How do I remove the border-bottom from Post headings?

Hi,

I am using a child theme for Twenty Seventeen. Where is the CSS that is controlling the headers in Posts? I found the CSS to turn off the extra bolding and the border-bottoms for the links and headers in Pages but that CSS doesn’t affect the Post headers. I want to have no bottom border and normal bolding (500 to 600; not 800).

I have tried adding the following CSS to my child theme’s style:

aside .entry-header,
aside h2.entry-title a:link {
	font-size: 1.25em;
	font-size: 1.25rem;
	color: #333;   /*---- Very dark gray ----*/
	background-color: transparent; 
	font-weight: bold;
	text-decoration: none;
	border: none;
	outline: none;
	border-bottom: none;
	-webkit-box-shadow: none;
	box-shadow: none;
}

aside .entry-header,
aside h2.entry-title a:hover, aside h2.entry-title a:focus {
	font-size: 1.25em;
	font-size: 1.25rem;
	font-weight: bold;
	color: #006363;    /*   accessible cyan    */
	background-color: transparent;
	text-decoration: underline;
	border: none;
	outline: none;
	border-bottom: none;
	-webkit-box-shadow: none;
	box-shadow: none;
}

But the headers in Posts are still showing up with extra bolding and the heavy bottom border.

The following CSS changes worked for the Pages but these do not affect the POSTS. What do I need to modify above or add below to affect the Post headings?

.entry-content a,
.entry-summary a,
.widget a,
.site-footer .widget-area a,
.posts-navigation a,
.widget_authors a strong {
	border-bottom: none;
	-webkit-box-shadow: none;
	box-shadow: none;
}

.entry-title a,
.entry-meta a,
.page-links a,
.page-links a .page-number,
.entry-footer a,
.entry-footer .cat-links a,
.entry-footer .tags-links a,
.edit-link a,
.post-navigation a,
.logged-in-as a,
.comment-navigation a,
.comment-metadata a,
.comment-metadata a.comment-edit-link,
.comment-reply-link,
a .nav-title,
.pagination a,
.comments-pagination a,
.site-info a,
.widget .widget-title a,
.widget ul li a,
.site-footer .widget-area ul li a,
.site-footer .widget-area ul li a {
	border-bottom: none;
	-webkit-box-shadow: none;
	box-shadow: none;
}

.entry-content a:focus,
.entry-content a:hover,
.entry-summary a:focus,
.entry-summary a:hover,
.widget a:focus,
.widget a:hover,
.site-footer .widget-area a:focus,
.site-footer .widget-area a:hover,
.posts-navigation a:focus,
.posts-navigation a:hover,
.comment-metadata a:focus,
.comment-metadata a:hover,
.comment-metadata a.comment-edit-link:focus,
.comment-metadata a.comment-edit-link:hover,
.comment-reply-link:focus,
.comment-reply-link:hover,
.widget_authors a:focus strong,
.widget_authors a:hover strong,
.entry-title a:focus,
.entry-title a:hover,
.entry-meta a:focus,
.entry-meta a:hover,
.page-links a:focus .page-number,
.page-links a:hover .page-number,
.entry-footer a:focus,
.entry-footer a:hover,
.entry-footer .cat-links a:focus,
.entry-footer .cat-links a:hover,
.entry-footer .tags-links a:focus,
.entry-footer .tags-links a:hover,
.post-navigation a:focus,
.post-navigation a:hover,
.pagination a:not(.prev):not(.next):focus,
.pagination a:not(.prev):not(.next):hover,
.comments-pagination a:not(.prev):not(.next):focus,
.comments-pagination a:not(.prev):not(.next):hover,
.logged-in-as a:focus,
.logged-in-as a:hover,
a:focus .nav-title,
a:hover .nav-title,
.edit-link a:focus,
.edit-link a:hover,
.site-info a:focus,
.site-info a:hover,
.widget .widget-title a:focus,
.widget .widget-title a:hover,
.widget ul li a:focus,
.widget ul li a:hover {
/* 	color: #dc143c; */  /*--- crimson  ----*/
/* 	color: #129e6c;  */  /*   pool table green    */
/* 	color: #007580; */   /*   dark cyan    */
	color: #006363;    /*   accessible cyan    */
	background-color: transparent;
	text-decoration: underline;
	border-bottom: none;
	-webkit-box-shadow: none;
	box-shadow: none;
}

Thanks for your help.