fix(promo-banner): center by default + admin alignment selector (#482)

The gallery promotional banner (#440) read as visually offset from
the gallery footer because:

  - Footer used `container text-center px-4` (full container width,
    centered text).
  - Promo block used `container py-4 sm:py-6` with an inner
    `max-w-3xl mx-auto` wrapper holding left-aligned text — a
    narrower column with left-aligned content sitting in the
    middle of the page.

Two issues compounded: the column was narrower than the footer AND
its text alignment differed. Reported by Rekoo-PS in #482 with a
screenshot showing the misalignment, with a request for an admin
alignment option.

Fix:

- Drop the inner max-w-3xl wrapper. Promo content now spans the
  same .container width as the footer, eliminating the
  narrower-column visual.
- Default text alignment changed from left → center to match the
  footer.
- New `branding_promo_alignment` setting ('left' | 'center' | 'right',
  default 'center'). Surfaced as a dropdown next to the existing
  Position dropdown on the BrandingPage. Live preview block on the
  BrandingPage mirrors the gallery render so admins see what
  guests will see.
- Also replaced the no-op `prose-sm` prose-modifier with a real
  `prose prose-sm` outer class so the existing `prose-a:text-accent`
  modifier actually takes effect (it didn't before — modifiers
  without an outer .prose are silently ignored by Tailwind
  Typography).

Migration 103 seeds the new setting at 'center' so existing
installs that have a promo banner today see the corrected
alignment immediately on next deploy.

i18n: en + de hand-translated; nl/pt/ru/fr machine-translated and
flagged for native review per project convention.

frontend/src/components/gallery/GalleryLayout.tsx

@@ -47,6 +47,9 @@ interface GalleryLayoutProps {
     youtube_url?: string;
     promo_markdown?: string;
     promo_position?: 'above_footer' | 'below_footer';
+    // Horizontal alignment for the promo content (#482). Defaults
+    // to 'center' so the banner aligns with the footer.
+    promo_alignment?: 'left' | 'center' | 'right';
   };
   showLogout?: boolean;
   onLogout?: () => void;
@@ -226,12 +229,36 @@ export const GalleryLayout: React.FC<GalleryLayoutProps> = ({
   })().trim();
   const promoPosition: 'above_footer' | 'below_footer' = brandingSettings?.promo_position === 'below_footer' ? 'below_footer' : 'above_footer';
 
+  // Promo alignment (#482). Defaults to 'center' to match the gallery
+  // footer's `text-center px-4` so the banner reads as part of the
+  // same composition as the footer beneath it. Admin can flip to
+  // 'left' or 'right' from Settings → Branding.
+  const promoAlignment: 'left' | 'center' | 'right' =
+    brandingSettings?.promo_alignment === 'left' ? 'left'
+      : brandingSettings?.promo_alignment === 'right' ? 'right'
+      : 'center';
+  const promoTextAlignClass =
+    promoAlignment === 'left' ? 'text-left'
+      : promoAlignment === 'right' ? 'text-right'
+      : 'text-center';
+
   const promoSlot = promoMarkdown ? (
     <div className="gallery-promo border-t border-surface bg-surface/50">
-      <div className="container py-4 sm:py-6">
-        <div className="max-w-3xl mx-auto text-sm text-theme">
-          <MarkdownContent source={promoMarkdown} className="prose-sm prose-a:text-accent" />
-        </div>
+      {/*
+       * Inner block uses .container (matches the footer's container
+       * width) + the alignment class. We deliberately drop the
+       * previous max-w-3xl wrapper — it created a narrower column
+       * that read as visually offset from the full-width footer
+       * (#482, reported by Rekoo-PS). The `prose` class is needed
+       * for the prose-a:text-accent modifier to actually take effect
+       * (modifiers without an outer .prose are no-ops in Tailwind
+       * Typography).
+       */}
+      <div className={`container py-4 sm:py-6 px-4 ${promoTextAlignClass}`}>
+        <MarkdownContent
+          source={promoMarkdown}
+          className={`prose prose-sm max-w-none mx-auto text-sm text-theme prose-a:text-accent ${promoTextAlignClass}`}
+        />
       </div>
     </div>
   ) : null;

frontend/src/components/gallery/GalleryView.tsx

@@ -253,6 +253,11 @@ export const GalleryView: React.FC<GalleryViewProps> = ({ slug, event }) => {
         youtube_url: settingsData.branding_youtube_url || '',
         promo_markdown: settingsData.branding_promo_markdown || '',
         promo_position: settingsData.branding_promo_position === 'below_footer' ? 'below_footer' : 'above_footer',
+        // Promo alignment (#482). Defaults to 'center' to match the
+        // gallery footer; see GalleryLayout.
+        promo_alignment: ['left', 'center', 'right'].includes(settingsData.branding_promo_alignment)
+          ? settingsData.branding_promo_alignment
+          : 'center',
       });
     }
   }, [settingsData]);

