Một số style CSS đơn giản mà hữu dụng

.verticalcenter{
  position: relative;
  top: 50%;
  -webkit-transform: translateY(-50%);
  -o-transform: translateY(-50%);
  transform: translateY(-50%);
}

html, 
body {
 height: 100%;
}

div {
  height: 100%;
}

a[href^="http://"]{
    padding-right: 20px;
    background: url(external.gif) no-repeat center right;
}
/* emails */
a[href^="mailto:"]{
    padding-right: 20px;
    background: url(email.png) no-repeat center right;
}
   
/* pdfs */
a[href$=".pdf"]{
    padding-right: 20px;
    background: url(pdf.png) no-repeat center right;
}

td {
    white-space: nowrap;
}

pre {
  white-space: pre-line;
  word-wrap: break-word;
}

Before: After:

button {
  background-image: linear-gradient(#5187c4, #1c2f45);
  background-size: auto 200%;
  background-position: 0 100%;
  transition: background-position 0.5s;
}  
button:hover {
  background-position: 0 0;
}