initial styling for tabstrip (stub)

gtk/theme/Adwaita/_common.scss

@@ -2288,6 +2288,28 @@ notebook {
   }
 }
 
+/************
+ * Tabstrip *
+ ************/
+
+tabs {
+  button {
+    @include button(undecorated);
+    border-radius: 50%;
+    margin: 10px;
+    padding: 0;
+  }
+  tab {
+    min-width: 6em;
+    padding: 13px; // keeping width when paging buttons show up
+    border-right: 1px solid $borders_color;
+    &:last-child {}
+    &:checked { //FIXME not really working
+      border-bottom: 2px solid $selected_bg_color;
+    }
+  }
+}
+
 
 /**************
  * Scrollbars *

gtk/theme/Adwaita/gtk-contained-dark.css

@@ -2570,6 +2570,26 @@ notebook > stack:not(:only-child) {
   notebook > stack:not(:only-child):backdrop {
     background-color: #252a2c; }
 
+/************
+ * Tabstrip *
+ ************/
+tabs button {
+  border-color: transparent;
+  background-color: transparent;
+  background-image: none;
+  box-shadow: inset 0 1px rgba(255, 255, 255, 0);
+  text-shadow: none;
+  -gtk-icon-shadow: none;
+  border-radius: 50%;
+  margin: 10px;
+  padding: 0; }
+tabs tab {
+  min-width: 6em;
+  padding: 13px;
+  border-right: 1px solid #1b1f20; }
+  tabs tab:checked {
+    border-bottom: 2px solid #215d9c; }
+
 /**************
  * Scrollbars *
  **************/

gtk/theme/Adwaita/gtk-contained.css

@@ -2583,6 +2583,26 @@ notebook > stack:not(:only-child) {
   notebook > stack:not(:only-child):backdrop {
     background-color: #fcfcfc; }
 
+/************
+ * Tabstrip *
+ ************/
+tabs button {
+  border-color: transparent;
+  background-color: transparent;
+  background-image: none;
+  box-shadow: inset 0 1px rgba(255, 255, 255, 0);
+  text-shadow: none;
+  -gtk-icon-shadow: none;
+  border-radius: 50%;
+  margin: 10px;
+  padding: 0; }
+tabs tab {
+  min-width: 6em;
+  padding: 13px;
+  border-right: 1px solid #b6b6b3; }
+  tabs tab:checked {
+    border-bottom: 2px solid #4a90d9; }
+
 /**************
  * Scrollbars *
  **************/