feat(wizard): modernize the first-run wizard to the current design language

The first-run wizard predated the modal-unification pass and was the least
on-brand surface left — a flat Surface() slab with a 3-card masonry whose
inactive steps were heavily greyed (alpha 165) and whose focused card used a
hard 2px border + a hand-drawn offset shadow.

Keeping the working phase logic and the "see all steps at once" masonry:
- Reveal the skin backdrop: the app already paints its marble / gradient /
  acrylic backdrop behind every window (drawWindowBackdrop), so drop the opaque
  Surface() fill (transparent WindowBg) and lay a gentle theme-tinted scrim over
  it. The wizard now sits on the same rich backdrop as the rest of the app.
- Focused card lifts with the shared DrawCardDropShadow (the uniform, non-
  clipping card shadow) instead of a bespoke offset rect, and a softer 1.5px
  accent ring.
- Inactive cards get lighter veils (upcoming 165->115, completed 110->70) so
  they read as "waiting" / "done" rather than disabled-grey.
- Warmer header: a one-line subtitle under the welcome title.

Verified on the headless sweep across all four phases (appearance / bootstrap /
encrypt / pin) on marble + obsidian at 1.0 and 1.5x DPI — backdrop shows, cards
float cleanly, geometry scales, nothing clipped.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/app_wizard.cpp

@@ -121,16 +121,21 @@ void App::renderFirstRunWizard() {
                              ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoScrollWithMouse;
 
     ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0, 0));
+    ImGui::PushStyleColor(ImGuiCol_WindowBg, ImVec4(0, 0, 0, 0));   // reveal the skin backdrop behind
     ImGui::Begin("##FirstRunWizard", nullptr, flags);
+    ImGui::PopStyleColor();
     ImGui::PopStyleVar();
 
     ImDrawList* dl = ImGui::GetWindowDrawList();
     ImVec2 winPos = ImGui::GetWindowPos();
     ImVec2 winSize = ImGui::GetWindowSize();
 
-    // Background fill
-    ImU32 bgCol = ui::material::Surface();
-    dl->AddRectFilled(winPos, ImVec2(winPos.x + winSize.x, winPos.y + winSize.y), bgCol);
+    // The app's skin backdrop (marble / gradient / acrylic) is already painted behind every window by
+    // drawWindowBackdrop(); reveal it here instead of a flat Surface() slab, under a gentle theme-tinted
+    // scrim so the wizard cards and text keep their contrast on busy skins.
+    ImU32 bgCol = ui::material::Surface();   // still used by the completed / not-reached card overlays
+    dl->AddRectFilled(winPos, ImVec2(winPos.x + winSize.x, winPos.y + winSize.y),
+                      ui::material::WithAlpha(ui::material::Background(), 120));
 
     // --- Determine which of the 3 masonry sections is focused ---
     // 0 = Appearance, 1 = Bootstrap, 2 = Encrypt + PIN
@@ -188,7 +193,14 @@ void App::renderFirstRunWizard() {
         ImVec2 wts = titleFont->CalcTextSizeA(titleFont->LegacySize, FLT_MAX, 0, welcomeTitle);
         dl->AddText(titleFont, titleFont->LegacySize,
                     ImVec2(winPos.x + (winSize.x - wts.x) * 0.5f, headerCy), textCol, welcomeTitle);
-        headerCy += wts.y + 16.0f * dp;
+        headerCy += wts.y + 6.0f * dp;
+
+        // Warmer, less-sparse header: a one-line subtitle under the welcome (dimmed body).
+        const char* welcomeSub = "A few quick choices and your full node is ready.";
+        ImVec2 sts = bodyFont->CalcTextSizeA(bodyFont->LegacySize, FLT_MAX, 0, welcomeSub);
+        dl->AddText(bodyFont, bodyFont->LegacySize,
+                    ImVec2(winPos.x + (winSize.x - sts.x) * 0.5f, headerCy), dimCol, welcomeSub);
+        headerCy += sts.y + 16.0f * dp;
     }
 
     // --- Masonry: 2 columns ---
@@ -223,11 +235,8 @@ void App::renderFirstRunWizard() {
         // Background (channel 0)
         dl->ChannelsSetCurrent(0);
         if (state == 1) {
-            // Focused card: subtle drop shadow
-            float shadowOff = 3.0f * dp;
-            dl->AddRectFilled(
-                ImVec2(cMin.x + shadowOff, cMin.y + shadowOff), ImVec2(cMax.x + shadowOff, cMax.y + shadowOff),
-                IM_COL32(0, 0, 0, 35), cardRound);
+            // Focused card lifts off the backdrop with the app's uniform card shadow (not a hard offset).
+            ui::material::DrawCardDropShadow(dl, cMin, cMax, cardRound);
         }
         // Use DrawGlassPanel for proper acrylic/opacity/noise/theme effects
         ui::material::GlassPanelSpec glass;
@@ -237,14 +246,14 @@ void App::renderFirstRunWizard() {
         // Overlays & borders (channel 2)
         dl->ChannelsSetCurrent(2);
         if (state == 1) {
-            // Focused: accent border
-            dl->AddRect(cMin, cMax, ui::material::Primary(), cardRound, 0, 2.0f * dp);
+            // Focused: soft accent ring
+            dl->AddRect(cMin, cMax, ui::material::Primary(), cardRound, 0, 1.5f * dp);
         } else if (state == 2) {
-            // Completed: dim overlay (preserves color)
-            dl->AddRectFilled(cMin, cMax, (bgCol & 0x00FFFFFF) | IM_COL32(0, 0, 0, 110), cardRound);
+            // Completed: a light veil — reads as "done", not disabled.
+            dl->AddRectFilled(cMin, cMax, (bgCol & 0x00FFFFFF) | IM_COL32(0, 0, 0, 70), cardRound);
         } else {
-            // Not reached: heavy overlay (creates greyscale look)
-            dl->AddRectFilled(cMin, cMax, (bgCol & 0x00FFFFFF) | IM_COL32(0, 0, 0, 165), cardRound);
+            // Upcoming: a gentle veil — reads as "waiting", not greyed-out.
+            dl->AddRectFilled(cMin, cMax, (bgCol & 0x00FFFFFF) | IM_COL32(0, 0, 0, 115), cardRound);
         }
 
         dl->ChannelsSetCurrent(1);