diff --git a/app/Models/DeviceModel.php b/app/Models/DeviceModel.php
index 7142829..bdc4b98 100644
--- a/app/Models/DeviceModel.php
+++ b/app/Models/DeviceModel.php
@@ -11,6 +11,7 @@ use Illuminate\Database\Eloquent\Relations\BelongsTo;
 
 /**
  * @property-read array<string, string> $css_variables
+ * @property-read string|null $css_name
  * @property-read DevicePalette|null $palette
  */
 final class DeviceModel extends Model
@@ -74,6 +75,19 @@ final class DeviceModel extends Model
         return null;
     }
 
+    /**
+     * Returns css_name for v2 (per-device sizing); for v1 returns 'og' to preserve legacy single-variant behaviour.
+     *
+     * @return Attribute<string|null, string|null>
+     */
+    protected function cssName(): Attribute
+    {
+        /** @var Attribute<string|null, string|null> */
+        return Attribute::get(
+            fn (mixed $value): ?string => config('app.puppeteer_window_size_strategy') === 'v2' ? ($value !== null ? (string) $value : null) : 'og'
+        );
+    }
+
     public function palette(): BelongsTo
     {
         return $this->belongsTo(DevicePalette::class, 'palette_id');
diff --git a/app/Models/Plugin.php b/app/Models/Plugin.php
index 31a08ad..3f84bc5 100644
--- a/app/Models/Plugin.php
+++ b/app/Models/Plugin.php
@@ -738,8 +738,8 @@ class Plugin extends Model
             }
         }
 
-        // Append " (Copy)" to the name
-        $attributes['name'] = $this->name.' (Copy)';
+        // Append "_copy" to the name
+        $attributes['name'] = $this->name.'_copy';
 
         // Set user_id - use provided userId or fall back to original plugin's user_id
         $attributes['user_id'] = $userId ?? $this->user_id;
diff --git a/tests/Unit/Models/DeviceModelTest.php b/tests/Unit/Models/DeviceModelTest.php
index 8c2b6e9..f2ef29d 100644
--- a/tests/Unit/Models/DeviceModelTest.php
+++ b/tests/Unit/Models/DeviceModelTest.php
@@ -3,6 +3,7 @@
 declare(strict_types=1);
 
 use App\Models\DeviceModel;
+use Illuminate\Support\Facades\Config;
 
 test('device model has required attributes', function (): void {
     $deviceModel = DeviceModel::factory()->create([
@@ -117,3 +118,27 @@ test('device model factory creates valid data', function (): void {
     expect($deviceModel->offset_x)->toBeInt();
     expect($deviceModel->offset_y)->toBeInt();
 });
+
+test('css_name returns og when puppeteer_window_size_strategy is v1', function (): void {
+    Config::set('app.puppeteer_window_size_strategy', 'v1');
+
+    $deviceModel = DeviceModel::factory()->create(['css_name' => 'my_device']);
+
+    expect($deviceModel->css_name)->toBe('og');
+});
+
+test('css_name returns db value when puppeteer_window_size_strategy is v2', function (): void {
+    Config::set('app.puppeteer_window_size_strategy', 'v2');
+
+    $deviceModel = DeviceModel::factory()->create(['css_name' => 'my_device']);
+
+    expect($deviceModel->css_name)->toBe('my_device');
+});
+
+test('css_name returns null when puppeteer_window_size_strategy is v2 and db value is null', function (): void {
+    Config::set('app.puppeteer_window_size_strategy', 'v2');
+
+    $deviceModel = DeviceModel::factory()->create(['css_name' => null]);
+
+    expect($deviceModel->css_name)->toBeNull();
+});
diff --git a/tests/Unit/Models/PluginTest.php b/tests/Unit/Models/PluginTest.php
index 82813d9..1e2cda2 100644
--- a/tests/Unit/Models/PluginTest.php
+++ b/tests/Unit/Models/PluginTest.php
@@ -824,7 +824,7 @@ test('plugin duplicate copies all attributes except id and uuid', function (): v
 
     expect($duplicate->id)->not->toBe($original->id)
         ->and($duplicate->uuid)->not->toBe($original->uuid)
-        ->and($duplicate->name)->toBe('Original Plugin (Copy)')
+        ->and($duplicate->name)->toBe('Original Plugin_copy')
         ->and($duplicate->user_id)->toBe($original->user_id)
         ->and($duplicate->data_stale_minutes)->toBe($original->data_stale_minutes)
         ->and($duplicate->data_strategy)->toBe($original->data_strategy)
@@ -859,7 +859,7 @@ test('plugin duplicate sets trmnlp_id to null to avoid unique constraint violati
 
     expect($duplicate->trmnlp_id)->toBeNull()
         ->and($original->trmnlp_id)->toBe('test-trmnlp-id-123')
-        ->and($duplicate->name)->toBe('Plugin with trmnlp_id (Copy)');
+        ->and($duplicate->name)->toBe('Plugin with trmnlp_id_copy');
 });
 
 test('plugin duplicate copies render_markup_view file content to render_markup', function (): void {
@@ -890,7 +890,7 @@ test('plugin duplicate copies render_markup_view file content to render_markup',
         expect($duplicate->render_markup)->toBe($testContent)
             ->and($duplicate->markup_language)->toBe('blade')
             ->and($duplicate->render_markup_view)->toBeNull()
-            ->and($duplicate->name)->toBe('View Plugin (Copy)');
+            ->and($duplicate->name)->toBe('View Plugin_copy');
     } finally {
         // Clean up test file
         if (file_exists($testViewPath)) {
@@ -949,7 +949,7 @@ test('plugin duplicate handles missing view file gracefully', function (): void
     $duplicate = $original->duplicate();
 
     expect($duplicate->render_markup_view)->toBeNull()
-        ->and($duplicate->name)->toBe('Missing View Plugin (Copy)');
+        ->and($duplicate->name)->toBe('Missing View Plugin_copy');
 });
 
 test('plugin duplicate uses provided user_id', function (): void {