diff --git a/css/form.css b/css/form.css
new file mode 100644
index 0000000..4a46ff9
--- /dev/null
+++ b/css/form.css
@@ -0,0 +1,175 @@
+/* Formular-Modal zum Anlegen/Bearbeiten eines Ausflugsziels (Phase 3):
+   Vollbild auf Mobile, zentriertes Panel ab 1024px (siehe Breakpoint in
+   css/responsive.css). Struktur wird von js/ui/form.js in
+   #place-form-modal eingehängt. Grundgerüst analog zu css/detail.css. */
+
+.place-form-modal {
+  position: fixed;
+  inset: 0;
+  z-index: 2100;
+}
+
+.place-form-modal[hidden] {
+  display: none;
+}
+
+.place-form-modal__backdrop {
+  position: absolute;
+  inset: 0;
+  background: rgba(0, 0, 0, 0.55);
+}
+
+.place-form-modal__panel {
+  position: relative;
+  display: flex;
+  flex-direction: column;
+  width: 100%;
+  height: 100%;
+  background: var(--color-surface);
+  overflow-y: auto;
+}
+
+.place-form-modal__close {
+  position: absolute;
+  top: var(--space-sm);
+  right: var(--space-sm);
+  z-index: 1;
+  width: 36px;
+  height: 36px;
+  border: none;
+  border-radius: 50%;
+  background: rgba(0, 0, 0, 0.55);
+  color: #fff;
+  font-size: 1rem;
+  line-height: 1;
+  cursor: pointer;
+}
+
+.place-form__title {
+  padding: var(--space-lg) var(--space-lg) 0;
+  font-size: 1.3rem;
+  font-weight: 700;
+}
+
+.place-form {
+  padding: var(--space-md) var(--space-lg) var(--space-lg);
+  display: flex;
+  flex-direction: column;
+  gap: var(--space-lg);
+}
+
+.place-form__section {
+  display: flex;
+  flex-direction: column;
+  gap: var(--space-md);
+  border: none;
+  border-top: 1px solid var(--color-border);
+  padding: var(--space-md) 0 0;
+  margin: 0;
+}
+
+.place-form__section:first-of-type {
+  border-top: none;
+  padding-top: 0;
+}
+
+.place-form__section-label {
+  padding: 0;
+  font-size: 0.85rem;
+  font-weight: 700;
+  text-transform: uppercase;
+  letter-spacing: 0.02em;
+  color: var(--color-text-muted);
+}
+
+.place-form__row {
+  display: flex;
+  flex-wrap: wrap;
+  gap: var(--space-md);
+}
+
+.place-form__row .form-field {
+  flex: 1 1 160px;
+}
+
+.form-field {
+  display: flex;
+  flex-direction: column;
+  gap: var(--space-xs);
+}
+
+.form-field__label {
+  font-size: 0.85rem;
+  font-weight: 600;
+}
+
+.form-field__required {
+  color: var(--color-danger);
+}
+
+.form-field input,
+.form-field select,
+.form-field textarea {
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-sm);
+  padding: var(--space-sm);
+  font: inherit;
+  background: var(--color-surface);
+  color: var(--color-text);
+  width: 100%;
+}
+
+.form-field textarea {
+  resize: vertical;
+  min-height: 80px;
+}
+
+.form-field input[aria-invalid='true'],
+.form-field select[aria-invalid='true'],
+.form-field textarea[aria-invalid='true'] {
+  border-color: var(--color-danger);
+}
+
+.form-field__error {
+  color: var(--color-danger);
+  font-size: 0.8rem;
+}
+
+.form-field__error[hidden] {
+  display: none;
+}
+
+.place-form__checkbox-group {
+  display: flex;
+  flex-wrap: wrap;
+  gap: var(--space-md);
+}
+
+.form-checkbox {
+  display: flex;
+  align-items: center;
+  gap: var(--space-xs);
+  font-size: 0.9rem;
+  cursor: pointer;
+}
+
+.place-form__actions {
+  display: flex;
+  flex-wrap: wrap;
+  gap: var(--space-sm);
+  padding-top: var(--space-md);
+  border-top: 1px solid var(--color-border);
+}
+
+@media (min-width: 1024px) {
+  .place-form-modal__panel {
+    position: absolute;