frontend/src/i18n/locales/de.json

@@ -1792,6 +1792,12 @@
       "sizeMedium": "Mittel (Standard)",
       "sizeLarge": "Groß",
       "sizeXLarge": "Sehr groß"
+    },
+    "promo": {
+      "alignment": "Ausrichtung",
+      "alignLeft": "Links",
+      "alignCenter": "Zentriert (Standard – wie der Footer)",
+      "alignRight": "Rechts"
     }
   },
   "admin": {

frontend/src/i18n/locales/en.json

@@ -1462,6 +1462,12 @@
       "sizeMedium": "Medium (default)",
       "sizeLarge": "Large",
       "sizeXLarge": "Extra large"
+    },
+    "promo": {
+      "alignment": "Alignment",
+      "alignLeft": "Left",
+      "alignCenter": "Center (default — matches footer)",
+      "alignRight": "Right"
     }
   },
   "admin": {

frontend/src/i18n/locales/fr.json

@@ -1400,6 +1400,12 @@
       "sizeMedium": "Moyenne (par défaut)",
       "sizeLarge": "Grande",
       "sizeXLarge": "Très grande"
+    },
+    "promo": {
+      "alignment": "Alignement",
+      "alignLeft": "À gauche",
+      "alignCenter": "Centré (par défaut — identique au pied de page)",
+      "alignRight": "À droite"
     }
   },
   "admin": {

frontend/src/i18n/locales/nl.json

@@ -1462,6 +1462,12 @@
       "sizeMedium": "Middel (standaard)",
       "sizeLarge": "Groot",
       "sizeXLarge": "Extra groot"
+    },
+    "promo": {
+      "alignment": "Uitlijning",
+      "alignLeft": "Links",
+      "alignCenter": "Gecentreerd (standaard — komt overeen met footer)",
+      "alignRight": "Rechts"
     }
   },
   "admin": {

frontend/src/i18n/locales/pt.json

@@ -1479,6 +1479,12 @@
       "sizeMedium": "Médio (padrão)",
       "sizeLarge": "Grande",
       "sizeXLarge": "Extra grande"
+    },
+    "promo": {
+      "alignment": "Alinhamento",
+      "alignLeft": "Esquerda",
+      "alignCenter": "Centro (padrão — igual ao rodapé)",
+      "alignRight": "Direita"
     }
   },
   "admin": {

frontend/src/i18n/locales/ru.json

@@ -1496,6 +1496,12 @@
       "sizeMedium": "Средний (по умолчанию)",
       "sizeLarge": "Большой",
       "sizeXLarge": "Очень большой"
+    },
+    "promo": {
+      "alignment": "Выравнивание",
+      "alignLeft": "По левому краю",
+      "alignCenter": "По центру (по умолчанию — как в подвале)",
+      "alignRight": "По правому краю"
     }
   },
   "admin": {

frontend/src/pages/admin/BrandingPage.tsx

@@ -43,6 +43,7 @@ export const BrandingPage: React.FC = () => {
     youtube_url: '',
     promo_markdown: '',
     promo_position: 'above_footer',
+    promo_alignment: 'center',
   });
 
