diff --git a/app/qt/main_window.py b/app/qt/main_window.py
index b591585..a5d62ec 100644
--- a/app/qt/main_window.py
+++ b/app/qt/main_window.py
@@ -1,14 +1,183 @@
-"""Main PySide6 window with custom title bar."""
+"""Main PySide6 window emulating the legacy Tk interface."""
 
 from __future__ import annotations
 
+from dataclasses import dataclass
 from pathlib import Path
+from typing import Callable, Dict, List, Tuple
 
 from PySide6 import QtCore, QtGui, QtWidgets
 
+DEFAULT_COLOUR = "#763e92"
+PRESET_COLOURS: List[Tuple[str, str]] = [
+    ("Red", "#ff3b30"),
+    ("Orange", "#ff9500"),
+    ("Yellow", "#ffd60a"),
+    ("Green", "#34c759"),
+    ("Teal", "#5ac8fa"),
+    ("Blue", "#0a84ff"),
+    ("Violet", "#af52de"),
+    ("Magenta", "#ff2d55"),
+    ("White", "#ffffff"),
+    ("Grey", "#8e8e93"),
+    ("Black", "#000000"),
+]
+
+SLIDER_SPECS: List[Tuple[str, str, int, int, int]] = [
+    ("Hue min", "hue_min", 0, 360, 0),
+    ("Hue max", "hue_max", 0, 360, 360),
+    ("Sat min", "sat_min", 0, 100, 25),
+    ("Value min", "val_min", 0, 100, 15),
+    ("Value max", "val_max", 0, 100, 100),
+    ("Overlay alpha", "alpha", 0, 255, 120),
+]
+
+
+class ToolbarButton(QtWidgets.QPushButton):
+    """Rounded toolbar button inspired by the legacy design."""
+
+    def __init__(self, icon_text: str, label: str, callback: Callable[[], None], parent: QtWidgets.QWidget | None = None):
+        super().__init__(f"{icon_text}  {label}", parent)
+        self.setCursor(QtCore.Qt.PointingHandCursor)
+        self.setFixedHeight(34)
+        self.setStyleSheet(
+            """
+            QPushButton {
+                padding: 8px 16px;
+                border-radius: 10px;
+                border: 1px solid rgba(255, 255, 255, 0.08);
+                background-color: rgba(255, 255, 255, 0.04);
+                color: #f7f7fb;
+                font-weight: 600;
+            }
+            QPushButton:hover {
+                background-color: rgba(255, 255, 255, 0.12);
+            }
+            QPushButton:pressed {
+                background-color: rgba(255, 255, 255, 0.18);
+            }
+            """
+        )
+        self.clicked.connect(callback)
+
+
+class ColourSwatch(QtWidgets.QPushButton):
+    """Clickable palette swatch."""
+
+    def __init__(self, name: str, hex_code: str, callback: Callable[[str, str], None], parent: QtWidgets.QWidget | None = None):
+        super().__init__(parent)
+        self.hex_code = hex_code
+        self.name = name
+        self.setToolTip(f"{name} ({hex_code})")
+        self.setCursor(QtCore.Qt.PointingHandCursor)
+        self.setFixedSize(28, 28)
+        self.setStyleSheet(
+            f"""
+            QPushButton {{
+                background-color: {hex_code};
+                border: 2px solid rgba(255, 255, 255, 0.18);
+                border-radius: 6px;
+            }}
+            QPushButton:hover {{
+                border-color: rgba(255, 255, 255, 0.45);
+            }}
+            """
+        )
+        self.clicked.connect(lambda: callback(hex_code, name))
+
+
+class SliderControl(QtWidgets.QWidget):
+    """Slider with header and live value label."""
+
+    value_changed = QtCore.Signal(str, int)
+
+    def __init__(self, title: str, key: str, minimum: int, maximum: int, initial: int):
+        super().__init__()
+        self.key = key
+
+        layout = QtWidgets.QVBoxLayout(self)
+        layout.setContentsMargins(0, 0, 0, 0)
+        layout.setSpacing(4)
+
+        header = QtWidgets.QHBoxLayout()
+        header.setContentsMargins(0, 0, 0, 0)
+        title_label = QtWidgets.QLabel(title)
+        title_label.setStyleSheet("color: rgba(255,255,255,0.85); font-weight: 500;")
+        header.addWidget(title_label)
+        header.addStretch(1)
+        self.value_label = QtWidgets.QLabel(str(initial))
+        self.value_label.setStyleSheet("color: rgba(255,255,255,0.6);")
+        header.addWidget(self.value_label)
+        layout.addLayout(header)
+
+        self.slider = QtWidgets.QSlider(QtCore.Qt.Horizontal)
+        self.slider.setRange(minimum, maximum)
+        self.slider.setValue(initial)
+        self.slider.setCursor(QtCore.Qt.PointingHandCursor)
+        self.slider.setStyleSheet(
+            """
+            QSlider::groove:horizontal {
+                border: 1px solid rgba(255,255,255,0.08);
+                height: 6px;
+                background: rgba(255,255,255,0.1);
+                border-radius: 4px;
+            }
+            QSlider::handle:horizontal {
+                background: #9a4dff;
+                border: 1px solid rgba(255,255,255,0.2);
+                width: 14px;
+                margin: -5px 0;
+                border-radius: 7px;
+            }
+            """
+        )
+        self.slider.valueChanged.connect(self._sync_value)
+        layout.addWidget(self.slider)
+
+    def _sync_value(self, value: int) -> None:
+        self.value_label.setText(str(value))
+        self.value_changed.emit(self.key, value)
+
+    def set_value(self, value: int) -> None:
+        self.slider.blockSignals(True)
+        self.slider.setValue(value)
+        self.slider.blockSignals(False)
+        self.value_label.setText(str(value))
+
+
+class ImageView(QtWidgets.QLabel):
+    """Aspect-ratio aware image view."""
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.setAlignment(QtCore.Qt.AlignCenter)
+        self._pixmap: QtGui.QPixmap | None = None
+
+    def set_image(self, pixmap: QtGui.QPixmap | None) -> None:
+        self._pixmap = pixmap
+        self._rescale()
+
+    def resizeEvent(self, event: QtGui.QResizeEvent) -> None:
+        super().resizeEvent(event)
+        self._rescale()
+
+    def _rescale(self) -> None:
+        if self._pixmap is None:
+            self.setPixmap(QtGui.QPixmap())
+            self.setText("<No image loaded>")
+            self.setStyleSheet("color: rgba(255,255,255,0.45); font-size: 14px;")
+            return
+        target = self._pixmap.scaled(
+            self.size(),
+            QtCore.Qt.KeepAspectRatio,
+            QtCore.Qt.SmoothTransformation,
+        )
+        self.setPixmap(target)
+        self.setStyleSheet("")
+
 
