sergey

сначала нужно хорошо разобраться во флоатах, флексах и им подобным?)

Все стили прописываю под media screen and (max-width:1200px){

@media only screen and (min-width: 320px) and (max-width: 479px) {....}
@media only screen and (min-width: 480px) and (max-width: 767px) {....}
@media only screen and (min-width: 768px) and (max-width: 991px) {....}
@media only screen and (min-width: 992px) and (max-width: 1199px) {....}
@media only screen and (min-width: 1200px) and (max-width: 1920px) {....}

<div><a class="navbar-brand" href="#"><img src="img/logo.png" class="img-responsive" alt="Blockchain"></a></div>

<a class="navbar-brand" href="#"><img src="img/logo.png" class="img-responsive" alt="Blockchain"></a>