Its the margin style on your hr.. min-width of 700px is one cause and the width in media query is 200%.. make it 100%
@media only screen and (max-width: 768px) and (min-width: 320px)
hr {
margin-left: -20%;
width: 200%;
margin-top: -60px;
}
hr {
margin-top: -80px;
border: 0;
clear: both;
display: block;
min-width: 700px;
background-color:#70B2FF;
height: 1px;
}
change to
@media only screen and (max-width: 768px) and (min-width: 320px)
hr {
margin-left: -20%;
width: 100%;
margin-top: -60px;
}
hr {
margin-top: -80px;
border: 0;
clear: both;
display: block;
background-color:#70B2FF;
height: 1px;
}