+    top: 50%;
+    left: 50%;
+    transform: translate(-50%, -50%);
+    width: min(720px, 90vw);
+    height: min(90vh, 960px);
+    border-radius: var(--radius-md);
+    box-shadow: var(--shadow-card);
+  }
+}
diff --git a/css/layout.css b/css/layout.css
index 844c451..9b65d7d 100644
--- a/css/layout.css
+++ b/css/layout.css
@@ -39,6 +39,9 @@
   top: var(--space-sm);
   left: var(--space-sm);
   z-index: 1000;
+  display: flex;
+  flex-wrap: wrap;
+  gap: var(--space-sm);
 }
 
 .map-panel__map {
diff --git a/index.html b/index.html
index 9579a88..b9e6d27 100644
--- a/index.html
+++ b/index.html
@@ -14,6 +14,7 @@
   <link rel="stylesheet" href="css/layout.css" />
   <link rel="stylesheet" href="css/components.css" />
   <link rel="stylesheet" href="css/detail.css" />
+  <link rel="stylesheet" href="css/form.css" />
   <link rel="stylesheet" href="css/responsive.css" />
 </head>
 <body>
@@ -30,6 +31,9 @@
         <button id="locate-btn" type="button" class="btn btn--secondary">
           Meinen Standort verwenden
         </button>
+        <button id="add-place-btn" type="button" class="btn btn--primary">
+          + Neues Ausflugsziel hinzufügen
+        </button>
       </div>
       <div id="map" class="map-panel__map">
         <p class="map-panel__loading">Karte wird geladen…</p>
@@ -45,6 +49,7 @@
   </main>
 
   <div id="detail-modal" class="detail-modal" hidden></div>
+  <div id="place-form-modal" class="place-form-modal" hidden></div>
 
   <script src="vendor/leaflet/leaflet.js"></script>
   <script src="vendor/leaflet.markercluster/leaflet.markercluster.js"></script>
@@ -69,6 +74,7 @@
   <script src="js/map/mapController.js"></script>
   <script src="js/ui/list.js"></script>
   <script src="js/ui/detail.js"></script>
+  <script src="js/ui/form.js"></script>
   <script src="js/main.js"></script>
 </body>
 </html>
diff --git a/js/main.js b/js/main.js
index e78c082..aa9d34d 100644
--- a/js/main.js
+++ b/js/main.js
@@ -3,7 +3,7 @@
 (function () {
   const { initStore } = EventMap.store;
   const { initMap, centerOnCoords, requestUserLocation } = EventMap.map;
-  const { initList, initDetail } = EventMap.ui;
+  const { initList, initDetail, initForm } = EventMap.ui;
 
   function showFatalError(message) {
     const status = document.getElementById('app-status');
@@ -39,12 +39,23 @@
     });
   }
 
+  function setupAddPlaceButton() {
+    const button = document.getElementById('add-place-btn');
+    if (!button) return;
+
+    button.addEventListener('click', () => {
+      EventMap.ui.openPlaceForm();
+    });
+  }
+
   async function bootstrap() {
     await initStore();
     initMap('map');
     initList('place-list');
     initDetail('detail-modal');
+    initForm('place-form-modal');
     setupGeolocationButton();
+    setupAddPlaceButton();
   }
 
   bootstrap().catch((err) => {
diff --git a/js/ui/detail.js b/js/ui/detail.js
index df54983..a249958 100644
--- a/js/ui/detail.js
+++ b/js/ui/detail.js
@@ -37,6 +37,7 @@
   let refs = null;
   let miniMap = null;
   let lastSelectedPlaceId = null;
+  let currentPlace = null;
 
   function formatAgeRecommendation(ageRecommendation) {
     const { min, max } = ageRecommendation || {};
@@ -115,8 +116,13 @@
         attrs: { type: 'button', id: 'detail-edit-btn' },
         on: {
           click: () => {
-            // TODO Phase 3: Formular zum Bearbeiten des Ausflugsziels öffnen.
