How to lean border to another border'u?

Question

css

Can you please tell me what css properties you need to set in order to get the result, as in the second picture?
The first picture is the current result.
Styles are set as follows:

.product_info - outer block
.product_specifications - inner block

.product_info {
  border: 1px solid black;
  border-radius: 5px;
  height: 100px;
  margin-top: 10px;
  padding: 0;
  text-align: left;
}

.product_specifications{
  text-align: center;
  border: 1px solid black;
  border-radius: 5px;
  font: bold calc(100vw/70) 'Roboto Condensed', sans-serif;
  padding-left: 3px;
  padding-right: 3px;
  position: relative;
  top: 0;
}

C position seems to work, but if you reduce the resolution, then the .product_specifications inner block flies down

Answer 1

Through position: absolute, if you still want it not to fly down when it is reduced
:

Answer 2

outline instead of border can be used