Hi
For smooth update reason, all css is not include in style.css, I have put the css in “css/layout.css”, because I’m not recommend you to edit this css file, it will influence you to update the theme in the future.
The best way is add your own custom CSS to override the native CSS, you can put your own CSS in to “custom codes > custom css” or custom.css file. I would like to give you an example, I suppose you want to increase the height of LOGO container, then, you can use the following CSS to make that change:
h1.logo,h1.logo a{
height:90px;
}
Before you add own custom CSS, you can refer to the layout.css http://demo.themevan.com/oldcar/wp-content/themes/oldcar/css/layout.css?ver=1.0
Also, you can create a child theme. Any way, if you edit the core files of the theme, you must paste all your custom codes to the new version when you update your theme in the future, that’s very incovenient, it’s not recommended in the most premium themes.
If you really want to edit all the CSS files, you can find them under CSS folder.
Thanks!