Added Isso dark mode styles

static/stylesheet/dark-theme-styles.less

@@ -44,6 +44,49 @@ main {
       background-color: #080808;
       border-color: #000;
     }
+
+    section#isso-thread {
+      div.textarea,
+      .auth-section p.input-wrapper input,
+      .notification-section input {
+        background: @very-dark-grey;
+        color: @light-grey;
+      }
+
+      >h4 {
+        color: @light-grey;
+      }
+
+      .isso-postbox > .form-wrapper .preview {
+        background: repeating-linear-gradient(
+          -45deg,
+          @solid-dark-grey, @solid-dark-grey 10px,
+          @very-dark-grey 10px, @very-dark-grey 20px
+        );
+      }
+
+      .isso-comment > div.text-wrapper {
+        > .isso-comment-header {
+          .author {
+            color: @light-grey;
+          }
+
+          .spacer, a.permalink, .note, a.parent {
+            color: @med-grey;
+
+            &:hover {
+              color: @light-grey;
+            }
+          }
+        }
+
+        > .isso-comment-footer a:hover {
+          // Unfortunately, Isso uses a lot of !important in its styles, so I
+          // have to override that.
+          text-shadow: @dark-grey 0 0 1px !important;
+        }
+      }
+    }
   }
 
   footer {

static/stylesheet/variables.less

@@ -7,6 +7,7 @@
 @med-grey:  #999999;
 @dark-grey: #242121;
 @solid-dark-grey: #222222;
+@very-dark-grey: #1a1a1a;
 
 // Font family
 @sans: 'Source Sans Pro', 'Roboto', 'Open Sans', 'Liberation Sans', 'DejaVu Sans', 'Verdana', 'Helvetica', 'Arial', sans-serif;