 class TitleBar(QtWidgets.QWidget):
-    """Custom title bar mimicking modern Windows applications."""
+    """Custom title bar with native window controls."""
 
     HEIGHT = 40
 
@@ -17,8 +186,8 @@ class TitleBar(QtWidgets.QWidget):
         self.window = window
         self.setFixedHeight(self.HEIGHT)
         self.setCursor(QtCore.Qt.ArrowCursor)
-
         self.setAutoFillBackground(True)
+
         palette = self.palette()
         palette.setColor(QtGui.QPalette.Window, QtGui.QColor("#16171d"))
         self.setPalette(palette)
@@ -31,13 +200,12 @@ class TitleBar(QtWidgets.QWidget):
         if logo_path.exists():
             pixmap = QtGui.QPixmap(str(logo_path))
             logo_label = QtWidgets.QLabel()
-            logo_label.setPixmap(pixmap.scaled(24, 24, QtCore.Qt.KeepAspectRatio, QtCore.Qt.SmoothTransformation))
+            logo_label.setPixmap(pixmap.scaled(26, 26, QtCore.Qt.KeepAspectRatio, QtCore.Qt.SmoothTransformation))
             layout.addWidget(logo_label)
 
         title_label = QtWidgets.QLabel("Interactive Color Range Analyzer")
         title_label.setStyleSheet("color: #f7f7fb; font-weight: 600;")
         layout.addWidget(title_label)
-
         layout.addStretch(1)
 
         self.min_btn = self._create_button("–", "Minimise window")
@@ -52,7 +220,7 @@ class TitleBar(QtWidgets.QWidget):
         close_btn.clicked.connect(window.close)
         close_btn.setStyleSheet(
             """
-            QPushButton { background-color: transparent; color: #f7f7fb; border: none; padding: 4px 10px; }
+            QPushButton { background: transparent; color: #f7f7fb; border: none; padding: 4px 10px; }
             QPushButton:hover { background-color: #d0342c; }
             """
         )
@@ -72,7 +240,7 @@ class TitleBar(QtWidgets.QWidget):
                 padding: 4px 10px;
             }
             QPushButton:hover {
-                background-color: rgba(255, 255, 255, 0.12);
+                background-color: rgba(255, 255, 255, 0.1);
             }
             """
         )
@@ -90,46 +258,15 @@ class TitleBar(QtWidgets.QWidget):
         super().mousePressEvent(event)
 
