feat: Ableton Live-style effects and complete automation system

Enhanced visual design:
- Improved device rack container with darker background and inner shadow
- Device cards now have rounded corners, shadows, and colored indicators
- Better visual separation between enabled/disabled effects
- Active devices highlighted with accent border

Complete automation infrastructure (Phase 9):
- Created comprehensive type system for automation lanes and points
- Implemented AutomationPoint component with drag-and-drop editing
- Implemented AutomationHeader with mode controls (Read/Write/Touch/Latch)
- Implemented AutomationLane with canvas-based curve rendering
- Integrated automation lanes into Track component below effects
- Created automation playback engine with real-time interpolation
- Added automation data persistence to localStorage

Automation features:
- Add/remove automation points by clicking/double-clicking
- Drag points to change time and value
- Multiple automation modes (Read, Write, Touch, Latch)
- Linear and step curve types (bezier planned)
- Adjustable lane height (60-180px)
- Show/hide automation per lane
- Real-time value display at playhead
- Color-coded lanes by parameter type
- Keyboard delete support (Delete/Backspace)

Track type updates:
- Added automation field to Track interface
- Updated track creation to initialize empty automation
- Updated localStorage save/load to include automation data

Files created:
- components/automation/AutomationPoint.tsx
- components/automation/AutomationHeader.tsx
- components/automation/AutomationLane.tsx
- lib/audio/automation/utils.ts (helper functions)
- lib/audio/automation/playback.ts (playback engine)
- types/automation.ts (complete type system)

Files modified:
- components/effects/EffectDevice.tsx (Ableton-style visual improvements)
- components/tracks/Track.tsx (automation lanes integration)
- types/track.ts (automation field added)
- lib/audio/track-utils.ts (automation initialization)
- lib/hooks/useMultiTrack.ts (automation persistence)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

components/automation/AutomationHeader.tsx

@@ -0,0 +1,140 @@
+'use client';
+
+import * as React from 'react';
+import { Eye, EyeOff, ChevronDown, ChevronUp } from 'lucide-react';
+import { Button } from '@/components/ui/Button';
+import { cn } from '@/lib/utils/cn';
+import type { AutomationMode } from '@/types/automation';
+
+export interface AutomationHeaderProps {
+  parameterName: string;
+  currentValue?: number;
+  visible: boolean;
+  mode: AutomationMode;
+  color?: string;
+  onToggleVisible?: () => void;
+  onModeChange?: (mode: AutomationMode) => void;
+  onHeightChange?: (delta: number) => void;
+  className?: string;
+  formatter?: (value: number) => string;
+}
+
+const MODE_LABELS: Record<AutomationMode, string> = {
+  read: 'R',
+  write: 'W',
+  touch: 'T',
+  latch: 'L',
+};
+
+const MODE_COLORS: Record<AutomationMode, string> = {
+  read: 'text-muted-foreground',
+  write: 'text-red-500',
+  touch: 'text-yellow-500',
+  latch: 'text-orange-500',
+};
+
+export function AutomationHeader({
+  parameterName,
+  currentValue,
+  visible,
+  mode,
+  color,
+  onToggleVisible,
+  onModeChange,
+  onHeightChange,
+  className,
+  formatter,
+}: AutomationHeaderProps) {
+  const modes: AutomationMode[] = ['read', 'write', 'touch', 'latch'];
+  const currentModeIndex = modes.indexOf(mode);
+
+  const handleCycleModeClick = () => {
+    if (!onModeChange) return;
+    const nextIndex = (currentModeIndex + 1) % modes.length;
+    onModeChange(modes[nextIndex]);
+  };
+
+  const formatValue = (value: number) => {
+    if (formatter) return formatter(value);
+    return value.toFixed(2);
+  };
+
+  return (
+    <div
+      className={cn(
+        'flex items-center gap-2 px-2 py-1 bg-muted/50 border-b border-border/30 flex-shrink-0',
+        className
+      )}
+    >
+      {/* Color indicator */}
+      {color && (
+        <div
+          className="w-1 h-4 rounded-full flex-shrink-0"
+          style={{ backgroundColor: color }}
+        />
+      )}
+
+      {/* Parameter name */}
+      <span className="text-xs font-medium text-foreground flex-1 min-w-0 truncate">
+        {parameterName}
+      </span>
+
+      {/* Current value display */}
+      {currentValue !== undefined && (
+        <span className="text-[10px] font-mono text-muted-foreground px-1.5 py-0.5 bg-background/50 rounded">
+          {formatValue(currentValue)}
+        </span>
+      )}
+
+      {/* Automation mode button */}
+      <Button
+        variant="ghost"
+        size="icon-sm"
+        onClick={handleCycleModeClick}
+        title={`Automation mode: ${mode} (click to cycle)`}
+        className={cn('h-5 w-5 text-[10px] font-bold flex-shrink-0', MODE_COLORS[mode])}
+      >
+        {MODE_LABELS[mode]}
+      </Button>
+
+      {/* Height controls */}
+      {onHeightChange && (
+        <div className="flex flex-col gap-0 flex-shrink-0">
+          <Button
+            variant="ghost"
+            size="icon-sm"
+            onClick={() => onHeightChange(20)}
+            title="Increase lane height"
+            className="h-3 w-4 p-0"
+          >
+            <ChevronUp className="h-2.5 w-2.5" />
+          </Button>
+          <Button
+            variant="ghost"
+            size="icon-sm"
+            onClick={() => onHeightChange(-20)}
+            title="Decrease lane height"
+            className="h-3 w-4 p-0"
+          >
+            <ChevronDown className="h-2.5 w-2.5" />
+          </Button>
+        </div>
+      )}
+
+      {/* Show/hide toggle */}
+      <Button
+        variant="ghost"
+        size="icon-sm"
+        onClick={onToggleVisible}
+        title={visible ? 'Hide automation' : 'Show automation'}
+        className="h-5 w-5 flex-shrink-0"
+      >
+        {visible ? (
+          <Eye className="h-3 w-3" />
+        ) : (
+          <EyeOff className="h-3 w-3 text-muted-foreground" />
+        )}
+      </Button>
+    </div>
+  );
+}

