studio: make the start screen follow the theme

The welcome screen (title, Open button, My Environments and Recent lists)
hardcoded dark greys for its backdrop, cards and muted text, so it ignored
the theme system and looked wrong on light themes especially. Now it draws
from the theme tokens: the backdrop is the theme's base background and the
cards sit a step lighter on it (kPanel, hovering to kWidgetHover with a blue
edge), the empty-state text is kDim, and the "file missing" rows read as a
subdued grey chip on any theme.

The kind chip (E / H / M) is now a solid saturated tile with a white initial
instead of a faint tint, so it stays legible and distinct in light and dark.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

studio/studio.cpp

@@ -1853,33 +1853,36 @@ struct Studio {
         ImGui::SetCursorScreenPos(a);
         const bool clicked = ImGui::InvisibleButton(id, ImVec2(w, h));
         const bool hov = ImGui::IsItemHovered(), held = ImGui::IsItemActive();
-        dl->AddRectFilled(a, b, col(held ? 0x33363c : hov ? 0x34373d : 0x2a2c30), 8 * scale);
-        dl->AddRect(a, b, col(hov ? kBlue : kLine, hov ? 0.85f : 0.6f), 8 * scale, 0, 1.0f);
-        // The tile: green for a Frame environment, blue for a Meta home, violet for models, grey when a file is gone.
+        const float round = 9 * scale;
+        dl->AddRectFilled(a, b, col(held ? kWidgetActive : hov ? kWidgetHover : kPanel), round);
+        dl->AddRect(a, b, col(hov ? kBlue : kLine, hov ? 0.9f : 1.0f), round, 0, (hov ? 1.5f : 1.0f) * scale);
+        // The tile: a solid chip with the kind's initial \u2014 green for a Frame environment, blue for a Meta home, violet
+        // for models, grey when a file is gone. Fixed hues so the chip reads on any theme (light and dark alike).
         const bool missing = info.kind.find("missing") != std::string::npos;
         const bool env = info.kind.rfind("Frame environment", 0) == 0, models = info.kind.rfind("Models", 0) == 0;
-        const uint32_t tint = missing ? 0x6b6f76 : env ? 0x3f9a5c : models ? 0x8a63d2 : 0x3f7bd6;
+        const uint32_t tint = env ? 0x3f9a5c : models ? 0x8a63d2 : 0x3f7bd6;
         const char* letter = env ? "E" : models ? "M" : "H";
         const float t = h - 16 * scale;
-        const ImVec2 t0(a.x + 8 * scale, a.y + 8 * scale), t1(t0.x + t, t0.y + t);
-        dl->AddRectFilled(t0, t1, col(tint, 0.22f), 6 * scale);
+        const ImVec2 t0(a.x + 10 * scale, a.y + 8 * scale), t1(t0.x + t, t0.y + t);
+        dl->AddRectFilled(t0, t1, missing ? col(kDim, 0.22f) : col(tint, 0.95f), 7 * scale);
         ImFont* bf = fontOr(g_fontBold);
         const ImVec2 ls = bf->CalcTextSizeA(bf->FontSize, FLT_MAX, 0, letter);
-        dl->AddText(bf, bf->FontSize, ImVec2((t0.x + t1.x - ls.x) * 0.5f, (t0.y + t1.y - ls.y) * 0.5f), col(tint == 0x6b6f76 ? kDim : 0xffffff, 0.9f), letter);
-        const float tx = t1.x + 12 * scale, lh = ImGui::GetTextLineHeight();
+        dl->AddText(bf, bf->FontSize, ImVec2((t0.x + t1.x - ls.x) * 0.5f, (t0.y + t1.y - ls.y) * 0.5f), missing ? col(kText, 0.45f) : col(0xffffff, 0.95f), letter);
+        const float tx = t1.x + 14 * scale, lh = ImGui::GetTextLineHeight();
         const float ty = a.y + (h - 2 * lh - 2 * scale) * 0.5f;
         dl->PushClipRect(a, ImVec2(b.x - 28 * scale, b.y), true);
         dl->AddText(ImVec2(tx, ty), col(missing ? kDim : kText), info.title.c_str());
         dl->AddText(ImVec2(tx, ty + lh + 2 * scale), col(kDim), info.kind.c_str());
         dl->PopClipRect();
-        if (hov) dl->AddText(ImVec2(b.x - 22 * scale, a.y + (h - lh) * 0.5f), col(kDim), "\u203a");
+        if (hov) dl->AddText(ImVec2(b.x - 22 * scale, a.y + (h - lh) * 0.5f), col(kBlue), "\u203a");
         return clicked;
     }
 
     void startScreen() {
-        // A quieter backdrop than the 3D view's grey, so the cards read as the screen's content.
+        // A quieter backdrop than the 3D view's grey, so the cards read as the screen's content (themed: the base
+        // background, with the cards a step lighter on top of it).
         ImDrawList* dl = ImGui::GetWindowDrawList();
-        dl->AddRectFilled(viewPos, ImVec2(viewPos.x + viewSize.x, viewPos.y + viewSize.y), col(0x25272b));
+        dl->AddRectFilled(viewPos, ImVec2(viewPos.x + viewSize.x, viewPos.y + viewSize.y), col(kBar));
         const float w = std::min(viewSize.x - 80 * scale, 720 * scale), x0 = viewPos.x + (viewSize.x - w) * 0.5f;
         float y = viewPos.y + std::max(36 * scale, viewSize.y * 0.10f);
         ImFont* tf = fontOr(g_fontTitle);
@@ -1918,7 +1921,7 @@ struct Studio {
             static auto listed = std::chrono::steady_clock::time_point();
             if (std::chrono::steady_clock::now() - listed > std::chrono::seconds(2)) { mine = libraryEnvs(); listed = std::chrono::steady_clock::now(); }
             if (mine.empty()) {
-                dl->AddText(ImVec2(x0, y), col(0x6b6f76), "Nothing yet. Open a home, make it yours, and Save (Ctrl+S): it's kept here.");
+                dl->AddText(ImVec2(x0, y), col(kDim), "Nothing yet. Open a home, make it yours, and Save (Ctrl+S): it's kept here.");
                 y += ImGui::GetTextLineHeight() + 22 * scale;
             }
             for (size_t r = 0; r < mine.size() && r < 6; ++r) {
@@ -1936,7 +1939,7 @@ struct Studio {
         listTitle("RECENT");
         y += ImGui::GetTextLineHeight() + 10 * scale;
         if (recent.empty()) {
-            dl->AddText(ImVec2(x0, y), col(0x6b6f76), "Nothing yet. Homes and environments you open show up here.");
+            dl->AddText(ImVec2(x0, y), col(kDim), "Nothing yet. Homes and environments you open show up here.");
             return;
         }
         for (size_t r = 0; r < recent.size(); ++r) {