Grid Layout Overlapping Row with full height - html

Question

I have started using Grid CSS and i am stuck in building a Layout using Grid system.
I am looking to build a layout where the column would overlap a row and take full height. I have attached a screenshot of the layout and what i have tried so far.
body {
margin: 40px;
}
.sidebar {
grid-area: sidebar;
}
.content {
grid-area: content;
}
.header {
grid-area: header;
}
.wrapper {
display: grid;
grid-gap: 10px;
grid-template-columns: 120px 120px 120px;
grid-template-areas:
"header header header"
"sidebar content content";
background-color: #fff;
color: #444;
}
.box {
background-color: #444;
color: #fff;
border-radius: 5px;
padding: 20px;
font-size: 150%;
}
.header {
background-color: #999;
}
.overlay {
background-color: red;
z-index: 10;
grid-column: content-start / content-end;
grid-row: header-start / content-end;
}
<div class="wrapper">
<div class="box header">Header</div>
<div class="box sidebar">Sidebar</div>
<div class="overlay">Content</div>
</div>

Answer 1

Depending on how you want to overlap the following code works, but need to be adapted:
There's a lot of other way to do this...
body {
margin: 40px;
}
.sidebar {
grid-area: sidebar;
}
.content {
grid-area: content;
}
.header {
grid-area: header;
}
.wrapper {
display: grid;
grid-gap: 10px;
grid-template-columns: 120px 120px 120px;
grid-template-rows: 30px 30px auto auto;
grid-template-areas:
"header header header"
"sidebar content content";
background-color: #fff;
color: #444;
}
.box {
background-color: #444;
color: #fff;
border-radius: 5px;
padding: 20px;
font-size: 150%;
}
.header {
background-color: #999;
grid-row: 1 / 3;
}
.sidebar {
background-color: red;
z-index: 10;
grid-row: 2 / 4;
height: 300px;
}
.overlay {
background-color: red;
z-index: 10;
grid-column: content-start / content-end;
grid-row: 3 / 4;
}
<div class="wrapper">
<div class="box header">Header</div>
<div class="box sidebar">Sidebar</div>
<div class="overlay">Content</div>
</div>