Change the size of my own logo

hello, how i can change the size of my own logo on the login page?

This is set in the file nextcloud/core/css/header.css

#header .logo {
        background-image: url('../img/logo-icon.svg?v=1');
        background-repeat: no-repeat;
        background-size: 175px;
        background-position: center;
        width: 252px;
        height: 120px;
        margin: 0 auto;

Best practice is to create your own theme (folder) in nextcloud/themes and clone the file (in the same folder structure as from original core folder) to avoid risk of losing any changes during an upgrade. This way you can change the templates and design of the GUI in more detail according to your own requirements.

Thank you very much. Now it works fine.