Font Characteristics Observed:
Navigation/Headers

Font: Clean sans-serif (likely Segoe UI on Windows)
Weight: 400-500 (Regular to Medium)
Size: ~16-18px for navigation items
Letter-spacing: Normal
Body Text

Font: System sans-serif
Weight: 400 (Regular)
Size: ~14px
Line-height: ~1.5
Form Labels

Font: Same sans-serif family
Weight: 500-600 (Medium to Semi-bold)
Size: ~14px
Color: Darker shade for emphasis
Button Text

Font: Consistent with system font
Weight: 500 (Medium)
Size: ~14-16px
Text-transform: None (sentence case)