CSS overlapping transparent arrow elements [closed]

Question

Is something like this possible with CSS? I have attempted via before/after pseudo-elements, and while I can get something to work for solid colors, I am having trouble coming up with a way to do it with transparency.

Any suggestions?

Answer 1

If you don't need the black borders around each item (as can be seen in the posted image), you still could create the needed shapes by border as follows:

.timeline-unit:before, .timeline-unit:after {
    top: 0;
    border: solid transparent;
    border-width: 1.65em;
    height: 0;
    width: 0;
    position: absolute;
    pointer-events: none;
}

.timeline-unit:after {
    content: " ";
    left: 100%;
    border-left-color: rgba(51, 51, 51, 0.8);
}

.timeline-unit {
    position: relative;
    display: inline-block;
    background: rgba(51,51,51,.8);
    padding: 1em;
    line-height: 1.25em;
    color: #FFF;
}

.timeline-unit:before { content: none; }

.timeline-unit + .timeline-unit:before {
    content: " ";
    border-color: rgba(51, 51, 51, 0.8);
    border-left-color: transparent;
    border-right: 0;
    right: 100%;
}

.timeline-unit + .timeline-unit {
    margin-left: 2em;
}

/**************  D E M O  **************/

body {
  background: red;
    
  -webkit-animation: bgcolor 4s linear 0s infinite alternate;
     -moz-animation: bgcolor 4s linear 0s infinite alternate;
       -o-animation: bgcolor 4s linear 0s infinite alternate;
          animation: bgcolor 4s linear 0s infinite alternate;
}

@-webkit-keyframes bgcolor { from { background: red; } to { background: green; }  }
   @-moz-keyframes bgcolor { from { background: red; } to { background: green; }  }
     @-o-keyframes bgcolor { from { background: red; } to { background: green; }  }
        @keyframes bgcolor { from { background: red; } to { background: green; }  }

<div class="timeline-unit"> Timeline 1 </div>
<div class="timeline-unit"> Timeline 2 </div>
<div class="timeline-unit"> Timeline 3 </div>

However if you need add a border on each item, there are two options:

• Using drop-shadow() filter to fake the border - Example Here (supported in Webkit/Firefox35+).
• Using CSS transforms in order to create the CSS shapes, so border would be unused and available for later usages (supported in IE9+ as well).