You don’t need to tweak .php, custom CSS should be enough I think.
header.navbar {
height="WHAT EVER YOU WANT - IN PIXELS(200px) OR PERCENTAGE OF SCREEN HEIGHT(5%)";
}
If you want to tweak anything yourself, here is a short guide – open two tabs:
1st one – WP admin panel -> appearance -> custom CSS
2nd one – open the page you want to change in your browser, right-click on what you want to change (header in your case) and “Inspect element”.
Now you can see few lists – one should be a HTML – if you hover any code-line, it should be showing what element it stands for on screen.
Look for part you want to change!
Under styles you can change sizes, layers, colors any everything you want.. PS! Changes in inspector is not saved – it’s a preview!
If you want to save it, insert element name (can be seen if you hover it – div.modal or header.navbar for example) and code (check online for different options, background-color: red or width: 20% for example) to custom CSS under the appearance in WP admin panel.