-            window.alert('Bearbeiten ist ab Phase 3 verfügbar.');
+            // Detailansicht schließen und das Bearbeiten-Formular öffnen
+            // (js/ui/form.js, wird nach diesem Modul geladen, daher hier zur
+            // Aufrufzeit über den globalen Namespace referenziert statt beim
+            // Datei-Laden destrukturiert).
+            const place = currentPlace;
+            setState({ selectedPlaceId: null });
+            EventMap.ui.openPlaceForm(place);
           },
         },
       },
@@ -298,6 +304,7 @@
   }
 
   function renderContent(place) {
+    currentPlace = place;
     const category = getPlaceCategory(place);
 
     refs.name.textContent = place.name;
diff --git a/js/ui/form.js b/js/ui/form.js
new file mode 100644
index 0000000..2b96e42
--- /dev/null
+++ b/js/ui/form.js
@@ -0,0 +1,604 @@
+// Formular (Modal) zum manuellen Anlegen und Bearbeiten eines
+// Ausflugsziels (Phase 3, siehe anforderung.md Abschnitt 6).
+//
+// API: EventMap.ui.initForm(containerId) initialisiert das Modal einmalig
+// (analog zu js/ui/detail.js). EventMap.ui.openPlaceForm(placeOrNull) öffnet
+// es: ohne Argument im "Neu anlegen"-Modus, mit einem Place-Objekt im
+// "Bearbeiten"-Modus (überschreibt den bestehenden Eintrag statt einen
+// neuen anzulegen).
+//
+// Rendering ausschließlich über textContent/DOM-APIs (el()), niemals
+// innerHTML mit Formular-/Place-Daten (siehe js/utils/dom.js).
+
+(function () {
+  const { getState, setState, persistPlaces } = EventMap.store;
+  const { normalizePlace } = EventMap.models;
+  const { COST_TYPES, ENVIRONMENT_TYPES } = EventMap.models;
+  const { CATEGORIES } = EventMap.config;
+  const { el, isSafeHttpUrl, isValidCoordinate } = EventMap.utils;
+
+  const COST_LABELS = {
+    free: 'Kostenlos',
+    paid: 'Kostenpflichtig',
+    mixed: 'Teilweise kostenpflichtig',
+    unknown: 'Keine Angabe',
+  };
+
+  const ENVIRONMENT_LABELS = {
+    indoor: 'Drinnen (Indoor)',
+    outdoor: 'Draußen (Outdoor)',
+    mixed: 'Drinnen & draußen',
+  };
+
+  // Felder, für die ein eigenes Fehler-Element existiert (siehe fieldWrapper()).
+  const ERROR_FIELDS = [
+    'name',
+    'category',
+    'latitude',
+    'longitude',
+    'ageMin',
+    'ageMax',
+    'duration',
+    'image',
+    'website',
+  ];
+
+  let container = null;
+  let refs = null;
+  let editingPlace = null;
+
+  function fieldWrapper(id, labelText, inputNode, { required = false } = {}) {
+    inputNode.id = id;
+    if (required) {
+      inputNode.setAttribute('required', '');
+      inputNode.setAttribute('aria-required', 'true');
+    }
+
+    const errorEl = el('p', {
+      className: 'form-field__error',
+      attrs: { id: `${id}-error`, role: 'alert' },
+    });
+    errorEl.hidden = true;
+    inputNode.setAttribute('aria-describedby', `${id}-error`);
+
+    const labelChildren = [labelText];
+    if (required) {
+      labelChildren.push(
+        el('span', { className: 'form-field__required', attrs: { 'aria-hidden': 'true' } }, [' *'])
+      );
+    }
+
+    const wrapper = el('div', { className: 'form-field' }, [
+      el('label', { className: 'form-field__label', attrs: { for: id } }, labelChildren),
+      inputNode,
+      errorEl,
+    ]);
+
+    return { wrapper, input: inputNode, errorEl };
+  }
+
+  function textInput(type = 'text', extraAttrs = {}) {
+    return el('input', { attrs: { type, ...extraAttrs } });
+  }
+
+  function buildCategorySelect() {
