Web design involves creating the visual elements and layout of a website. This includes the structure, color scheme, typography, images, and overall user interface (UI) to ensure an appealing, functional, and user-friendly experience.

Responsive web design is an approach that ensures a website looks good and functions well on all devices, from desktops to tablets and smartphones. It uses flexible layouts, grids, and media queries to adjust content based on the screen size.

Mobile-first design prioritizes the mobile experience when building a website, ensuring it works optimally on smaller screens before scaling up for larger devices. With the majority of internet traffic now coming from mobile devices, it's essential to design for mobile users first.

A wireframe is a basic blueprint of a website, outlining the layout and structure without any design elements like color or images. It's used in the planning stage to map out where different elements will appear on each page.