Check out example codes for "css border bottom". It will help you in understanding the concepts better.

Code Example 1

.bottomBorder {
  /*           width style color  */
  border-bottom: 5px solid black;
}

Code Example 2

div {
  border-bottom: 4px dashed blue;
  background-color: gold;
  height: 100px;
  width: 100px;
  font-weight: bold;
  text-align: center;
}

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