+    const select = el('select', {}, [
+      el('option', { attrs: { value: '' }, text: '-- Bitte wählen --' }),
+      ...CATEGORIES.map((cat) =>
+        el('option', { attrs: { value: cat.id }, text: `${cat.icon} ${cat.label}` })
+      ),
+    ]);
+    return select;
+  }
+
+  function buildCostTypeSelect() {
+    return el(
+      'select',
+      {},
+      COST_TYPES.map((type) =>
+        el('option', { attrs: { value: type }, text: COST_LABELS[type] || type })
+      )
+    );
+  }
+
+  function buildEnvironmentSelect() {
+    return el(
+      'select',
+      {},
+      ENVIRONMENT_TYPES.map((type) =>
+        el('option', { attrs: { value: type }, text: ENVIRONMENT_LABELS[type] || type })
+      )
+    );
+  }
+
+  function checkboxField(id, labelText) {
+    const input = el('input', { attrs: { type: 'checkbox', id } });
+    const wrapper = el('label', { className: 'form-checkbox', attrs: { for: id } }, [
+      input,
+      labelText,
+    ]);
+    return { wrapper, input };
+  }
+
+  function section(legendText, children) {
+    return el('fieldset', { className: 'place-form__section' }, [
+      el('legend', { className: 'place-form__section-label', text: legendText }),
+      ...children,
+    ]);
+  }
+
+  function row(children) {
+    return el('div', { className: 'place-form__row' }, children);
+  }
+
+  function buildSkeleton(rootContainer) {
+    const nodeRefs = {};
+
+    nodeRefs.backdrop = el('div', {
+      className: 'place-form-modal__backdrop',
+      on: { click: () => closeForm() },
+    });
+
+    nodeRefs.closeBtn = el(
+      'button',
+      {
+        className: 'place-form-modal__close',
+        attrs: { type: 'button', 'aria-label': 'Formular schließen' },
+        on: { click: () => closeForm() },
+      },
+      ['✕']
+    );
+
+    nodeRefs.title = el('h2', {
+      className: 'place-form__title',
+      attrs: { id: 'place-form-title' },
+    });
+
+    // Basisdaten
+    const nameField = fieldWrapper('pf-name', 'Name', textInput('text'), { required: true });
+    const categoryField = fieldWrapper('pf-category', 'Kategorie', buildCategorySelect(), {
+      required: true,
+    });
+    const shortDescriptionField = fieldWrapper(
+      'pf-short-description',
+      'Kurzbeschreibung',
+      textInput('text')
+    );
+    const descriptionField = fieldWrapper(
+      'pf-description',
+      'Ausführliche Beschreibung',
+      el('textarea', {})
+    );
+
+    // Adresse / Position
+    const addressField = fieldWrapper('pf-address', 'Adresse', textInput('text'));
+    const cityField = fieldWrapper('pf-city', 'Ort', textInput('text'));
+    const latitudeField = fieldWrapper(
+      'pf-latitude',
+      'Breitengrad',
+      textInput('number', { step: 'any' }),
+      { required: true }
+    );
+    const longitudeField = fieldWrapper(
+      'pf-longitude',
+      'Längengrad',
+      textInput('number', { step: 'any' }),
+      { required: true }
+    );
+
+    // Altersgruppe / Kosten / Öffnungszeiten / Dauer
+    const ageMinField = fieldWrapper(
+      'pf-age-min',
+      'Altersgruppe – ab (Jahre)',
+      textInput('number', { step: '1', min: '0' })
+    );
+    const ageMaxField = fieldWrapper(
+      'pf-age-max',
+      'Altersgruppe – bis (Jahre)',
+      textInput('number', { step: '1', min: '0' })
+    );
+    const costTypeField = fieldWrapper('pf-cost-type', 'Kosten', buildCostTypeSelect());
+    const costDescriptionField = fieldWrapper(
