css

/* <length> values */
overflow-clip-margin: 20px;
overflow-clip-margin: 1em;

/* <visual-box> | <length> */
overflow-clip-margin: content-box 5px;

/* Global values */
overflow-clip-margin: inherit;
overflow-clip-margin: initial;
overflow-clip-margin: revert;
overflow-clip-margin: revert-layer;
overflow-clip-margin: unset;

The <visual-box> value, which defaults to padding-box, specifies the box edge to use as the overflow clip edge origin. The <length> value specified in overflow-clip-margin must be nonnegative.

Note: If the element does not have overflow: clip then this property will be ignored.

overflow-clip-margin = 
  <visual-box>  ||
  <length>      

<visual-box> = 
  content-box  |
  padding-box  |
  border-box

html

<div class="box">
  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.
</div>

css

.box {
  border: 3px solid black;
  width: 250px;
  height: 100px;
  overflow: clip;
  overflow-clip-margin: 20px;
}