HI Bonnie,
Please use the following css to fix your issue;
.page-id-7 .left_sidebar {
color: #fff;
}
.page-id-7 #recent-posts-3 h3, h3 a, #recent-posts-3 ul li a {
color: #fff !important;
}
NOTE: Please use the child theme style.css or custom css plugin to write the css.
Thanks