diff --git a/cube.scad b/cube.scad
index 765a458..29fc82c 100644
--- a/cube.scad
+++ b/cube.scad
@@ -19,7 +19,13 @@ W = 115;          // width  (X)
 D = 115;          // depth  (Y)  — front face is -Y, back face is +Y
 H = 115;          // height (Z)
 wall = 2.0;
-split_z = 70;     // bottom shell height (top shell = H - split_z = 45)
+
+// Lid (top shell) height — half of v2's 45 mm. Bottom shell grows to fill the
+// rest of H. The front panel sits between two equal frames of bottom-shell
+// color: `lid_h` of frame above (= top shell) and `lid_h` of frame below
+// (= bottom-shell front-wall section under the panel).
+lid_h   = 22.5;
+split_z = H - lid_h;          // bottom shell height (= 92.5)
 
 // ---- snap lip (3-sided: left, right, back; no front) ----
 lip_h       = 6.0;
@@ -37,6 +43,7 @@ ledge_h     = 1.5;
 panel_thick   = 2.5;   // panel Y thickness
 panel_recess  = 1.0;   // panel front face recessed from cube front face by this
 slide_clear   = 0.3;   // sliding-fit clearance (per side)
+front_frame_h = lid_h; // bottom-shell front-wall height under the panel
 
 // ---- front channel rib parameters ----
 rib_x_extra   = 3.0;   // rib extends inward from inner wall face by this in X
@@ -53,12 +60,15 @@ back_ports = [
         18],                           // z above floor
 ];
 
-// front panel: data ports (panel-local coords; x=0 is panel left edge, z=0 is bottom)
+// front panel: data ports (panel-local coords; x=0 is panel left edge, z=0 is bottom).
+// Vertically centered: each port's z is `panel_h/2 - port_h/2`, with
+// panel_h derived below.
+function port_z(h) = (split_z - front_frame_h)/2 - h/2;
 panel_ports = [
-    ["hdmi_in",  14.0, 6.5, 20, 25],
-    ["hdmi_out", 14.0, 6.5, 39, 25],
-    ["usb_a",    13.0, 6.0, 58, 26],
-    ["usb_c",     9.0, 3.5, 76, 27.5],
+    ["hdmi_in",  14.0, 6.5, 20, port_z(6.5)],
+    ["hdmi_out", 14.0, 6.5, 39, port_z(6.5)],
+    ["usb_a",    13.0, 6.0, 58, port_z(6.0)],
+    ["usb_c",     9.0, 3.5, 76, port_z(3.5)],
 ];
 
 // ---- preview / explode ----
@@ -76,8 +86,8 @@ slot_x_min_L = wall + rib_x_extra - slot_x_depth;
 slot_x_max_L = wall + rib_x_extra + 0.1;            // breaks through inner face
 slot_y_min   = panel_recess - slide_clear/2;
 slot_y_max   = panel_recess + panel_thick + slide_clear/2;
-slot_z_min   = wall;
-slot_z_max   = split_z + 1;                          // extends above rib top
+slot_z_min   = front_frame_h;                       // slot bottom = panel bottom
+slot_z_max   = split_z + 1;                         // extends above rib top
 
 // Panel X extent — left edge at -X end of left slot (with clearance), mirrored
 panel_x_min  = slot_x_min_L + slide_clear;
@@ -86,7 +96,7 @@ panel_x_max  = W - slot_x_min_L - slide_clear;
 // Panel Y / Z extents
 panel_y_min  = panel_recess;
 panel_y_max  = panel_recess + panel_thick;
-panel_z_min  = wall;
+panel_z_min  = front_frame_h;    // panel sits on top of the bottom-shell front wall
 panel_z_max  = split_z;          // top of panel meets the top shell exactly
 
 // Snap positions (3 sides, no front)
@@ -155,11 +165,13 @@ module lip_ring_3sided() {
 
 // Front-left channel rib: block at the inner front-left corner with a vertical
 // slot cut through its inner face. Panel's left edge slides down into the slot.
+// Rib extends the full height of the bottom-shell side walls; the slot only
+// exists above the front-wall section (z >= front_frame_h).
 module left_front_rib() {
     difference() {
         translate([wall, 0, wall])
             cube([rib_x_extra, rib_y, split_z - wall]);
-        translate([slot_x_min_L, slot_y_min, slot_z_min - 0.01])
+        translate([slot_x_min_L, slot_y_min, slot_z_min])
             cube([slot_x_max_L - slot_x_min_L,
                   slot_y_max - slot_y_min,
                   slot_z_max - slot_z_min + 0.01]);
@@ -186,10 +198,13 @@ module back_port_cuts() {
 module bottom_shell() {
     difference() {
         union() {
-            // 3 outer walls (left, right, back)
-            translate([0, 0, wall])             cube([wall, D, split_z - wall]);
-            translate([W - wall, 0, wall])      cube([wall, D, split_z - wall]);
-            translate([wall, D - wall, wall])   cube([W - 2*wall, wall, split_z - wall]);
+            // 4 outer walls — left/right/back full height, front partial (frame under panel)
+            translate([0, 0, wall])           cube([wall, D, split_z - wall]);
+            translate([W - wall, 0, wall])    cube([wall, D, split_z - wall]);
+            translate([wall, D - wall, wall]) cube([W - 2*wall, wall, split_z - wall]);
+            // front frame wall — only up to panel bottom
+            translate([wall, 0, wall])
+                cube([W - 2*wall, wall, front_frame_h - wall]);
 
             // floor
             cube([W, D, wall]);