feat: implement absolute positioning for slide editor with viewport-aware layout

## Major Improvements:

### Absolute Positioning System
- Implemented fixed positioning for slide editor to break out of DOM flow
- Editor uses full viewport (top: 80px; left: 0; right: 0; bottom: 0)
- Fixed header at top with z-index layering for proper overlap
- Background overlay to separate from underlying content

### Viewport-Optimized Layout
- True 50/50 split using full available viewport width
- Height calculations based on actual viewport (100vh) not container constraints
- Responsive top positioning (80px desktop, 60px tablet, 50px mobile)
- No scrolling issues - content always fits within viewport boundaries

### Enhanced Live Preview
- Applied presentation aspect ratio classes to preview container
- Dynamic aspect ratio detection (16:9, 4:3, 16:10)
- Viewport-aware sizing with proper aspect ratio preservation
- Added aspect ratio indicator in preview meta information

### Improved User Experience
- Compact header design with reduced padding and font sizes
- Internal scrolling for content fields while keeping actions visible
- Better space utilization with reduced margins and gaps
- Consistent behavior across all screen sizes and orientations

### Technical Enhancements
- Z-index management for proper layering (header: 20, content: 10)
- Flexbox structure for optimal space distribution
- Overflow handling for different content types
- Mobile-responsive design with appropriate scaling

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

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

src/components/presentations/SlideEditor.css

@@ -9,18 +9,24 @@
 .slide-editor-header {
   background: white;
   border-bottom: 1px solid #e2e8f0;
-  padding: 1rem 2rem;
+  padding: 0.75rem 2rem;
   display: flex;
   justify-content: space-between;
   align-items: center;
-  gap: 2rem;
+  gap: 1.5rem;
   flex-wrap: wrap;
+  position: fixed;
+  top: 0;
+  left: 0;
+  right: 0;
+  z-index: 20;
+  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
 }
 
 .editor-info {
   display: flex;
   align-items: center;
-  gap: 1.5rem;
+  gap: 1rem;
   flex: 1;
   min-width: 0;
 }
@@ -49,15 +55,15 @@
 
 .editor-title h1 {
   margin: 0;
-  font-size: 1.5rem;
+  font-size: 1.25rem;
   font-weight: 600;
   color: #1e293b;
 }
 
 .editor-title p {
-  margin: 0.25rem 0 0 0;
+  margin: 0.125rem 0 0 0;
   color: #64748b;
-  font-size: 0.875rem;
+  font-size: 0.75rem;
 }
 
 .editor-actions {
@@ -114,12 +120,12 @@
 /* Step Header */
 .step-header {
   text-align: center;
-  margin-bottom: 2rem;
+  margin-bottom: 1.5rem;
 }
 
 .step-header h2 {
-  margin: 0 0 0.5rem 0;
+  margin: 0 0 0.25rem 0;
-  font-size: 1.5rem;
+  font-size: 1.25rem;
   font-weight: 600;
   color: #1e293b;
 }
@@ -127,13 +133,21 @@
 .step-header p {
   margin: 0;
   color: #64748b;
-  font-size: 1rem;
+  font-size: 0.875rem;
 }
 
 /* Layout Selection */
 .layout-selection {
-  max-width: 1200px;
+  position: fixed;
-  margin: 0 auto;
+  top: 80px;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  background: #f8fafc;
+  z-index: 10;
+  overflow-y: auto;
+  padding: 2rem;
+  box-sizing: border-box;
 }
 
 .layouts-grid {
@@ -257,28 +271,47 @@
 
 /* Content Editing */
 .content-editing {
-  max-width: 1400px;
+  /* Use absolute positioning to break out of all DOM constraints */
-  margin: 0 auto;
+  position: fixed;
+  top: 80px;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  background: #f8fafc;
+  z-index: 10;
+  overflow: hidden;
 }
 
 .editing-layout {
   display: grid;
-  grid-template-columns: 1fr 400px;
+  grid-template-columns: 1fr 1fr;
   gap: 2rem;
-  align-items: start;
+  align-items: stretch;
+  height: 100%;
+  width: 100%;
+  padding: 2rem;
+  box-sizing: border-box;
+  max-width: none;
 }
 
 .content-form {
   background: white;
   border-radius: 0.75rem;
   border: 1px solid #e2e8f0;
-  padding: 2rem;
+  padding: 1.5rem;
+  overflow-y: auto;
+  height: 100%;
+  display: flex;
+  flex-direction: column;
 }
 
 .content-fields {
   display: flex;
   flex-direction: column;
-  gap: 1.5rem;
+  gap: 1rem;
+  flex: 1;
+  overflow-y: auto;
+  min-height: 0;
 }
 
 .content-field {
@@ -381,9 +414,10 @@
   background: white;
   border-radius: 0.75rem;
   border: 1px solid #e2e8f0;
-  padding: 1.5rem;
+  padding: 1rem;
-  position: sticky;
+  height: 100%;
-  top: 2rem;
+  display: flex;
+  flex-direction: column;
 }
 
 .content-preview h3 {
@@ -407,6 +441,9 @@
   border-radius: 0.75rem;
   background: white;
   overflow: hidden;
+  flex: 1;
+  display: flex;
+  flex-direction: column;
 }
 
