After analyzing the website quickly, a number of issues have been identified.
Problem 1 - The Shopping Cart has a set margin-left property which is causing the page to expand (located in style.css line 88)
.m-shoppingbasket {
width: 295px;
position: absolute;
margin-left: 739px;
top: 6px;
background: #8bbeb7;
}
Possible Solution - Eliminate the margin-left and instead use float right, adjusting as needed
Problem 2 - The feature boxes (fp-boxes) are using tables with fixed widths
<td style="width: 334px; height: 201px;" valign="top">...</td>
<td style="width: 334px;" valign="top">...</td>
<td style="width: 334px;" valign="top">...</td>
Solution - Remove fixed widths and consider using a responsive grid or setting percentages. Using tables for displaying three boxes side by side might not be the best approach...
Additionally, a media query has been noticed (style.css line 733)
This issue can be addressed by implementing a responsive image class that allows featured promos to adapt based on table size
.img-responsive {
display:block;
max-width:100%;
height:auto
}
Problem 3 - The footer text container has been assigned a width of 1000px (style.css line 610)
.footer-container .footer {
width: 1000px;
height: 80px;
margin: 0 auto;
padding-top: 20px;
}
Solution - Remove the specified width
While there may be additional issues present, addressing these should provide a good starting point.