diff --git a/ts/src/library.ts b/ts/src/library.ts
index 5996463..57dbe80 100644
--- a/ts/src/library.ts
+++ b/ts/src/library.ts
@@ -40,304 +40,39 @@
 //   FONT INDEX: 0..32767 = built-in; 0x8000+ = custom font in file (0x8000=first).
 // =============================================================================
 
-// ---------------------------------------------------------------------------
-// Enums
-// ---------------------------------------------------------------------------
-
-export enum SectionType {
-  ElementsAlways   = 1,
-  ElementsTimespan = 2,
-  CustomFont       = 32,
-}
-
-export enum ElementType {
-  Image2D          = 1,
-  Animation        = 2,
-  HorizontalScroll = 3,
-  VerticalScroll   = 4,
-  Line             = 5,
-  ClippedText      = 16,
-  HScrollText      = 17,
-  // NOTE: spec shows CurrentTime as type 16 — likely a spec typo; treat as reserved until clarified
-}
-
-// ---------------------------------------------------------------------------
-// Section flags (section types 1 and 2)
-// ---------------------------------------------------------------------------
-
-export interface SectionFlags {
-  /** Bit 0: draw on the front side (default true for elements_always) */
-  drawFront?:    boolean;
-  /** Bit 1: draw on the back side */
-  drawBack?:     boolean;
-  /** Bit 2: clear the draw buffer(s) before drawing elements in this section */
-  clearBuffer?:  boolean;
-  // bits 3-15: reserved, must be 0 when writing
-}
-
-// ---------------------------------------------------------------------------
-// Scroll flags (HorizontalScroll / VerticalScroll elements)
-// ---------------------------------------------------------------------------
-
-export interface ScrollElementFlags {
-  endless?:         boolean; // bit 0
-  invertDirection?: boolean; // bit 1
-  padStart?:        boolean; // bit 2: padLeft (H) / padTop (V)
-  padEnd?:          boolean; // bit 3: padRight (H) / padBottom (V)
-}
-
-// ---------------------------------------------------------------------------
-// User-facing element descriptors (MonoDisplayFile input)
-// Pixels are always 1 byte/pixel (0=off, 1=on) in the API; packed at write time.
-// ---------------------------------------------------------------------------
-
-export interface Image2DElement {
-  type: ElementType.Image2D;
-  /** 1 byte per pixel (0=off 1=on), row-major. Packed to 1bpp in binary. */
-  pixels: Uint8Array;
-  width:   number;
-  height:  number;
-  xOffset?: number; // default 0
-  yOffset?: number; // default 0
-}
-
-export interface AnimationFrameDescriptor {
-  /** 1 byte per pixel, same dimensions as parent AnimationElement */
-  pixels: Uint8Array;
-}
-
-export interface AnimationElement {
-  type: ElementType.Animation;
-  width:  number;
-  height: number;
-  frames: AnimationFrameDescriptor[];
-  /**
-   * Advance frame every (updateInterval+1) ticks.
-   * 0 = every tick, 1 = every 2nd tick, etc. Default 0.
-   */
-  updateInterval?: number;
-  xOffset?: number;
-  yOffset?: number;
-}
-
-export interface HScrollElement {
-  type: ElementType.HorizontalScroll;
-  width:  number; // viewport width
-  height: number; // viewport height
-  /** Pixel content to scroll horizontally; must be (contentWidth × height) pixels */
-  pixels:       Uint8Array; // 1 byte/pixel
-  contentWidth: number;
-  /**
-   * Scroll speed byte SS; moves (SS+1)/16 pixels per tick. Default 0 (1/16 px/tick).
-   * Range 0-255.
-   */
-  scrollSpeed?: number;
-  flags?:       ScrollElementFlags;
-  xOffset?: number;
-  yOffset?: number;
-}
-
-export interface VScrollElement {
-  type: ElementType.VerticalScroll;
-  width:  number;
-  height: number; // viewport height
-  pixels:        Uint8Array; // 1 byte/pixel
-  contentHeight: number;
-  scrollSpeed?:  number;
-  flags?:        ScrollElementFlags;
-  xOffset?: number;
-  yOffset?: number;
-}
-
-export interface LineElement {
-  type: ElementType.Line;
-  xOrigin: number;
-  yOrigin: number;
-  xTarget: number;
-  yTarget: number;
-  lineStyle?:   number;  // reserved, default 0
-  invertPixels?: boolean; // flags bit 0
-}
-
-export interface ClippedTextElement {
-  type: ElementType.ClippedText;
-  text:  string;
-  width:  number;
-  height: number;
-  /** 0-32767 built-in font, 0x8000+ custom font in file. Default 0. */
-  fontIndex?: number;
-  xOffset?: number;
-  yOffset?: number;
-}
-
-export interface HScrollTextElement {
-  type: ElementType.HScrollText;
-  text:   string;
-  width:  number;
-  height: number;
-  scrollSpeed?: number; // SS byte, default 0
-  fontIndex?:   number;
-  flags?:       ScrollElementFlags;
-  xOffset?: number;
-  yOffset?: number;
-}
-
-export type DrawElement =
-  | Image2DElement
-  | AnimationElement
-  | HScrollElement
-  | VScrollElement
-  | LineElement
-  | ClippedTextElement
-  | HScrollTextElement;
-
-// ---------------------------------------------------------------------------
-// MonoDisplayFile descriptor
-// ---------------------------------------------------------------------------
-
-export interface ElementsAlwaysDescriptor {
-  flags?:    SectionFlags;
-  elements:  DrawElement[];
-}
-
-/**
- * JSON descriptor passed to MonoDisplayFile.
