Increase default platform font sizes to meet accessibility standards

Adjust the default font sizing across the Polyester platform so body text and UI elements meet recognized accessibility guidelines (recommendation: minimum 16px for body text). Use case: users with visual impairments, high-DPI displays, or without browser zoom should be able to comfortably read and interact with labels, buttons, dropdowns, and content text. Expected behavior: default typography scales and CSS variables ensure readable sizes on desktop and mobile, text passes standard accessibility checks (WCAG contrast/readability where applicable), and UI components retain layout integrity. Verify changes across supported browsers (e.g., Chrome, Edge) and screen resolutions.