+      'pf-cost-description',
+      'Kosten – Details',
+      textInput('text')
+    );
+    const openingHoursField = fieldWrapper('pf-opening-hours', 'Öffnungszeiten', textInput('text'));
+    const durationField = fieldWrapper(
+      'pf-duration',
+      'Aufenthaltsdauer (Minuten)',
+      textInput('number', { step: '1', min: '0' })
+    );
+
+    // Ausstattung
+    const strollerCheckbox = checkboxField('pf-facility-stroller', 'Kinderwagen geeignet');
+    const wheelchairCheckbox = checkboxField('pf-facility-wheelchair', 'Barrierefrei');
+    const toiletsCheckbox = checkboxField('pf-facility-toilets', 'Toiletten vorhanden');
+    const parkingCheckbox = checkboxField('pf-facility-parking', 'Parkplatz vorhanden');
+    const restaurantCheckbox = checkboxField('pf-facility-restaurant', 'Gastronomie vorhanden');
+
+    const environmentField = fieldWrapper('pf-environment', 'Indoor / Outdoor', buildEnvironmentSelect());
+
+    // Weitere Informationen
+    const imageField = fieldWrapper('pf-image', 'Bild-URL', textInput('url'));
+    const websiteField = fieldWrapper('pf-website', 'Website', textInput('url'));
+    const tagsField = fieldWrapper(
+      'pf-tags',
+      'Tags (kommagetrennt)',
+      textInput('text')
+    );
+
+    nodeRefs.cancelBtn = el(
+      'button',
+      { className: 'btn btn--secondary', attrs: { type: 'button' }, on: { click: () => closeForm() } },
+      ['Abbrechen']
+    );
+    nodeRefs.submitBtn = el(
+      'button',
+      { className: 'btn btn--primary', attrs: { type: 'submit' } },
+      ['Ausflugsziel speichern']
+    );
+
+    nodeRefs.form = el(
+      'form',
+      { className: 'place-form', attrs: { id: 'place-form', novalidate: '' }, on: { submit: handleSubmit } },
+      [
+        section('Basisdaten', [
+          nameField.wrapper,
+          categoryField.wrapper,
+          shortDescriptionField.wrapper,
+          descriptionField.wrapper,
+        ]),
+        section('Adresse & Position', [
+          addressField.wrapper,
+          cityField.wrapper,
+          row([latitudeField.wrapper, longitudeField.wrapper]),
+        ]),
+        section('Altersgruppe, Kosten & Zeiten', [
+          row([ageMinField.wrapper, ageMaxField.wrapper]),
+          row([costTypeField.wrapper, costDescriptionField.wrapper]),
+          openingHoursField.wrapper,
+          durationField.wrapper,
+        ]),
+        section('Ausstattung', [
+          el('div', { className: 'place-form__checkbox-group' }, [
+            strollerCheckbox.wrapper,
+            wheelchairCheckbox.wrapper,
+            toiletsCheckbox.wrapper,
+            parkingCheckbox.wrapper,
+            restaurantCheckbox.wrapper,
+          ]),
+          environmentField.wrapper,
+        ]),
+        section('Weitere Informationen', [
+          imageField.wrapper,
+          websiteField.wrapper,
+          tagsField.wrapper,
+        ]),
+        el('div', { className: 'place-form__actions' }, [nodeRefs.cancelBtn, nodeRefs.submitBtn]),
+      ]
+    );
+
+    nodeRefs.panel = el(
+      'div',
+      {
+        className: 'place-form-modal__panel',
+        attrs: { role: 'dialog', 'aria-modal': 'true', 'aria-labelledby': 'place-form-title' },
+      },
+      [nodeRefs.closeBtn, nodeRefs.title, nodeRefs.form]
+    );
+
+    rootContainer.appendChild(nodeRefs.backdrop);
+    rootContainer.appendChild(nodeRefs.panel);
+
+    // Flache Referenzen für Lesen/Schreiben/Fehleranzeige der Feldwerte.
