在codeigniter中更改验证错误消息的字体颜色

How can we change the font colour of validation error messages in Codeigniter?

As per the documentation, you can change the delimiters applied to form validation errors, like this:

$this->form_validation->set_error_delimiters('<div class="error">', '</div>');

So, basically, all your errors will now be wrapped in a <div> with the CSS class 'error'. Now, in your CSS, just define:

.error {
    color: red;
}