CSS box-sizing border-box still adding border size to element width

Question

The following sample exemplifies the issue I'm having.

So, if I have a container with a width of 200 pixels,

In the container, I add a 200px wide row (will add lots of rows)

I'd like to add 200px wide divs to the row (different each row)

Everything works perfectly until I add a 1px solid edge to the.cont div.

Why isn't the.cont boundary taken into account for box-sizing?

*,
*:before,
*:after {
  -webkit-box-sizing: border-box !important;
  -moz-box-sizing: border-box !important;
  -ms-box-sizing: border-box !important;
  box-sizing: border-box !important;
}

.cont {
  position: absolute;
  background-color: white;
  font-size: 12px;
  overflow: hidden;
  border: solid;
  /* Remove this and it works */
  border-color: purple;
  border-width: 1px;
  height: 200px;
  width: 200px;
  margin: 0;
  padding: 0;
}

.h_row {
  display: block;
  width: 100%;
  height: 22px;
  line-height: 22px;
  background-color: red;
  overflow: hidden;
  border-bottom: solid;
  border-bottom-color: orange;
  border-width: 1px;
  margin: 0;
  padding: 0;
}

.cell {
  display: block;
  float: left;
  font-size: 11px;
  height: 20px;
  line-height: 20px;
  text-align: left;
  text-indent: 2px;
  overflow: hidden;
  margin: 0;
  padding: 0;
}

.h_row>.cell {
  font-size: 12px;
  text-align: center;
  height: 22px;
  line-height: 22px;
  border-right: solid;
  border-right-color: pink;
  border-right-width: 1px;
  background-color: green;
}

.h_row>.cell:last-child {
  border-right: none;
}

.w50 {
  width: 50px;
}

.w100 {
  width: 100px;
}

<div class="cont">
  <div class="h_row">
    <div class="cell w100">100</div>
    <div class="cell w50">50</div>
    <div class="cell w50">50</div>
  </div>
</div>

Answer 1

Instead of using a border, you could use a box-shadow but place it inside your box, resulting in a 1px border inside the container.

Another option is to avoid using pixels altogether and instead use percentages for width, such as 50% or 10%.