 
-class ImageView(QtWidgets.QLabel):
-    """Simple image display widget that keeps aspect ratio."""
-
-    def __init__(self) -> None:
-        super().__init__()
-        self.setAlignment(QtCore.Qt.AlignCenter)
-        self._pixmap: QtGui.QPixmap | None = None
-
-    def set_image(self, pixmap: QtGui.QPixmap | None) -> None:
-        self._pixmap = pixmap
-        self._rescale()
-
-    def resizeEvent(self, event: QtGui.QResizeEvent) -> None:
-        super().resizeEvent(event)
-        self._rescale()
-
-    def _rescale(self) -> None:
-        if self._pixmap is None:
-            self.clear()
-            self.setText("<No image loaded>")
-            self.setStyleSheet("color: rgba(255,255,255,0.5); font-size: 14px;")
-            return
-        target = self._pixmap.scaled(
-            self.size(),
-            QtCore.Qt.KeepAspectRatio,
-            QtCore.Qt.SmoothTransformation,
-        )
-        self.setPixmap(target)
-        self.setStyleSheet("")
-
-
 class MainWindow(QtWidgets.QMainWindow):
-    """Main application window containing custom chrome and content area."""
+    """Main application window containing all controls."""
 
     def __init__(self) -> None:
         super().__init__()
         self.setWindowFlag(QtCore.Qt.FramelessWindowHint)
         self.setWindowFlag(QtCore.Qt.Window)
         self.setAttribute(QtCore.Qt.WA_TranslucentBackground, False)
-        self.setMinimumSize(900, 600)
+        self.setMinimumSize(1100, 680)
 
         container = QtWidgets.QWidget()
         container_layout = QtWidgets.QVBoxLayout(container)
@@ -145,46 +282,22 @@ class MainWindow(QtWidgets.QMainWindow):
         content_layout.setContentsMargins(24, 24, 24, 24)
         content_layout.setSpacing(18)
 
-        toolbar = QtWidgets.QHBoxLayout()
-        toolbar.setSpacing(12)
-
-        self.open_button = QtWidgets.QPushButton("Open Image…")
-        self.open_button.setCursor(QtCore.Qt.PointingHandCursor)
-        self.open_button.setStyleSheet(
-            """
-            QPushButton {
-                background: linear-gradient(135deg, #5168ff, #9a4dff);
-                border: none;
-                color: #ffffff;
-                font-weight: 600;
-                padding: 10px 16px;
-                border-radius: 10px;
-            }
-            QPushButton:hover {
-                filter: brightness(1.1);
-            }
-            """
-        )
-        self.open_button.clicked.connect(self.open_image)
-        toolbar.addWidget(self.open_button)
-
-        toolbar.addStretch(1)
-
-        self.status_label = QtWidgets.QLabel("No image loaded")
-        self.status_label.setStyleSheet("color: rgba(255,255,255,0.7); font-weight: 500;")
-        toolbar.addWidget(self.status_label)
-
-        content_layout.addLayout(toolbar)
-
-        self.image_view = ImageView()
-        self.image_view.setStyleSheet("border: 1px solid rgba(255,255,255,0.08); border-radius: 12px;")
-        content_layout.addWidget(self.image_view, 1)
+        content_layout.addLayout(self._build_toolbar())
+        content_layout.addLayout(self._build_palette())
+        content_layout.addLayout(self._build_sliders())
+        content_layout.addWidget(self._build_previews(), 1)
+        content_layout.addLayout(self._build_status_section())
 
         container_layout.addWidget(self.content, 1)
         self.setCentralWidget(container)
 
         self._is_maximised = False
         self._current_image_path: Path | None = None
+        self._current_colour = DEFAULT_COLOUR
+        self._toolbar_actions: Dict[str, Callable[[], None]] = {}
+        self._slider_controls: Dict[str, SliderControl] = {}
+        self._register_default_actions()
+        self._update_colour_display(DEFAULT_COLOUR, "Default colour")
 
     # Window control helpers -------------------------------------------------
 
@@ -206,6 +319,166 @@ class MainWindow(QtWidgets.QMainWindow):
         if handle:
             handle.startSystemMove()
 
