feat: implement premium gamified Concepts Map dashboard, custom skill-tree, and secure tenant gating

src/NexusReader.Application/Queries/Concepts/BookConceptsMapResultDto.cs

@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+using System.Text.Json.Serialization;
+using NexusReader.Application.Queries.Graph;
+
+namespace NexusReader.Application.Queries.Concepts;
+
+public record BookConceptsMapResultDto(
+    [property: JsonPropertyName("nodes")] List<GraphNodeDto> Nodes,
+    [property: JsonPropertyName("lastReadBlockId")] string LastReadBlockId
+);

src/NexusReader.Application/Queries/Concepts/GetBookConceptsMapQuery.cs

@@ -0,0 +1,9 @@
+using NexusReader.Application.Abstractions.Messaging;
+
+namespace NexusReader.Application.Queries.Concepts;
+
+public record GetBookConceptsMapQuery(
+    Guid BookId,
+    string UserId,
+    string TenantId
+) : IQuery<BookConceptsMapResultDto>;

src/NexusReader.Application/Queries/Concepts/GetBookConceptsMapQueryHandler.cs

@@ -0,0 +1,114 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using FluentResults;
+using Microsoft.EntityFrameworkCore;
+using NexusReader.Application.Abstractions.Messaging;
+using NexusReader.Application.Queries.Graph;
+using NexusReader.Data.Persistence;
+
+namespace NexusReader.Application.Queries.Concepts;
+
+internal sealed class GetBookConceptsMapQueryHandler : IQueryHandler<GetBookConceptsMapQuery, BookConceptsMapResultDto>
+{
+    private readonly IDbContextFactory<AppDbContext> _dbContextFactory;
+
+    public GetBookConceptsMapQueryHandler(IDbContextFactory<AppDbContext> dbContextFactory)
+    {
+        _dbContextFactory = dbContextFactory;
+    }
+
+    public async Task<Result<BookConceptsMapResultDto>> Handle(GetBookConceptsMapQuery request, CancellationToken cancellationToken)
+    {
+        using var dbContext = await _dbContextFactory.CreateDbContextAsync(cancellationToken);
+
+        // 1. Fetch user to extract reading progress (LastReadPageId)
+        var user = await dbContext.Users
+            .Where(u => u.Id == request.UserId)
+            .Select(u => new { u.LastReadPageId })
+            .FirstOrDefaultAsync(cancellationToken);
+
+        if (user == null)
+        {
+            return Result.Fail<BookConceptsMapResultDto>("User not found.");
+        }
+
+        var lastReadBlockId = user.LastReadPageId ?? string.Empty;
+
+        // 2. Fetch all KnowledgeUnits associated with the ebook and user's tenant
+        var units = await dbContext.KnowledgeUnits
+            .Where(k => k.EbookId == request.BookId && 
+                       (k.TenantId == request.TenantId || k.TenantId == "global" || string.IsNullOrEmpty(k.TenantId)))
+            .OrderBy(k => k.CreatedAt)
+            .ToListAsync(cancellationToken);
+
+        var nodes = new List<GraphNodeDto>();
+
+        foreach (var unit in units)
+        {
+            // Only process units representing sections or conceptual milestones (usually starting with "seg-")
+            if (string.IsNullOrEmpty(unit.Id) || !unit.Id.StartsWith("seg-"))
+            {
+                continue;
+            }
+
+            string label = unit.Id;
+            string group = "concept";
+            string summary = unit.Content;
+            var keyTerms = new List<string>();
+
+            if (!string.IsNullOrEmpty(unit.MetadataJson))
+            {
+                try
+                {
+                    using var doc = JsonDocument.Parse(unit.MetadataJson);
+                    if (doc.RootElement.TryGetProperty("label", out var labelProp))
+                        label = labelProp.GetString() ?? label;
+                    if (doc.RootElement.TryGetProperty("group", out var groupProp))
+                        group = groupProp.GetString() ?? group;
+                    if (doc.RootElement.TryGetProperty("summary", out var summaryProp))
+                        summary = summaryProp.GetString() ?? summary;