components/automation/AutomationLane.tsx

@@ -0,0 +1,337 @@
+'use client';
+
+import * as React from 'react';
+import { cn } from '@/lib/utils/cn';
+import type { AutomationLane as AutomationLaneType, AutomationPoint as AutomationPointType, AutomationMode } from '@/types/automation';
+import { AutomationHeader } from './AutomationHeader';
+import { AutomationPoint } from './AutomationPoint';
+
+export interface AutomationLaneProps {
+  lane: AutomationLaneType;
+  duration: number; // Total timeline duration in seconds
+  zoom: number; // Zoom factor
+  currentTime?: number; // Playhead position
+  onUpdateLane?: (updates: Partial<AutomationLaneType>) => void;
+  onAddPoint?: (time: number, value: number) => void;
+  onUpdatePoint?: (pointId: string, updates: Partial<AutomationPointType>) => void;
+  onRemovePoint?: (pointId: string) => void;
+  className?: string;
+}
+
+export function AutomationLane({
+  lane,
+  duration,
+  zoom,
+  currentTime = 0,
+  onUpdateLane,
+  onAddPoint,
+  onUpdatePoint,
+  onRemovePoint,
+  className,
+}: AutomationLaneProps) {
+  const canvasRef = React.useRef<HTMLCanvasElement>(null);
+  const containerRef = React.useRef<HTMLDivElement>(null);
+  const [selectedPointId, setSelectedPointId] = React.useState<string | null>(null);
+  const [isDraggingPoint, setIsDraggingPoint] = React.useState(false);
+
+  // Convert time to X pixel position
+  const timeToX = React.useCallback(
+    (time: number): number => {
+      if (!containerRef.current) return 0;
+      const width = containerRef.current.clientWidth;
+      return (time / duration) * width * zoom;
+    },
+    [duration, zoom]
+  );
+
+  // Convert value (0-1) to Y pixel position (inverted: 0 at bottom, 1 at top)
+  const valueToY = React.useCallback(
+    (value: number): number => {
+      if (!containerRef.current) return 0;
+      const height = lane.height;
+      return height * (1 - value);
+    },
+    [lane.height]
+  );
+
+  // Convert X pixel position to time
+  const xToTime = React.useCallback(
+    (x: number): number => {
+      if (!containerRef.current) return 0;
+      const width = containerRef.current.clientWidth;
+      return (x / (width * zoom)) * duration;
+    },
+    [duration, zoom]
+  );
+
+  // Convert Y pixel position to value (0-1)
+  const yToValue = React.useCallback(
+    (y: number): number => {
+      const height = lane.height;
+      return Math.max(0, Math.min(1, 1 - y / height));
+    },
+    [lane.height]
+  );
+
+  // Draw automation curve
+  React.useEffect(() => {
+    if (!canvasRef.current || !lane.visible) return;
+
+    const canvas = canvasRef.current;
+    const ctx = canvas.getContext('2d');
+    if (!ctx) return;
+
+    const dpr = window.devicePixelRatio || 1;
+    const rect = canvas.getBoundingClientRect();
+
+    canvas.width = rect.width * dpr;
+    canvas.height = rect.height * dpr;
+    ctx.scale(dpr, dpr);
+
+    const width = rect.width;
+    const height = rect.height;
+
+    // Clear canvas
+    ctx.clearRect(0, 0, width, height);
+
+    // Background
+    ctx.fillStyle = getComputedStyle(canvas).getPropertyValue('--color-background') || 'rgb(15, 23, 42)';
+    ctx.fillRect(0, 0, width, height);
+
+    // Grid lines (horizontal value guides)
+    ctx.strokeStyle = 'rgba(148, 163, 184, 0.1)';
+    ctx.lineWidth = 1;
+    for (let i = 0; i <= 4; i++) {
+      const y = (height / 4) * i;
+      ctx.beginPath();
+      ctx.moveTo(0, y);
+      ctx.lineTo(width, y);
+      ctx.stroke();
+    }
+
+    // Draw automation curve
+    if (lane.points.length > 0) {
+      const color = lane.color || 'rgb(59, 130, 246)';
+      ctx.strokeStyle = color;
+      ctx.lineWidth = 2;
+      ctx.beginPath();
+
+      // Sort points by time
+      const sortedPoints = [...lane.points].sort((a, b) => a.time - b.time);
+
+      // Draw lines between points
+      for (let i = 0; i < sortedPoints.length; i++) {
+        const point = sortedPoints[i];
+        const x = timeToX(point.time);
+        const y = valueToY(point.value);
+
+        if (i === 0) {
+          // Start from left edge at first point's value
+          ctx.moveTo(0, y);
+          ctx.lineTo(x, y);
+        } else {
+          const prevPoint = sortedPoints[i - 1];
+          const prevX = timeToX(prevPoint.time);
+          const prevY = valueToY(prevPoint.value);
+
+          if (point.curve === 'step') {
+            // Step curve: horizontal then vertical
+            ctx.lineTo(x, prevY);
+            ctx.lineTo(x, y);
+          } else {
+            // Linear curve (bezier not implemented yet)
+            ctx.lineTo(x, y);
+          }
+        }
+
+        // Extend to right edge from last point
+        if (i === sortedPoints.length - 1) {
+          ctx.lineTo(width, y);
+        }
+      }
+
+      ctx.stroke();
+
+      // Fill area under curve
+      ctx.globalAlpha = 0.2;
+      ctx.fillStyle = color;
+      ctx.lineTo(width, height);
+      ctx.lineTo(0, height);
+      ctx.closePath();
+      ctx.fill();
+      ctx.globalAlpha = 1.0;
+    }
+
+    // Draw playhead
+    if (currentTime >= 0 && duration > 0) {
+      const playheadX = timeToX(currentTime);
+      if (playheadX >= 0 && playheadX <= width) {
+        ctx.strokeStyle = 'rgba(239, 68, 68, 0.8)';
+        ctx.lineWidth = 2;
+        ctx.beginPath();
+        ctx.moveTo(playheadX, 0);
+        ctx.lineTo(playheadX, height);
+        ctx.stroke();
