Try using standards mode html.

A while ago I started working on a more gradual transition, but never
finished it. So instead just try it out and see if anything breaks.

doc/Jamfile.v2

@@ -124,6 +124,8 @@ boostbook doc
     <implicit-dependency>../libs/type_index/doc//type_index
 
     <xsl:param>boost.libraries=../../libs/libraries.htm
+    <format>html:<xsl:param>chunker.output.doctype-public="-//W3C//DTD HTML 4.01 Transitional//EN"
+    <format>html:<xsl:param>chunker.output.doctype-system="http://www.w3.org/TR/html4/loose.dtd"
 
     <dependency>images
     <dependency>callouts

doc/src/boostbook.css

@@ -289,6 +289,22 @@ Tables
         border: none !important;
     }
 
+/*=============================================================================
+Suppress margins in tables
+=============================================================================*/
+
+    table th > *:first-child,
+    table td > *:first-child
+    {
+        margin-top: 0;
+    }
+
+    table th > *:last-child,
+    table td > *:last-child
+    {
+        margin-bottom: 0;
+    }
+
 /*=============================================================================
 Blurbs
 =============================================================================*/