Here’s the updated pastel color palette with a darker mint green for improved visibility and contrast:

 <Calm Music Vibes> 
1. Soft Blue - 
                            
                            #7AC6D9
                         - A deeper, soothing blue that retains a tranquil quality, reminiscent of a clear sky at dusk.
2. Soft Lavender - 
                            
                            #D49DD2
                         - A richer lavender that enhances the sense of calmness and creativity, offering a more pronounced touch of tranquility.
3. Dark Mint Green - 
                            
                            #3A9A7E
                         - A darker mint green that remains fresh and vibrant, symbolizing renewal and harmony while providing better contrast.
4. Warm Peach - 
                            
                            #F2B2B1
                         - A deeper peach that adds warmth and comfort, harmonizing beautifully with the other colors.
5. Light Grey - 
                            
                            #B0B0B0
                         - A medium grey that provides a solid balance and sophistication, grounding the palette while allowing the pastel colors to shine.

The darker mint green complements the other colors while offering improved visibility against a white background.

Would you like any more adjustments, or do you have specific design elements in mind for using this palette?