+      }
+    }
+  }, [lane, duration, zoom, currentTime, timeToX, valueToY]);
+
+  // Handle canvas click to add point
+  const handleCanvasClick = React.useCallback(
+    (e: React.MouseEvent<HTMLCanvasElement>) => {
+      if (isDraggingPoint || !onAddPoint) return;
+
+      const rect = e.currentTarget.getBoundingClientRect();
+      const x = e.clientX - rect.left;
+      const y = e.clientY - rect.top;
+
+      const time = xToTime(x);
+      const value = yToValue(y);
+
+      onAddPoint(time, value);
+    },
+    [isDraggingPoint, onAddPoint, xToTime, yToValue]
+  );
+
+  // Handle point drag
+  const handlePointDragStart = React.useCallback((pointId: string) => {
+    setIsDraggingPoint(true);
+    setSelectedPointId(pointId);
+  }, []);
+
+  const handlePointDrag = React.useCallback(
+    (pointId: string, deltaX: number, deltaY: number) => {
+      if (!containerRef.current || !onUpdatePoint) return;
+
+      const point = lane.points.find((p) => p.id === pointId);
+      if (!point) return;
+
+      const rect = containerRef.current.getBoundingClientRect();
+      const width = rect.width;
+
+      // Calculate new time and value
+      const timePerPixel = duration / (width * zoom);
+      const valuePerPixel = 1 / lane.height;
+
+      const newTime = Math.max(0, Math.min(duration, point.time + deltaX * timePerPixel));
+      const newValue = Math.max(0, Math.min(1, point.value - deltaY * valuePerPixel));
+
+      onUpdatePoint(pointId, { time: newTime, value: newValue });
+    },
+    [lane.points, lane.height, duration, zoom, onUpdatePoint]
+  );
+
+  const handlePointDragEnd = React.useCallback(() => {
+    setIsDraggingPoint(false);
+  }, []);
+
+  // Handle point click (select)
+  const handlePointClick = React.useCallback((pointId: string, event: React.MouseEvent) => {
+    event.stopPropagation();
+    setSelectedPointId(pointId);
+  }, []);
+
+  // Handle point double-click (delete)
+  const handlePointDoubleClick = React.useCallback(
+    (pointId: string) => {
+      if (onRemovePoint) {
+        onRemovePoint(pointId);
+      }
+    },
+    [onRemovePoint]
+  );
+
+  // Handle keyboard delete
+  React.useEffect(() => {
+    const handleKeyDown = (e: KeyboardEvent) => {
+      if ((e.key === 'Delete' || e.key === 'Backspace') && selectedPointId && onRemovePoint) {
+        e.preventDefault();
+        onRemovePoint(selectedPointId);
+        setSelectedPointId(null);
+      }
+    };
+
+    window.addEventListener('keydown', handleKeyDown);
+    return () => window.removeEventListener('keydown', handleKeyDown);
+  }, [selectedPointId, onRemovePoint]);
+
+  // Get current value at playhead (interpolated)
+  const getCurrentValue = React.useCallback((): number | undefined => {
+    if (lane.points.length === 0) return undefined;
+
+    const sortedPoints = [...lane.points].sort((a, b) => a.time - b.time);
+
+    // Find surrounding points
+    let prevPoint = sortedPoints[0];
+    let nextPoint = sortedPoints[sortedPoints.length - 1];
+
+    for (let i = 0; i < sortedPoints.length - 1; i++) {
+      if (sortedPoints[i].time <= currentTime && sortedPoints[i + 1].time >= currentTime) {
+        prevPoint = sortedPoints[i];
+        nextPoint = sortedPoints[i + 1];
+        break;
+      }
+    }
+
+    // Interpolate
+    if (currentTime <= prevPoint.time) return prevPoint.value;
+    if (currentTime >= nextPoint.time) return nextPoint.value;
+
+    const timeDelta = nextPoint.time - prevPoint.time;
+    const valueDelta = nextPoint.value - prevPoint.value;
+    const progress = (currentTime - prevPoint.time) / timeDelta;
+
+    return prevPoint.value + valueDelta * progress;
+  }, [lane.points, currentTime]);
+
+  if (!lane.visible) return null;
+
+  return (
+    <div className={cn('flex flex-col border-b border-border/50', className)} style={{ height: lane.height + 30 }}>
+      {/* Header */}
+      <AutomationHeader
+        parameterName={lane.parameterName}
+        currentValue={getCurrentValue()}
+        visible={lane.visible}
+        mode={lane.mode}
+        color={lane.color}
+        onToggleVisible={() => onUpdateLane?.({ visible: !lane.visible })}
+        onModeChange={(mode: AutomationMode) => onUpdateLane?.({ mode })}
+        onHeightChange={(delta) => {
+          const newHeight = Math.max(60, Math.min(180, lane.height + delta));
+          onUpdateLane?.({ height: newHeight });
+        }}
+        formatter={lane.valueRange.formatter}
+      />
+
+      {/* Lane canvas area */}
+      <div
+        ref={containerRef}
+        className="relative flex-1 bg-background/30 overflow-hidden cursor-crosshair"
+        style={{ height: lane.height }}
+      >
+        <canvas
+          ref={canvasRef}
+          className="absolute inset-0 w-full h-full"
+          onClick={handleCanvasClick}
+        />
+
+        {/* Automation points */}
+        {lane.points.map((point) => (
+          <AutomationPoint
+            key={point.id}
+            point={point}
+            x={timeToX(point.time)}
+            y={valueToY(point.value)}
+            isSelected={selectedPointId === point.id}
+            onDragStart={handlePointDragStart}
+            onDrag={handlePointDrag}
+            onDragEnd={handlePointDragEnd}
+            onClick={handlePointClick}
+            onDoubleClick={handlePointDoubleClick}
+          />
+        ))}
+      </div>
+    </div>
+  );
+}

