[Trunk | Library]: library.css: Add css for '.landing-modal-header' (background & padding), '.landing-modal .modal-title' (font & margin), '.square-button' (border-radius).
[Trunk | Library]: library.css: Add css for '.landing-modal-header' (background & padding), '.landing-modal .modal-title' (font & margin), '.square-button' (border-radius).