如何使用CSS制作半透明边框？

Question

I have a popup and I want to give it a transparent border. I have these properties set:

li.sub-nav ul.megamenu {
    position: absolute;
    left: 0;
    margin-top: 10px;
    z-index: 100;
    padding-top: 3px;
    -moz-background-clip: border; /* Firefox 3.6 */
    -webkit-background-clip: border; /* Safari 4? Chrome 6? */
    background-clip: border-box;
}

.nav-top-container .megamenu {
    background: #005525;
    background: rgba(0, 85, 37, .98);
    border-top: 1px solid #227b33;
    border-bottom: #005525;
    border-bottom:8px solid rgba(0, 85, 37, .98);
}

I added the background-clip properties according to this article , I also tried setting it to content and padding , but it isn't working.

Answer 1

Use background-clip on the padding , as it is the closest box-model to the border. The default is border , which causes the background to be behind the transparent border.

 body { background: yellow; } div { padding: 30px; background-color: white; border: 15px solid rgba(255,0,0,0.5); -moz-background-clip: padding; -webkit-background-clip: padding; background-clip: padding-box; } 

 <div></div> 

Answer 2

As I indicated in my comment to @LGSon, the issue you are frustrated with is that the background of your element extends into the border area. An easy workaround for this is to apply that background to a nested element like in the following example:

https://jsfiddle.net/yqx7abd8/

 body { background: url(http://lorempixel.com/800/800/city/1) center / cover; } .border { margin: 30px; border: 15px solid rgba(255,0,0,0.3); } .content { background: #fff; padding: 30px; } 

 <div class="border"> <div class="content"> <p> My Content </p> </div> </div>