move default (light) theme LESS source to a more appropriate place

add compact_dark theme variant

themes/compact.less

@@ -1,33 +1,2 @@
-@import "../css/default_base.less";
-
-/* rules specific to compact.css */
-
-body.ttrss_main.ttrss_index.flat {
-
-  #feedTree.dijitTree .dijitTreeLabel {
-    font-size : 13px ! important;
-  }
-
-  .dijitMenu .dijitMenuItemLabel,
-  .content-inner,
-  #content-insert,
-  .cdm .content,
-  .post .content {
-    font-size : 12px ! important;
-  }
-
-  div[id*=RROW] {
-    i.material-icons {
-      font-size: 18px;
-    }
-  }
-
-  .hl,
-  .post .header .title,
-  #floatingTitle a.title,
-  .cdm .title {
-    font-size : 13px ! important;
-  }
-
-
-}
+@import "light/light_base.less";
+@import "compact_base.less";

themes/compact_base.less

@@ -0,0 +1,31 @@
+/* rules specific to compact.css */
+
+body.ttrss_main.ttrss_index.flat {
+
+  #feedTree.dijitTree .dijitTreeLabel {
+    font-size : 13px ! important;
+  }
+
+  .dijitMenu .dijitMenuItemLabel,
+  .content-inner,
+  #content-insert,
+  .cdm .content,
+  .post .content {
+    font-size : 12px ! important;
+  }
+
+  div[id*=RROW] {
+    i.material-icons {
+      font-size: 18px;
+    }
+  }
+
+  .hl,
+  .post .header .title,
+  #floatingTitle a.title,
+  .cdm .title {
+    font-size : 13px ! important;
+  }
+
+
+}

themes/compact_night.less

@@ -0,0 +1,2 @@
+@import "night_base.less";
+@import "compact_base.less";

themes/light.less

@@ -1 +1 @@
-@import "../css/default_base.less";
+@import "light/light_base.less";

themes/light/light_base.less

@@ -1,4 +1,4 @@
 @import "defines.less";
 @import "dijit_light.less";
 @import "zoom.less";
-@import "../lib/flat-ttrss/flat_combined.css";
+@import "../lib/flat-ttrss/flat_combined.css";

themes/night_base.less

@@ -1,6 +1,6 @@
-@import "../css/defines.less";
-@import "../css/utility.less";
-@import "../css/zoom.less";
+@import "light/defines.less";
+@import "light/utility.less";
+@import "light/zoom.less";
 @import "../lib/flat-ttrss/flat_combined_dark.css";
 
 @color-accent: #b87d2c;