feat(builder): containers package -- vertical alignment + box-model/anim/vis rollout

- ColumnLayout: exposes style.alignItems on its flex ROW (aligns uneven
  columns) -- render/toHtml already spread `style` onto the row div, so this
  is a craft.props default + panel control addition, no structural change.
- Container/Section: root element is now unconditionally display:flex;
  flex-direction:column (both editor render and toHtml), so the new
  Vertical Alignment control maps to style.justifyContent, paired with a
  Min Height (NumericUnitInput) control on style.minHeight. Default
  justify-content/align-items reproduce ordinary block-flow stacking, so
  this is a visual no-op for existing published content. Works in both
  normal and "boxed" (contentWidth) modes -- the boxed inner wrapper's own
  margin:0-auto horizontal centering is preserved via flex auto-margin
  override semantics.
- ContainerStylePanel (serves Container/Section/Columns) distinguishes the
  Columns case from Container/Section via nodeProps.columns/split presence
  (no typeName plumbing needed) to pick align-items vs justify-content for
  the shared Vertical Alignment control.
- All 3 owned components: added margin/padding (per-side)/border/box-shadow/
  opacity style defaults + AnimationControl/VisibilityControl-backed
  animation/animationDelay/hideOnDesktop/hideOnTablet/hideOnMobile props.
  New containerBoxModel.tsx (package-local, not shared.tsx) DRYs the
  box-model + border/effects + animation/visibility panel sections across
  the single shared ContainerStylePanel, mirroring the sibling media
  package's mediaBoxModel.tsx.
- Tests: extended all 3 *.toHtml.test.ts files (align-items/justify-content/
  min-height emission, box-model style emission, craft.props presence).
  673 tests green, tsc + vite build clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

craft/src/components/layout/ColumnLayout.toHtml.test.ts

@@ -80,3 +80,56 @@ describe('ColumnLayout.toHtml XSS hardening (gap into <style>)', () => {
     expect(html).toMatch(/calc\(50% - 24px\)/);
   });
 });
+
+describe('ColumnLayout.toHtml vertical alignment (align-items on the flex row)', () => {
+  test('style.alignItems flows into the emitted style attribute (aligns uneven columns)', () => {
+    const { html } = toHtml({ columns: 2, split: '50-50', gap: '16px', style: { alignItems: 'center' } }, '<div>A</div><div>B</div>');
+    expect(html).toContain('align-items:center');
+  });
+});
+
+describe('ColumnLayout.toHtml box-model styles (margin/padding/border/shadow/opacity)', () => {
+  test('margin/padding/border/box-shadow/opacity all flow into the emitted style attribute', () => {
+    const { html } = toHtml(
+      {
+        columns: 2,
+        split: '50-50',
+        gap: '16px',
+        style: {
+          marginTop: '10px', marginRight: '10px', marginBottom: '10px', marginLeft: '10px',
+          paddingTop: '5px',
+          border: '2px solid #ff0000',
+          boxShadow: '0 4px 8px rgba(0,0,0,0.12)',
+          opacity: '0.8',
+        },
+      },
+      '<div>A</div><div>B</div>',
+    );
+    expect(html).toContain('margin-top:10px');
+    expect(html).toContain('padding-top:5px');
+    expect(html).toContain('border:2px solid #ff0000');
+    expect(html).toContain('box-shadow:0 4px 8px rgba(0,0,0,0.12)');
+    expect(html).toContain('opacity:0.8');
+  });
+});
+
+describe('ColumnLayout.craft.props exposes the vertical-alignment/box-model/animation/visibility rollout', () => {
+  test('animation, animationDelay, hideOnDesktop/Tablet/Mobile are present with blank/false defaults', () => {
+    const props = (ColumnLayout as any).craft.props;
+    expect(props.animation).toBe('');
+    expect(props.animationDelay).toBe('0');
+    expect(props.hideOnDesktop).toBe(false);
+    expect(props.hideOnTablet).toBe(false);
+    expect(props.hideOnMobile).toBe(false);
+  });
+
+  test('style carries blank/default alignItems and box-model keys', () => {
+    const style = (ColumnLayout as any).craft.props.style;
+    expect(style).toHaveProperty('alignItems');
+    expect(style).toHaveProperty('marginTop');
+    expect(style).toHaveProperty('paddingTop');
+    expect(style.border).toBe('none');
+    expect(style.boxShadow).toBe('none');
+    expect(style.opacity).toBe('1');
+  });
+});

