cleanup of guide part ii (#92)

* cleanup of guide part ii

* capitalization

* update JOSS instructions

* update styles

* JOSS language update

* notes and important blocks styles

Author: Leah Wasser

_static/pyos.css

@@ -0,0 +1,27 @@
+
+div.admonition.note .admonition-title, div.admonition.note .admonition-title::before {
+  background-color: #C1CFD4;
+  color: #222;
+
+}
+
+div.admonition.note {
+    border-color: #C1CFD4;
+    background-color: #E3F4FA;
+}
+
+
+div.admonition.important .admonition-title, div.admonition.important .admonition-title::before {
+  background-color: #107762;
+  color: #ffffff!important;
+}
+
+div.admonition.important .admonition-title {
+  background-color: #107762;
+  border-color: #1abc9c;
+}
+
+div.admonition.important {
+    border-color: #0e6654;
+    background-color: #ecfcf9;
+}