Customizing Squarespace Layouts with Advanced CSS Techniques

I've been using Squarespace for my website, and while I love the platform's ease-of-use and pre-designed templates, I'm struggling to personalize my site to match my brand's aesthetic and functionality. I'm specifically looking for advanced CSS techniques Online status and last seen status are hidden, Scheduling of messages is done https://www.gbgenie.com/gb-whatsapp/ Settings for time limits on status to customize my Squarespace layout and make it more unique. I'm aware of the Platform's built-in customization tools and tried them, but they aren't enough. Can anyone share their best practices, tips, or resources for using advanced CSS to modify Squarespace layouts? I'm looking to change the site's typography, spacing, color schemes and layouts, while keeping it responsive and mobile-friendly.