style: refine callout box margins, selection popover positioning, and footer hover contrast

src/NexusReader.UI.Shared/Components/Molecules/CalloutBox.razor.css

@@ -1,6 +1,6 @@
 .nexus-callout-box {
-    padding: 1.25rem 1.5rem;
+    padding: 1rem 1.25rem;
-    margin: 1.5rem 0;
+    margin: 1.5rem 0 1.5rem 0;
     border-radius: 0 8px 8px 0;
     font-family: var(--nexus-font-sans, sans-serif);
     font-size: 0.95rem;

src/NexusReader.UI.Shared/Components/Molecules/SelectionAiPanel.razor

@@ -58,7 +58,7 @@
     private bool IsVisible => !string.IsNullOrEmpty(SelectedText) && Coordinates != null;
     private bool IsLoading = false;
     private KnowledgePacket? Packet;
-    private bool PositionBelow => Coordinates != null && Coordinates.Top < 320;
+    private bool PositionBelow => Coordinates != null && Coordinates.Top < 250;
 
     protected override void OnParametersSet()
     {
@@ -69,7 +69,7 @@
 
     private string PanelStyle => Coordinates != null 
         ? string.Create(System.Globalization.CultureInfo.InvariantCulture, 
-            $"top: {(PositionBelow ? Coordinates.Top + 35 : Coordinates.Top - 15):F1}px !important; " +
+            $"top: {(PositionBelow ? Coordinates.Bottom + 8 : Coordinates.Top - 8):F1}px !important; " +
             $"left: {Math.Clamp(Coordinates.Left + Coordinates.Width / 2, 280, 1600):F1}px !important; " +
             $"transform: translate(-50%, {(PositionBelow ? "0" : "-100%")}) !important;")
         : "";

src/NexusReader.UI.Shared/Components/Organisms/ReaderCanvas.razor.css

@@ -89,8 +89,8 @@
 ::deep .nexus-ebook blockquote {
     background-color: rgba(255, 255, 255, 0.02);
     border-left: 4px solid var(--nexus-neon);
-    padding: 1.25rem 1.5rem;
+    padding: 1rem 1.25rem;
-    margin: 1.5rem 0;
+    margin: 1.5rem 0 1.5rem 0;
     border-radius: 0 8px 8px 0;
     font-size: 1.05rem;
     color: #e2e8f0;

src/NexusReader.UI.Shared/Components/Organisms/ReaderFooter.razor.css

@@ -51,14 +51,17 @@
     align-items: center;
     justify-content: center;
     cursor: pointer;
-    transition: all 0.2s ease;
+    transition: color 0.2s ease-in-out, background-color 0.2s ease-in-out, border-color 0.2s ease-in-out, transform 0.2s ease-in-out;
-    color: #e4e4e7;
+    color: #a1a1aa; /* Zinc-400 default contrast */
 }
 
-.nav-btn:hover:not(:disabled) {
+.nav-btn:hover:not(:disabled),
-    background: rgba(255, 255, 255, 0.1);
+.nav-btn:focus:not(:disabled) {
-    border-color: rgba(255, 255, 255, 0.2);
+    background: rgba(255, 255, 255, 0.08);
+    border-color: var(--nexus-neon, #00ff99);
+    color: var(--nexus-neon, #00ff99); /* Brand neon green hover/focus signal */
     transform: scale(1.05);
+    outline: none;
 }
 
 .nav-btn:disabled {
@@ -69,12 +72,15 @@
 :global(.theme-light) .nav-btn {
     background: rgba(0, 0, 0, 0.02);
     border-color: rgba(0, 0, 0, 0.08);
-    color: #333333;
+    color: #71717a; /* Zinc-500 for light mode */
 }
 
-:global(.theme-light) .nav-btn:hover:not(:disabled) {
+:global(.theme-light) .nav-btn:hover:not(:disabled),
+:global(.theme-light) .nav-btn:focus:not(:disabled) {
     background: rgba(0, 0, 0, 0.05);
-    border-color: rgba(0, 0, 0, 0.15);
+    border-color: var(--nexus-neon, #00bb77);
+    color: var(--nexus-neon, #00bb77);
+    outline: none;
 }
 
 .chapter-info {
@@ -84,11 +90,11 @@
     justify-content: center;
     min-width: 0;
     flex: 1;
-    color: #e4e4e7;
+    color: #e2e8f0; /* Slate-200 for clean high readability */
 }
 
 :global(.theme-light) .chapter-info {
-    color: #333333;
+    color: #18181b; /* Zinc-900 for high light contrast */
 }
 
 .chapter-title {
@@ -102,10 +108,14 @@
 }
 
 .chapter-count {
-    opacity: 0.5;
+    color: #a1a1aa; /* Zinc-400 for secondary info clarity */
     font-size: 0.7rem;
 }
 
+:global(.theme-light) .chapter-count {
+    color: #71717a; /* Zinc-500 secondary info for light mode */
+}
+
 .progress-container {
     width: 80px;
     height: 4px;

src/NexusReader.UI.Shared/Models/ReaderModels.cs

@@ -15,7 +15,7 @@ public enum MobileReaderTab
 /// <summary>
 /// Screen coordinates for text selection popup positioning.
 /// </summary>
-public record SelectionCoordinates(double Top, double Left, double Width);
+public record SelectionCoordinates(double Top, double Left, double Width, double Height, double Bottom);
 
 /// <summary>
 /// Represents a message in the KM-RAG global and mobile intelligence chat threads.

src/NexusReader.UI.Shared/wwwroot/js/selectionHandler.js

@@ -27,7 +27,9 @@ export function initSelectionListener(dotNetHelper, container) {
                         { 
                             Top: rect.top, 
                             Left: rect.left,
-                            Width: rect.width
+                            Width: rect.width,
+                            Height: rect.height,
+                            Bottom: rect.bottom
                         });
                 }
         } else {