Trying to Hide Header and Tagline in Screwdriver Theme

I’m using the Screwdriver Theme on my site and I’m trying to hide my title and tagline description. I put the following at the end of my css, but it didn’t work.

#site-title, #site-description {display: none; }

The Title and Description were still showing up in my header, so I tried breaking it apart, and adding the following at the end of my css

#site-title {display: none; }

#site-tagline {display: none; }

This didn’t work either. Right now I have left those fields blank so that my header renders properly, until I can figure out the code to hide them.

my blogsite is –

bigredworkwear.com/blog

Thank you in advance for helping me with this.