[html] CSS Inset Borders

I need to create a solid color inset border. This is the bit of CSS I'm using:

border: 10px inset rgba(51,153,0,0.65);

Unfortunately that creates a 3D ridged border (ignore the squares and dark description box)

Simple SCSS solution with pseudo-elements

Live demo: https://codepen.io/vlasterx/pen/xaMgag

// Change border size here_x000D_
$border-width: 5px;_x000D_
_x000D_
.element-with-border {_x000D_
 display: flex;_x000D_
 height: 100px;_x000D_
 width: 100%;_x000D_
 position: relative;_x000D_
 background-color: #f2f2f2;_x000D_
 box-sizing: border-box;_x000D_
 _x000D_
 // Use pseudo-element to create inset border_x000D_
 &:before {_x000D_
  position: absolute;_x000D_
  content: ' ';_x000D_
  display: flex;_x000D_
  border: $border-width solid black;_x000D_
  left: 0;_x000D_
  right: 0;_x000D_
  top: 0;_x000D_
  bottom: 0;_x000D_
  border: $border-width solid black;_x000D_
  // Important: We must deduct border size from width and height_x000D_
  width: calc(100% - $border-width); _x000D_
  height: calc(100% - $border-width);_x000D_
 }_x000D_
}

<div class="element-with-border">_x000D_
  Lorem ipsum dolor sit amet_x000D_
</div>

It's an old trick, but I still find the easiest way to do this is to use outline-offset with a negative value (example below uses -6px). Here's a fiddle of it—I've made the outer border red and the outline white to differentiate the two:

.outline-offset {
width:300px;
height:200px;
background:#333c4b;
border:2px solid red;
outline:2px #fff solid;
outline-offset:-6px;
}

<div class="outline-offset"></div>

So I was trying to have a border appear on hover but it moved the entire bottom bar of the main menu which didn't look all that good I fixed it with the following:

#top-menu .menu-item a:hover {
    border-bottom:4px solid #ec1c24;
    padding-bottom:14px !important;
}
#top-menu .menu-item a {
    padding-bottom:18px !important;
}

I hope this will help someone out there.

To produce a border inset within an element the only solution I've found (and I've tried all the suggestions in this thread to no avail) is to use a pseudo-element such as :before

E.g.

.has-inset-border:before {
  content: "foo"; /* you need something or it will be invisible at least on Chrome */
  color: transparent;
  position: absolute;
  left: 10px;
  right: 10px;
  top: 10px;
  bottom: 10px;
  border: 4px dashed red;
}

The box-sizing property won't work, as the border always ends up outside everything.

The box-shadow options has the dual disadvantages of not really working and not being supported as widely (and costing more CPU cycles to render, if you care).

If you want to make sure the border is on the inside of your element, you can use

box-sizing:border-box;

this will place the following border on the inside of the element:

border: 10px solid black;

(similar result you'd get using the additonal parameter inset on box-shadow, but instead this one is for the real border and you can still use your shadow for something else.)

Note to another answer above: as soon as you use any inset on box-shadow of a certain element, you are limited to a maximum of 2 box-shadows on that element and would require a wrapper div for further shadowing.

Both solutions should as well get you rid of the undesired 3D effects. Also note both solutions are stackable (see the example I've added in 2018)

.example-border {_x000D_
  width:100px;_x000D_
  height:100px;_x000D_
  border:40px solid blue;_x000D_
  box-sizing:border-box;_x000D_
  float:left;_x000D_
}_x000D_
_x000D_
.example-shadow {_x000D_
  width:100px;_x000D_
  height:100px;_x000D_
  float:left;_x000D_
  margin-left:20px;_x000D_
  box-shadow:0 0 0 40px green inset;_x000D_
}_x000D_
_x000D_
.example-combined {_x000D_
  width:100px;_x000D_
  height:100px;_x000D_
  float:left;_x000D_
  margin-left:20px;_x000D_
  border:20px solid orange;_x000D_
  box-sizing:border-box;_x000D_
  box-shadow:0 0 0 20px red inset;_x000D_
}

<div class="example-border"></div>_x000D_
<div class="example-shadow"></div>_x000D_
<div class="example-combined"></div>

If box-sizing is not an option, another way to do this is just to make it a child of the sized element.

Demo

CSS

.box {
  width: 100px;
  height: 100px;
  display: inline-block;
  margin-right: 5px;
}
.border {
  border: 1px solid;
  display: block;
}
.medium { border-width: 10px; }
.large  { border-width: 25px; }

HTML

<div class="box">
  <div class="border small">A</div>
</div>
<div class="box">
  <div class="border medium">B</div>
</div>
<div class="box">
  <div class="border large">C</div>
</div>

You can do this:

.thing {
  border: 2px solid transparent;
}
.thing:hover {
  border: 2px solid green;
}

I don't know what you are comparing to.

But a super simple way to have a border look inset when compared to other non-bordered items is to add a border: ?px solid transparent; to whatever items do not have a border.

It will make the bordered item look inset.

http://jsfiddle.net/cmunns/cgrtd/

You may use background-clip: border-box;

Example:

.example {
padding: 2em;
border: 10px solid rgba(51,153,0,0.65);
background-clip: border-box;
background-color: yellow;
}

<div class="example">Example with background-clip: border-box;</div>

I would recomnend using box-sizing.

*{
  -webkit-box-sizing:border-box;
  -moz-box-sizing:border-box;
  -ms-box-sizing:border-box;
  box-sizing:border-box;
}

#bar{
  border: 10px solid green;
  }

I know this is three years old, but thought it might be helpful to someone.

The concept is to use the :after (or :before) selector to position a border within the parent element.

    .container{
        position:relative; /*Position must be set to something*/
    }

    .container:after{
        position:relative;
        top: 0;
        content:"";
        left:0;
        height: 100%; /*Set pixel height and width if not defined in parent element*/
        width: 100%; 

        -webkit-box-sizing:border-box;
        -moz-box-sizing:border-box;
        -ms-box-sizing:border-box;
        box-sizing:border-box;

        border:1px solid #000; /*set your border style*/

    }