+                    if (doc.RootElement.TryGetProperty("key_terms", out var ktProp) && ktProp.ValueKind == JsonValueKind.Array)
+                    {
+                        foreach (var term in ktProp.EnumerateArray())
+                        {
+                            if (term.GetString() is string s)
+                                keyTerms.Add(s);
+                        }
+                    }
+                }
+                catch
+                {
+                    // Fallback to defaults
+                }
+            }
+
+            nodes.Add(new GraphNodeDto(
+                Id: unit.Id,
+                Label: label,
+                Group: group,
+                Description: unit.Content,
+                Type: unit.Type.ToString(),
+                Summary: summary,
+                KeyTerms: keyTerms
+            ));
+        }
+
+        // Return sorted by the numeric value in the seg-ID to ensure topdown vertical alignment
+        var sortedNodes = nodes
+            .OrderBy(n => ParseSegmentNumber(n.Id))
+            .ToList();
+
+        return Result.Ok(new BookConceptsMapResultDto(sortedNodes, lastReadBlockId));
+    }
+
+    private static int ParseSegmentNumber(string? id)
+    {
+        if (string.IsNullOrEmpty(id)) return 0;
+        var digits = new string(id.Where(char.IsDigit).ToArray());
+        return int.TryParse(digits, out var val) ? val : 0;
+    }
+}

src/NexusReader.UI.Shared/Components/Organisms/ConceptsMap.razor

@@ -0,0 +1,114 @@
+@using NexusReader.Application.Queries.Graph
+@using NexusReader.UI.Shared.Components.Atoms
+
+<div class="concepts-map">
+    @if (Nodes == null || !Nodes.Any())
+    {
+        <div class="empty-map-state">
+            <NexusIcon Name="map" Size="48" Class="dim-icon" />
+            <p>Brak wygenerowanej mapy pojęć dla tej książki.</p>
+        </div>
+    }
+    else
+    {
+        <div class="timeline-container">
+            @for (int i = 0; i < Nodes.Count; i++)
+            {
+                var index = i;
+                var node = Nodes[index];
+                var isUnlocked = IsUnlocked(node.Id);
+                var isSelected = SelectedNode?.Id == node.Id;
+                
+                var showTrack = index < Nodes.Count - 1;
+                var isNextUnlocked = showTrack && IsUnlocked(Nodes[index + 1].Id);
+                
+                <div class="timeline-step @(isUnlocked ? "unlocked" : "locked") @(isSelected ? "selected" : "")" 
+                     @onclick="() => HandleNodeClick(node)">
+                    
+                    <div class="node-connector-wrapper">
+                        <div class="node-circle">
+                            @if (isUnlocked)
+                            {
+                                <div class="node-glow"></div>
+                                <NexusIcon Name="check" Size="16" Class="check-icon" />
+                            }
+                            else
+                            {
+                                <NexusIcon Name="lock" Size="16" Class="lock-icon" />
+                            }
+                        </div>
+                        
+                        @if (showTrack)
+                        {
+                            <div class="vertical-track @(isNextUnlocked ? "track-active" : "track-inactive")"></div>
+                        }
+                    </div>
+                    
+                    <div class="node-content">
+                        <div class="node-header">
+                            <span class="segment-tag">@node.Id.ToUpper()</span>
+                            @if (isUnlocked)
+                            {
+                                <span class="badge badge-unlocked">Odblokowane</span>
+                            }
+                            else
+                            {
+                                <span class="badge badge-locked">Zablokowane</span>
