diff --git a/App.tsx b/App.tsx
index 46e6dff..62bc986 100644
--- a/App.tsx
+++ b/App.tsx
@@ -8,7 +8,6 @@ import {ApolloProvider} from '@apollo/client';
 import {useEffect, useState} from 'react';
 import {
   ActivityIndicator,
-  Modal,
   Pressable,
   StatusBar,
   StyleSheet,
@@ -30,6 +29,7 @@ import {
   useAuthHydrated,
 } from './src/auth/tokenStore';
 import {MapScreen} from './src/map/MapScreen';
+import {Sheet} from './src/ui/Sheet';
 
 function App() {
   const isDarkMode = useColorScheme() === 'dark';
@@ -93,35 +93,26 @@ function AccountMenu({user}: {user: AuthUser}) {
         ]}>
         <Text style={styles.avatarText}>{initial}</Text>
       </Pressable>
-      <Modal
-        animationType="slide"
-        transparent
+      <Sheet
         visible={open}
-        onRequestClose={() => setOpen(false)}>
-        <Pressable style={styles.sheetBackdrop} onPress={() => setOpen(false)}>
-          <View
-            style={[styles.sheet, {paddingBottom: safeAreaInsets.bottom + 12}]}
-            // Stop taps inside the sheet from dismissing it via the backdrop.
-            onStartShouldSetResponder={() => true}>
-            <View style={styles.sheetHandle} />
-            <Text style={styles.sheetEmail} numberOfLines={1}>
-              {user.email}
-            </Text>
-            <Pressable
-              accessibilityRole="button"
-              onPress={() => {
-                setOpen(false);
-                logout();
-              }}
-              style={({pressed}) => [
-                styles.sheetItem,
-                pressed && styles.sheetItemPressed,
-              ]}>
-              <Text style={styles.sheetItemText}>Log out</Text>
-            </Pressable>
-          </View>
+        onClose={() => setOpen(false)}
+        scrimAccessibilityLabel="Close account menu">
+        <Text style={styles.sheetEmail} numberOfLines={1}>
+          {user.email}
+        </Text>
+        <Pressable
+          accessibilityRole="button"
+          onPress={() => {
+            setOpen(false);
+            logout();
+          }}
+          style={({pressed}) => [
+            styles.sheetItem,
+            pressed && styles.sheetItemPressed,
+          ]}>
+          <Text style={styles.sheetItemText}>Log out</Text>
         </Pressable>
-      </Modal>
+      </Sheet>
     </>
   );
 }
@@ -155,26 +146,6 @@ const styles = StyleSheet.create({
     fontSize: 16,
     fontWeight: '600',
   },
-  sheetBackdrop: {
-    flex: 1,
-    backgroundColor: 'rgba(0,0,0,0.35)',
-    justifyContent: 'flex-end',
-  },
-  sheet: {
-    backgroundColor: '#ffffff',
-    borderTopLeftRadius: 16,
-    borderTopRightRadius: 16,
-    paddingTop: 8,
-    paddingHorizontal: 8,
-  },
-  sheetHandle: {
-    alignSelf: 'center',
-    width: 36,
-    height: 4,
-    borderRadius: 2,
-    backgroundColor: '#d0d0d0',
-    marginBottom: 12,
-  },
   sheetEmail: {
     fontSize: 12,
     color: '#666',
diff --git a/src/map/ElementDetailModal.tsx b/src/map/ElementDetailModal.tsx
index 05742ae..b393d82 100644
--- a/src/map/ElementDetailModal.tsx
+++ b/src/map/ElementDetailModal.tsx
@@ -1,7 +1,6 @@
 import {
   ActivityIndicator,
   Image,
-  Modal,
   Pressable,
   ScrollView,
   StyleSheet,
@@ -13,6 +12,7 @@ import {
   type ElementDetailQuery,
   useElementDetailQuery,
 } from '../graphql/__generated__/types';
+import {Sheet} from '../ui/Sheet';
 
 type Props = {
   elementId: string | null;
@@ -28,17 +28,13 @@ export function ElementDetailModal({elementId, onClose}: Props) {
   });
 
   return (
-    <Modal
-      animationType="slide"
-      visible={elementId !== null}
-      onRequestClose={onClose}
-      presentationStyle="fullScreen">
+    <Sheet visible={elementId !== null} onClose={onClose} variant="fullscreen">
       <ModalContents
         element={data?.element ?? null}
         loading={loading}
         onClose={onClose}
       />
-    </Modal>
+    </Sheet>
   );
 }
 