+    # UI builders ------------------------------------------------------------
+
+    def _build_toolbar(self) -> QtWidgets.QHBoxLayout:
+        layout = QtWidgets.QHBoxLayout()
+        layout.setSpacing(12)
+
+        buttons = [
+            ("open_image", "🖼", "Open image…"),
+            ("open_folder", "📂", "Open folder…"),
+            ("choose_color", "🎨", "Choose colour"),
+            ("pick_from_image", "🖱", "Pick from image"),
+            ("save_overlay", "💾", "Save overlay"),
+            ("toggle_free_draw", "△", "Toggle free-draw"),
+            ("clear_excludes", "🧹", "Clear exclusions"),
+            ("undo_exclude", "↩", "Undo last exclusion"),
+            ("reset_sliders", "🔄", "Reset sliders"),
+            ("toggle_theme", "🌓", "Toggle theme"),
+        ]
+        self._toolbar_buttons: Dict[str, ToolbarButton] = {}
+        for key, icon_txt, label in buttons:
+            button = ToolbarButton(icon_txt, label, lambda k=key: self._invoke_action(k))
+            layout.addWidget(button)
+            self._toolbar_buttons[key] = button
+
+        layout.addStretch(1)
+        self.status_label = QtWidgets.QLabel("No image loaded")
+        self.status_label.setStyleSheet("color: rgba(255,255,255,0.7); font-weight: 500;")
+        layout.addWidget(self.status_label, 0, QtCore.Qt.AlignRight)
+        return layout
+
+    def _build_palette(self) -> QtWidgets.QHBoxLayout:
+        layout = QtWidgets.QHBoxLayout()
+        layout.setContentsMargins(0, 0, 0, 0)
+        layout.setSpacing(16)
+
+        current_group = QtWidgets.QHBoxLayout()
+        current_group.setSpacing(8)
+        current_label = QtWidgets.QLabel("Current colour")
+        current_label.setStyleSheet("color: rgba(255,255,255,0.75); font-weight: 500;")
+        current_group.addWidget(current_label)
+
+        self.current_colour_swatch = QtWidgets.QLabel()
+        self.current_colour_swatch.setFixedSize(28, 28)
+        self.current_colour_swatch.setStyleSheet(f"background-color: {DEFAULT_COLOUR}; border-radius: 6px;")
+        current_group.addWidget(self.current_colour_swatch)
+
+        self.current_colour_label = QtWidgets.QLabel(f"({DEFAULT_COLOUR})")
+        self.current_colour_label.setStyleSheet("color: rgba(255,255,255,0.65);")
+        current_group.addWidget(self.current_colour_label)
+        layout.addLayout(current_group)
+
+        more_label = QtWidgets.QLabel("More colours")
+        more_label.setStyleSheet("color: rgba(255,255,255,0.65); font-weight: 500;")
+        layout.addWidget(more_label)
+
+        swatch_container = QtWidgets.QHBoxLayout()
+        swatch_container.setSpacing(8)
+        for name, hex_code in PRESET_COLOURS:
+            swatch = ColourSwatch(name, hex_code, self._update_colour_display)
+            swatch_container.addWidget(swatch)
+        layout.addLayout(swatch_container)
+        layout.addStretch(1)
+        return layout
+
+    def _build_sliders(self) -> QtWidgets.QHBoxLayout:
+        layout = QtWidgets.QHBoxLayout()
+        layout.setSpacing(16)
+        self._slider_controls.clear()
+        for title, key, minimum, maximum, initial in SLIDER_SPECS:
+            control = SliderControl(title, key, minimum, maximum, initial)
+            control.value_changed.connect(self._on_slider_change)
+            layout.addWidget(control)
+            self._slider_controls[key] = control
+        return layout
+
+    def _build_previews(self) -> QtWidgets.QWidget:
+        container = QtWidgets.QWidget()
+        layout = QtWidgets.QGridLayout(container)
+        layout.setContentsMargins(0, 0, 0, 0)
+        layout.setHorizontalSpacing(16)
+        layout.setVerticalSpacing(0)
+
+        self.prev_button = QtWidgets.QToolButton()
+        self.prev_button.setText("◀")
+        self.prev_button.setCursor(QtCore.Qt.PointingHandCursor)
+        self.prev_button.setFixedSize(44, 44)
+        self.prev_button.setStyleSheet(
+            """
+            QToolButton {
+                border-radius: 22px;
+                background-color: rgba(255, 255, 255, 0.08);
+                color: #f7f7fb;
+                font-size: 18px;
+            }
+            QToolButton:hover {
+                background-color: rgba(255, 255, 255, 0.16);
+            }
+            """
+        )
+        self.prev_button.clicked.connect(lambda: self._invoke_action("show_previous_image"))
+        layout.addWidget(self.prev_button, 0, 0, QtCore.Qt.AlignVCenter)
+
+        self.image_view = ImageView()
+        self.image_view.setStyleSheet("border: 1px solid rgba(255,255,255,0.08); border-radius: 12px;")
+        layout.addWidget(self.image_view, 0, 1)
+
+        self.overlay_view = ImageView()
+        self.overlay_view.setStyleSheet("border: 1px solid rgba(255,255,255,0.08); border-radius: 12px;")
+        layout.addWidget(self.overlay_view, 0, 2)
+
+        self.next_button = QtWidgets.QToolButton()
+        self.next_button.setText("▶")
+        self.next_button.setCursor(QtCore.Qt.PointingHandCursor)
+        self.next_button.setFixedSize(44, 44)
+        self.next_button.setStyleSheet(self.prev_button.styleSheet())
+        self.next_button.clicked.connect(lambda: self._invoke_action("show_next_image"))
+        layout.addWidget(self.next_button, 0, 3, QtCore.Qt.AlignVCenter)
+        layout.setColumnStretch(1, 1)
+        layout.setColumnStretch(2, 1)
+        return container
+
+    def _build_status_section(self) -> QtWidgets.QVBoxLayout:
+        layout = QtWidgets.QVBoxLayout()
+        layout.setSpacing(8)
+        layout.setContentsMargins(0, 0, 0, 0)
+
+        self.filename_label = QtWidgets.QLabel("—")
+        self.filename_label.setAlignment(QtCore.Qt.AlignCenter)
+        self.filename_label.setStyleSheet("color: rgba(255,255,255,0.85); font-weight: 600;")
+        layout.addWidget(self.filename_label)
+
+        self.ratio_label = QtWidgets.QLabel("Matches with exclusions: —")
+        self.ratio_label.setAlignment(QtCore.Qt.AlignCenter)
+        self.ratio_label.setStyleSheet("color: #e6b84b; font-weight: 600;")
+        layout.addWidget(self.ratio_label)
+        return layout
+
+    # Action wiring ----------------------------------------------------------
+
+    def _register_default_actions(self) -> None:
+        self._toolbar_actions = {
+            "open_image": self.open_image,
+            "open_folder": self._coming_soon,
+            "choose_color": self._coming_soon,
+            "pick_from_image": self._coming_soon,
+            "save_overlay": self._coming_soon,
+            "toggle_free_draw": self._coming_soon,
+            "clear_excludes": self._coming_soon,
+            "undo_exclude": self._coming_soon,
+            "reset_sliders": self._reset_sliders,
+            "toggle_theme": self._coming_soon,
+            "show_previous_image": self._coming_soon,
+            "show_next_image": self._coming_soon,
+        }
+
+    def _invoke_action(self, key: str) -> None:
+        action = self._toolbar_actions.get(key)
+        if action:
+            action()
+
     # Image handling ---------------------------------------------------------
 