+                            }
+                        </div>
+                        <h4 class="node-title">@node.Label</h4>
+                        <p class="node-desc">@GetShortDescription(node.Description)</p>
+                    </div>
+                </div>
+            }
+        </div>
+    }
+</div>
+
+@code {
+    [Parameter] public List<GraphNodeDto> Nodes { get; set; } = new();
+    [Parameter] public string LastReadBlockId { get; set; } = string.Empty;
+    [Parameter] public EventCallback<GraphNodeDto> OnNodeSelected { get; set; }
+    [Parameter] public GraphNodeDto? SelectedNode { get; set; }
+
+    private bool IsUnlocked(string nodeId)
+    {
+        if (string.IsNullOrEmpty(nodeId)) return false;
+        
+        var nodeSeq = ParseSegmentNumber(nodeId);
+        
+        // Always unlock the very first segment so the user has a starting node
+        var minNodeSeq = Nodes.Any() ? Nodes.Min(n => ParseSegmentNumber(n.Id)) : 0;
+        if (nodeSeq == minNodeSeq) return true;
+
+        if (string.IsNullOrEmpty(LastReadBlockId))
+        {
+            return false;
+        }
+
+        var progressSeq = ParseSegmentNumber(LastReadBlockId);
+        return nodeSeq <= progressSeq;
+    }
+
+    private static int ParseSegmentNumber(string? id)
+    {
+        if (string.IsNullOrEmpty(id)) return 0;
+        var digits = new string(id.Where(char.IsDigit).ToArray());
+        return int.TryParse(digits, out var val) ? val : 0;
+    }
+
+    private async Task HandleNodeClick(GraphNodeDto node)
+    {
+        if (OnNodeSelected.HasDelegate)
+        {
+            await OnNodeSelected.InvokeAsync(node);
+        }
+    }
+
+    private string GetShortDescription(string? desc)
+    {
+        if (string.IsNullOrEmpty(desc)) return "Brak opisu.";
+        if (desc.Length <= 110) return desc;
+        return desc[..107] + "...";
+    }
+}

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

@@ -0,0 +1,235 @@
+.concepts-map {
+    width: 100%;
+    max-height: 72vh;
+    overflow-y: auto;
+    padding: 1.5rem;
+    box-sizing: border-box;
+}
+
+/* Scrollbar Customization for modern aesthetic */
+.concepts-map::-webkit-scrollbar {
+    width: 6px;
+}
+.concepts-map::-webkit-scrollbar-track {
+    background: rgba(255, 255, 255, 0.02);
+}
+.concepts-map::-webkit-scrollbar-thumb {
+    background: rgba(255, 255, 255, 0.1);
+    border-radius: 3px;
+}
+.concepts-map::-webkit-scrollbar-thumb:hover {
+    background: var(--nexus-neon);
+}
+
+.empty-map-state {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    padding: 3rem;
+    background: rgba(255, 255, 255, 0.02);
+    border: 1px dashed rgba(255, 255, 255, 0.08);
+    border-radius: 12px;
+    color: rgba(255, 255, 255, 0.4);
+    text-align: center;
+}
+
+.empty-map-state .dim-icon {
+    margin-bottom: 1rem;
+    color: rgba(255, 255, 255, 0.2);
+}
+
+.timeline-container {
+    display: flex;
+    flex-direction: column;
+    gap: 0;
+    position: relative;
+    padding-left: 0.5rem;
+}
+
+.timeline-step {
+    display: flex;
+    flex-direction: row;
+    gap: 1.5rem;
+    padding: 1rem;
+    border-radius: 12px;
+    border: 1px solid transparent;
+    cursor: pointer;
+    transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
+    margin-bottom: 0.5rem;
+}
+
+.timeline-step:hover {
+    background: rgba(255, 255, 255, 0.02);
+    transform: translateX(4px);
+}
+
+.timeline-step.unlocked:hover {
+    border-color: rgba(0, 243, 255, 0.15);
+    box-shadow: 0 4px 20px rgba(0, 243, 255, 0.05);
+}
+
+.timeline-step.selected {
+    background: rgba(0, 243, 255, 0.04);
+    border-color: var(--nexus-neon);
+    box-shadow: 0 0 15px rgba(0, 243, 255, 0.1);
+}
+
+.node-connector-wrapper {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    width: 32px;
+    position: relative;
+    flex-shrink: 0;
+}
+
+.node-circle {
+    width: 32px;
+    height: 32px;
