left border on H2 only

Hey

I just implemented this CSS to achieve left border on H2 only but it has some issue on my other pages. Could you take a closer look at this and help me to find the error in the CSS.

body:not(.blog):not(.archive):not(.home)
h2 {
  border-left: 6px solid #b21212;
	padding-left: 20px;
}

I just want a left border on H2 only on all of my posts and pages. But on my WP Coupons posts - left border is showing on H1, featured images but not showing on H2. I want to show it only on H2.
Live issue URL: https://www.masteryblogging.com/coupons/semrush-free-trial/
Here's the screenshot of that error: https://ibb.co/VQrKJF4