How to remove heading styles with an inline CSS code - css

Question

I have a question about CSS, i don't know how to remove​styles of a class with an inline CSS code.
Let me explain more,
I have a CSS file named styles.css
In this file for example my h2 has some styles, now in my article i want to use h2 but i want to remove h2's default styles(written in styles.css) for this heading.
I guess there should be a way for this case, but i don't know how?
Please tell me this css code and teach me something new.
Thanks
Edit:
Please take a look to bellow picture. As you can see this h2 has some styles, can you see the pink vertical line in right side?
Now i want to remove this h2's styles with a css code. I guess something like my heading here should exist in CSS3. Am i right? Is there any css code for removing external css styles with an inline css code?
https://preview.ibb.co/m4BLda/Screenshot_2017_09_04_01_44_09_1.png
Here is the code:
h2 {
border-right: 4px solid #E20070;
font-size: 22px;
margin: 1.5em 0;
padding-right: 1em;
font-family: "Yekan",'irans',tahoma;
font-weight: normal !important;
}

Answer 1

You said inline, but you should really keep your styles in a separate stylesheet file. Now, in your styles.css file add your own class:
/* styles.css */
h2 {
font-size: 18px;
}
.my-other-title {
color: red;
border-right: 0;
}
<h2>My title</h2>
<h2 class="my-other-title">My other title</h2>
Why does this even work? Because of CSS specificity:
Specificity determines, which CSS rule is applied by the browsers
Take your time learning more by reading this article

Answer 2

Remove the existing class for your heading if there is and use your own custom class instead of writing everything inline.
h1{
font-size:15px;
color:blue;
}
/* target your h1 element */
.custom-css{
font-size:25px;
color:red;
}
<h1>Heading with general css<h1>
<h1 class="custom-css">Heading with custom css</h1>
Although its not good to change the semantic of an HTML Element.

Answer 3

CSS - Default for h2 (from external css source)
h2 {
border-right: 4px solid #E20070;
font-size: 22px;
margin: 1.5em 0;
padding-right: 1em;
font-family: "Yekan",'irans',tahoma;
font-weight: normal !important;
}
You want to override the default css through inline css. Try using below code for your h2.
<h2 style="border-right: 0px; padding: 0; margin: 0;"> Hello </h2>
You can also add a class to the h2 and call the class to your stylesheet if this style is applied to most of the h2 tags. Try to avoid inline css if possible, it may cause loading time.

Answer 4

<h2 style="color:white; font-size:80px"> My Cool Text </h2>
You have to write what you want to replace, for example, I changed color here.