custom fonts wrapped into the same style structure of Apple (/// https://developer.apple.com/design/human-interface-guidelines/ios/visual-design/typography/)

font_manager.swift

enum TintFont {
	
	enum TypeFace {
		
		case bold
		case boldItalic
		case book
		case bookItalic
		case medium
		case mediumItalic
		
		func getFont(tint: TintFont) -> Font {
			var result: Font?
			switch self {
			case .bold:
				if let valid = UIFont(name: "CircularStd-Bold", size: tint.size) {
					result = Font(valid)
				}
			case .boldItalic:
				if let valid = UIFont(name: "CircularStd-BoldItalic", size: tint.size) {
					result = Font(valid)
				}
			case .book:
				if let valid = UIFont(name: "CircularStd-Book", size: tint.size) {
					result = Font(valid)
				}
			case .bookItalic:
				if let valid = UIFont(name: "CircularStd-BookItalic", size: tint.size) {
					result = Font(valid)
				}
			case .medium:
				if let valid = UIFont(name: "CircularStd-Medium", size: tint.size) {
					result = Font(valid)
				}
			case .mediumItalic:
				if let valid = UIFont(name: "CircularStd-MediumItalic", size: tint.size) {
					result = Font(valid)
				}
			}
			
			return result == nil ? tint.getFallBackFont() : result!.weight(tint.weight)
		}
	}
	
	case largeTitle
	case title
	case title2
	case title3
	case headline
	case subheadline
	case body
	case callout
	case footnote
	case caption
	case caption2
	
	/// This functions returns the system font equivalent of the design fonts,
	/// this fall back process manages the situation where the font may have not been loaded properly.
	/// - Returns: Font
	private func getFallBackFont() -> Font {
		switch self {
		case .largeTitle:
			return Font.largeTitle
		case .title:
			return Font.title
		case .title2:
			return Font.title2
		case .title3:
			return Font.title3
		case .headline:
			return Font.headline
		case .subheadline:
			return Font.subheadline
		case .body:
			return Font.body
		case .callout:
			return Font.callout
		case .footnote:
			return Font.footnote
		case .caption:
			return Font.caption
		case .caption2:
			return Font.caption
		}
	}
	
	var font: Font {
		switch self {
		case .headline:
			return TintFont.TypeFace.bold.getFont(tint: self)
		default:
			return TintFont.TypeFace.medium.getFont(tint: self)
		}
	}
	
	/// https://developer.apple.com/design/human-interface-guidelines/ios/visual-design/typography/
	var size: CGFloat {
		switch self {
		case .largeTitle:
			return 34.0
		case .title:
			return 28.0
		case .title2:
			return 22.0
		case .title3:
			return 20.0
		case .headline:
			return 17.0
		case .subheadline:
			return 15.0
		case .body:
			return 17.0
		case .callout:
			return 16.0
		case .footnote:
			return 13.0
		case .caption:
			return 12.0
		case .caption2:
			return 11.0
		}
	}
	
	var weight: Font.Weight {
		switch self {
		case .headline:
			return .semibold
		default:
			return .regular
		}
	}
}