Looks as if the ERB and the SASS got out of sync. The rendered page with the ERB and SASS in the book yields the following—the grand total floating higher than the Total: label and without the border above it:

Screen Shot 2021-09-29 at 7.49.47 AM519×323 24.4 KB

… which (ignoring the line items) does not match the screenshot on p. 148:

Screen Shot 2021-09-29 at 8.07.45 AM475×232 14.2 KB

Suggest the following edits:

ERB, p. 146
…
<tfoot>
<tr>
<th colspan="2">Total:</th>
<td class="price"><%= number_to_currency(@cart.total_price) %></td>
<th class="price"><%= number_to_currency(@cart.total_price) %></th>
</tr>
</tfoot>
…

SASS, p. 147
…
tfoot {
th, th.price {
font-weight: bold;
padding-top: 1em;
}
th {
text-align: right;
}
th {
font-weight: bold;
text-align: right;
padding: 1em 0.5em;
}
th.price {
border-top: solid thin;
}
}
…