To implement a brand style guide using out-of-the box Experience Builder features, the best option is to apply brand fonts and colors. This can be done by using themes and branding sets in Experience Builder. Themes are collections of information that define the visual flow of a site, such as colors, fonts, and spacing. Branding sets are groups of assets that can be applied to a theme, such as logos, images, and icons. By using themes and branding sets, CK can customize the look and feel of their site without coding or using a different template.Add Style to Your Experience Builder Site with Themes,Use Branding Sets in Experience Builder

A diary study is a research methodology that involves asking participants to record their thoughts, feelings, behaviors, and activities over a period of time, usually in response to prompts or questions from the researcher1. A diary study is suitable for Cloud Kicks (CK) to conduct discovery phase research to understand more about the customers' purchasing habits, as it will allow them to remotely observe customers' buying patterns over the course of a 2-month period.A diary study will also provide rich and contextual data on the customers' needs, preferences, motivations, and pain points, as well as the factors that influence their purchasing decisions1.Salesforce User Experience Designer Exam Guide,Diary Studies: How to Conduct from Start-to-Finish

Card sorting is a UX research method where participants group ideas or information into different categories, based on what feels natural to them. Card sorting is ideal for the early stages of a website project, when the UX designer needs to understand how users organize and label content. Card sorting can help the UX designer to suggest a suitable architecture for the internal community, based on the employees' mental model and expectations. Card sorting can also reveal any gaps or overlaps in the content, and provide insights for naming the categories and subcategories.Card Sorting / Tree Testing | Bentley University,Tree Testing vs. Card Sorting: Which is Right for You? | Maze

The SLDS utility that provides the most flexible system to meet the requirements of designing a responsive page isGrid. Grid is a utility that allows you to create a layout using a series of rows and columns that house your content. Grid uses a 12-column structure that can be adjusted based on breakpoints, which are predefined screen sizes that trigger a change in the layout. Grid also supports nesting, alignment, ordering, and offsetting of the columns.By using Grid, you can create a responsive page that can adapt to different screen resolutions and devices12[Grid - Lightning Design System], [Mastering Salesforce Lightning Design System Grids and Lightning Layouts]
https://www.lightningdesignsystem.com/utilities/grid/
https://developer.salesforce.com/blogs/developer-relations/2017/04/mastering-salesforce-lightning-design-system-grids-lightning-layouts

These three features allow fields to be available when viewing a record in Salesforce.
Ahighlights paneldisplays key fields at the top of a record page in Lightning Experience. It can be customized to show the most important information for each object.
Acompact layoutdetermines which fields appear in the highlights panel, the list view hover, and the Salesforce app. It can be assigned to different record types and profiles.
Alist viewdisplays a set of records that meet specified filter criteria. It can be sorted and filtered by different fields, and users can select which fields to display in the list view.
[Customize the Highlights Panel]
[Create and Assign Compact Layouts]
[Create and Customize List Views]