Index: src/wp-content/themes/twentyfifteen/css/editor-blocks.css
===================================================================
--- src/wp-content/themes/twentyfifteen/css/editor-blocks.css	(revision 58387)
+++ src/wp-content/themes/twentyfifteen/css/editor-blocks.css	(working copy)
@@ -414,7 +414,7 @@
 
 /* Captions */
 
-[class^="wp-block-"] figcaption {
+figure[class*="wp-block-"] > figcaption {
 	color: #707070;
 	font-family: "Noto Sans", sans-serif;
 	font-size: 12px;
@@ -422,36 +422,36 @@
 	padding: 0.5em 0;
 }
 
-.editor-block-list__block [class^="wp-block-"] figcaption {
+.editor-styles-wrapper figure[class*="wp-block-"] > figcaption {
 	line-height: 1.5;
 }
 
 @media screen and (min-width: 46.25em) {
-	[class^="wp-block-"] figcaption {
+	figure[class*="wp-block-"] > figcaption {
 		font-size: 14px;
 	}
 }
 
 @media screen and (min-width: 55em) {
-	[class^="wp-block-"] figcaption {
+	figure[class*="wp-block-"] > figcaption {
 		font-size: 16px;
 	}
 }
 
 @media screen and (min-width: 59.6875em) {
-	[class^="wp-block-"] figcaption {
+	figure[class*="wp-block-"] > figcaption {
 		font-size: 12px;
 	}
 }
 
 @media screen and (min-width: 68.75em) {
-	[class^="wp-block-"] figcaption {
+	figure[class*="wp-block-"] > figcaption {
 		font-size: 14px;
 	}
 }
 
 @media screen and (min-width: 77.5em) {
-	[class^="wp-block-"] figcaption {
+	figure[class*="wp-block-"] > figcaption {
 		font-size: 16px;
 	}
 }
Index: src/wp-content/themes/twentyfifteen/css/editor-style.css
===================================================================
--- src/wp-content/themes/twentyfifteen/css/editor-style.css	(revision 58387)
+++ src/wp-content/themes/twentyfifteen/css/editor-style.css	(working copy)
@@ -287,7 +287,6 @@
 table caption {
 	border-width: 0 1px 1px 0;
 	font-family: "Noto Serif", serif;
-	font-size: 17px;
 	font-weight: 700;
 	padding: 7px;
 	text-align: left;
@@ -294,11 +293,14 @@
 	vertical-align: baseline;
 }
 
+table caption {
+	font-weight: normal;
+}
+
 table td,
 .mce-item-table td {
 	border-width: 0 1px 1px 0;
 	font-family: "Noto Serif", serif;
-	font-size: 17px;
 	padding: 7px;
 	vertical-align: baseline;
 }