Change Color for Buttons Per Slide On Presentation Template Homepage

Hi I would like to do two things, one is change the color of the border of the buttons on my presentation pages. Please see images below.
Second thing i would like to do is change the text for where it says username or email address and password on the wp-admin login page as well as any login to Client ID and Client Key. Please see image below.

https://drive.google.com/file/d/17DsTCSVbaCebvjA6UbtDFkMtEmYV-tHO/view?usp=sharing
https://drive.google.com/file/d/1lFwdRlbXjUaiHJ2LoFml6ijic6OJjq-S/view?usp=sharing
https://drive.google.com/file/d/1vkqW6Rhta3hmIGKV2CfjglxC9O12jdVE/view?usp=sharing