how should i give input box red colour in validation in laravel5.4 - validation

Question

When user click on the submit button I want to give that text box color as red.
but Laravel comes up with the validation with message..
How can we do the validation as red color text box?
Here is my validation in controller:
protected function validator(array $data) {
return Validator::make($data, [
'first_name' => 'required|max:255',
'last_name' => 'required|max:255',
'email' => 'required|email|max:255|unique:users',
'password' => 'required|min:6|confirmed',
'contact_no' => 'required|numeric',
]);
}
here is my view:
<div class="form-group{{ $errors->has('first_name') ? ' has-error' : '' }}">
<label for="name" class="col-md-4 control-label">First Name</label>
<div class="col-md-6">
<input id="first_name" type="text" class="form-control" name="first_name" value="{{ old('name') }}" placeholder="first name" required autofocus>
#if ($errors->has('first_name'))
<span class="help-block">
<strong>{{ $errors->first('first_name') }}</strong>
</span>
#endif
</div>
</div>
<div class="form-group{{ $errors->has('last_name') ? ' has-error' : '' }}">
<label for="name" class="col-md-4 control-label">Last Name</label>
<div class="col-md-6">
<input id="last_name" type="text" class="form-control" name="last_name" value="{{ old('last_name') }}" placeholder="last name" required autofocus>
#if ($errors->has('name'))
<span class="help-block">
<strong>{{ $errors->first('name') }}</strong>
</span>
#endif
</div>
</div>
<div class="form-group{{ $errors->has('email') ? ' has-error' : '' }}">
<label for="email" class="col-md-4 control-label">E-Mail Address</label>
<div class="col-md-6">
<input id="email" type="email" class="form-control" name="email" value="{{ old('email') }}" placeholder="email" required>
#if ($errors->has('email'))
<span class="help-block">
<strong>{{ $errors->first('email') }}</strong>
</span>
#endif
</div>
</div>
Can any one help me..please

Answer 1

Laravel will addclass has-error according to following line form-group{{ $errors->has('...') ? ' has-error' : '' }}, So you just need to add CSS style.
.has-error .form-control {
border-color: #a94442;
}