I'll create an authentic Windows 7 style application using only the 7.css library. This will be a complete HTML file with proper Windows 7 styling and functionality.

This Windows 7 style application features:

Authentic Windows 7 Design:

• Uses only the 7.css library for authentic styling
• Proper window structure with title bars and controls
• Windows 7 blue gradient desktop background
• Taskbar with Start button
• Desktop icons with hover effects

Functional Applications:

• Calculator: Full working calculator with number input, operations, and memory
• Notepad: Text editor with save/load functionality using localStorage
• Main App: System information display and user input forms

Interactive Features:

• Draggable windows by clicking and dragging title bars
• Window management (open/close/bring to front)
• Desktop icons that launch applications
• Working buttons and form controls
• Alert dialogs with Windows 7 styling

Technical Implementation:

• Complete HTML file with embedded CSS and JavaScript
• No external dependencies except 7.css
• Responsive window positioning
• Local storage for notepad content persistence
• Authentic Windows 7 color scheme and typography

The application provides a nostalgic Windows 7 experience with fully functional desktop metaphors and authentic styling throughout.