my UI goes disturbed when i use in CodeIgniter

my web page design remains normal until i write

once i use it, the content portion of the web just disturb code is given below

        <?php echo form_open('regform/register');?>
            <div class="first">
                <fieldset>
                    <label for="name"><strong>Name:<br /></strong> </label><input type="text" name="name" maxlength="55" id="name" class="inputtext" />
                    <label for="email"><strong>Email:<br /></strong></label><input type="text" name="email" maxlength="55" id="email" class="inputtext" />
                    <label for="password"><strong>Password:<br /></strong></label><input type="text" name="password" maxlength="55" id="password" class="inputtext" />
                    <label for="confirmpass"><strong>Confirm Password:<br /></strong></label><input type="text" name="confirm" maxlength="55" id="confirmpass" class="inputtext" />
                    <div>
                        <label for="newsletter"><input type="checkbox" id="newsletter" /><span>Subscribe to newsletter</span></label> 
                        <label class="terms" for="terms"><input type="checkbox" id="terms" /><span>I agree to the Terms and Conditions</span></label>
                    </div>
                </fieldset>
            </div>
            <div>
                <fieldset>
                    <label for="completename"><strong>Complete name:</strong></label><input type="text" maxlength="55" id="completename" class="inputtext" />
                    <label for="address"><strong>Primary address:</strong></label><input type="text" maxlength="55" id="address" class="inputtext" />
                    <label for="billing"><strong>Billing address:</strong></label><input type="text" maxlength="55" id="billing" class="inputtext" />
                    <label for="city"><strong>City:</strong></label><label class="zipcode" for="zipcode"><strong>Zip Code:</strong></label>
                    <input type="text" maxlength="30" id="city" /> 
                    <input type="text" maxlength="30" id="zipcode" class="zipcode" />
                    <div>
                        <label for="shipping"><input type="checkbox" id="shipping" /><span> Same Shipping and Billing address</span></label> 
                        <label class="saveas" for="saveas"><input type="checkbox" id="saveas" /><span> Save as default address</span></label>
                    </div>
                </fieldset>
            </div>
            <input type="submit" value="" id="createaccount" />
        </form>
    </div>

this is how it looks after using "php echo form_open"