- *
- * elements_always — section type 1; drawn on every render tick.
- *   Pass a DrawElement[] as shorthand (flags default to drawFront=true).
- *
- * PLAN: elements_timespan (section 2), custom_fonts (section 32)
- */
-export interface MonoDisplayFileDescriptor {
-  elements_always?: DrawElement[] | ElementsAlwaysDescriptor;
-}
-
-// ---------------------------------------------------------------------------
-// MonoFormat types (parser output → renderer input)
-// Pixels are always unpacked (1 byte/pixel) after parsing.
-// ---------------------------------------------------------------------------
-
-export interface MonoFormatPixelImage {
-  /** Unpacked: 1 byte per pixel, 0=off 1=on, row-major */
-  pixels: Uint8Array;
-  width:  number;
-  height: number;
-}
-
-export interface MonoFormatImage2D {
-  type:    ElementType.Image2D;
-  xOffset: number;
-  yOffset: number;
-  image:   MonoFormatPixelImage;
-}
-
-export interface MonoFormatAnimation {
-  type:           ElementType.Animation;
-  xOffset:        number;
-  yOffset:        number;
-  width:          number;
-  height:         number;
-  updateInterval: number;
-  frames:         MonoFormatPixelImage[];
-}
-
-export interface MonoFormatHScroll {
-  type:         ElementType.HorizontalScroll;
-  xOffset:      number;
-  yOffset:      number;
-  width:        number;
-  height:       number;
-  contentWidth: number;
-  scrollSpeed:  number;
-  flags:        { endless: boolean; invertDirection: boolean; padStart: boolean; padEnd: boolean };
-  content:      MonoFormatPixelImage;
-}
-
-export interface MonoFormatVScroll {
-  type:          ElementType.VerticalScroll;
-  xOffset:       number;
-  yOffset:       number;
-  width:         number;
-  height:        number;
-  contentHeight: number;
-  scrollSpeed:   number;
-  flags:         { endless: boolean; invertDirection: boolean; padStart: boolean; padEnd: boolean };
-  content:       MonoFormatPixelImage;
-}
-
-export interface MonoFormatLine {
-  type:        ElementType.Line;
-  xOrigin:     number;
-  yOrigin:     number;
-  xTarget:     number;
-  yTarget:     number;
-  lineStyle:   number;
-  invertPixels: boolean;
-}
-
-export interface MonoFormatClippedText {
-  type:      ElementType.ClippedText;
-  xOffset:   number;
-  yOffset:   number;
-  width:     number;
-  height:    number;
-  fontIndex: number;
-  text:      string;
-}
-
-export interface MonoFormatHScrollText {
-  type:        ElementType.HScrollText;
-  xOffset:     number;
-  yOffset:     number;
-  width:       number;
-  height:      number;
-  scrollSpeed: number;
-  fontIndex:   number;
-  flags:       { endless: boolean; invertDirection: boolean; padStart: boolean; padEnd: boolean };
-  text:        string;
-}
-
-export type MonoFormatElement =
-  | MonoFormatImage2D
-  | MonoFormatAnimation
-  | MonoFormatHScroll
-  | MonoFormatVScroll
-  | MonoFormatLine
-  | MonoFormatClippedText
-  | MonoFormatHScrollText;
-
-export interface MonoFormatSectionFlags {
-  drawFront:   boolean;
-  drawBack:    boolean;
-  clearBuffer: boolean;
-}
-
-export interface MonoFormatElementsAlways {
-  sectionType: SectionType.ElementsAlways;
-  flags:       MonoFormatSectionFlags;
-  elements:    MonoFormatElement[];
-}
-
-export interface MonoFormatElementsTimespan {
-  sectionType:     SectionType.ElementsTimespan;
-  flags:           MonoFormatSectionFlags;
-  startTimestamp:  bigint; // POSIX seconds
-  endTimestamp:    bigint;
-  elements:        MonoFormatElement[];
-}
-
-export interface MonoFormatCustomFont {
-  sectionType: SectionType.CustomFont;
-  /** Raw U8G2 font data */
-  fontData:    Uint8Array;
-}
-
-export type MonoFormatSection = MonoFormatElementsAlways | MonoFormatElementsTimespan | MonoFormatCustomFont;
-
-/** Top-level parser output */
-export interface MonoFormatFile {
-  sections: MonoFormatSection[];
-}
+export * from "./types.js";
+import {
+  SectionType,
+  ElementType,
+  type SectionFlags,
+  type ScrollElementFlags,
+  type Image2DElement,
+  type AnimationElement,
+  type HScrollElement,
+  type VScrollElement,
+  type LineElement,
+  type ClippedTextElement,
+  type HScrollTextElement,
+  type DrawElement,
+  type ElementsAlwaysDescriptor,
+  type MonoDisplayFileDescriptor,
+  type MonoFormatPixelImage,
+  type MonoFormatImage2D,
+  type MonoFormatAnimation,
+  type MonoFormatScrollFlags,
+  type MonoFormatHScroll,
+  type MonoFormatVScroll,
+  type MonoFormatLine,
+  type MonoFormatClippedText,
+  type MonoFormatHScrollText,
+  type MonoFormatElement,
+  type MonoFormatSectionFlags,
+  type MonoFormatElementsAlways,
+  type MonoFormatElementsTimespan,
+  type MonoFormatCustomFont,
+  type MonoFormatSection,
+  type MonoFormatFile,
+} from "./types.js";
 
 // ---------------------------------------------------------------------------
 // Pixel pack/unpack helpers