The code was removed from your theme options panel.. were you editing it at the time?
table.totals_table {
width: 100%;
max-width: 320px;
}
.woocommerce table.my_account_orders {
border-top: 0;
}
.woocommerce .order-info, .woocommerce .order-info mark {
background: #000!important;
}
.woocommerce .order-info {
line-height: 140%;
}
@media only screen and (max-width: 479px) {
.woocommerce table.my_account_orders tr td {
font-size: 10px;
text-align: center;
}
}
– Ed