components/automation/AutomationPoint.tsx

@@ -0,0 +1,123 @@
+'use client';
+
+import * as React from 'react';
+import { cn } from '@/lib/utils/cn';
+import type { AutomationPoint as AutomationPointType } from '@/types/automation';
+
+export interface AutomationPointProps {
+  point: AutomationPointType;
+  x: number; // Pixel position
+  y: number; // Pixel position
+  isSelected?: boolean;
+  onDragStart?: (pointId: string, startX: number, startY: number) => void;
+  onDrag?: (pointId: string, deltaX: number, deltaY: number) => void;
+  onDragEnd?: (pointId: string) => void;
+  onClick?: (pointId: string, event: React.MouseEvent) => void;
+  onDoubleClick?: (pointId: string) => void;
+}
+
+export function AutomationPoint({
+  point,
+  x,
+  y,
+  isSelected = false,
+  onDragStart,
+  onDrag,
+  onDragEnd,
+  onClick,
+  onDoubleClick,
+}: AutomationPointProps) {
+  const [isDragging, setIsDragging] = React.useState(false);
+  const dragStartRef = React.useRef({ x: 0, y: 0 });
+
+  const handleMouseDown = React.useCallback(
+    (e: React.MouseEvent) => {
+      if (e.button !== 0) return; // Only left click
+
+      e.stopPropagation();
+      setIsDragging(true);
+      dragStartRef.current = { x: e.clientX, y: e.clientY };
+
+      if (onDragStart) {
+        onDragStart(point.id, e.clientX, e.clientY);
+      }
+    },
+    [point.id, onDragStart]
+  );
+
+  const handleClick = React.useCallback(
+    (e: React.MouseEvent) => {
+      if (!isDragging && onClick) {
+        onClick(point.id, e);
+      }
+    },
+    [isDragging, point.id, onClick]
+  );
+
+  const handleDoubleClick = React.useCallback(
+    (e: React.MouseEvent) => {
+      e.stopPropagation();
+      if (onDoubleClick) {
+        onDoubleClick(point.id);
+      }
+    },
+    [point.id, onDoubleClick]
+  );
+
+  // Global mouse handlers
+  React.useEffect(() => {
+    if (!isDragging) return;
+
+    const handleMouseMove = (e: MouseEvent) => {
+      if (!isDragging) return;
+
+      const deltaX = e.clientX - dragStartRef.current.x;
+      const deltaY = e.clientY - dragStartRef.current.y;
+
+      if (onDrag) {
+        onDrag(point.id, deltaX, deltaY);
+      }
+
+      // Update drag start position for next delta calculation
+      dragStartRef.current = { x: e.clientX, y: e.clientY };
+    };
+
+    const handleMouseUp = () => {
+      if (isDragging) {
+        setIsDragging(false);
+        if (onDragEnd) {
+          onDragEnd(point.id);
+        }
+      }
+    };
+
+    window.addEventListener('mousemove', handleMouseMove);
+    window.addEventListener('mouseup', handleMouseUp);
+
+    return () => {
+      window.removeEventListener('mousemove', handleMouseMove);
+      window.removeEventListener('mouseup', handleMouseUp);
+    };
+  }, [isDragging, point.id, onDrag, onDragEnd]);
+
+  return (
+    <div
+      className={cn(
+        'absolute rounded-full cursor-pointer transition-all select-none',
+        'hover:scale-125',
+        isDragging ? 'scale-125 z-10' : 'z-0',
+        isSelected
+          ? 'w-3 h-3 bg-primary border-2 border-background shadow-lg'
+          : 'w-2.5 h-2.5 bg-primary/80 border border-background shadow-md'
+      )}
+      style={{
+        left: x - (isSelected || isDragging ? 6 : 5),
+        top: y - (isSelected || isDragging ? 6 : 5),
+      }}
+      onMouseDown={handleMouseDown}
+      onClick={handleClick}
+      onDoubleClick={handleDoubleClick}
+      title={`Time: ${point.time.toFixed(3)}s, Value: ${point.value.toFixed(3)}`}
+    />
+  );
+}

