fix: titlebar button rendering — proper colors and bevel

- Background: matches titlebar background (sampled)
- Foreground: uses title text color (the color parameter)
- Pressed state: swaps fg/bg (inverted colors)
- Border: raised bevel when normal, sunken when pushed
- Icon pixels rendered in fg color (not raw XPM colors)

src/backend/wayland/wl_backend.c

@@ -7581,7 +7581,7 @@ static void wl_noop_frame_update_texture(struct WFrameWindow *fwin) { (void)fwin
 static void wl_frame_paint_button(WCoreWindow *button, WTexture *texture,
     unsigned long color, WPixmap *image, int pushed)
 {
-    (void)texture; (void)color; (void)image;
+    (void)texture; (void)image;
     WFrameWindow *fwin = (WFrameWindow *)button->descriptor.parent;
     if (!fwin || !fwin->core)
         return;
@@ -7609,11 +7609,10 @@ static void wl_frame_paint_button(WCoreWindow *button, WTexture *texture,
     if (!icon)
         return;
 
-    /* Clear button buffer with titlebar background */
+    /* Get titlebar background color */
     struct wl_frame_buf *tb_fb = fwin->titlebar ? frame_buf_find(fwin->titlebar->window) : NULL;
     uint32_t bg_pixel = 0xFF333333;
     if (tb_fb && tb_fb->image) {
-        /* Sample background color from titlebar at button position */
         uint32_t *tb_data = pixman_image_get_data(tb_fb->image);
         int tb_stride = pixman_image_get_stride(tb_fb->image) / 4;
         int sample_y = btn_fb->rel_y + bh / 2;
@@ -7622,13 +7621,28 @@ static void wl_frame_paint_button(WCoreWindow *button, WTexture *texture,
             sample_x >= 0 && sample_x < tb_fb->width)
             bg_pixel = tb_data[sample_y * tb_stride + sample_x];
     }
+
+    /* Foreground = title text color; when pushed, swap fg/bg */
+    uint32_t fg_pixel = 0xFF000000 | ((color >> 16 & 0xFF) << 16) |
+                        ((color >> 8 & 0xFF) << 8) | (color & 0xFF);
+    uint32_t fill_bg = pushed ? fg_pixel : bg_pixel;
+    uint32_t fill_fg = pushed ? bg_pixel : fg_pixel;
+
     uint32_t *dst = pixman_image_get_data(btn_fb->image);
     int dst_stride = pixman_image_get_stride(btn_fb->image) / 4;
+
+    /* Fill background */
     for (int y = 0; y < bh; y++)
         for (int x = 0; x < bw; x++)
-            dst[y * dst_stride + x] = bg_pixel;
+            dst[y * dst_stride + x] = fill_bg;
 
-    /* Blit icon centered in button area */
+    /* Draw border bevel (raised when normal, sunken when pushed) */
+    uint32_t hi = pushed ? 0xFF222222 : 0xFFDDDDDD;
+    uint32_t lo = pushed ? 0xFFDDDDDD : 0xFF222222;
+    for (int x = 0; x < bw; x++) { dst[x] = hi; dst[(bh-1) * dst_stride + x] = lo; }
+    for (int y = 0; y < bh; y++) { dst[y * dst_stride] = hi; dst[y * dst_stride + bw - 1] = lo; }
+
+    /* Blit icon centered, using fill_fg color for opaque pixels */
     int ix = (bw - icon->width) / 2 + (pushed ? 1 : 0);
     int iy = (bh - icon->height) / 2 + (pushed ? 1 : 0);
 
@@ -7639,19 +7653,13 @@ static void wl_frame_paint_button(WCoreWindow *button, WTexture *texture,
         for (int x = 0; x < icon->width; x++) {
             int dx = ix + x;
             if (dx < 0 || dx >= bw) continue;
-            unsigned char r, g, b, a;
+            unsigned char a;
-            if (icon->format == RRGBAFormat) {
+            if (icon->format == RRGBAFormat)
-                int off = (y * icon->width + x) * 4;
+                a = icon->data[(y * icon->width + x) * 4 + 3];
-                r = icon->data[off]; g = icon->data[off+1];
+            else
-                b = icon->data[off+2]; a = icon->data[off+3];
+                a = 255;
-            } else {
-                int off = (y * icon->width + x) * 3;
-                r = icon->data[off]; g = icon->data[off+1];
-                b = icon->data[off+2]; a = 255;
-            }
             if (a == 0) continue;
-            dst_row[dx] = ((uint32_t)a << 24) | ((uint32_t)r << 16) |
+            dst_row[dx] = fill_fg;
-                          ((uint32_t)g << 8) | (uint32_t)b;
         }
     }