theming – Adjusting the height of the panel's columns with the help of CSS

I'm using panel-2col-brick to create a 2 x 2 block of information. The HTML structure of the page is as follows

...

Now, I need to change the height of the second instance of panel-col-first and panel col-second. I have tried

.panel-2col-bricks .center-wrapper .panel-col-first: first of type,
.panel-2col-bricks .center-wrapper .panel-col-last: first of type {
height: 80px;
hidden overflow;
}

However, this changes the height of the columns at the top, at the top, and at the bottom. Is there a way to adjust the height of the two rows separately?