If you experience this site title layout issue on mobile:



Please add the following code to Customize > Additional CSS:


@media (max-width: 900px) {
    .responsive-layout header.main-header .logo-tagline {
        max-width: 100%;
    }

    .responsive-layout header.main-header .first-row .logo-wrapper .text-logo {
        white-space: normal;
    }
}


You can check this guide:  How to add custom CSS / PHP code or modify the theme code