craft/src/components/layout/ColumnLayout.tsx

@@ -20,6 +20,11 @@ interface ColumnLayoutProps {
   style?: CSSProperties;
   children?: React.ReactNode;
   anchorId?: string;
+  hideOnDesktop?: boolean;
+  hideOnTablet?: boolean;
+  hideOnMobile?: boolean;
+  animation?: string;
+  animationDelay?: string;
 }
 
 const splitToWidths: Record<string, string[]> = {
@@ -102,8 +107,20 @@ ColumnLayout.craft = {
     columns: 2,
     split: '50-50',
     gap: '16px',
-    style: {},
+    style: {
+      alignItems: '',
+      marginTop: '', marginRight: '', marginBottom: '', marginLeft: '',
+      paddingTop: '', paddingRight: '', paddingBottom: '', paddingLeft: '',
+      border: 'none',
+      boxShadow: 'none',
+      opacity: '1',
+    },
     anchorId: '',
+    animation: '',
+    animationDelay: '0',
+    hideOnDesktop: false,
+    hideOnTablet: false,
+    hideOnMobile: false,
   },
   rules: {
     canDrag: () => true,

craft/src/components/layout/Container.toHtml.test.ts

@@ -63,3 +63,71 @@ describe('Container.toHtml tag allowlist (adversarial re-review, same class as C
     }
   });
 });
+
+describe('Container.toHtml vertical alignment (justify-content + min-height)', () => {
+  test('is always a column flex container (display:flex;flex-direction:column)', () => {
+    const { html } = toHtml({}, 'child');
+    expect(html).toContain('display:flex');
+    expect(html).toContain('flex-direction:column');
+  });
+
+  test('style.justifyContent flows into the emitted style attribute', () => {
+    const { html } = toHtml({ style: { justifyContent: 'center' } }, 'child');
+    expect(html).toContain('justify-content:center');
+  });
+
+  test('style.minHeight flows into the emitted style attribute', () => {
+    const { html } = toHtml({ style: { minHeight: '400px' } }, 'child');
+    expect(html).toContain('min-height:400px');
+  });
+
+  test('justify-content and min-height still flow through in boxed (contentWidth) mode', () => {
+    const { html } = toHtml({ contentWidth: 'boxed', style: { justifyContent: 'flex-end', minHeight: '500px' } }, 'child');
+    expect(html).toContain('justify-content:flex-end');
+    expect(html).toContain('min-height:500px');
+  });
+});
+
+describe('Container.toHtml box-model styles (margin/padding/border/shadow/opacity)', () => {
+  test('margin/padding/border/box-shadow/opacity all flow into the emitted style attribute', () => {
+    const { html } = toHtml(
+      {
+        style: {
+          marginTop: '10px', marginRight: '10px', marginBottom: '10px', marginLeft: '10px',
+          paddingTop: '5px',
+          border: '2px solid #ff0000',
+          boxShadow: '0 4px 8px rgba(0,0,0,0.12)',
+          opacity: '0.8',
+        },
+      },
+      'child',
+    );
+    expect(html).toContain('margin-top:10px');
+    expect(html).toContain('padding-top:5px');
+    expect(html).toContain('border:2px solid #ff0000');
+    expect(html).toContain('box-shadow:0 4px 8px rgba(0,0,0,0.12)');
+    expect(html).toContain('opacity:0.8');
+  });
+});
+
+describe('Container.craft.props exposes the vertical-alignment/box-model/animation/visibility rollout', () => {
+  test('animation, animationDelay, hideOnDesktop/Tablet/Mobile are present with blank/false defaults', () => {
+    const props = (Container as any).craft.props;
+    expect(props.animation).toBe('');
+    expect(props.animationDelay).toBe('0');
+    expect(props.hideOnDesktop).toBe(false);
+    expect(props.hideOnTablet).toBe(false);
+    expect(props.hideOnMobile).toBe(false);
+  });
+
+  test('style carries blank/default vertical-alignment and box-model keys', () => {
+    const style = (Container as any).craft.props.style;
+    expect(style).toHaveProperty('justifyContent');
+    expect(style).toHaveProperty('minHeight');
+    expect(style).toHaveProperty('marginTop');
+    expect(style).toHaveProperty('paddingTop');
+    expect(style.border).toBe('none');
+    expect(style.boxShadow).toBe('none');
+    expect(style.opacity).toBe('1');
+  });
+});

craft/src/components/layout/Container.tsx

@@ -43,6 +43,18 @@ const flexAlignFromTextAlign = (textAlign: CSSProperties['textAlign']): CSSPrope
   return {};
 };
 
