Gradient background can change the card appearance suddenly but this time you are using more than one color and hence your responsibility also increased. While selecting the colors for gradient you need to consider overall design of the card first and then think of every attributes and its color.
Lets say you have selected black or dark blue and light blue for gradient. This means you are using two color gradient for your card background. Now you have to think first where exactly you want to see dark and light color. It can be at the top, bottom or even left and right. Secondly how much percentage of the dark or the light color you want to place in the card. Placement of the gradient is of importance because it decides other factor and their colors. Gradient can be placed diagonally also and hence there are no limits for the placement and the percentage of colors in the gradient.
Using simple gradient background
Here we have designed the card using simple gradient background with dark and light color. Please make a note that the dark color is at the bottom and the light color is at the top. The percentage is almost 50/50 for the distribution of the colors.
The darkest portion of the color comes at the bottom where the address is generally placed. We have used lighter color for address to make it stand out against the dark background. As we proceed upwards, the gradient color becomes lighter and hence we can use bit darker shade or any shade that can attract the attention of the user. At the top portion the color is of the lightest shade and we have kept the dark color for logo.
Using simple background in a different direction
We have used the similar gradient in the following card where the dark color is in the left and light color is at right. This color scheme is different than the previous card though both share the similar colors because in this card some of the text is spread across the width of the card where they undergo dark and light color at the same time.
In this case we have reconsider the colors if some of the attributes. We have changed the description color that will be suitable in both light and dark background.
The color of the designation is changed because it will merge in the dark background with the same color.
Lets try diagonal color scheme and check the impact of the gradient background on the card.
We have kept most of the things similar. Just changed the color of the logo because it was almost merging with the dark background with previous color. And changed the color of the designation because it was lighter and the background is also light now.
So we have to see where the shade of the color travel across the card background and then place the matter and add colors to it. It must be noted that the economical factor is also important. You may come across the client with the limited budget and still wish to go for gradient background. In such a case you can not advice him to add different colors as it add the cost of the card. You have to consider every.htmlect of the card and suggest the solution carefully to this client with minimum possible colors.