doc: fix rst-columns display

Using ``.. rst-class:: rst-columns`` wasn't processed correctly because
of an error in the acrn-custom.css file.  Fix that, update the
documentation guidelines, and make use of the multi-column display in
documents where the toctree created a long list.  Now it will
appear in columns.

Also tweaked the toctree listing to use bold for the first-level items
(making a multi-column display look better, particularly when it has
subsections).

Signed-off-by: David B. Kinder <david.b.kinder@intel.com>

doc/contribute.rst

@@ -15,6 +15,8 @@ Read about ACRN's high-level design and architecture principles that led
 to the development of the ACRN hypervisor and its components.  You'll
 also find details about specific architecture topics.
 
+.. rst-class:: rst-columns2
+
 .. toctree::
    :maxdepth: 1
 
@@ -36,6 +38,8 @@ project. Here's where you'll find how the development team works and the
 guidelines they (and you) use to contribute code (and documentation) to
 the project.
 
+.. rst-class:: rst-columns2
+
 .. toctree::
    :maxdepth: 1
 

doc/develop.rst

@@ -7,6 +7,8 @@ Advanced Guides
 Configuration and Tools
 ***********************
 
+.. rst-class:: rst-columns2
+
 .. toctree::
    :glob:
    :maxdepth: 1
@@ -23,6 +25,8 @@ Configuration and Tools
 Service VM Tutorials
 ********************
 
+.. rst-class:: rst-columns2
+
 .. toctree::
    :maxdepth: 1
 
@@ -32,6 +36,8 @@ Service VM Tutorials
 User VM Tutorials
 *****************
 
+.. rst-class:: rst-columns2
+
 .. toctree::
    :maxdepth: 1
 
@@ -48,6 +54,8 @@ User VM Tutorials
 Enable ACRN Features
 ********************
 
+.. rst-class:: rst-columns2
+
 .. toctree::
    :maxdepth: 1
 
@@ -70,6 +78,8 @@ Enable ACRN Features
 Debug
 *****
 
+.. rst-class:: rst-columns2
+
 .. toctree::
    :maxdepth: 1
 
@@ -80,6 +90,8 @@ Debug
 Additional Tutorials
 ********************
 
+.. rst-class:: rst-columns2
+
 .. toctree::
    :maxdepth: 1
 
@@ -91,7 +103,3 @@ Additional Tutorials
    tutorials/sign_clear_linux_image
    tutorials/enable_laag_secure_boot
    tutorials/kbl-nuc-sdc
-
-
-
-

doc/developer-guides/doc_guidelines.rst

@@ -197,10 +197,11 @@ would be rendered as:
    * space on
    * the page
 
-A maximum of three columns will be displayed, and change based on the
-available width of the display window, reducing to one column on narrow
-(phone) screens if necessary.  We've deprecated use of the ``hlist``
-directive because it misbehaves on smaller screens.
+A maximum of three columns will be displayed if you use ``rst-columns``
+or ``rst-columns3`` (and two columns for ``rst-columns2``), and change
+based on the available width of the display window, reducing to one
+column on narrow (phone) screens if necessary.  We've deprecated use of
+the ``hlist`` directive because it misbehaves on smaller screens.
 
 Tables
 ******

doc/developer-guides/hld/index.rst

@@ -13,6 +13,8 @@ These chapters describe the ACRN architecture, high-level design,
 background, and motivation for specific areas within the ACRN hypervisor
 system.
 
+.. rst-class:: rst-columns
+
 .. toctree::
    :maxdepth: 2
 

doc/release_notes/index.rst

@@ -12,6 +12,8 @@ The project ACRN reference code can be found on GitHub in
 https://github.com/projectacrn.  It includes the ACRN hypervisor, the
 ACRN device model, and documentation.
 
+.. rst-class:: rst-columns
+
 .. toctree::
    :maxdepth: 1
    :glob:

doc/static/acrn-custom.css

@@ -5,7 +5,7 @@
    max-width: 1100px;
 }
 
-/* (temporarily) add an under development tagline to the bread crumb 
+/* (temporarily) add an under development tagline to the bread crumb
 .wy-breadcrumbs::after {
    content: " (Content reorganization in progress)";
    background-color: #FFFACD;
@@ -266,10 +266,12 @@ kbd
 .rst-columns2 {
    column-width: 28em;
    column-fill: balance;
+   margin-bottom: 1em;
 }
-.rst-columns3 .rst-columns {
+.rst-columns3, .rst-columns {
    column-width: 18em;
    column-fill: balance;
+   margin-bottom: 1em;
 }
 
 /* numbered "h2" steps */
@@ -292,3 +294,8 @@ div.numbered-step h2::before {
   margin-right: 5px;
   text-align: center;
   width: 1.6em;}
+
+/* bold the level1 headings in on-page toctree displays */
+.rst-content  .toctree-l1 > a {
+  font-weight: bold;
+}