 .slide-preview-wrapper {
@@ -415,21 +452,41 @@
   display: flex;
   align-items: center;
   justify-content: center;
-  min-height: 200px;
+  flex: 1;
   position: relative;
+  /* Ensure this container doesn't exceed available space */
+  max-height: 100%;
+  overflow: hidden;
 }
 
-.slide-preview {
+/* Use the global aspect ratio classes for proper slide display */
-  max-width: 100%;
+.slide-preview-wrapper .slide-container {
-  transform: scale(0.6);
+  /* Use a width-based approach and let aspect-ratio handle height */
-  transform-origin: center;
+  width: min(80%, 70vw);
-  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
+  max-height: 60vh;
+  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.15);
   border-radius: 0.5rem;
   background: white;
   border: 1px solid #e2e8f0;
   overflow: hidden;
 }
 
+/* Override global aspect ratio classes for preview context */
+.slide-preview-wrapper .slide-container.aspect-16-9 {
+  aspect-ratio: 16 / 9;
+  width: min(80%, min(70vw, 60vh * (16/9)));
+}
+
+.slide-preview-wrapper .slide-container.aspect-4-3 {
+  aspect-ratio: 4 / 3;
+  width: min(80%, min(70vw, 60vh * (4/3)));
+}
+
+.slide-preview-wrapper .slide-container.aspect-16-10 {
+  aspect-ratio: 16 / 10;
+  width: min(80%, min(70vw, 60vh * (16/10)));
+}
+
 .preview-meta {
   display: flex;
   justify-content: space-between;
@@ -437,6 +494,8 @@
   padding: 0.75rem 1rem;
   background: #f8fafc;
   border-top: 1px solid #e2e8f0;
+  flex-wrap: wrap;
+  gap: 0.5rem;
 }
 
 .layout-name {
@@ -445,6 +504,15 @@
   color: #374151;
 }
 
+.aspect-ratio-info {
+  font-size: 0.625rem;
+  color: #3b82f6;
+  background: #eff6ff;
+  padding: 0.25rem 0.5rem;
+  border-radius: 0.25rem;
+  font-weight: 500;
+}
+
 .content-count {
   font-size: 0.625rem;
   color: #6b7280;
@@ -516,23 +584,57 @@
 
 /* Responsive Design */
 @media (max-width: 1024px) {
+  .content-editing {
+    top: 60px;
+  }
+  
+  .layout-selection {
+    top: 60px;
+  }
+  
   .editing-layout {
     grid-template-columns: 1fr;
     gap: 1.5rem;
+    padding: 1rem;
   }
   
   .content-preview {
-    position: relative;
+    height: 300px;
-    top: auto;
+    min-height: 300px;
+  }
+  
+  .slide-preview-wrapper {
+    padding: 0.5rem;
+  }
+  
+  /* Adjust viewport calculations for smaller screens */
+  .slide-preview-wrapper .slide-container {
+    width: min(90%, 90vw);
+    max-height: 250px;
+  }
+  
+  .slide-preview-wrapper .slide-container.aspect-16-9,
+  .slide-preview-wrapper .slide-container.aspect-4-3,
+  .slide-preview-wrapper .slide-container.aspect-16-10 {
+    width: min(90%, min(90vw, 250px * var(--aspect-multiplier, 1.78)));
   }
 }
 
 @media (max-width: 768px) {
-  .slide-editor-header {
+  .content-editing {
+    top: 50px;
+  }
+  
+  .layout-selection {
+    top: 50px;
     padding: 1rem;
+  }
+  
+  .slide-editor-header {
+    padding: 0.5rem 1rem;
     flex-direction: column;
     align-items: stretch;
-    gap: 1rem;
+    gap: 0.5rem;
   }
   
   .editor-info {

src/components/presentations/SlideEditor.tsx

@@ -304,7 +304,7 @@ export const SlideEditor: React.FC = () => {
           </div>
         )}
 
-        {currentStep === 'content' && selectedLayout && (
+        {currentStep === 'content' && selectedLayout && presentation && (
           <div className="content-editing">
             <div className="editing-layout">
               <div className="content-form">
@@ -389,7 +389,7 @@ export const SlideEditor: React.FC = () => {
                 <div className="preview-container">
                   <div className="slide-preview-wrapper">
                     <div 
-                      className="slide-preview"
+                      className={`slide-container ${presentation.metadata.aspectRatio ? `aspect-${presentation.metadata.aspectRatio.replace(':', '-')}` : 'aspect-16-9'}`}
                       dangerouslySetInnerHTML={{
                         __html: renderTemplateWithContent(selectedLayout, slideContent)
                       }}
@@ -397,6 +397,9 @@ export const SlideEditor: React.FC = () => {
                   </div>
                   <div className="preview-meta">
                     <span className="layout-name">{selectedLayout.name}</span>
+                    <span className="aspect-ratio-info">
+                      {presentation.metadata.aspectRatio || '16:9'} aspect ratio
+                    </span>
                     <span className="content-count">
                       {Object.values(slideContent).filter(v => v.trim()).length} / {selectedLayout.slots.length} slots filled
                     </span>