Add some CSS for HTML tables (e.g. Pandas dataframes)

Fixes #182.

src/nbsphinx.py

@@ -156,6 +156,7 @@
 
 {{ output.data['text/latex'] | indent | indent }}
 {%- elif datatype == 'text/html' %}
+    :class: rendered_html
 
     .. raw:: html
 
@@ -556,6 +557,40 @@
 
 .ansi-bold { font-weight: bold; }
 .ansi-underline { text-decoration: underline; }
+
+/* Some additional styling taken form the Jupyter notebook CSS */
+.rendered_html table {
+  border: none;
+  border-collapse: collapse;
+  border-spacing: 0;
+  color: black;
+  font-size: 12px;
+  table-layout: fixed;
+}
+.rendered_html thead {
+  border-bottom: 1px solid black;
+  vertical-align: bottom;
+}
+.rendered_html tr,
+.rendered_html th,
+.rendered_html td {
+  text-align: right;
+  vertical-align: middle;
+  padding: 0.5em 0.5em;
+  line-height: normal;
+  white-space: normal;
+  max-width: none;
+  border: none;
+}
+.rendered_html th {
+  font-weight: bold;
+}
+.rendered_html tbody tr:nth-child(odd) {
+  background: #f5f5f5;
+}
+.rendered_html tbody tr:hover {
+  background: rgba(66, 165, 245, 0.2);
+}
 """
 
 CSS_STRING_READTHEDOCS = """