feat: app icon button round

web/css/components/app-details-titlebar.css

@@ -43,22 +43,7 @@
     white-space: nowrap;
   }
 
-  .app-details-titlebar h1 i {
-    background: var(--app-background-color);
-    width: 35px;
-    height: 29px;
-    font-size: 15px; /* icon-font metric — intentional px */
-    border-radius: var(--app-border-radius);
-    display: inline-flex;
-    align-items: center;
-    justify-content: center;
-    color: var(--app-contrast);
-    border: 1px solid var(--app-border);
-    color: var(--app-muted-color);
-    box-shadow: rgba(0, 0, 0, 0.1) 0px 1px 2px;
-  }
-
-  .app-details-titlebar h1:has(i) {
+  .app-details-titlebar h1:has(.app-icon-button) {
     display: flex;
     align-items: center;
     gap: 7px;

web/css/components/app-icon-button.css

@@ -0,0 +1,34 @@
+@layer components {
+  /* Reusable round ghost icon button — transparent circle with subtle hover.
+     Used for back buttons, inline icon actions, etc. */
+  .app-icon-button {
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    width: 28px;
+    height: 28px;
+    padding: 0;
+    border: none;
+    border-radius: 50%;
+    background: transparent;
+    color: var(--app-muted-color);
+    font-size: var(--text-sm);
+    line-height: 1;
+    cursor: pointer;
+    text-decoration: none;
+    transition:
+      background-color var(--app-transition),
+      color var(--app-transition);
+  }
+
+  .app-icon-button:hover,
+  .app-icon-button:focus-visible {
+    background: color-mix(in srgb, var(--app-contrast) 8%, transparent);
+    color: var(--app-contrast);
+  }
+
+  .app-icon-button i {
+    font-size: 15px; /* icon-font metric — intentional px */
+    line-height: 1;
+  }
+}