Making paragraph responsive in CSS - css

Question

I'm new to CSS and have encountered a problem. I'm trying to display paragraphs on my website on desktop/global view as
#aeromexico
p {
float: left;
position: fixed;
text-align: left;
max-width: 25%;
padding: 0px 0px 0px 0px;
display:inline-block;
}
but when viewed in mobile and tablet I want them to be viewed as
#aeromexico .col-sm
p {
object-position: top;
text-align: left;
max-width:100%;
display:block;
padding-bottom: 60px;
}
However the second part of the code for mobile view is being ignored and is still displaying as desktop view on mobile. I have attached my whole code below
/Desktop / Global View/
body {
max-width: 1366px;
margin-left: auto;
margin-right: auto;
font-family: 'Open Sans', sans-serif;
padding: 1px;
}
#homepage .col {
float: left;
}
.col-lg {
width: 33.3%;
}
.col-lg img {
width: 100%;
height: auto;
display: block;
}
.slicknav_menu {
display:none;
}
#menu {
float: right;
}
#menu li {
display:inline-block;
}
#menu li a {
text-decoration:none;
color: #454545;
padding: 8px;
font-size: 18px;
}
header {
padding: 10px 0px 20px 0px;
}
ul {
padding-top: 40px;
}
.mylogo {
width: 95px;
}
/*aeromexico*/
#aeromexico .row {
padding:5px;
}
#aeromexico .col {
width: 70%;
margin-right: auto;
float: right;
display:inline-block;
padding-bottom: 40px;
}
#aeromexico .col-lg {
width: 65%;
}
#aeromexico
p {
float: left;
position: fixed;
text-align: left;
max-width: 25%;
padding: 0px 0px 0px 0px;
display:inline-block;
}
/*Tablet View*/
#media (max-width: 768px) {
#menu li {
display:block;
text-align: right;
}
header {
padding:10px;
}
.col-md {
width: 50%;
}
.mylogo {
width: 95px;
}
body {
padding:10px;
}
}
/*Mobile View*/
#media (max-width: 400px) {
.slicknav_menu {
display:block;
}
#menu {
display:none;
}
alt {
width: 95px;
}
.mylogo {
width: 95px;
}
.col-sm {
width:100%;
}
body {
padding:10px;
}
#aeromexico .col-sm {
width:100%;
}
#aeromexico .col-sm
p {
object-position: top;
text-align: left;
max-width:100%;
display:block;
padding-bottom: 60px;
}
}

Answer 1

Did you set up the metatag for the viewport on the HTML header?
<meta name="viewport" content="width=device-width, initial-scale=1">