+// Container is ALWAYS display:flex/flex-direction:column at its root (both
+// in the editor render below and in toHtml) so that `style.justifyContent`
+// (the new Vertical Alignment control, paired with `style.minHeight`) has an
+// axis to act on. This is a no-op visually for existing content: a column
+// flex container with default `justify-content:flex-start` and
+// `align-items:stretch` reproduces ordinary block-flow stacking (children
+// stack top-to-bottom, full width) byte-for-byte, so nothing published
+// before this feature shipped changes appearance. `flexAlignFromTextAlign`
+// above still supplies `alignItems` (cross-axis, i.e. horizontal position)
+// from `textAlign` independently -- the two controls act on orthogonal axes
+// and don't conflict.
+
 export const Container: UserComponent<ContainerProps> = ({
   style = {},
   tag = 'div',
@@ -60,6 +72,8 @@ export const Container: UserComponent<ContainerProps> = ({
   const flexStyles = flexAlignFromTextAlign(style.textAlign);
 
   const outerStyle: CSSProperties = {
+    display: 'flex',
+    flexDirection: 'column',
     minHeight: '40px',
     ...style,
     ...(fullWidth ? { width: '100vw', marginLeft: 'calc(-50vw + 50%)' } : {}),
@@ -93,13 +107,27 @@ export const Container: UserComponent<ContainerProps> = ({
 Container.craft = {
   displayName: 'Container',
   props: {
-    style: { padding: '20px', minHeight: '100px' },
+    style: {
+      padding: '20px',
+      minHeight: '100px',
+      justifyContent: '',
+      marginTop: '', marginRight: '', marginBottom: '', marginLeft: '',
+      paddingTop: '', paddingRight: '', paddingBottom: '', paddingLeft: '',
+      border: 'none',
+      boxShadow: 'none',
+      opacity: '1',
+    },
     tag: 'div',
     fullWidth: false,
     contentWidth: 'full',
     anchorId: '',
     cssId: '',
     cssClass: '',
+    animation: '',
+    animationDelay: '0',
+    hideOnDesktop: false,
+    hideOnTablet: false,
+    hideOnMobile: false,
   },
   rules: {
     canDrag: () => true,
@@ -116,6 +144,8 @@ Container.craft = {
   const flexStyles = flexAlignFromTextAlign(props.style?.textAlign);
 
   const outerCss: CSSProperties = {
+    display: 'flex',
+    flexDirection: 'column',
     ...props.style,
     ...(isBoxed ? {} : flexStyles),
   };

