If you'd like to change the style of the input fields in Identity Management templates, you can do so by adding the below CSS to the ID Layout template.
.placeholder {color:red}
This will change the style of all input fields. If you'd like only to update selected fields, you can do so, for example, by using the following CSS code.
For the email input field, add:
.icon-email + t {color:red }
For the password input field, add:
.icon-password + t {color:red }