Add resizable compact folder sidebar

server/public/styles.css

@@ -313,7 +313,7 @@
 }
 
 .u-nav .explorer-layout.with-tree {
-  grid-template-columns: clamp(180px, 25%, 250px) minmax(0, 1fr);
+  grid-template-columns: clamp(150px, var(--tree-width, 220px), 55%) 6px minmax(0, 1fr);
 }
 
 .u-nav .explorer-content {
@@ -331,6 +331,32 @@
   min-width: 0;
 }
 
+.u-nav .tree-resizer {
+  background: var(--surface);
+  border-left: 1px solid transparent;
+  border-right: 1px solid var(--line);
+  cursor: ew-resize;
+  min-height: 0;
+  position: relative;
+  touch-action: none;
+  width: 6px;
+  z-index: 3;
+}
+
+.u-nav .tree-resizer::after {
+  background: transparent;
+  border-radius: 999px;
+  content: "";
+  inset: 8px 1px;
+  position: absolute;
+  transition: background-color 140ms ease;
+}
+
+.u-nav .tree-resizer:hover::after,
+.u-nav .tree-resizer.active::after {
+  background: var(--accent);
+}
+
 .u-nav .tree-heading {
   align-items: center;
   border-bottom: 1px solid var(--line);
@@ -398,12 +424,17 @@
   color: inherit;
   display: flex;
   flex: 1;
-  gap: 7px;
-  justify-content: flex-start;
+  gap: 5px !important;
+  justify-content: flex-start !important;
   min-width: 0;
   overflow: hidden;
   padding: 0 5px 0 2px;
-  text-align: left;
+  text-align: left !important;
+}
+
+.u-nav .tree-label > * {
+  margin-left: 0 !important;
+  margin-right: 0 !important;
 }
 
 .u-nav .tree-label:hover,