+    border-radius: 50%;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    position: relative;
+    z-index: 2;
+    transition: all 0.3s ease;
+    background: #0d0d0d;
+}
+
+.unlocked .node-circle {
+    border: 2px solid var(--nexus-neon);
+    color: var(--nexus-neon);
+    box-shadow: 0 0 10px rgba(0, 243, 255, 0.3);
+}
+
+.locked .node-circle {
+    border: 2px solid rgba(255, 255, 255, 0.1);
+    color: rgba(255, 255, 255, 0.2);
+}
+
+.node-glow {
+    position: absolute;
+    width: 100%;
+    height: 100%;
+    border-radius: 50%;
+    background: var(--nexus-neon);
+    opacity: 0.15;
+    filter: blur(4px);
+    z-index: -1;
+    animation: pulse-glow 2s infinite ease-in-out;
+}
+
+@keyframes pulse-glow {
+    0% { transform: scale(1); opacity: 0.15; }
+    50% { transform: scale(1.25); opacity: 0.3; }
+    100% { transform: scale(1); opacity: 0.15; }
+}
+
+.vertical-track {
+    width: 2px;
+    position: absolute;
+    top: 32px;
+    bottom: -18px; /* Extends to link to next node circle */
+    z-index: 1;
+    transition: all 0.3s ease;
+}
+
+.track-active {
+    background: linear-gradient(180deg, var(--nexus-neon), rgba(0, 243, 255, 0.2));
+    box-shadow: 0 0 6px rgba(0, 243, 255, 0.2);
+}
+
+.track-inactive {
+    background: rgba(255, 255, 255, 0.08);
+}
+
+.node-content {
+    flex-grow: 1;
+    background: rgba(255, 255, 255, 0.02);
+    border: 1px solid rgba(255, 255, 255, 0.04);
+    border-radius: 8px;
+    padding: 1rem;
+    display: flex;
+    flex-direction: column;
+    gap: 0.5rem;
+    transition: all 0.3s ease;
+    backdrop-filter: blur(4px);
+}
+
+.timeline-step.selected .node-content {
+    background: rgba(255, 255, 255, 0.03);
+    border-color: rgba(0, 243, 255, 0.2);
+}
+
+.node-header {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+}
+
+.segment-tag {
+    font-family: 'Outfit', sans-serif;
+    font-size: 0.75rem;
+    font-weight: 600;
+    letter-spacing: 0.05em;
+    color: rgba(255, 255, 255, 0.4);
+}
+
+.unlocked .segment-tag {
+    color: var(--nexus-neon);
+}
+
+.badge {
+    font-size: 0.7rem;
+    padding: 0.2rem 0.5rem;
+    border-radius: 12px;
+    font-weight: 500;
+}
+
+.badge-unlocked {
+    background: rgba(0, 243, 255, 0.08);
+    color: var(--nexus-neon);
+    border: 1px solid rgba(0, 243, 255, 0.2);
+}
+
+.badge-locked {
+    background: rgba(255, 255, 255, 0.05);
+    color: rgba(255, 255, 255, 0.3);
+    border: 1px solid rgba(255, 255, 255, 0.03);
+}
+
+.node-title {
+    margin: 0;
+    font-size: 0.95rem;
+    font-weight: 600;
+    color: #fff;
+    transition: color 0.2s ease;
+}
+
+.timeline-step.unlocked:hover .node-title {
+    color: var(--nexus-neon);
+}
+
+.locked .node-title {
+    color: rgba(255, 255, 255, 0.4);
+}
+
+.node-desc {
+    margin: 0;
+    font-size: 0.8rem;
+    line-height: 1.4;
+    color: rgba(255, 255, 255, 0.5);
+}
+
+.locked .node-desc {
+    color: rgba(255, 255, 255, 0.3);
+}
+
+.check-icon {
+    color: var(--nexus-neon);
+}
+
+.lock-icon {
+    color: rgba(255, 255, 255, 0.2);
+}

src/NexusReader.UI.Shared/Pages/ConceptsDashboard.razor

@@ -0,0 +1,306 @@
+@page "/book/{BookId:guid}/concepts"
+@page "/concepts-map"
+@using Microsoft.AspNetCore.Authorization
+@using NexusReader.UI.Shared.Components.Atoms
+@using NexusReader.UI.Shared.Components.Organisms
+@using NexusReader.UI.Shared.Services
+@using NexusReader.Application.Queries.Graph
+@using NexusReader.Application.Queries.Concepts
+@using System.Net.Http.Json
+@inject HttpClient Http
+@inject NavigationManager NavigationManager
+@inject IIdentityService IdentityService
+@inject ISyncService SyncService
+@attribute [Authorize]
+@implements IDisposable
+
+<PageTitle>Mapa Pojęć | Nexus Reader</PageTitle>
+
+<div class="concepts-dashboard-container">
+    @if (_isLoading)
+    {
+        <div class="loading-state glass-panel">
+            <div class="preloader-robot">
+                <NexusIcon Name="robot" Size="64" Class="neon-pulse" />
