Create Header, left Menu using Master page in ASP.Net

Hi,

I want to create an inverted Header and Menu Section layout using HTML and CSS as shown in below url:

https://imgur.com/a/Ts93peg

Note: This Header and Menu section background color has to be same so that the inverted section should look as 1 section. And it should have 'box-shadow' css as well.

Please also note that the inverted Header and Menu section is in Master Page and the 'Content' section is in .aspx web page.

Kindly let me know how to achieve the inverted Header and Menu section using HTML and CSS. Different shapes used in the template is to show that I will be adding the icons and images in that section.

Thank you in advance.