I decided to go for a dark blue theme to give it a sleek and professional look.

This is the only card with a different colour scheme as its background. 

I went with a light blue gradient to still match the overall theme, but be noticeable enough to stand out as this is the main card.

Applied an inner shadow (centred) to give it a 3D appearance.

Kept this one simple. 

Formatted chart colour scheme to fit within the overall theme.

Very simple design too. Focus on staying on-theme.

One downside is that the "annual return" text is hard to see. I maintained it at such a blue colour in order to match the colour of the chart series it represents. However, it is reduces readability.

There are 3 line charts in the dashboard, representing the investment performance for stocks, bonds & real estate.

I added a small, white icon next to the title of each card. The icon choice is specific to the asset class.

I used a green font to represent the percentage growth.

I chose to represent the growth using a simple blue line chart with all other chart elements removed.

The radar chart visually shows the skewness of the asset allocation. In this case, the investor's portfolio is largely skewed towards stocks, bonds, and ETFs, with a lesser allocation for real estate and cash.

I opted for white gridlines and a purple radar outline to fit appropriately with the theme.

I used a combo chart (line chart + area chart) to achieve the effect pictured here. 

The area chart uses a very faint gradient fill with a lot of transparency.

I find this style of design to be most visually appealing.