html

<form action="url_of_form">
  <label for="FirstField">First field (enabled):</label>
  <input type="text" id="FirstField" value="Lorem" /><br />

  <label for="SecondField">Second field (disabled):</label>
  <input type="text" id="SecondField" value="Ipsum" disabled="disabled" /><br />

  <input type="button" value="Submit" />
</form>

css

input:enabled {
  color: #2b2;
}

input:disabled {
  color: #aaa;
}