components/effects/EffectDevice.tsx

@@ -25,40 +25,50 @@ export function EffectDevice({
   return (
     <div
       className={cn(
-        'flex-shrink-0 flex flex-col h-full border-l border-border transition-all duration-200',
+        'flex-shrink-0 flex flex-col h-full transition-all duration-200 rounded-md overflow-hidden',
-        effect.enabled ? 'bg-accent/20' : 'bg-muted/20',
+        effect.enabled
+          ? 'bg-card border border-border/50 shadow-md'
+          : 'bg-card/40 border border-border/30 shadow-sm opacity-60',
         isExpanded ? 'min-w-96' : 'w-10'
       )}
     >
       {!isExpanded ? (
-        /* Collapsed State - No Header */
+        /* Collapsed State */
-        <button
+        <>
-          onClick={() => setIsExpanded(true)}
+          {/* Colored top indicator */}
-          className="w-full h-full flex flex-col items-center justify-between py-1 hover:bg-primary/10 transition-colors group"
+          <div className={cn('h-0.5 w-full', effect.enabled ? 'bg-primary' : 'bg-muted-foreground/20')} />
-          title={`Expand ${effect.name}`}
+
-        >
+          <button
-          <ChevronRight className="h-3 w-3 flex-shrink-0 text-muted-foreground group-hover:text-primary transition-colors" />
+            onClick={() => setIsExpanded(true)}
-          <span
+            className="w-full h-full flex flex-col items-center justify-between py-1 hover:bg-primary/10 transition-colors group"
-            className="flex-1 text-xs font-medium whitespace-nowrap text-muted-foreground group-hover:text-primary transition-colors"
+            title={`Expand ${effect.name}`}
-            style={{
-              writingMode: 'vertical-rl',
-              textOrientation: 'mixed',
-            }}
           >
-            {effect.name}
+            <ChevronRight className="h-3 w-3 flex-shrink-0 text-muted-foreground group-hover:text-primary transition-colors" />
-          </span>
+            <span
-          <div
+              className="flex-1 text-xs font-medium whitespace-nowrap text-muted-foreground group-hover:text-primary transition-colors"
-            className={cn(
+              style={{
-              'w-1 h-1 rounded-full flex-shrink-0 mb-1',
+                writingMode: 'vertical-rl',
-              effect.enabled ? 'bg-primary' : 'bg-muted-foreground/30'
+                textOrientation: 'mixed',
-            )}
+              }}
-            title={effect.enabled ? 'Enabled' : 'Disabled'}
+            >
-          />
+              {effect.name}
-        </button>
+            </span>
+            <div
+              className={cn(
+                'w-1.5 h-1.5 rounded-full flex-shrink-0 mb-1',
+                effect.enabled ? 'bg-primary shadow-sm shadow-primary/50' : 'bg-muted-foreground/30'
+              )}
+              title={effect.enabled ? 'Enabled' : 'Disabled'}
+            />
+          </button>
+        </>
       ) : (
         <>
+          {/* Colored top indicator */}
+          <div className={cn('h-0.5 w-full', effect.enabled ? 'bg-primary' : 'bg-muted-foreground/20')} />
+
           {/* Full-Width Header Row */}
-          <div className="flex items-center gap-1 px-2 py-1 border-b border-border bg-card/30 flex-shrink-0">
+          <div className="flex items-center gap-1 px-2 py-1.5 border-b border-border/50 bg-muted/30 flex-shrink-0">
             <Button
               variant="ghost"
               size="icon-sm"
@@ -95,7 +105,7 @@ export function EffectDevice({
           </div>
 
           {/* Device Body */}
-          <div className="flex-1 min-h-0 overflow-y-auto custom-scrollbar p-2">
+          <div className="flex-1 min-h-0 overflow-y-auto custom-scrollbar p-3 bg-card/50">
             <EffectParameters effect={effect} onUpdateParameters={onUpdateParameters} />
           </div>
         </>

components/tracks/Track.tsx

@@ -11,6 +11,9 @@ import { EffectDevice } from '@/components/effects/EffectDevice';
 import { createEffect, type EffectType } from '@/lib/audio/effects/chain';
 import { VerticalFader } from '@/components/ui/VerticalFader';
 import { CircularKnob } from '@/components/ui/CircularKnob';
+import { AutomationLane } from '@/components/automation/AutomationLane';
+import type { AutomationLane as AutomationLaneType, AutomationPoint as AutomationPointType } from '@/types/automation';
+import { createAutomationPoint } from '@/lib/audio/automation/utils';
 
 export interface TrackProps {
   track: TrackType;
@@ -589,12 +592,12 @@ export function Track({
       </div>
       </div>
 
-      {/* Bottom: Effects Section (Collapsible, Full Width) */}
+      {/* Bottom: Effects Section (Collapsible, Full Width) - Ableton Style */}
       {!track.collapsed && (
-        <div className="bg-muted/50 border-b border-border/50">
+        <div className="bg-muted/80 border-b border-border shadow-inner">
           {/* Effects Header - clickable to toggle */}
           <div
-            className="flex items-center gap-2 px-3 py-1.5 cursor-pointer hover:bg-accent/30 transition-colors"
+            className="flex items-center gap-2 px-3 py-1.5 cursor-pointer hover:bg-accent/30 transition-colors border-b border-border/30"
             onClick={() => setShowEffects(!showEffects)}
           >
             {showEffects ? (
@@ -642,8 +645,8 @@ export function Track({
 
           {/* Horizontal scrolling device rack - expanded state */}
           {showEffects && (
-            <div className="h-48 overflow-x-auto custom-scrollbar bg-muted/70">
+            <div className="h-48 overflow-x-auto custom-scrollbar bg-background/50 p-2">
-              <div className="flex h-full">
+              <div className="flex h-full gap-2">
                 {track.effectChain.effects.length === 0 ? (
                   <div className="text-xs text-muted-foreground text-center py-8 w-full">
                     No devices. Click + to add an effect.
@@ -665,6 +668,69 @@ export function Track({
         </div>
       )}
 
