Answers for "border top"

css border bottom

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

css border top

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

css border different sides

/*className     property     values: width style color*/
.rightBorder  { border-right: 1px solid black }

.leftBorder   { border-left: 2px dashed red }

.topBorder    { border-top: 3px dotted blue }

.bottomBorder { border-bottom: 4px double yellow }