+                <div class="scan-line"></div>
+            </div>
+            <p class="loading-text">Inicjalizowanie mapy pojęć...</p>
+        </div>
+    }
+    else if (!string.IsNullOrEmpty(_errorMessage))
+    {
+        <div class="error-state glass-panel">
+            <NexusIcon Name="alert-triangle" Size="48" Class="error-icon" />
+            <h3>Wystąpił Błąd</h3>
+            <p>@_errorMessage</p>
+            <button class="nexus-btn secondary-neon" @onclick="LoadDataAsync">Spróbuj ponownie</button>
+        </div>
+    }
+    else if (!BookId.HasValue || BookId.Value == Guid.Empty || Nodes == null || !Nodes.Any())
+    {
+        <div class="empty-dashboard-state glass-panel">
+            <NexusIcon Name="book-open" Size="64" Class="dim-icon" />
+            <h2>Brak Aktywnych Książek</h2>
+            <p>Nie wybrano żadnej książki lub ta książka nie ma jeszcze wygenerowanej mapy pojęć przez Nexus AI.</p>
+            <a href="/library" class="nexus-btn primary-neon">Przejdź do Biblioteki</a>
+        </div>
+    }
+    else
+    {
+        <header class="dashboard-header">
+            <div class="header-back">
+                <button class="btn-back" @onclick="GoBackToLibrary">
+                    <NexusIcon Name="arrow-left" Size="16" />
+                    <span>Biblioteka</span>
+                </button>
+            </div>
+            <div class="header-title">
+                <h1>Mapa Pojęć</h1>
+                <span class="subtitle">Interaktywna ścieżka rozwoju Twoich postępów nauki</span>
+            </div>
+            <div class="header-actions">
+                <button class="btn-action" @onclick="GoToReader">
+                    <span>Otwórz Czytnik</span>
+                    <NexusIcon Name="book-open" Size="16" />
+                </button>
+            </div>
+        </header>
+
+        <div class="concepts-dashboard">
+            <!-- Left Pane: Interactive Skill Tree -->
+            <section class="left-pane glass-panel">
+                <div class="pane-header">
+                    <h3><NexusIcon Name="map" Size="18" /> Ścieżka Rozwoju Wiedzy</h3>
+                </div>
+                <div class="pane-content">
+                    <ConceptsMap Nodes="Nodes" 
+                                 LastReadBlockId="LastReadBlockId" 
+                                 SelectedNode="SelectedNode" 
+                                 OnNodeSelected="HandleNodeSelected" />
+                </div>
+            </section>
+
+            <!-- Right Pane: Reactive Deep-Dive Workspace -->
+            <section class="right-pane glass-panel">
+                @if (SelectedNode == null)
+                {
+                    <div class="workspace-empty">
+                        <div class="empty-glowing-brain">
+                            <NexusIcon Name="cpu" Size="48" Class="neon-pulse" />
+                        </div>
+                        <h4>Wybierz węzeł na mapie</h4>
+                        <p>Kliknij dowolne pojęcie z lewego panelu, aby uruchomić głęboką analizę i prześledzić szczegóły wygenerowane przez sztuczną inteligencję.</p>
+                    </div>
+                }
+                else
+                {
+                    var isSelectedNodeUnlocked = IsUnlocked(SelectedNode.Id);
+                    
+                    <div class="workspace-content">
+                        <div class="workspace-header">
+                            <div class="node-meta">
+                                <span class="node-id">@SelectedNode.Id.ToUpper()</span>
+                                @if (isSelectedNodeUnlocked)
+                                {
+                                    <span class="badge badge-unlocked">
+                                        <NexusIcon Name="check" Size="12" /> Odblokowane
+                                    </span>
+                                }
+                                else
