Desktop first using basic Flexbox

Hi, Debabrata Bhakat ~ I have studied you work. So good at the moment ~ 👍

Here are some of my opinions ~

For container-2, you would be better not to use align-items: flex-end property. Without that, you can adjust height of two boxes.

On 1024px and some other resolutions, image of box-3 goes weird. You can set width of string to calc(100% - 60px), for example.

Hope these can help you even a bit. Happy coding ~

For a first time, it looks decent only notable improvement would be on your width and height of each section

in this kind of situation, grid would be more suitable to use in my opinion because it allows you to allocate the total amount of rows and columns for the "table" and makes assigning the width and height easier to do.