop))+'px');
}

/*	CSS3 Speech Bubble	*/
.chat-bubble {
    background-color: #ededed;
    border: 2px solid #666;
    font-size: 35px;
    line-height: 1.3em;
    margin: 10px auto;
    padding: 10px;
    position: relative;
    text-align: center;
    width: 300px;
    -moz-border-radius: 20px;
    -webkit-border-radius: 20px;
    -moz-box-shadow: 0 0 5px #888;
    -webkit-box-shadow: 0 0 5px #888;
    font-family: 'Bangers', arial, serif; 
}
.chat-bubble-arrow-border {
    border-color: #666 transparent transparent transparent;
    border-style: solid;
    border-width: 20px;
    height: 0;
    width: 0;
    position: absolute;
    bottom: -42px;
    left: 30px;
}
.chat-bubble-arrow {
    border-color: #ededed transparent transparent transparent;
    border-style: solid;
    border-width: 20px;
    height: 0;
    width: 0;
    position: absolute;
    bottom: -39px;
    left: 30px;
}

/*	Continued List Ordering	*/
ol.chapters {
    list-style: none;
    margin-left: 0;
}
ol.chapters > li:before {
    content: counter(chapter) ". ";
    counter-increment: chapter;
    font-weight: bold;
    float: left;
    width: 40px;
}
ol.chapters li {
    clear: left;
}
ol.start {
    counter-reset: chapter;
}
ol.continue {
    counter-reset: chapter 11;
}

/*	CSS Tooltip Hovers	*/
a { 
    border-bottom:1px solid #bbb;
    color:#666;
    display:inline-block;
    position:relative;
    text-decoration:none;

	&:hover, &:focus {
	    color:#36c;
	}
	&:active {
	    top:1px; 
	}
}
  
	/* Tooltip styling */
a[data-tooltip]:after {
    border-top: 8px solid #222;
    border-top: 8px solid hsla(0,0%,0%,.85);
    border-left: 8px solid transparent;
    border-right: 8px solid transparent;
    content: "";
    display: none;
    height: 0;
    width: 0;
    left: 25%;
    position: absolute;
}
a[data-tooltip]:before {
    background: #222;
    background: hsla(0,0%,0%,.85);
    color: #f6f6f6;
    content: attr(data-tooltip);
    display: none;
    font-family: sans-serif;
    font-size: 14px;
    height: 32px;
    left: 0;
    line-height: 32px;
    padding: 0 15px;
    position: absolute;
    text-shadow: 0 1px 1px hsla(0,0%,0%,1);
    white-space: nowrap;
    -webkit-border-radius: 5px;
    -moz-border-radius: 5px;
    -o-border-radius: 5px;
    border-radius: 5px;
}
a[data-tooltip]:hover:after {
    display: block;
    top: -9px;
}
a[data-tooltip]:hover:before {
    display: block;
    top: -41px;
}
a[data-tooltip]:active:after {
    top: -10px;
}
a[data-tooltip]:active:before {
    top: -42px;
}

/*	Paper Page Curl Effect	*/
ul.box {
    position: relative;
    z-index: 1; /* prevent shadows falling behind containers with backgrounds */
    overflow: hidden;
    list-style: none;
    margin: 0;
    padding: 0; 
}
ul.box li {
    position: relative;
    float: left;
    width: 250px;
    height: 150px;
    padding: 0;
    border: 1px solid #efefef;
    margin: 0 30px 30px 0;
    background: #fff;
    -webkit-box-shadow: 0 1px 4px rgba(0, 0, 0, 0.27), 0 0 40px rgba(0, 0, 0, 0.06) inset;
    -moz-box-shadow: 0 1px 4px rgba(0, 0, 0, 0.27), 0 0 40px rgba(0, 0, 0, 0.06) inset; 
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.27), 0 0 40px rgba(0, 0, 0, 0.06) inset; 
}
ul.box li:before, ul.box li:after {
    content: '';
    z-index: -1;
    position: absolute;
    left: 10px;
    bottom: 10px;
    width: 70%;
    max-width: 300px; /* avoid rotation causing ugly appearance at large container widths */
    max-height: 100px;
    height: 55%;
    -webkit-box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
    -moz-box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
    -webkit-transform: skew(-15deg) rotate(-6deg);
    -moz-transform: skew(-15deg) rotate(-6deg);
    -ms-transform: skew(-15deg) rotate(-6deg);
    -o-transform: skew(-15deg) rotate(-6deg);
    transform: skew(-15deg) rotate(-6deg); 
}
ul.box li:after {
    left: auto;
    right: 10px;
    -webkit-transform: skew(15deg) rotate(6deg);
    -moz-transform: skew(15deg) rotate(6deg);
    -ms-transform: skew(15deg) rotate(6deg);
    -o-transform: skew(15deg) rotate(6deg);
    transform: skew(15deg) rotate(6deg); 
}

/*	Featured CSS3 Display Banner	*/
.featureBanner {
    position: relative;
    margin: 20px
}
.featureBanner:before {
    content: "Featured";
    position: absolute;
    top: 5px;
    left: -8px;
    padding-right: 10px;
    color: #232323;
    font-weight: bold;
    height: 0px;
    border: 15px solid #ffa200;
    border-right-color: transparent;
    line-height: 0px;
    box-shadow: -0px 5px 5px -5px #000;
    z-index: 1;
}
.featureBanner:after {
    content: "";
    position: absolute;
    top: 35px;
    left: -8px;
    border: 4px solid #89540c;
    border-left-color: transparent;
    border-bottom-color: transparent;
}

I found these snippets here, so I am passing them on.