+                                {
+                                    <span class="badge badge-locked">
+                                        <NexusIcon Name="lock" Size="12" /> Zablokowane
+                                    </span>
+                                }
+                            </div>
+                            <h2 class="workspace-title">@SelectedNode.Label</h2>
+                        </div>
+
+                        <div class="workspace-body scrollable-content">
+                            @if (!isSelectedNodeUnlocked)
+                            {
+                                <div class="locked-warning">
+                                    <NexusIcon Name="lock" Size="20" Class="lock-warning-icon" />
+                                    <div>
+                                        <strong>Ten etap jest zablokowany</strong>
+                                        <p>Kontynuuj czytanie książki, aby odblokować to pojęcie. Po przeczytaniu rozdziału, postęp zsynchronizuje się automatycznie.</p>
+                                    </div>
+                                </div>
+                            }
+
+                            <div class="metadata-section">
+                                <h4><NexusIcon Name="info" Size="14" /> Opis Pojęcia</h4>
+                                <p class="section-text">@SelectedNode.Description</p>
+                            </div>
+
+                            <div class="metadata-section">
+                                <h4><NexusIcon Name="file-text" Size="14" /> Podsumowanie AI</h4>
+                                <div class="summary-box">
+                                    <p class="section-text">@SelectedNode.Summary</p>
+                                </div>
+                            </div>
+
+                            @if (SelectedNode.KeyTerms != null && SelectedNode.KeyTerms.Any())
+                            {
+                                <div class="metadata-section">
+                                    <h4><NexusIcon Name="list" Size="14" /> Kluczowe Terminy</h4>
+                                    <div class="key-terms-grid">
+                                        @foreach (var term in SelectedNode.KeyTerms)
+                                        {
+                                            <span class="term-pill">@term</span>
+                                        }
+                                    </div>
+                                </div>
+                            }
+                        </div>
+
+                        <div class="workspace-footer">
+                            <button class="nexus-btn primary-neon w-100" @onclick="GoToSelectedChapter">
+                                <NexusIcon Name="book-open" Size="16" />
+                                <span>Czytaj ten rozdział</span>
+                            </button>
+                        </div>
+                    </div>
+                }
+            </section>
+        </div>
+    }
+</div>
+
+@code {
+    [Parameter] public Guid? BookId { get; set; }
+
+    private List<GraphNodeDto> Nodes { get; set; } = new();
+    private string LastReadBlockId { get; set; } = string.Empty;
+    private GraphNodeDto? SelectedNode { get; set; }
+    private bool _isLoading = true;
+    private string _errorMessage = string.Empty;
+
+    protected override async Task OnInitializedAsync()
+    {
+        IdentityService.OnStateInvalidated += HandleStateInvalidatedAsync;
+        await SyncService.InitializeAsync();
+        SyncService.OnProgressReceived += HandleProgressReceivedAsync;
+        await LoadDataAsync();
+    }
+
+    private async Task LoadDataAsync()
+    {
+        _isLoading = true;
+        _errorMessage = string.Empty;
+        StateHasChanged();
+
+        try
+        {
+            if (!BookId.HasValue || BookId.Value == Guid.Empty)
+            {
