How to make a pure css triangle which has a white center

Question

I want to create an upward and downward facing arrow with css like the following: http://apps.eky.hk/css-triangle-generator/

However, instead of a solid color, I want to

Answer 1

If you want to create a triangle with borders (or box shadow look-alike) in pure CSS, you should use pseudo-elements :before and :after.

In my example, I added display:inline-block; to the element .arrow-dropdown to be able to create some kind of dropdown menu with a drop shadow. It is followed by .arrow-only which is a a basic triangle with a red border.

body {
    margin: 10px;
    background: #1670c4;
}
.text {
    display: inline-block;
    font-size: 15px;
    color: #fff;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.4);
    cursor: default;
}
.arrow-dropdown {
    display: inline-block;
    position: relative;
    vertical-align: middle;
    margin: 1px 0 0 8px;
    width: 8px;
    height: 7px;
}
.arrow-dropdown:after {
    content: '';
    position: absolute;
    border-style: solid;
    border-width: 7px 4px 0;
    border-color: #fff transparent transparent transparent;
    display: block;
    width: 0;
    z-index: 1;
}
.arrow-dropdown:before {
    content: '';
    position: absolute;
    border-style: solid;
    border-width: 8px 5px 0;
    border-color: rgba(0,0,0,0.3) transparent transparent transparent;
    display: block;
    width: 0;
    z-index: 0;
}
.arrow-only {
    position: relative;
    vertical-align: middle;
    margin: 10px 0 0 8px;
    width: 8px;
    height: 7px;
}
.arrow-only:after {
    content: '';
    position: absolute;
    border-style: solid;
    border-width: 12px 9px 0;
    border-color: #fff transparent transparent transparent;
    display: block;
    width: 0;
    z-index: 1;
}
.arrow-only:before {
    content: '';
    position: absolute;
    border-style: solid;
    border-width: 15px 11px 0;
    border-color: #f00 transparent transparent transparent;
    display: block;
    width: 0;
    z-index: 0;
    margin:-1px 0 0 -2px;
}

  Dropdown text