Fewer lines, not just fainter: drop second-level divider rules

One soft line per major boundary (top bar, pane seams, composer edge);
the rules under the Files toolbar, chat session header, editor
toolbar, tab bar, and between tabs are gone — spacing and background
shifts do the separating inside a pane.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: jherforth

packages/web-ui/src/components/ChatPane.tsx

@@ -332,7 +332,7 @@ export function ChatPane({
 
       {/* Chat header — session switcher (sessions belong to the chat, not the file tree) */}
       {onSelectSession && (
-        <div className="relative z-20 flex items-center gap-1 px-3 py-1.5 border-b border-monastery-dark-border shrink-0">
+        <div className="relative z-20 flex items-center gap-1 px-3 py-1.5 shrink-0">
           <div className="relative min-w-0">
             <button
               onClick={() => setSessionMenuOpen(o => !o)}

packages/web-ui/src/components/EditorPane.tsx

@@ -35,14 +35,14 @@ export function EditorPane({
 }: EditorPaneProps) {
   return (
     <div className="h-full bg-monastery-dark-surface flex flex-col animate-slideInRight">
-      {/* Tab Bar */}
+      {/* Tab Bar — tabs separate themselves by background, not ruled lines */}
       {tabs.length > 0 && (
-        <div className="flex items-center border-b border-monastery-dark-border bg-monastery-dark-bg overflow-x-auto shrink-0">
+        <div className="flex items-center bg-monastery-dark-bg overflow-x-auto shrink-0">
           {tabs.map((tab, i) => (
             <div
               key={tab.path}
               onClick={() => onSelectTab(i)}
-              className={`group flex items-center gap-1.5 px-3 py-1.5 text-xs cursor-pointer border-r border-monastery-dark-border transition-colors shrink-0 ${
+              className={`group flex items-center gap-1.5 px-3 py-1.5 text-xs cursor-pointer transition-colors shrink-0 ${
                 i === activeTabIndex
                   ? 'bg-monastery-dark-surface text-monastery-text-primary border-t-2 border-t-monastery-lantern'
                   : 'text-monastery-text-secondary hover:bg-monastery-dark-surface hover:text-monastery-text-primary'
@@ -64,7 +64,7 @@ export function EditorPane({
       )}
 
       {/* Editor Toolbar */}
-      <div className="flex items-center justify-between px-3 py-1.5 border-b border-monastery-dark-border shrink-0">
+      <div className="flex items-center justify-between px-3 py-1.5 shrink-0">
         <span className="text-xs text-monastery-text-muted truncate">
           {currentFile || 'No file selected'}
         </span>

packages/web-ui/src/components/Sidebar.tsx

@@ -234,7 +234,9 @@ export function Sidebar({
         {(
           <div>
             {/* Files Toolbar */}
-            <div className="flex items-center gap-1 px-3 py-1.5 border-b border-monastery-dark-border mb-1">
+            {/* No rule under the toolbar — the label + spacing is the header; one soft line
+                per major boundary, none inside a pane. */}
+            <div className="flex items-center gap-1 px-3 py-1.5 mb-1">
               <span className="text-xs text-monastery-text-muted flex-1">Files</span>
 
               {/* Refresh from disk — surfaces files written outside Monastery (e.g. by Hermes) */}