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lib/pages/epub_reader/widgets/integer_stepper.dart

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+import 'package:flutter/material.dart';
+
+/// A compact card-style stepper for an integer value.
+class IntegerStepper extends StatelessWidget {
+  const IntegerStepper({
+    super.key,
+    required this.label,
+    required this.value,
+    required this.min,
+    required this.max,
+    required this.step,
+    required this.onChanged,
+  });
+
+  final String label;
+  final int value;
+  final int min;
+  final int max;
+  final int step;
+  final ValueChanged<int> onChanged;
+
+  @override
+  Widget build(BuildContext context) {
+    final colorScheme = Theme.of(context).colorScheme;
+    return Container(
+      padding: const EdgeInsets.fromLTRB(12, 8, 8, 8),
+      decoration: BoxDecoration(
+        color: colorScheme.surfaceContainerHighest,
+        borderRadius: BorderRadius.circular(12),
+        border: Border.all(color: colorScheme.outlineVariant, width: 1.5),
+      ),
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          Text(
+            label,
+            style: TextStyle(fontSize: 12, color: colorScheme.onSurfaceVariant),
+          ),
+          Row(
+            mainAxisAlignment: MainAxisAlignment.spaceBetween,
+            children: [
+              IconButton(
+                icon: const Icon(Icons.remove_outlined, size: 16),
+                onPressed: value > min ? () => onChanged(value - step) : null,
+                padding: EdgeInsets.zero,
+                constraints: const BoxConstraints(minWidth: 28, minHeight: 28),
+                visualDensity: VisualDensity.compact,
+                color: colorScheme.primary,
+                disabledColor: colorScheme.outline,
+              ),
+              Text(
+                '$value',
+                style: TextStyle(
+                  fontSize: 14,
+                  color: colorScheme.onSurfaceVariant,
+                ),
+              ),
+              IconButton(
+                icon: const Icon(Icons.add_outlined, size: 16),
+                onPressed: value < max ? () => onChanged(value + step) : null,
+                padding: EdgeInsets.zero,
+                constraints: const BoxConstraints(minWidth: 28, minHeight: 28),
+                visualDensity: VisualDensity.compact,
+                color: colorScheme.primary,
+                disabledColor: colorScheme.outline,
+              ),
+            ],
+          ),
+        ],
+      ),
+    );
+  }
+}

lib/pages/epub_reader/widgets/reader_scale_slider.dart

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+import 'package:flutter/material.dart';
+
+/// A horizontal scale slider with small/large "A" tap targets on either side.
+///
+/// The slider range is fixed to [0.5, 2.5] with 0.1 increments.
+/// Tapping the letter glyphs nudges the value by 0.1 in the respective
+/// direction; the glyph is greyed-out when the limit is reached.
+class ReaderScaleSlider extends StatelessWidget {
+  const ReaderScaleSlider({
+    super.key,
+    required this.value,
+    required this.onChanged,
+  });
+
+  final double value;
+  final ValueChanged<double> onChanged;
+
+  static const double _min = 0.5;
+  static const double _max = 2.5;
+  static const double _nudge = 0.1;
+
+  @override
+  Widget build(BuildContext context) {
+    final color = Theme.of(context).colorScheme.onSurfaceVariant;
+    final disabledColor = Theme.of(context).colorScheme.outline;
+
+    return Row(
+      children: [
+        GestureDetector(
+          onTap: value > _min
+              ? () => onChanged((value - _nudge).clamp(_min, _max))
+              : null,
+          child: Text(
+            'A',
+            style: TextStyle(
+              fontSize: 12,
+              color: value > _min ? color : disabledColor,
+            ),
+          ),
+        ),
+        Expanded(
+          child: Slider(
+            value: value,
+            min: _min,
+            max: _max,
+            divisions: 20,
+            label: value.toStringAsFixed(1),
+            onChanged: onChanged,
+          ),
+        ),
+        GestureDetector(
+          onTap: value < _max
+              ? () => onChanged((value + _nudge).clamp(_min, _max))
+              : null,
+          child: Text(
+            'A',
+            style: TextStyle(
+              fontSize: 22,
+              color: value < _max ? color : disabledColor,
+            ),
+          ),
+        ),
+      ],
+    );
+  }
+}