Make the consent notice styleable and keep the back-to-top button reachable in 1.14.1

The back-to-top button was hidden as long as the consent question was open,
on every device - and on a phone the question tends to stay open. Instead
of `display:none` it now anchors itself 12px above the bar wherever the bar
covers its corner: below 800px for the centred card, at every width for the
full-width bar and the corner card. Browsers without anchor positioning keep
hiding it there. The bar renders before the button so it can be an anchor,
and the reserved bottom padding grows to 320px below 620px, where the bar
with its default text is up to 299px tall.

The notice itself gets a face. Settings → Einwilligung now carries layout
(card, bar, corner), shape (soft, round, square - one setting for the box and
its buttons), a heading and four colours, each as #hex or @palette key.
`Theme::cssColor()` resolves both, replacing the copy inside the back-to-top
code; `Consent::styles()` writes the values as `--kant-consent-*` into the
hashed style block. The base layout changes with it: an accent stripe and
shield icon, equal-width buttons, a disclosure with a chevron, underlined
legal links, a two-column bar on wide screens. Declining stays an outlined
button of the same size next to accepting. The archive and the consent page
carry the same variables - the archive had no palette at all until now.

In the editor, rows with an own value are labelled in orange rather than
bold with a dot; the device chips sit 6px apart with the focus ring inside
the gap.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/Content/Consent.php

@@ -172,8 +172,39 @@ final class Consent
             'decided' => null !== $decision,
             'decidedAt' => $decision['at'] ?? null,
             'text' => $settings['consentText'],
+            'title' => $settings['consentTitle'],
+            'layout' => $settings['consentLayout'],
             'privacyPath' => $settings['privacyPath'],
             'imprintPath' => $settings['imprintPath'],
         ];
     }
+
+    /**
+     * Die Gestaltung des Hinweises als CSS-Variablen für den Kopf der Seite.
+     *
+     * Das Stylesheet kennt die Standardwerte; hier stehen nur die Abweichungen, die jemand in den
+     * Einstellungen gewählt hat. Die Form bestimmt zwei Radien auf einmal - Fläche und Knöpfe
+     * gehören zusammen, und zwei Regler dafür wären zwei Regler, die man gegeneinander verstellt.
+     */
+    public function styles(array $theme): string
+    {
+        $settings = $this->settings->load();
+        if (!$settings['consentBanner']) {
+            return '';
+        }
+        [$box, $button] = match ($settings['consentShape']) {
+            'rund' => ['28px', '999px'],
+            'eckig' => ['0', '0'],
+            default => ['18px', '10px'],
+        };
+        $values = ['--kant-consent-radius:'.$box, '--kant-consent-button-radius:'.$button];
+        foreach (['consentColor' => '--kant-consent-bg', 'consentInk' => '--kant-consent-ink', 'consentAccent' => '--kant-consent-accent', 'consentAccentInk' => '--kant-consent-accent-ink'] as $field => $variable) {
+            $value = Theme::cssColor((string) $settings[$field], $theme);
+            if (null !== $value) {
+                $values[] = $variable.':'.$value;
+            }
+        }
+
+        return ':root{'.implode(';', $values).'}';
+    }
 }

src/Content/SiteSettings.php

@@ -75,6 +75,14 @@ final class SiteSettings
         'consentBanner' => false,
         'consentGroups' => ['external'],
         'consentText' => '',
+        // Sein Aussehen: Anordnung, Form, Farben, Überschrift. Leer heißt Theme-Standard.
+        'consentLayout' => 'karte',
+        'consentShape' => 'weich',
+        'consentTitle' => '',
+        'consentColor' => '',
+        'consentInk' => '',
+        'consentAccent' => '',
+        'consentAccentInk' => '',
         'privacyPath' => '',
         'imprintPath' => '',
     ];
@@ -303,6 +311,16 @@ final class SiteSettings
             array_map(static fn (mixed $group): string => (string) $group, (array) ($input['consentGroups'] ?? [])),
         ));
         $values['consentText'] = mb_substr(trim((string) ($input['consentText'] ?? '')), 0, 600);
+        $values['consentLayout'] = in_array($input['consentLayout'] ?? '', ['karte', 'leiste', 'ecke'], true) ? $input['consentLayout'] : 'karte';
+        $values['consentShape'] = in_array($input['consentShape'] ?? '', ['weich', 'rund', 'eckig'], true) ? $input['consentShape'] : 'weich';
+        $values['consentTitle'] = mb_substr(trim((string) ($input['consentTitle'] ?? '')), 0, 80);
+        foreach (['consentColor', 'consentInk', 'consentAccent', 'consentAccentInk'] as $feld) {
+            $farbe = trim((string) ($input[$feld] ?? ''));
+            if ('' !== $farbe && 1 !== preg_match(StyleSchema::COLOR, $farbe)) {
+                throw new InvalidPage('Die Farben des Einwilligungshinweises werden als #1a2b3c oder als @schlüssel aus der Palette angegeben.');
+            }
+            $values[$feld] = $farbe;
+        }
         foreach (['privacyPath', 'imprintPath'] as $key) {
             $path = trim(trim((string) ($input[$key] ?? '')), '/');
             if ('' !== $path && 1 !== preg_match('#^[a-z0-9]+(?:[-/][a-z0-9]+)*$#D', $path)) {

src/Content/Theme.php

@@ -269,6 +269,29 @@ final class Theme
     }
 
     /** The stylesheet every page carries: palette variables, font variables and base typography. */
+    /**
+     * Eine Farbe aus den Einstellungen als CSS-Wert: `@schlüssel` wird zur Palettenvariablen,
+     * ein Hexwert bleibt, und leer heißt "nicht gesetzt" - dann gilt der Standard des Stylesheets.
+     * Ein Schlüssel, den die Palette nicht kennt, wird ebenfalls zu null: lieber der Standard als
+     * eine Variable, die auf nichts zeigt.
+     */
+    public static function cssColor(string $value, array $theme): ?string
+    {
+        if ('' === $value) {
+            return null;
+        }
+        if (!str_starts_with($value, '@')) {
+            return $value;
+        }
+        foreach ($theme['colors'] as $color) {
+            if ($color['key'] === substr($value, 1)) {
+                return sprintf('var(--k-%s)', $color['key']);
+            }
+        }
+
+        return null;
+    }
+
     public function css(array $theme): string
     {
         $variables = [];