+    nodeRefs.name = nameField.input;
+    nodeRefs.nameError = nameField.errorEl;
+    nodeRefs.category = categoryField.input;
+    nodeRefs.categoryError = categoryField.errorEl;
+    nodeRefs.shortDescription = shortDescriptionField.input;
+    nodeRefs.description = descriptionField.input;
+    nodeRefs.address = addressField.input;
+    nodeRefs.city = cityField.input;
+    nodeRefs.latitude = latitudeField.input;
+    nodeRefs.latitudeError = latitudeField.errorEl;
+    nodeRefs.longitude = longitudeField.input;
+    nodeRefs.longitudeError = longitudeField.errorEl;
+    nodeRefs.ageMin = ageMinField.input;
+    nodeRefs.ageMinError = ageMinField.errorEl;
+    nodeRefs.ageMax = ageMaxField.input;
+    nodeRefs.ageMaxError = ageMaxField.errorEl;
+    nodeRefs.costType = costTypeField.input;
+    nodeRefs.costDescription = costDescriptionField.input;
+    nodeRefs.openingHours = openingHoursField.input;
+    nodeRefs.duration = durationField.input;
+    nodeRefs.durationError = durationField.errorEl;
+    nodeRefs.stroller = strollerCheckbox.input;
+    nodeRefs.wheelchair = wheelchairCheckbox.input;
+    nodeRefs.toilets = toiletsCheckbox.input;
+    nodeRefs.parking = parkingCheckbox.input;
+    nodeRefs.restaurant = restaurantCheckbox.input;
+    nodeRefs.environment = environmentField.input;
+    nodeRefs.image = imageField.input;
+    nodeRefs.imageError = imageField.errorEl;
+    nodeRefs.website = websiteField.input;
+    nodeRefs.websiteError = websiteField.errorEl;
+    nodeRefs.tags = tagsField.input;
+
+    return nodeRefs;
+  }
+
+  function parseOptionalNumber(raw) {
+    const trimmed = (raw || '').trim();
+    if (trimmed === '') return null;
+    const num = Number(trimmed);
+    return Number.isFinite(num) ? num : NaN;
+  }
+
+  function readValues() {
+    return {
+      name: refs.name.value.trim(),
+      category: refs.category.value,
+      shortDescription: refs.shortDescription.value.trim(),
+      description: refs.description.value.trim(),
+      address: refs.address.value.trim(),
+      city: refs.city.value.trim(),
+      latitude: parseOptionalNumber(refs.latitude.value),
+      longitude: parseOptionalNumber(refs.longitude.value),
+      ageMin: parseOptionalNumber(refs.ageMin.value),
+      ageMax: parseOptionalNumber(refs.ageMax.value),
+      costType: refs.costType.value,
+      costDescription: refs.costDescription.value.trim(),
+      openingHours: refs.openingHours.value.trim(),
+      duration: parseOptionalNumber(refs.duration.value),
+      stroller: refs.stroller.checked,
+      wheelchair: refs.wheelchair.checked,
+      toilets: refs.toilets.checked,
+      parking: refs.parking.checked,
+      restaurant: refs.restaurant.checked,
+      environment: refs.environment.value,
+      image: refs.image.value.trim(),
+      website: refs.website.value.trim(),
+      tags: refs.tags.value,
+    };
+  }
+
+  /** Validiert die gelesenen Formularwerte. Gibt ein Objekt {feldname: Fehlermeldung} zurück. */
+  function validate(values) {
+    const errors = {};
+
+    if (!values.name) {
+      errors.name = 'Bitte einen Namen angeben.';
+    }
+    if (!values.category) {
+      errors.category = 'Bitte eine Kategorie auswählen.';
+    }
+
+    if (values.latitude === null) {
+      errors.latitude = 'Bitte einen Breitengrad angeben.';
+    } else if (Number.isNaN(values.latitude) || values.latitude < -90 || values.latitude > 90) {
+      errors.latitude = 'Breitengrad muss eine Zahl zwischen -90 und 90 sein.';
+    }
+
+    if (values.longitude === null) {
+      errors.longitude = 'Bitte einen Längengrad angeben.';