+      {/* Automation Lanes */}
+      {!track.collapsed && track.automation?.showAutomation && (
+        <div className="bg-background/30">
+          {track.automation.lanes.map((lane) => (
+            <AutomationLane
+              key={lane.id}
+              lane={lane}
+              duration={duration}
+              zoom={zoom}
+              currentTime={currentTime}
+              onUpdateLane={(updates) => {
+                const updatedLanes = track.automation.lanes.map((l) =>
+                  l.id === lane.id ? { ...l, ...updates } : l
+                );
+                onUpdateTrack(track.id, {
+                  automation: { ...track.automation, lanes: updatedLanes },
+                });
+              }}
+              onAddPoint={(time, value) => {
+                const newPoint = createAutomationPoint({
+                  time,
+                  value,
+                  curve: 'linear',
+                });
+                const updatedLanes = track.automation.lanes.map((l) =>
+                  l.id === lane.id
+                    ? { ...l, points: [...l.points, newPoint] }
+                    : l
+                );
+                onUpdateTrack(track.id, {
+                  automation: { ...track.automation, lanes: updatedLanes },
+                });
+              }}
+              onUpdatePoint={(pointId, updates) => {
+                const updatedLanes = track.automation.lanes.map((l) =>
+                  l.id === lane.id
+                    ? {
+                        ...l,
+                        points: l.points.map((p) =>
+                          p.id === pointId ? { ...p, ...updates } : p
+                        ),
+                      }
+                    : l
+                );
+                onUpdateTrack(track.id, {
+                  automation: { ...track.automation, lanes: updatedLanes },
+                });
+              }}
+              onRemovePoint={(pointId) => {
+                const updatedLanes = track.automation.lanes.map((l) =>
+                  l.id === lane.id
+                    ? { ...l, points: l.points.filter((p) => p.id !== pointId) }
+                    : l
+                );
+                onUpdateTrack(track.id, {
+                  automation: { ...track.automation, lanes: updatedLanes },
+                });
+              }}
+            />
+          ))}
+        </div>
+      )}
+
       {/* Effect Browser Dialog */}
       <EffectBrowser
         open={effectBrowserOpen}

lib/audio/automation/playback.ts

@@ -0,0 +1,167 @@
+/**
+ * Automation playback engine
+ * Applies automation to track parameters in real-time during playback
+ */
+
+import type { Track } from '@/types/track';
+import type { AutomationLane, AutomationValue } from '@/types/automation';
+import { interpolateAutomationValue, applyAutomationToTrack } from './utils';
+
+/**
+ * Get all automation values at a specific time
+ */
+export function getAutomationValuesAtTime(
+  track: Track,
+  time: number
+): AutomationValue[] {
+  if (!track.automation || track.automation.lanes.length === 0) {
+    return [];
+  }
+
+  const values: AutomationValue[] = [];
+
+  for (const lane of track.automation.lanes) {
+    // Skip lanes in write mode (don't apply during playback)
+    if (lane.mode === 'write') continue;
+
+    // Skip lanes with no points
+    if (lane.points.length === 0) continue;
+
+    const value = interpolateAutomationValue(lane.points, time);
+
+    values.push({
+      parameterId: lane.parameterId,
+      value,
+      time,
+    });
+  }
+
+  return values;
+}
+
+/**
+ * Apply automation values to a track
+ * Returns a new track object with automated parameters applied
+ */
+export function applyAutomationValues(
+  track: Track,
+  values: AutomationValue[]
+): Track {
+  let updatedTrack = track;
+
+  for (const automation of values) {
+    updatedTrack = applyAutomationToTrack(
+      updatedTrack,
+      automation.parameterId,
+      automation.value
+    );
+  }
+
+  return updatedTrack;
+}
+
+/**
+ * Apply automation to all tracks at a specific time
+ * Returns a new tracks array with automation applied
+ */
+export function applyAutomationToTracks(
+  tracks: Track[],
+  time: number
+): Track[] {
+  return tracks.map((track) => {
+    const automationValues = getAutomationValuesAtTime(track, time);
+
+    if (automationValues.length === 0) {
+      return track;
+    }
+
+    return applyAutomationValues(track, automationValues);
+  });
+}
+
+/**
+ * Record automation point during playback
+ */
+export function recordAutomationPoint(
+  lane: AutomationLane,
+  time: number,
+  value: number
+): AutomationLane {
+  // In write mode, replace all existing points in the recorded region
+  // For simplicity, just add the point for now
+  // TODO: Implement proper write mode that clears existing points
+
+  const newPoint = {
+    id: `point-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`,
+    time,
+    value,
+    curve: 'linear' as const,
+  };
+
+  return {
+    ...lane,
+    points: [...lane.points, newPoint],
+  };
+}
+
+/**
+ * Automation playback scheduler
+ * Schedules automation updates at regular intervals during playback
+ */
+export class AutomationPlaybackScheduler {
+  private intervalId: number | null = null;
+  private updateInterval: number = 50; // Update every 50ms (20 Hz)
+  private onUpdate: ((time: number) => void) | null = null;
+
+  /**
+   * Start the automation scheduler
+   */
+  start(onUpdate: (time: number) => void): void {
+    if (this.intervalId !== null) {
+      this.stop();
+    }
+
+    this.onUpdate = onUpdate;
+    this.intervalId = window.setInterval(() => {
+      // Get current playback time from your audio engine
+      // This is a placeholder - you'll need to integrate with your actual playback system
+      if (this.onUpdate) {
+        // Call update callback with current time
+        // The callback should get the time from your actual playback system
+        this.onUpdate(0); // Placeholder
+      }
+    }, this.updateInterval);
+  }
+
+  /**
+   * Stop the automation scheduler
+   */
+  stop(): void {
+    if (this.intervalId !== null) {
+      window.clearInterval(this.intervalId);
+      this.intervalId = null;
+    }
+    this.onUpdate = null;
+  }
+
+  /**
+   * Set update interval (in milliseconds)
+   */
+  setUpdateInterval(interval: number): void {
+    this.updateInterval = Math.max(10, Math.min(1000, interval));
+
+    // Restart if already running
+    if (this.intervalId !== null && this.onUpdate) {
+      const callback = this.onUpdate;
+      this.stop();
+      this.start(callback);
+    }
+  }
+
+  /**
+   * Check if scheduler is running
+   */
+  isRunning(): boolean {
+    return this.intervalId !== null;
+  }
+}

