Redesign UI and improve class session calculator

Major overhaul of index.html with a new responsive layout, custom CSS, and improved user experience for managing semester dates, holidays, vacations, and group schedules. Adds dynamic group/session management, exclusion logic, and PDF export using jsPDF and autoTable. Updates README with new features, usage instructions, and tech stack details.

Author: arantxa-garcri

README.md

@@ -1,51 +1,95 @@
-# Class Schedule Generator
+# Semester Class Sessions Calculator (by Group)
 
-A simple web application that generates a PDF class schedule from user input.
+A simple, responsive web app to calculate how many class sessions and total hours you will teach per group during a semester.  
+It supports weekly schedules, holidays, vacation periods (date ranges), and exports a detailed PDF report.
+
+## Features
+
+- Add multiple groups (e.g., `1022`, `1041`, etc.)
+- Define a weekly schedule per group (e.g., Monday 2h, Friday 1h)
+- Exclude:
+  - Holidays (single dates)
+  - Vacation periods (date ranges)
+- Generate an on-screen report:
+  - Session list per group (date, weekday, hours)
+  - Total sessions and hours per group
+  - Grand total hours across all groups
+- Export a PDF report (jsPDF + autoTable)
+- Light/Dark mode toggle (☀️/🌙) with saved preference
+- Responsive layout for small and large screens (I'll try to improve it in later versions, promise!💜)
 
 ## Quick Start
 
-1. **Clone the repository**
-   ```bash
-   git clone https://github.com/<your-username>/class-schedule-generator.git
-   cd class-schedule-generator
-   ```
-
-2. **Open the app**
-   - Simply double-click `index.html` to open it in your default browser.  
-   - _Or_ serve it locally:
-     ```bash
-     npx serve .
-     ```
-
-3. **Enter schedule data**
-   1. Select **Semester Start** and **Semester End** dates.
-   2. List **Holidays** in `YYYY-MM-DD` format, separated by commas.
-   3. Fill in **Group** code (e.g., `1022`) and **Class Name** (e.g., `Calculus I`).
-   4. Click **+ Add day** to define weekly meetings:
-      - Choose **Day of week**.
-      - Enter **Hours** for that day.
-      - Repeat for each meeting day.
-
-4. **Generate PDF**
-   - Click **Generate PDF**.  
-   - Download will start automatically with your schedule.
-
-## What’s Included
-
-- `index.html`: Main application file.
-- `LICENSE`: MIT License granting permission with credit requirement.
-- **No build steps** or dependencies beyond a modern browser.
+### Option A) Run locally (no setup)
+
+1. Download or clone this repository.
+2. Open `index.html` in your browser (Chrome/Firefox/Safari).
+
+### Option B) Run with a local server (recommended)
+
+This avoids some browser restrictions and behaves closer to production.
+
+- Using Python:
+  ```bash
+  python -m http.server 8000
+  ```
+  Then open `http://localhost:8000`
+
+- Using Node (http-server):
+  ```bash
+  npx http-server .
+  ```
+  Then open the provided local URL.
+
+## How to Use
+
+1. **Set the semester range**
+   - Choose Start and End dates.
+
+2. **Add exclusions**
+   - Add **holidays** as single dates.
+   - Add **vacation periods** as date ranges.
+   - These dates will be omitted from the final count.
+
+3. **Create groups**
+   - Enter a group name.
+   - Add one or more weekly schedule rows:
+     - Select weekday
+     - Enter hours per session
+   - Click **Save group**.
+
+4. **Generate report**
+   - Click **Calculate report** to view the full breakdown on screen.
+
+5. **Export PDF**
+   - Click **Export PDF** to generate a downloadable report including:
+     - Semester summary and exclusions
+     - Summary table per group
+     - Detailed session tables per group
+
+## PDF Export Notes
+
+- PDF generation runs entirely in the browser.
+- Powered by:
+  - `jsPDF`
+  - `jspdf-autotable`
+
+## Tech Stack
+
+- HTML + CSS + Vanilla JavaScript
+- jsPDF + autoTable (CDN)
 
 ## Contributing
 
-- Feel free to fork and submit pull requests.  
-- Keep credit in header and LICENSE intact.
+Contributions are welcome! Feel free to:
 
-## License
+- Fork the repo
+- Create a feature branch
+- Submit a Pull Request
 
-Distributed under the MIT License.  
-See `LICENSE` for details.
+If you fork or reuse the project, please provide **credit** by referencing this repository in your fork and/or documentation.  
+(And if you improve it, even better: PRs are appreciated. 😄)
 
----
+## License
 
-*Developed by ArantxaGC © 2025*
+MIT License. See `LICENSE` for details.