+                var profileResult = await IdentityService.GetProfileAsync();
+                if (profileResult.IsSuccess && profileResult.Value.LastReadBook != null)
+                {
+                    BookId = profileResult.Value.LastReadBook.Id;
+                }
+            }
+
+            if (BookId.HasValue && BookId.Value != Guid.Empty)
+            {
+                var result = await Http.GetFromJsonAsync<BookConceptsMapResultDto>($"api/book/{BookId}/concepts-map");
+                if (result != null)
+                {
+                    Nodes = result.Nodes;
+                    LastReadBlockId = result.LastReadBlockId;
+
+                    if (Nodes.Any())
+                    {
+                        SelectedNode = Nodes.FirstOrDefault(n => IsUnlocked(n.Id)) ?? Nodes.First();
+                    }
+                }
+                else
+                {
+                    _errorMessage = "Brak odpowiedzi od serwera.";
+                }
+            }
+        }
+        catch (Exception ex)
+        {
+            _errorMessage = $"Błąd podczas pobierania danych: {ex.Message}";
+        }
+        finally
+        {
+            _isLoading = false;
+            StateHasChanged();
+        }
+    }
+
+    private bool IsUnlocked(string nodeId)
+    {
+        if (string.IsNullOrEmpty(nodeId)) return false;
+        var nodeSeq = ParseSegmentNumber(nodeId);
+        
+        var minNodeSeq = Nodes.Any() ? Nodes.Min(n => ParseSegmentNumber(n.Id)) : 0;
+        if (nodeSeq == minNodeSeq) return true;
+
+        if (string.IsNullOrEmpty(LastReadBlockId)) return false;
+
+        var progressSeq = ParseSegmentNumber(LastReadBlockId);
+        return nodeSeq <= progressSeq;
+    }
+
+    private static int ParseSegmentNumber(string? id)
+    {
+        if (string.IsNullOrEmpty(id)) return 0;
+        var digits = new string(id.Where(char.IsDigit).ToArray());
+        return int.TryParse(digits, out var val) ? val : 0;
+    }
+
+    private void HandleNodeSelected(GraphNodeDto node)
+    {
+        SelectedNode = node;
+        StateHasChanged();
+    }
+
+    private void GoBackToLibrary()
+    {
+        NavigationManager.NavigateTo("/library");
+    }
+
+    private void GoToReader()
+    {
+        if (BookId.HasValue)
+        {
+            NavigationManager.NavigateTo($"/reader/{BookId.Value}");
+        }
+    }
+
+    private void GoToSelectedChapter()
+    {
+        if (BookId.HasValue && SelectedNode != null)
+        {
+            var chapterIndex = ParseSegmentNumber(SelectedNode.Id);
+            NavigationManager.NavigateTo($"/reader/{BookId.Value}?chapter={chapterIndex}");
+        }
+    }
+
+    private async Task HandleStateInvalidatedAsync()
+    {
+        await InvokeAsync(async () =>
+        {
+            await LoadDataAsync();
+        });
+    }
+
+    private async Task HandleProgressReceivedAsync(string pageId, DateTime timestamp)
+    {
+        await InvokeAsync(() =>
+        {
+            LastReadBlockId = pageId;
+            StateHasChanged();
+            return Task.CompletedTask;
+        });
+    }
+
+    public void Dispose()
+    {
+        IdentityService.OnStateInvalidated -= HandleStateInvalidatedAsync;
+        SyncService.OnProgressReceived -= HandleProgressReceivedAsync;
+    }
+}

src/NexusReader.UI.Shared/Pages/ConceptsDashboard.razor.css

@@ -0,0 +1,475 @@
+.concepts-dashboard-container {
+    width: 100%;
+    max-width: 1400px;
+    margin: 0 auto;
+    padding: 2rem 1.5rem;
+    box-sizing: border-box;
+    display: flex;
+    flex-direction: column;
+    gap: 1.5rem;
+    min-height: calc(100vh - 80px);
+}
+
+/* Header Section */
+.dashboard-header {
+    display: grid;
+    grid-template-columns: auto 1fr auto;
+    align-items: center;
+    gap: 2rem;
+    padding: 1.25rem 2rem;
+    background: rgba(20, 20, 20, 0.35);
+    border: 1px solid rgba(255, 255, 255, 0.05);
+    border-radius: 16px;
