docs: Remove redundant custom CSS

My fork `sphinx_rtd_theme` handles everything but the logo

Trying this again after RTD switched on the `PIP_ALWAYS_UPGRADE` flag
for the project: readthedocs/readthedocs.org#4156

Author: wmayner

docs/_static/custom.css

@@ -1,148 +1,3 @@
-@import url(//fonts.googleapis.com/css?family=Roboto+Mono:400,700|Roboto:400,700);
-/* Layout */
-.wy-nav-content-wrap {
-    background: #fff;
-}
-@media screen and (min-width: 1400px) {
-    .wy-nav-content-wrap {
-        background: #f3f4f4;
-    }
-}
-.wy-nav-content {
-    max-width: 900px;
-    background: #fff;
-}
-
-/* Typography */
-body,
-h1, h2, h3, h4, h5, h6 {
-    font-family: 'Roboto', 'Helvetica Neue', sans-serif;
-}
-body {
-  font-size: 16px;
-}
-body p {
-  line-height: 1.5;
-}
-
-/* Headers */
-h2 {
-    border-bottom: 1px solid #eaecef;
-    padding-bottom: 10px;
-    margin-top: 30px;
-}
-
-/* Paragraphs */
-p {
-    margin-bottom: 16px;
-}
-
-/* Code */
-pre,
-code,
-tt,
-.highlight
-.docutils.literal span.pre,
-.rst-content pre,
-.rst-content tt,
-.rst-content code {
-    font-family: 'Roboto Mono', 'Monaco', monospace;
-    font-size: 85%;
-    border: none;
-    border-radius: 3px;
-    background: rgba(27, 31, 35, 0.05);
-}
-
-/* Code literals */
-.rst-content code.literal {
-    color: inherit;
-    padding-top: 0.15em;
-    padding-right: 0.5em;
-    padding-bottom: 0.15em;
-    padding-left: 0.5em;
-    font-weight: normal;
-}
-
-/* Syntax-highlighted blocks */
-.rst-content div[class^='highlight'],
-div[class^='highlight'] {
-    border: none;
-    border-radius: 3px;
-    background: #f6f8fa;
-}
-/* Code blocks */
-.rst-content div[class^='highlight'] pre,
-div[class^='highlight'] pre {
-    font-family: 'Roboto Mono', 'Monaco', monospace;
-    font-size: 90%;
-    background: none;
-    padding: 16px;
-    border: none;
-    line-height: 1.45;
-}
-.admonition div[class^='highlight'] {
-    background: rgba(27, 31, 35, 0.05);
-}
-
-
-/* Module headers */
-h1 > code.xref.py.py-mod.docutils.literal {
-    background: none;
-    padding-left: 0;
-    margin-left: 0;
-    font-size: 100%;
-}
-code.xref.py.docutils.literal {
-  font-weight: normal;
-}
-
-/* Lists with code items */
-ul.simple > li > a.reference.internal > code.literal {
-    line-height: 2.25;
-}
-
-/* Class/function headers */
-.rst-content dl:not(.docutils) dt {
-    border-top: none;
-    border-radius: 3px;
-    border-left: solid 3px #6ab0de;
-    font-size: 100%;
-}
-.rst-content dl.attribute:not(.docutils) dt,
-.rst-content dl.method:not(.docutils) dt {
-    font-size: 95%;
-}
-
-/* Warnings, notes, etc. */
-div.admonition {
-    border-radius: 3px;
-}
-p.first.admonition-title {
-    border-radius: 3px 3px 0 0;
-}
-
- /* Code links */
-a.reference.internal > code.docutils.literal {
-    color: inherit;
-}
-a.reference.internal > .docutils.literal:hover {
-    text-decoration: underline;
-}
-
-/* Breadcrumbs */
-ul.wy-breadcrumbs > li > code.docutils.literal {
-    font-size: 100%;
-    background: none;
-}
-
-/* Navbar */
-.wy-menu.wy-menu-vertical a.reference.internal > .docutils.literal {
-    font-size: 100%;
-    margin: 5px;
-}
-.wy-menu-vertical li.current > a {
-    border: none;
-}
 .wy-side-nav-search > a img.logo {
     background-image: url(https://github.com/wmayner/pyphi/raw/develop/docs/_static/phi_144x144.png);
     background-size: 144px 144px;
@@ -157,48 +12,3 @@ ul.wy-breadcrumbs > li > code.docutils.literal {
         background-image: url(https://github.com/wmayner/pyphi/raw/develop/docs/_static/phi_288x288.png);
     }
 }
-
-/* Napoleon style fixes (parameters, return type, etc.) */
-.wy-table td, .rst-content table.docutils td, .rst-content table.field-list td,
-.wy-table th, .rst-content table.docutils th, .rst-content table.field-list th {
-    font-size: 100%
-}
-.rst-content table.field-list th {
-    padding-top: 5px;
-}
-.rst-content table.field-list td>strong {
-    margin-top: 0;
-}
-.rst-content dt > em {
-    font-size: 100%;
-}
-.rst-content dt > .sig-paren {
-    font-family: 'Roboto Mono', 'Monaco', monospace;
-    font-size: 100%;
-}
-table.field-list td.field-body > p {
-    line-height: 1.5;
-}
-table.field-list td.field-body {
-    padding-top: 3px;
-}
-.section ul > li {
-    line-height: 1.5;
-    margin-top: 5px;
-}
-
-/* Table of contents */
-.toctree-wrapper ul > li {
-    line-height: 1.5;
-}
-
-.toctree-wrapper ul > li > a.reference.internal > code.literal {
-    line-height: 2.25;
-}
-
-/* Search result highlighting */
-.rst-content .highlighted {
-    background: yellow;
-    font-weight: inherit;
-    padding: 0;
-}