<form class="form-horizontal" role="form" id="contactf" action="http://titan.csit.rmit.edu.au/~e54061/wp/form-tester.php" method="post">
<div class="form-group">
<label class="control-label col-sm-2 lb" for="email">Email : </label>
<div class="col-sm-6">
<input type="email" class="form-control" id="email" name="email" placeholder="Enter email" required>
</div>
</div>
<div class="form-group">
<label class="control-label col-sm-2" for="pwd">Subject : </label>
<div class="col-sm-6">
<select class="form-control col-sm-6 lb" id="subj" name="subject" required>
<option>General queries</option>
<option>Group and corporate bookings</option>
<option>Suggestion and complaints</option>
</select>
</div>
</div>
<div class="form-group">
<label class="control-label col-sm-2 lb" for="pwd">Message : </label>
<div class="col-sm-6">
<div class="checkbox">
<textarea class="form-control" id="message" name="message" required></textarea>
</div>
</div>
</div>
<div class="form-group">
<div class="col-sm-offset-4 col-sm-6">
<button type="submit" class="btn btn-success">Submit</button>
</div>
</div>
</form>
I have created a form using Bootstrap, but I need help in centering it perfectly and making it responsive to different screen sizes. Can someone assist me with this? Thank you!