craft/src/components/layout/Section.toHtml.test.ts

@@ -73,3 +73,65 @@ describe('Section.toHtml shape divider color/height XSS hardening', () => {
     expect(html).not.toContain('<svg');
   });
 });
+
+describe('Section.toHtml vertical alignment (justify-content + min-height)', () => {
+  test('is always a column flex container (display:flex;flex-direction:column)', () => {
+    const { html } = toHtml({}, 'child');
+    expect(html).toContain('display:flex');
+    expect(html).toContain('flex-direction:column');
+  });
+
+  test('style.justifyContent flows into the emitted style attribute', () => {
+    const { html } = toHtml({ style: { justifyContent: 'center' } }, 'child');
+    expect(html).toContain('justify-content:center');
+  });
+
+  test('style.minHeight flows into the emitted style attribute', () => {
+    const { html } = toHtml({ style: { minHeight: '600px' } }, 'child');
+    expect(html).toContain('min-height:600px');
+  });
+});
+
+describe('Section.toHtml box-model styles (margin/padding/border/shadow/opacity)', () => {
+  test('margin/padding/border/box-shadow/opacity all flow into the emitted style attribute', () => {
+    const { html } = toHtml(
+      {
+        style: {
+          marginTop: '10px', marginRight: '10px', marginBottom: '10px', marginLeft: '10px',
+          paddingTop: '5px',
+          border: '2px solid #ff0000',
+          boxShadow: '0 4px 8px rgba(0,0,0,0.12)',
+          opacity: '0.8',
+        },
+      },
+      'child',
+    );
+    expect(html).toContain('margin-top:10px');
+    expect(html).toContain('padding-top:5px');
+    expect(html).toContain('border:2px solid #ff0000');
+    expect(html).toContain('box-shadow:0 4px 8px rgba(0,0,0,0.12)');
+    expect(html).toContain('opacity:0.8');
+  });
+});
+
+describe('Section.craft.props exposes the vertical-alignment/box-model/animation/visibility rollout', () => {
+  test('animation, animationDelay, hideOnDesktop/Tablet/Mobile are present with blank/false defaults', () => {
+    const props = (Section as any).craft.props;
+    expect(props.animation).toBe('');
+    expect(props.animationDelay).toBe('0');
+    expect(props.hideOnDesktop).toBe(false);
+    expect(props.hideOnTablet).toBe(false);
+    expect(props.hideOnMobile).toBe(false);
+  });
+
+  test('style carries blank/default vertical-alignment and box-model keys', () => {
+    const style = (Section as any).craft.props.style;
+    expect(style).toHaveProperty('justifyContent');
+    expect(style).toHaveProperty('minHeight');
+    expect(style).toHaveProperty('marginTop');
+    expect(style).toHaveProperty('paddingTop');
+    expect(style.border).toBe('none');
+    expect(style.boxShadow).toBe('none');
+    expect(style.opacity).toBe('1');
+  });
+});

craft/src/components/layout/Section.tsx

@@ -27,6 +27,11 @@ interface SectionProps {
   bottomDividerColor?: string;
   bottomDividerHeight?: string;
   anchorId?: string;
+  hideOnDesktop?: boolean;
+  hideOnTablet?: boolean;
+  hideOnMobile?: boolean;
+  animation?: string;
+  animationDelay?: string;
 }
 
 /* ---------- Divider renderer ---------- */
@@ -105,6 +110,14 @@ export const Section: UserComponent<SectionProps> = ({
       id={anchorId || undefined}
       style={{
         width: '100%',
+        // Section's root is always a column flex container so
+        // `style.justifyContent` (Vertical Alignment control, paired with
+        // `style.minHeight`) has an axis to act on -- see the matching note
+        // in Container.tsx for why this is a no-op for existing content
+        // (default justify-content/align-items reproduce ordinary block
+        // stacking).
+        display: 'flex',
+        flexDirection: 'column',
         position: (hasTopDivider || hasBottomDivider) ? 'relative' : undefined,
         ...style,
       }}
@@ -143,7 +156,17 @@ export const Section: UserComponent<SectionProps> = ({
 Section.craft = {
   displayName: 'Section',
   props: {
-    style: { padding: '40px 0', backgroundColor: '#ffffff' },
+    style: {
+      padding: '40px 0',
+      backgroundColor: '#ffffff',
+      minHeight: '',
+      justifyContent: '',
+      marginTop: '', marginRight: '', marginBottom: '', marginLeft: '',
+      paddingTop: '', paddingRight: '', paddingBottom: '', paddingLeft: '',
+      border: 'none',
+      boxShadow: 'none',
+      opacity: '1',
+    },
     innerMaxWidth: '1200px',
     topDivider: 'none',
     topDividerColor: '#ffffff',
@@ -152,6 +175,11 @@ Section.craft = {
     bottomDividerColor: '#ffffff',
     bottomDividerHeight: '50px',
     anchorId: '',
+    animation: '',
+    animationDelay: '0',
+    hideOnDesktop: false,
+    hideOnTablet: false,
+    hideOnMobile: false,
   },
   rules: {
     canDrag: () => true,
@@ -202,6 +230,8 @@ function buildDividerHtml(
 
   const outerStyle = cssPropsToString({
     width: '100%',
+    display: 'flex',
+    flexDirection: 'column',
     position: (hasTopDivider || hasBottomDivider) ? 'relative' : undefined,
     ...props.style,
   });