Error Compiling CSS Asset Heroku SASS

This has been bothering me for days now, ever since a week ago I launched to Heroku for probably the 30th time and all of a sudden I get this error

I DONT USE Sass!! It isnt in my gemfile or anywhere else! It works perfectly in localhost and all of the answers i've found online just dont work!

This is my application.css

/*
 * This is a manifest file that'll be compiled into application.css, which will include all the files
 * listed below.
 *
 * Any CSS and SCSS file within this directory, lib/assets/stylesheets, vendor/assets/stylesheets,
 * or vendor/assets/stylesheets of plugins, if any, can be referenced here using a relative path.
 *
 * You're free to add application-wide styles to this file and they'll appear at the top of the
 * compiled file, but it's generally better to create a new file per style scope.
 *
 *= require_self
 *= require_tree .
 */

Does anyone have any idea WHY heroku is giving me this annoying error

PS: Incase you're wondering, i've used stack cedar when create the heroku app so its not that

Thank You

Ok so after a while, I figured it out!

The simplest, not-so-fastest but least stressful way of working this error out is by going on the file which Heroku is having errors compiling, in my case base2.css, and copy one by one each line of css code and input it in here CSS Validator, I HIGHLY HIGHLY Recommend this, it'll tell you which lines have errors and which lines are okay. Furthermore, it'll re-write the code where it found the errors, it'll organise the new code given perfectly and even though it may seem like its as long as a book, it'll be the right code. You can then Minify the code they give you to turn the book long code into one line.