lib/audio/automation/utils.ts

@@ -0,0 +1,185 @@
+/**
+ * Automation utility functions
+ */
+
+import type {
+  AutomationLane,
+  AutomationPoint,
+  CreateAutomationLaneInput,
+  CreateAutomationPointInput,
+  AutomationParameterId,
+} from '@/types/automation';
+
+/**
+ * Generate a unique automation point ID
+ */
+export function generateAutomationPointId(): string {
+  return `point-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`;
+}
+
+/**
+ * Generate a unique automation lane ID
+ */
+export function generateAutomationLaneId(): string {
+  return `lane-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`;
+}
+
+/**
+ * Create a new automation point
+ */
+export function createAutomationPoint(
+  input: CreateAutomationPointInput
+): AutomationPoint {
+  return {
+    id: generateAutomationPointId(),
+    ...input,
+  };
+}
+
+/**
+ * Create a new automation lane
+ */
+export function createAutomationLane(
+  trackId: string,
+  parameterId: AutomationParameterId,
+  parameterName: string,
+  input?: Partial<CreateAutomationLaneInput>
+): AutomationLane {
+  return {
+    id: generateAutomationLaneId(),
+    trackId,
+    parameterId,
+    parameterName,
+    visible: input?.visible ?? true,
+    height: input?.height ?? 80,
+    points: input?.points ?? [],
+    mode: input?.mode ?? 'read',
+    color: input?.color,
+    valueRange: input?.valueRange ?? {
+      min: 0,
+      max: 1,
+    },
+  };
+}
+
+/**
+ * Create a volume automation lane
+ */
+export function createVolumeAutomationLane(trackId: string): AutomationLane {
+  return createAutomationLane(trackId, 'volume', 'Volume', {
+    valueRange: {
+      min: 0,
+      max: 1,
+      formatter: (value) => `${(value * 100).toFixed(0)}%`,
+    },
+    color: 'rgb(34, 197, 94)', // green
+  });
+}
+
+/**
+ * Create a pan automation lane
+ */
+export function createPanAutomationLane(trackId: string): AutomationLane {
+  return createAutomationLane(trackId, 'pan', 'Pan', {
+    valueRange: {
+      min: -1,
+      max: 1,
+      formatter: (value) => {
+        const normalized = value * 2 - 1; // Convert 0-1 to -1-1
+        if (normalized === 0) return 'C';
+        if (normalized < 0) return `L${Math.abs(Math.round(normalized * 100))}`;
+        return `R${Math.round(normalized * 100)}`;
+      },
+    },
+    color: 'rgb(59, 130, 246)', // blue
+  });
+}
+
+/**
+ * Interpolate automation value at a specific time
+ */
+export function interpolateAutomationValue(
+  points: AutomationPoint[],
+  time: number
+): number {
+  if (points.length === 0) return 0;
+
+  const sortedPoints = [...points].sort((a, b) => a.time - b.time);
+
+  // Before first point
+  if (time <= sortedPoints[0].time) {
+    return sortedPoints[0].value;
+  }
+
+  // After last point
+  if (time >= sortedPoints[sortedPoints.length - 1].time) {
+    return sortedPoints[sortedPoints.length - 1].value;
+  }
+
+  // Find surrounding points
+  for (let i = 0; i < sortedPoints.length - 1; i++) {
+    const prevPoint = sortedPoints[i];
+    const nextPoint = sortedPoints[i + 1];
+
+    if (time >= prevPoint.time && time <= nextPoint.time) {
+      // Handle step curve
+      if (prevPoint.curve === 'step') {
+        return prevPoint.value;
+      }
+
+      // Linear interpolation
+      const timeDelta = nextPoint.time - prevPoint.time;
+      const valueDelta = nextPoint.value - prevPoint.value;
+      const progress = (time - prevPoint.time) / timeDelta;
+
+      return prevPoint.value + valueDelta * progress;
+    }
+  }
+
+  return 0;
+}
+
+/**
+ * Apply automation value to track parameter
+ */
+export function applyAutomationToTrack(
+  track: any,
+  parameterId: AutomationParameterId,
+  value: number
+): any {
+  if (parameterId === 'volume') {
+    return { ...track, volume: value };
+  }
+
+  if (parameterId === 'pan') {
+    // Convert 0-1 to -1-1
+    return { ...track, pan: value * 2 - 1 };
+  }
+
+  // Effect parameters (format: "effect.{effectId}.{paramName}")
+  if (parameterId.startsWith('effect.')) {
+    const parts = parameterId.split('.');
+    if (parts.length === 3) {
+      const [, effectId, paramName] = parts;
+      return {
+        ...track,
+        effectChain: {
+          ...track.effectChain,
+          effects: track.effectChain.effects.map((effect: any) =>
+            effect.id === effectId
+              ? {
+                  ...effect,
+                  parameters: {
+                    ...effect.parameters,
+                    [paramName]: value,
+                  },
+                }
+              : effect
+          ),
+        },
+      };
+    }
+  }
+
+  return track;
+}

lib/audio/track-utils.ts

@@ -35,6 +35,10 @@ export function createTrack(name?: string, color?: TrackColor): Track {
     solo: false,
     recordEnabled: false,
     effectChain: createEffectChain(`${trackName} Effects`),
+    automation: {
+      lanes: [],
+      showAutomation: false,
+    },
     collapsed: false,
     selected: false,
     selection: null,

lib/hooks/useMultiTrack.ts

@@ -26,13 +26,14 @@ export function useMultiTrack() {
           return [];
         }
 