+    } else if (Number.isNaN(values.longitude) || values.longitude < -180 || values.longitude > 180) {
+      errors.longitude = 'Längengrad muss eine Zahl zwischen -180 und 180 sein.';
+    }
+
+    if (!errors.latitude && !errors.longitude && !isValidCoordinate(values.latitude, values.longitude)) {
+      errors.latitude = 'Koordinaten sind ungültig.';
+    }
+
+    if (values.ageMin !== null && (Number.isNaN(values.ageMin) || values.ageMin < 0)) {
+      errors.ageMin = 'Bitte ein gültiges Alter (mindestens 0) angeben.';
+    }
+    if (values.ageMax !== null && (Number.isNaN(values.ageMax) || values.ageMax < 0)) {
+      errors.ageMax = 'Bitte ein gültiges Alter (mindestens 0) angeben.';
+    }
+    if (
+      !errors.ageMin &&
+      !errors.ageMax &&
+      values.ageMin !== null &&
+      values.ageMax !== null &&
+      values.ageMin > values.ageMax
+    ) {
+      errors.ageMax = 'Der Wert "bis" darf nicht kleiner als "ab" sein.';
+    }
+
+    if (values.duration !== null && (Number.isNaN(values.duration) || values.duration < 0)) {
+      errors.duration = 'Bitte eine gültige Aufenthaltsdauer in Minuten (mindestens 0) angeben.';
+    }
+
+    if (values.image && !isSafeHttpUrl(values.image)) {
+      errors.image = 'Bitte eine gültige Bild-URL (http/https) angeben.';
+    }
+    if (values.website && !isSafeHttpUrl(values.website)) {
+      errors.website = 'Bitte eine gültige Website-URL (http/https) angeben.';
+    }
+
+    return errors;
+  }
+
+  function clearErrors() {
+    for (const key of ERROR_FIELDS) {
+      const input = refs[key];
+      const errorEl = refs[`${key}Error`];
+      if (!input || !errorEl) continue;
+      input.removeAttribute('aria-invalid');
+      errorEl.textContent = '';
+      errorEl.hidden = true;
+    }
+  }
+
+  function showErrors(errors) {
+    clearErrors();
+    for (const [key, message] of Object.entries(errors)) {
+      const input = refs[key];
+      const errorEl = refs[`${key}Error`];
+      if (!input || !errorEl) continue;
+      input.setAttribute('aria-invalid', 'true');
+      errorEl.textContent = message;
+      errorEl.hidden = false;
+    }
+  }
+
+  function focusFirstError(errors) {
+    const firstKey = ERROR_FIELDS.find((key) => errors[key]);
+    if (firstKey && refs[firstKey]) refs[firstKey].focus();
+  }
+
+  /** Baut aus Formularwerten + optionaler Basis (bestehendes Place-Objekt) ein Rohobjekt für normalizePlace(). */
+  function buildRawPlace(values, base) {
+    return {
+      ...base,
+      name: values.name,
+      category: values.category,
+      shortDescription: values.shortDescription,
+      description: values.description,
+      address: values.address,
+      city: values.city,
+      latitude: values.latitude,
+      longitude: values.longitude,
+      ageRecommendation: { min: values.ageMin, max: values.ageMax },
+      cost: { type: values.costType, description: values.costDescription },
+      openingHours: values.openingHours,
+      durationMinutes: values.duration,
+      facilities: {
+        strollerAccessible: values.stroller,
+        wheelchairAccessible: values.wheelchair,
+        toilets: values.toilets,
+        parking: values.parking,
+        restaurant: values.restaurant,
+      },
+      environment: values.environment,
+      image: values.image,
+      website: values.website,
+      tags: values.tags
+        .split(',')
+        .map((tag) => tag.trim())
+        .filter(Boolean),
+      // Explizit zurücksetzen: normalizePlace() setzt bei Bearbeiten dadurch
+      // einen neuen Zeitstempel, statt den aus `base` übernommenen zu behalten.
