How to align a css triangle vertically to a responsive rectangle - css

Question

i created a responsive rectangle and a responsive triangle with css only.
How can i align the triangle so it is always vertically centered on the right side of the box?
I´d like to do it just with css but if it is not possible i appreciate any hint for alternative options.
HTML:
<div class="container">
<div class="box green rightbox">
<div class="innerbox">Lorem ipsum....</div>
</div>
<div class="mother-triangle">
<div class="triangle-right green"></div>
</div>
</div>
CSS:
.container {
max-width: 1200px;
margin-right: auto;
margin-left: auto;
z-index: 1;
position: relative;
}
.box {
height: auto!important;
min-height: 300px;
}
.box.green {
background-color: rgba(51, 223, 9, 0.75)!important;
}
.innerbox {
padding: 12px;
}
.triangle-right {
width: 0;
height: 0;
padding-top: 10%;
padding-bottom: 10%;
padding-left: 10%;
overflow: hidden;
position: relative;
margin-top: auto;
margin-bottom: auto;
display: inline-block;
vertical-align: middle;
}
.triangle-right:after {
content: "";
display: block;
width: 0;
height: 0;
margin-top: -500px;
margin-left: -500px;
border-top: 500px solid transparent;
border-bottom: 500px solid transparent;
border-left: 500px solid rgba(51, 223, 9, 0.75);
}
.rightbox {
width: 90%;
float: left;
}
JSFiddel demo:

Answer 1

You can use absolute positioning to do that.
Just change position: relative to position: absolute in .triangle-right.
Add top: 50% to move the triangle to the vertical middle.
Updated fiddle
.container {
max-width: 1200px;
margin-right: auto;
margin-left: auto;
z-index: 1;
position: relative;
}
.box {
height: auto!important;
min-height: 300px;
}
.box.green {
background-color: rgba(51, 223, 9, 0.75)!important;
}
.innerbox {
padding: 12px;
}
.triangle-right {
width: 0;
height: 0;
padding-top: 10%;
padding-bottom: 10%;
padding-left: 10%;
overflow: hidden;
position: absolute;
margin-top: auto;
margin-bottom: auto;
display: inline-block;
vertical-align: middle;
top: 50%;
}
.triangle-right:after {
position: absolute;
content: "";
display: block;
width: 0;
height: 0;
margin-top: -500px;
margin-left: -500px;
border-top: 500px solid transparent;
border-bottom: 500px solid transparent;
border-left: 500px solid rgba(51, 223, 9, 0.75);
}
.rightbox {
width: 90%;
float: left;
}
<!-----container start---->
<div class="container">
<div class="box green rightbox">
<div class="innerbox">Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure
dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</div>
</div>
<div class="mother-triangle">
<div class="triangle-right green"></div>
</div>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
<br>
</div>
<!-----container end ---->