you can use grayishblue as the background color to match the design
there is a typo in the icon images/icon-Karma.svg should use lowercase
you can train your eyes to be more careful in seeing the width, padding, and margin
try using grid-template-areas it seems that property is more comfortable to use for responsive layout
for box shadow you can visit this page https://www.cssmatic.com/box-shadow you can create box shadow easily and can make you understand box shadow better