Fix #9051: html theme: The style for figure are not applied

Since docutils-0.17, figure directive starts to output `<figure>` tag.
To support it, this modifies CSS.

7 files changed, 44 insertions, 23 deletions

diff --git a/CHANGES b/CHANGES
index d03a2533b..10efb47b8 100644
--- a/CHANGES
+++ b/CHANGES
@@ -20,8 +20,11 @@ Bugs fixed
 
 * #9078: autodoc: Async staticmethods and classmethods are considered as non
   async coroutine-functions
-* #8870: The style of toctree captions has been changed with docutils-0.17
-* #9001: The style of ``sidebar`` directive has been changed with docutils-0.17
+* #8870, #9001, #9051: html theme: The style are not applied with docutils-0.17
+
+  - toctree captions
+  - The content of ``sidebar`` directive
+  - figures
 
 Testing
 --------
diff --git a/sphinx/themes/agogo/static/agogo.css_t b/sphinx/themes/agogo/static/agogo.css_t
index 489ec17ea..0c78e4345 100644
--- a/sphinx/themes/agogo/static/agogo.css_t
+++ b/sphinx/themes/agogo/static/agogo.css_t
@@ -370,19 +370,25 @@ div.footer .left {
 
 /* Styles copied from basic theme */
 
-img.align-left, .figure.align-left, object.align-left {
+img.align-left, figure.align-left, .figure.align-left, object.align-left {
     clear: left;
     float: left;
     margin-right: 1em;
 }
 
-img.align-right, .figure.align-right, object.align-right {
+img.align-right, figure.align-right, .figure.align-right, object.align-right {
     clear: right;
     float: right;
     margin-left: 1em;
 }
 
-img.align-center, .figure.align-center, object.align-center {
+img.align-center, figure.align-center, .figure.align-center, object.align-center {
+  display: block;
+  margin-left: auto;
+  margin-right: auto;
+}
+
+img.align-default, figure.align-default, .figure.align-default {
   display: block;
   margin-left: auto;
   margin-right: auto;
@@ -407,11 +413,13 @@ table caption span.caption-number {
 table caption span.caption-text {
 }
 
-div.figure p.caption span.caption-number {
+div.figure p.caption span.caption-number,
+figcaption span.caption-number {
     font-style: italic;
 }
 
-div.figure p.caption span.caption-text {
+div.figure p.caption span.caption-text,
+figcaption span.caption-text {
 }
 
 /* -- search page ----------------------------------------------------------- */
diff --git a/sphinx/themes/basic/static/basic.css_t b/sphinx/themes/basic/static/basic.css_t
index 5fc83c848..c0158b27b 100644
--- a/sphinx/themes/basic/static/basic.css_t
+++ b/sphinx/themes/basic/static/basic.css_t
@@ -277,25 +277,25 @@ p.rubric {
     font-weight: bold;
 }
 
-img.align-left, .figure.align-left, object.align-left {
+img.align-left, figure.align-left, .figure.align-left, object.align-left {
     clear: left;
     float: left;
     margin-right: 1em;
 }
 
-img.align-right, .figure.align-right, object.align-right {
+img.align-right, figure.align-right, .figure.align-right, object.align-right {
     clear: right;
     float: right;
     margin-left: 1em;
 }
 
-img.align-center, .figure.align-center, object.align-center {
+img.align-center, figure.align-center, .figure.align-center, object.align-center {
   display: block;
   margin-left: auto;
   margin-right: auto;
 }
 
-img.align-default, .figure.align-default {
+img.align-default, figure.align-default, .figure.align-default {
   display: block;
   margin-left: auto;
   margin-right: auto;
@@ -458,20 +458,22 @@ td > :last-child {
 
 /* -- figures --------------------------------------------------------------- */
 
-div.figure {
+div.figure, figure {
     margin: 0.5em;
     padding: 0.5em;
 }
 
-div.figure p.caption {
+div.figure p.caption, figcaption {
     padding: 0.3em;
 }
 
-div.figure p.caption span.caption-number {
+div.figure p.caption span.caption-number,
+figcaption span.caption-number {
     font-style: italic;
 }
 
-div.figure p.caption span.caption-text {
+div.figure p.caption span.caption-text,
+figcaption span.caption-text {
 }
 
 /* -- field list styles ----------------------------------------------------- */
diff --git a/sphinx/themes/epub/static/epub.css_t b/sphinx/themes/epub/static/epub.css_t
index 46bbb93b3..9c9ca8565 100644
--- a/sphinx/themes/epub/static/epub.css_t
+++ b/sphinx/themes/epub/static/epub.css_t
@@ -325,11 +325,13 @@ table.citation td {
 
 /* -- figures --------------------------------------------------------------- */
 
-div.figure p.caption span.caption-number {
+div.figure p.caption span.caption-number,
+figcaption span.caption-number {
     font-style: italic;
 }
 
-div.figure p.caption span.caption-text {
+div.figure p.caption span.caption-text,
+figcaption span.caption-text {
 }
 
 /* -- field list styles ----------------------------------------------------- */
diff --git a/sphinx/themes/nonav/static/nonav.css b/sphinx/themes/nonav/static/nonav.css
index 63abb9f0d..c2d28a26b 100644
--- a/sphinx/themes/nonav/static/nonav.css
+++ b/sphinx/themes/nonav/static/nonav.css
@@ -314,11 +314,13 @@ table.citation td {
 
 /* -- figures --------------------------------------------------------------- */
 
-div.figure p.caption span.caption-number {
+div.figure p.caption span.caption-number,
+figcaption span.caption-number {
     font-style: italic;
 }
 
-div.figure p.caption span.caption-text {
+div.figure p.caption span.caption-text,
+figcaption span.caption-text {
 }
 
 /* -- field list styles ----------------------------------------------------- */
diff --git a/sphinx/themes/scrolls/static/scrolls.css_t b/sphinx/themes/scrolls/static/scrolls.css_t
index f039d9e2b..48b5af5fe 100644
--- a/sphinx/themes/scrolls/static/scrolls.css_t
+++ b/sphinx/themes/scrolls/static/scrolls.css_t
@@ -478,11 +478,13 @@ div.viewcode-block:target {
     padding: 0 5px;
 }
 
-div.figure p.caption span.caption-number {
+div.figure p.caption span.caption-number,
+figcaption span.caption-number {
     font-style: italic;
 }
 
-div.figure p.caption span.caption-text {
+div.figure p.caption span.caption-text,
+figcaption span.caption-text {
 }
 
 /* math display */
diff --git a/sphinx/themes/traditional/static/traditional.css_t b/sphinx/themes/traditional/static/traditional.css_t
index 4371d8e89..bd648b47e 100644
--- a/sphinx/themes/traditional/static/traditional.css_t
+++ b/sphinx/themes/traditional/static/traditional.css_t
@@ -743,11 +743,13 @@ div.literal-block-wrapper pre {
     margin: 0;
 }
 
-div.figure p.caption span.caption-number {
+div.figure p.caption span.caption-number,
+figcaption span.caption-number {
     font-style: italic;
 }
 
-div.figure p.caption span.caption-text {
+div.figure p.caption span.caption-text,
+figcaption span.caption-text {
 }
 
 /* :::: MATH DISPLAY :::: */