text-decoration-line

text-decoration-color

text-decoration-style

<p class="op1">
Texto sublinhado 1
</p>
<p class="op2">
Texto sublinhado 2
</p>
<style>
p.op1:before {
  content:"_______________";
  padding-top: 2px;
  position:absolute;
}
p.op2:before {
  content:"_______________";
  padding-top: 5px;
  position:absolute;
  color:red
}
</style>