+      updatedAt: undefined,
+    };
+  }
+
+  function savePlace(normalized) {
+    const state = getState();
+    const places = editingPlace
+      ? state.places.map((p) => (p.id === normalized.id ? normalized : p))
+      : [...state.places, normalized];
+
+    setState({ places });
+    persistPlaces();
+  }
+
+  function handleSubmit(event) {
+    event.preventDefault();
+
+    const values = readValues();
+    const errors = validate(values);
+    showErrors(errors);
+
+    if (Object.keys(errors).length > 0) {
+      focusFirstError(errors);
+      return;
+    }
+
+    const base = editingPlace ? { ...editingPlace } : {};
+    const normalized = normalizePlace(buildRawPlace(values, base));
+    savePlace(normalized);
+    closeForm();
+  }
+
+  function prefillForm(place) {
+    refs.name.value = place.name || '';
+    refs.category.value = place.category || '';
+    refs.shortDescription.value = place.shortDescription || '';
+    refs.description.value = place.description || '';
+    refs.address.value = place.address || '';
+    refs.city.value = place.city || '';
+    refs.latitude.value = place.latitude ?? '';
+    refs.longitude.value = place.longitude ?? '';
+
+    const age = place.ageRecommendation || {};
+    refs.ageMin.value = age.min ?? '';
+    refs.ageMax.value = age.max ?? '';
+
+    const cost = place.cost || {};
+    refs.costType.value = cost.type || 'unknown';
+    refs.costDescription.value = cost.description || '';
+
+    refs.openingHours.value = place.openingHours || '';
+    refs.duration.value = place.durationMinutes ?? '';
+
+    const facilities = place.facilities || {};
+    refs.stroller.checked = Boolean(facilities.strollerAccessible);
+    refs.wheelchair.checked = Boolean(facilities.wheelchairAccessible);
+    refs.toilets.checked = Boolean(facilities.toilets);
+    refs.parking.checked = Boolean(facilities.parking);
+    refs.restaurant.checked = Boolean(facilities.restaurant);
+
+    refs.environment.value = place.environment || 'outdoor';
+    refs.image.value = place.image || '';
+    refs.website.value = place.website || '';
+    refs.tags.value = Array.isArray(place.tags) ? place.tags.join(', ') : '';
+  }
+
+  /** Öffnet das Formular. Ohne Argument (bzw. mit null) im "Neu anlegen"-Modus, sonst im Bearbeiten-Modus. */
+  function openPlaceForm(place) {
+    if (!container || !refs) {
+      console.error('EventMap: Formular wurde noch nicht initialisiert (initForm()).');
+      return;
+    }
+
+    editingPlace = place || null;
+    clearErrors();
+    refs.form.reset();
+
+    if (editingPlace) {
+      refs.title.textContent = 'Ausflugsziel bearbeiten';
+      refs.submitBtn.textContent = 'Änderungen speichern';
+      prefillForm(editingPlace);
+    } else {
+      refs.title.textContent = 'Neues Ausflugsziel hinzufügen';
+      refs.submitBtn.textContent = 'Ausflugsziel speichern';
+      refs.category.value = '';
+      refs.costType.value = 'unknown';
+      refs.environment.value = 'outdoor';
+    }
+
+    container.hidden = false;
+    document.body.classList.add('place-form-modal-open');
+    refs.name.focus();
+  }
+
+  function closeForm() {
+    if (!container || container.hidden) return;
+    container.hidden = true;
+    document.body.classList.remove('place-form-modal-open');
+    editingPlace = null;
+  }
+
+  /** Initialisiert das Formular-Modal im Element mit der übergebenen id. */
+  function initForm(containerId) {
+    const containerEl = document.getElementById(containerId);
+    if (!containerEl) {
+      console.error(`EventMap: Formular-Container #${containerId} nicht gefunden.`);
+      return;
+    }
+
+    container = containerEl;
+    refs = buildSkeleton(container);
+
+    document.addEventListener('keydown', (event) => {
+      if (event.key === 'Escape' && !container.hidden) {
+        closeForm();
+      }
+    });
+  }
+
+  EventMap.ui.initForm = initForm;
+  EventMap.ui.openPlaceForm = openPlaceForm;
+})();