Responsive Css for Mobile Device

From few days Im facing issue on Responsive Css for bootstrap. I have try to make responsive Css but unable to do this css.
after that i discuss with my UI friend and he solved my issue. he given below CSS benchmark.

only solution is that we can write our desktop CSS after that write the below media query into CSS.
Media query write with from max 1280 then 768 and 312px.

@media only screen and (max-width: 1280px) {}
@media only screen and (max-width: 1200px) {}

@media only screen and (max-width: 1024px) {}
@media only screen and (max-width: 959px) {}
@media only screen and (max-width: 800px) {}




@media only screen and (max-width: 768px) {}
@media only screen and (max-width: 753px) {}
@media only screen and (max-width: 736px) {}
@media only screen and (max-width: 711px) {}
@media only screen and (max-width: 640px) {}
@media only screen and (max-width: 600px) {}

@media only screen and (max-width: 569px) {}
@media only screen and (max-width: 568px) {}
@media only screen and (max-width: 533px) {}




@media only screen and (max-width: 480px) {}
@media only screen and (max-width: 424px) {}
@media only screen and (max-width: 414px) {}
@media only screen and (max-width: 400px) {}
@media only screen and (max-width: 384px) {}
@media only screen and (max-width: 375px) {}
@media only screen and (max-width: 360px) {}
@media only screen and (max-width: 320px) {}