3 files changed, 42 insertions, 8 deletions

diff --git a/packages/kernel/src/file_watcher.cpp b/packages/kernel/src/file_watcher.cpp
index ae292c2..c747fe4 100644
--- a/packages/kernel/src/file_watcher.cpp
+++ b/packages/kernel/src/file_watcher.cpp
@@ -109,6 +109,19 @@ auto FileWatcher::add(const std::string& path, std::function<void()> on_change,
     return FileWatch(this, token);
 }
 
+auto FileWatcher::add_dir(const std::string& dir, std::function<void()> on_change, ExtensionId who)
+    -> FileWatch {
+    if (!ensure_started()) {
+        return FileWatch{};
+    }
+    std::string d = dir.empty() ? std::string(".") : dir;
+    const Token token = ++next_token_;
+    // Empty basename => match ANY file change in `d`.
+    entries_.emplace(token, Entry{std::move(d), std::string{}, std::move(on_change), who});
+    arm_dir(entries_.at(token).dir);
+    return FileWatch(this, token);
+}
+
 void FileWatcher::remove_watch(Token token) noexcept {
     auto it = entries_.find(token);
     if (it == entries_.end()) {
@@ -164,7 +177,9 @@ void FileWatcher::on_readable() {
     std::vector<Token> to_fire;
     for (const auto& [token, e] : entries_) {
         for (const auto& [dir, name] : changed) {
-            if (e.dir == dir && e.basename == name) {
+            // A file-specific entry matches its basename; a directory entry
+            // (empty basename) matches ANY file change in its dir.
+            if (e.dir == dir && (e.basename.empty() || e.basename == name)) {
                 to_fire.push_back(token);
                 break;
             }
diff --git a/packages/kernel/src/file_watcher.hpp b/packages/kernel/src/file_watcher.hpp
index fbd6d86..00806db 100644
--- a/packages/kernel/src/file_watcher.hpp
+++ b/packages/kernel/src/file_watcher.hpp
@@ -55,13 +55,21 @@ public:
     [[nodiscard]] auto add(const std::string& path, std::function<void()> on_change,
                            ExtensionId who) -> FileWatch;
 
+    // Watch the DIRECTORY `dir` for a change to ANY file within it (not a single
+    // basename). Used by the ui-substrate's asset hot-reload: a document and its
+    // `<link>`ed RCSS/assets live in the same dir, and editing ANY of them must
+    // reload — without parsing the document's link set. Same coalescing / error
+    // isolation / RAII as add(). `dir` should be an absolute directory path.
+    [[nodiscard]] auto add_dir(const std::string& dir, std::function<void()> on_change,
+                               ExtensionId who) -> FileWatch;
+
     // detail::WatchRegistry — stop the watch with this token (FileWatch dtor).
     void remove_watch(Token token) noexcept override;
 
 private:
     struct Entry {
         std::string dir;       // watched directory (absolute)
-        std::string basename;  // file within `dir` to match
+        std::string basename;  // file within `dir` to match; EMPTY = any file
         std::function<void()> on_change;
         ExtensionId who{};
     };
diff --git a/packages/kernel/src/ui_substrate.cpp b/packages/kernel/src/ui_substrate.cpp
index 8b7440e..1f289bd 100644
--- a/packages/kernel/src/ui_substrate.cpp
+++ b/packages/kernel/src/ui_substrate.cpp
@@ -809,14 +809,22 @@ Rml::ElementDocument* Substrate::Impl::load_document_first(Surface& s) {
             return nullptr;
         }
         // Dev-only: register an asset hot-reload watch on the kernel's SHARED
-        // file watcher (the same machinery Host::watch_file uses). The callback
-        // flags this surface for reload, applied (coalesced) at the next
-        // tick_all on the GL context. Only this DECISION is UNBOX_DEV-gated; the
-        // watcher infra itself is always available.
+        // file watcher (the same machinery Host::watch_file uses). We watch the
+        // document's whole DIRECTORY (add_dir), NOT just the .rml basename:
+        // RmlUi resolves `<link href="x.rcss">` and image srcs relative to the
+        // document dir, and the dock keeps its dock.rcss BESIDE dock.rml — so a
+        // change to ANY file in that dir (the .rml OR a linked .rcss/asset) must
+        // reload. (Watching only the .rml basename was the regression: editing
+        // dock.rcss fired no reload.) The callback flags this surface for reload,
+        // applied (coalesced) at the next tick_all on the GL context. Only this
+        // DECISION is UNBOX_DEV-gated; the watcher infra itself is always
+        // available (Host::watch_file is ungated).
         if (hot_reload_enabled() && watcher != nullptr) {
             Surface* sp = &s;
-            s.asset_watch = watcher->add(
-                s.resolved_path,
+            const std::string dir =
+                std::filesystem::path(s.resolved_path).parent_path().string();
+            s.asset_watch = watcher->add_dir(
+                dir,
                 [this, sp] {
                     if (std::find(pending_reloads.begin(), pending_reloads.end(), sp) ==
                         pending_reloads.end()) {
@@ -824,6 +832,9 @@ Rml::ElementDocument* Substrate::Impl::load_document_first(Surface& s) {
                     }
                 },
                 s.who);
+            wlr_log(WLR_INFO,
+                    "ui-substrate: dev hot-reload ON (inotify watching asset dir '%s')",
+                    dir.c_str());
         }
     } else {
         doc = s.context->LoadDocumentFromMemory(s.rml_inline);