Here's a light and cute color palette perfect for a girl study planner:

### Color Palette: "Sweet Study Vibes"

1. **Cotton Candy Pink**
   - **Hex Code:** 
          
          #FFB3D9
       
   - **Description:** A soft, playful pink that brings a sense of warmth and comfort, reminiscent of fluffy cotton candy.

2. **Lavender Mist**
   - **Hex Code:** 
          
          #E6E6FA
       
   - **Description:** A delicate, airy lavender that evokes a serene atmosphere, perfect for enhancing focus during study sessions.

3. **Mint Green**
   - **Hex Code:** 
          
          #B2E0D6
       
   - **Description:** A fresh and calming mint green that provides a refreshing pop of color while maintaining a lighthearted feel.

4. **Buttercup Yellow**
   - **Hex Code:** 
          
          #FFF9B0
       
   - **Description:** A cheerful, buttery yellow that radiates positivity and energy, ideal for motivating study time.

5. **Peachy Coral**
   - **Hex Code:** 
          
          #FF6F61
       
   - **Description:** A soft coral that adds a vibrant yet gentle contrast, bringing a lively touch to the planner.

6. **Sky Blue**
   - **Hex Code:** 
          
          #A4D7E1
       
   - **Description:** A light, tranquil blue that inspires calmness and clarity, creating an inviting environment for learning.

### Palette Summary:
This "Sweet Study Vibes" color palette combines gentle pastels with cheerful accents, making it perfect for a girl’s study planner. The colors are designed to uplift and inspire while remaining soothing and cute, helping to create an organized and enjoyable study experience.