   const [currentTheme, setCurrentTheme] = useState<ThemeConfig>(theme);
@@ -420,18 +421,36 @@ export const BrandingPage: React.FC = () => {
               {t('branding.promo.help', 'Markdown shown above or below the gallery footer (e.g. seasonal offer, print discount). Per-event overrides take priority.')}
             </p>
             <div className="space-y-3">
-              <div>
-                <label className="block text-sm font-medium text-neutral-700 dark:text-neutral-300 mb-2">
-                  {t('branding.promo.position', 'Position')}
-                </label>
-                <select
-                  value={brandingSettings.promo_position || 'above_footer'}
-                  onChange={(e) => handleBrandingChange('promo_position', e.target.value as 'above_footer' | 'below_footer')}
-                  className="w-full sm:w-64 px-3 py-2 border border-neutral-300 dark:border-neutral-600 bg-white dark:bg-neutral-800 text-neutral-900 dark:text-neutral-100 rounded-lg focus:ring-2 focus:ring-primary-500"
-                >
-                  <option value="above_footer">{t('branding.promo.aboveFooter', 'Above footer')}</option>
-                  <option value="below_footer">{t('branding.promo.belowFooter', 'Below footer')}</option>
-                </select>
+              <div className="flex flex-col sm:flex-row gap-3">
+                <div className="flex-1">
+                  <label className="block text-sm font-medium text-neutral-700 dark:text-neutral-300 mb-2">
+                    {t('branding.promo.position', 'Position')}
+                  </label>
+                  <select
+                    value={brandingSettings.promo_position || 'above_footer'}
+                    onChange={(e) => handleBrandingChange('promo_position', e.target.value as 'above_footer' | 'below_footer')}
+                    className="w-full px-3 py-2 border border-neutral-300 dark:border-neutral-600 bg-white dark:bg-neutral-800 text-neutral-900 dark:text-neutral-100 rounded-lg focus:ring-2 focus:ring-primary-500"
+                  >
+                    <option value="above_footer">{t('branding.promo.aboveFooter', 'Above footer')}</option>
+                    <option value="below_footer">{t('branding.promo.belowFooter', 'Below footer')}</option>
+                  </select>
+                </div>
+                {/* Horizontal alignment (#482). Defaults to center
+                    so the banner aligns with the gallery footer. */}
+                <div className="flex-1">
+                  <label className="block text-sm font-medium text-neutral-700 dark:text-neutral-300 mb-2">
+                    {t('branding.promo.alignment', 'Alignment')}
+                  </label>
+                  <select
+                    value={brandingSettings.promo_alignment || 'center'}
+                    onChange={(e) => handleBrandingChange('promo_alignment', e.target.value as 'left' | 'center' | 'right')}
+                    className="w-full px-3 py-2 border border-neutral-300 dark:border-neutral-600 bg-white dark:bg-neutral-800 text-neutral-900 dark:text-neutral-100 rounded-lg focus:ring-2 focus:ring-primary-500"
+                  >
+                    <option value="left">{t('branding.promo.alignLeft', 'Left')}</option>
+                    <option value="center">{t('branding.promo.alignCenter', 'Center (default — matches footer)')}</option>
+                    <option value="right">{t('branding.promo.alignRight', 'Right')}</option>
+                  </select>
+                </div>
               </div>
               <div>
                 <label className="block text-sm font-medium text-neutral-700 dark:text-neutral-300 mb-2">
@@ -453,9 +472,16 @@ export const BrandingPage: React.FC = () => {
                   <div className="text-xs uppercase tracking-wider text-neutral-500 dark:text-neutral-400 mb-2">
                     {t('branding.promo.preview', 'Preview')}
                   </div>
+                  {/* Preview mirrors the live gallery render — same
+                      alignment class so the admin sees what guests
+                      will see (#482). */}
                   <MarkdownContent
                     source={brandingSettings.promo_markdown}
-                    className="text-sm text-neutral-800 dark:text-neutral-200 prose-sm prose-a:text-primary-600 dark:prose-a:text-primary-400"
+                    className={`text-sm text-neutral-800 dark:text-neutral-200 prose prose-sm prose-a:text-primary-600 dark:prose-a:text-primary-400 ${
+                      brandingSettings.promo_alignment === 'left' ? 'text-left'
+                        : brandingSettings.promo_alignment === 'right' ? 'text-right'
+                        : 'text-center'
+                    }`}
                   />
                 </div>
               )}

frontend/src/services/publicSettings.service.ts

@@ -39,6 +39,9 @@ export interface PublicSettings {
   branding_youtube_url?: string;
   branding_promo_markdown?: string;
   branding_promo_position?: 'above_footer' | 'below_footer';
+  // Per-install promo banner alignment (#482). Defaults to 'center'
+  // so the banner aligns with the gallery footer's centering.
+  branding_promo_alignment?: 'left' | 'center' | 'right';
   theme_config: any;
   default_language: string;
   enable_analytics: boolean;

frontend/src/services/settings.service.ts

@@ -42,6 +42,9 @@ export interface BrandingSettings {
   youtube_url?: string;
   promo_markdown?: string;
   promo_position?: 'above_footer' | 'below_footer';
+  // Per-install promo banner alignment (#482). Defaults to center
+  // so the banner aligns with the gallery footer.
+  promo_alignment?: 'left' | 'center' | 'right';
 }
 
 export interface ThemeSettings {
@@ -336,7 +339,10 @@ export const settingsService = {
       twitter_url: rawSettings.branding_twitter_url || '',
       youtube_url: rawSettings.branding_youtube_url || '',
       promo_markdown: rawSettings.branding_promo_markdown || '',
-      promo_position: rawSettings.branding_promo_position === 'below_footer' ? 'below_footer' : 'above_footer'
+      promo_position: rawSettings.branding_promo_position === 'below_footer' ? 'below_footer' : 'above_footer',
+      promo_alignment: ['left', 'center', 'right'].includes(rawSettings.branding_promo_alignment)
+        ? rawSettings.branding_promo_alignment
+        : 'center'
     };
   },