Info on selecting link via attribut

i try to give every link with new window (these are all my external links) or every mailto link an icon in front of the link.
here we go:

you can select those links via attribut. f.e. you want an acrobat icon before every pdf link ( unfortunately entypo-fontello haven’t one) so i uploaded an extra icon font for those icons)

a[target="_blank"]:before {
    content: "\e822";
    font-family: entypo-fontello;
    font-size: 14px;
    padding-right: 6px;
}

a[href$=".pdf"]:before{
    content: "\e809" !important;
    font-family: paragraph;
    font-size: 14px;
    padding-right: 6px;
}

a[href^="mailto"]:before{
    content: "\e805" !important;
    font-family: entypo-fontello;
    font-size: 18px;
    padding-right: 6px;
    position: relative;
    top: 1px;
}

etc. pp