diff --git a/src/ui/Sheet.tsx b/src/ui/Sheet.tsx
new file mode 100644
index 0000000..5b2cdfe
--- /dev/null
+++ b/src/ui/Sheet.tsx
@@ -0,0 +1,150 @@
+import {type ReactNode, useEffect, useRef, useState} from 'react';
+import {
+  Animated,
+  BackHandler,
+  Pressable,
+  StyleSheet,
+  useWindowDimensions,
+  View,
+} from 'react-native';
+import {useSafeAreaInsets} from 'react-native-safe-area-context';
+
+const AnimatedPressable = Animated.createAnimatedComponent(Pressable);
+
+type SheetVariant = 'bottom' | 'fullscreen';
+
+type Props = {
+  visible: boolean;
+  onClose: () => void;
+  /** `bottom` (default): dim scrim + bottom-anchored card. `fullscreen`: opaque full-screen. */
+  variant?: SheetVariant;
+  /** Tap the scrim to close (bottom variant only). Defaults to true. */
+  dismissOnScrimPress?: boolean;
+  /** Accessibility label for the scrim's close affordance (bottom variant). */
+  scrimAccessibilityLabel?: string;
+  children: ReactNode;
+};
+
+/**
+ * In-tree modal sheet. Rendered as an absolute overlay (not a React Native
+ * `Modal`) so it inherits the app's edge-to-edge window and draws behind the
+ * status and navigation bars. RN's `Modal` renders in a separate window whose
+ * `statusBarTranslucent`/`navigationBarTranslucent` props don't reliably do
+ * this on RN 0.85 + Android 15, which left scrims and sheets stopping at the
+ * system bars.
+ *
+ * Owns the slide animation, hardware-back handling, and pointer-event gating;
+ * callers supply the content (and their own safe-area padding for fullscreen).
+ */
+export function Sheet({
+  visible,
+  onClose,
+  variant = 'bottom',
+  dismissOnScrimPress = true,
+  scrimAccessibilityLabel = 'Close',
+  children,
+}: Props) {
+  const safeAreaInsets = useSafeAreaInsets();
+  const {height} = useWindowDimensions();
+  const anim = useRef(new Animated.Value(0)).current;
+  const [sheetHeight, setSheetHeight] = useState(0);
+
+  useEffect(() => {
+    Animated.timing(anim, {
+      toValue: visible ? 1 : 0,
+      duration: variant === 'fullscreen' ? 250 : 220,
+      useNativeDriver: true,
+    }).start();
+  }, [visible, variant, anim]);
+
+  // The hardware back button closes the sheet (RN Modal used to handle this).
+  useEffect(() => {
+    if (!visible) {
+      return;
+    }
+    const sub = BackHandler.addEventListener('hardwareBackPress', () => {
+      onClose();
+      return true;
+    });
+    return () => sub.remove();
+  }, [visible, onClose]);
+
+  if (variant === 'fullscreen') {
+    const translateY = anim.interpolate({
+      inputRange: [0, 1],
+      outputRange: [height, 0],
+    });
+    return (
+      <Animated.View
+        style={[
+          StyleSheet.absoluteFill,
+          styles.fullscreen,
+          {transform: [{translateY}]},
+        ]}
+        pointerEvents={visible ? 'auto' : 'none'}>
+        {children}
+      </Animated.View>
+    );
+  }
+
+  const translateY = anim.interpolate({
+    inputRange: [0, 1],
+    outputRange: [sheetHeight || 320, 0],
+  });
+  return (
+    <View
+      style={StyleSheet.absoluteFill}
+      pointerEvents={visible ? 'auto' : 'none'}>
+      <AnimatedPressable
+        accessibilityLabel={scrimAccessibilityLabel}
+        style={[styles.scrim, {opacity: anim}]}
+        onPress={dismissOnScrimPress ? onClose : undefined}
+      />
+      <Animated.View
+        style={[styles.sheetWrap, {transform: [{translateY}]}]}
+        pointerEvents="box-none">
+        <View
+          onLayout={e => setSheetHeight(e.nativeEvent.layout.height)}
+          style={[styles.card, {paddingBottom: safeAreaInsets.bottom + 12}]}>
+          <View style={styles.handle} />
+          {children}
+        </View>
+      </Animated.View>
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  fullscreen: {
+    backgroundColor: '#ffffff',
+  },
+  scrim: {
+    position: 'absolute',
+    top: 0,
+    left: 0,
+    right: 0,
+    bottom: 0,
+    backgroundColor: 'rgba(0,0,0,0.35)',
+  },
+  sheetWrap: {
+    position: 'absolute',
+    left: 0,
+    right: 0,
+    bottom: 0,
+  },
+  card: {
+    backgroundColor: '#ffffff',
+    borderTopLeftRadius: 16,
+    borderTopRightRadius: 16,
+    paddingTop: 8,
+    paddingHorizontal: 8,
+  },
+  handle: {
+    alignSelf: 'center',
+    width: 36,
+    height: 4,
+    borderRadius: 2,
+    backgroundColor: '#d0d0d0',
+    marginBottom: 12,
+  },
+});