-        // Note: AudioBuffers can't be serialized, but EffectChains can
+        // Note: AudioBuffers can't be serialized, but EffectChains and Automation can
         return parsed.map((t: any) => ({
           ...t,
           name: String(t.name || 'Untitled Track'), // Ensure name is always a string
           height: t.height && t.height >= DEFAULT_TRACK_HEIGHT ? t.height : DEFAULT_TRACK_HEIGHT, // Migrate old heights
           audioBuffer: null, // Will need to be reloaded
           effectChain: t.effectChain || createEffectChain(`${t.name} Effects`), // Restore effect chain or create new
+          automation: t.automation || { lanes: [], showAutomation: false }, // Restore automation or create new
           selection: t.selection || null, // Initialize selection
         }));
       }
@@ -64,6 +65,7 @@ export function useMultiTrack() {
         collapsed: track.collapsed,
         selected: track.selected,
         effectChain: track.effectChain, // Save effect chain
+        automation: track.automation, // Save automation data
       }));
       localStorage.setItem(STORAGE_KEY, JSON.stringify(trackData));
     } catch (error) {

types/automation.ts

@@ -0,0 +1,105 @@
+/**
+ * Automation system type definitions
+ * Based on Ableton Live's automation model
+ */
+
+/**
+ * Automation curve types
+ * - linear: Straight line between points
+ * - bezier: Curved line with control handles
+ * - step: Horizontal lines with vertical transitions (for discrete values)
+ */
+export type AutomationCurveType = 'linear' | 'bezier' | 'step';
+
+/**
+ * Automation recording/playback modes
+ * - read: Only playback automation
+ * - write: Record automation (replaces existing)
+ * - touch: Record while touching control, then return to read mode
+ * - latch: Record from first touch until stop, then return to read mode
+ */
+export type AutomationMode = 'read' | 'write' | 'touch' | 'latch';
+
+/**
+ * Single automation breakpoint
+ */
+export interface AutomationPoint {
+  id: string;
+  time: number; // Position in seconds from track start
+  value: number; // Parameter value (normalized 0-1)
+  curve: AutomationCurveType;
+  // Bezier control handles (only used when curve is 'bezier')
+  handleIn?: { x: number; y: number }; // Relative to point position
+  handleOut?: { x: number; y: number }; // Relative to point position
+}
+
+/**
+ * Parameter identifier for automation
+ * Examples:
+ * - 'volume' - Track volume
+ * - 'pan' - Track pan
+ * - 'mute' - Track mute (step curve)
+ * - 'effect.compressor-1.threshold' - Effect parameter
+ * - 'effect.delay-2.time' - Effect parameter
+ */
+export type AutomationParameterId = string;
+
+/**
+ * Single automation lane for a specific parameter
+ */
+export interface AutomationLane {
+  id: string;
+  trackId: string;
+  parameterId: AutomationParameterId;
+  parameterName: string; // Display name (e.g., "Volume", "Compressor Threshold")
+  visible: boolean; // Show/hide lane
+  height: number; // Lane height in pixels (user-adjustable, 60-120px)
+  points: AutomationPoint[];
+  mode: AutomationMode;
+  color?: string; // Optional color override (defaults to parameter type color)
+  // Value range for display (actual values are normalized 0-1)
+  valueRange: {
+    min: number; // Display minimum (e.g., 0 for volume)
+    max: number; // Display maximum (e.g., 1 for volume)
+    unit?: string; // Display unit (e.g., 'dB', '%', 'ms', 'Hz')
+    formatter?: (value: number) => string; // Custom value formatter
+  };
+}
+
+/**
+ * All automation lanes for a single track
+ */
+export interface TrackAutomation {
+  trackId: string;
+  lanes: AutomationLane[];
+  showAutomation: boolean; // Master show/hide toggle for all lanes
+}
+
+/**
+ * Complete automation data for entire project
+ */
+export interface ProjectAutomation {
+  tracks: Record<string, TrackAutomation>;
+}
+
+/**
+ * Automation parameter value at a specific time
+ * Used for real-time playback
+ */
+export interface AutomationValue {
+  parameterId: AutomationParameterId;
+  value: number;
+  time: number;
+}
+
+/**
+ * Helper type for creating new automation points
+ */
+export type CreateAutomationPointInput = Omit<AutomationPoint, 'id'>;
+
+/**
+ * Helper type for creating new automation lanes
+ */
+export type CreateAutomationLaneInput = Omit<AutomationLane, 'id' | 'points'> & {
+  points?: AutomationPoint[];
+};

types/track.ts

@@ -4,6 +4,7 @@
 
 import type { EffectChain } from '@/lib/audio/effects/chain';
 import type { Selection } from './selection';
+import type { AutomationLane } from './automation';
 
 export interface Track {
   id: string;
@@ -22,6 +23,12 @@ export interface Track {
   // Effects
   effectChain: EffectChain;
 
+  // Automation
+  automation: {
+    lanes: AutomationLane[];
+    showAutomation: boolean; // Master show/hide toggle
+  };
+
   // UI state
   collapsed: boolean;
   selected: boolean;