     def open_image(self) -> None:
@@ -219,5 +492,34 @@ class MainWindow(QtWidgets.QMainWindow):
             QtWidgets.QMessageBox.warning(self, "ICRA", "Unable to open the selected image.")
             return
         self.image_view.set_image(pixmap)
+        self.overlay_view.set_image(None)
         self._current_image_path = path
         self.status_label.setText(f"{path.name}  ·  {pixmap.width()}×{pixmap.height()}")
+        self.filename_label.setText(f"{path.name}  ({pixmap.width()}×{pixmap.height()})")
+        self.ratio_label.setText("Matches with exclusions: pending")
+
+    # Helpers ----------------------------------------------------------------
+
+    def _update_colour_display(self, hex_code: str, label: str) -> None:
+        self._current_colour = hex_code
+        self.current_colour_swatch.setStyleSheet(f"background-color: {hex_code}; border-radius: 6px;")
+        self.current_colour_label.setText(f"({hex_code})")
+        self.status_label.setText(f"{label}: {hex_code}")
+
+    def _on_slider_change(self, key: str, value: int) -> None:
+        formatted = key.replace("_", " ").title()
+        self.status_label.setText(f"{formatted} → {value}")
+
+    def _reset_sliders(self) -> None:
+        for _, key, _, _, initial in SLIDER_SPECS:
+            control = self._slider_controls.get(key)
+            if control:
+                control.set_value(initial)
+        self.status_label.setText("Sliders reset to defaults")
+
+    def _coming_soon(self) -> None:
+        QtWidgets.QMessageBox.information(
+            self,
+            "Coming soon",
+            "This action is not yet wired up in the PySide6 migration prototype.",
+        )