Button goes out of the container and extends my page when i change the resolution

HTML/CSS
1

Hello, I’m at pt 3 of CSS and HTML mastery, and i don’t really know how to fix this.
I have this code for input-groups :

    <input

      class="input"

      type="text"

      placeholder="Enter domain name here ..."

    />

    <button class="btn btn--accent">Search</button>

  </div>

And when i resize the browser /w developer tools
Screenshot by Lightshot this is how it looks like.
Mostly, the button resizes just a bit, but when it goes near mobile screens , it goes out of the container of the form. Even out of the body
Screenshot by Lightshot

2

When i tried to open mosh’s file, it does the same thing Screenshot by Lightshot
I honestly don’t know what went wrong. Normally, the button should inherit the box-size of the div, and if i try to put width :100% it doesn’t do anything. Any tips &tricks?