+    backdrop-filter: blur(12px);
+    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.2);
+}
+
+.header-back .btn-back {
+    background: transparent;
+    border: 1px solid rgba(255, 255, 255, 0.1);
+    color: #aaa;
+    padding: 0.5rem 1rem;
+    border-radius: 8px;
+    cursor: pointer;
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+    font-size: 0.85rem;
+    transition: all 0.2s ease;
+}
+
+.header-back .btn-back:hover {
+    border-color: var(--nexus-neon);
+    color: var(--nexus-neon);
+    background: rgba(0, 243, 255, 0.05);
+    box-shadow: 0 0 10px rgba(0, 243, 255, 0.1);
+}
+
+.header-title h1 {
+    margin: 0;
+    font-size: 1.5rem;
+    font-weight: 700;
+    color: #fff;
+}
+
+.header-title .subtitle {
+    font-size: 0.85rem;
+    color: rgba(255, 255, 255, 0.4);
+}
+
+.header-actions .btn-action {
+    background: linear-gradient(135deg, rgba(0, 243, 255, 0.1), rgba(0, 243, 255, 0.05));
+    border: 1px solid var(--nexus-neon);
+    color: var(--nexus-neon);
+    padding: 0.6rem 1.2rem;
+    border-radius: 8px;
+    cursor: pointer;
+    display: flex;
+    align-items: center;
+    gap: 0.6rem;
+    font-size: 0.85rem;
+    font-weight: 600;
+    text-transform: uppercase;
+    letter-spacing: 0.05em;
+    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
+    box-shadow: 0 0 15px rgba(0, 243, 255, 0.15);
+}
+
+.header-actions .btn-action:hover {
+    background: var(--nexus-neon);
+    color: #000;
+    box-shadow: 0 0 25px var(--nexus-neon);
+    transform: translateY(-1px);
+}
+
+/* Grid Layout */
+.concepts-dashboard {
+    display: grid;
+    grid-template-columns: 1.1fr 1fr;
+    gap: 1.5rem;
+    height: 72vh;
+}
+
+/* Glass Panels */
+.glass-panel {
+    background: rgba(13, 13, 13, 0.45);
+    border: 1px solid rgba(255, 255, 255, 0.05);
+    border-radius: 16px;
+    backdrop-filter: blur(16px);
+    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.4);
+    display: flex;
+    flex-direction: column;
+    overflow: hidden;
+}
+
+.pane-header {
+    padding: 1.25rem 1.5rem;
+    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
+}
+
+.pane-header h3 {
+    margin: 0;
+    font-size: 1rem;
+    font-weight: 600;
+    color: #fff;
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+}
+
+.pane-content {
+    flex-grow: 1;
+    overflow: hidden;
+}
+
+/* Loading, Error and Empty States */
+.loading-state, .error-state, .empty-dashboard-state {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    padding: 4rem 2rem;
+    text-align: center;
+    margin: auto;
+    width: 100%;
+    max-width: 480px;
+    box-sizing: border-box;
+}
+
+.preloader-robot {
+    position: relative;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    margin-bottom: 1.5rem;
+}
+
+.neon-pulse {
+    color: var(--nexus-neon);
+    filter: drop-shadow(0 0 10px var(--nexus-neon));
+    animation: robot-pulse 2s infinite ease-in-out;
+}
+
+@keyframes robot-pulse {
+    0% { transform: scale(1); filter: drop-shadow(0 0 10px var(--nexus-neon)); }
+    50% { transform: scale(1.08); filter: drop-shadow(0 0 25px var(--nexus-neon)); }
+    100% { transform: scale(1); filter: drop-shadow(0 0 10px var(--nexus-neon)); }
+}
+
+.scan-line {
+    position: absolute;
+    top: 0;
+    left: 0;
+    width: 100%;
+    height: 2px;
+    background: var(--nexus-neon);
+    box-shadow: 0 0 15px var(--nexus-neon);
+    animation: scan 2s infinite linear;
+    opacity: 0.8;
+}
+
+@keyframes scan {
+    0% { top: 0; }
+    50% { top: 100%; }
+    100% { top: 0; }
+}
+
+.loading-text {
+    font-size: 0.95rem;
+    color: rgba(255, 255, 255, 0.7);
+    margin-top: 1rem;
+    letter-spacing: 0.05em;
+}
+
+.error-icon, .dim-icon {
+    margin-bottom: 1.5rem;
+}
+
+.error-icon {
+    color: #ff4a4a;
+    filter: drop-shadow(0 0 8px rgba(255, 74, 74, 0.4));
+}
+
+.dim-icon {
+    color: rgba(255, 255, 255, 0.15);
+}
+
+.empty-dashboard-state h2, .error-state h3 {
+    color: #fff;
+    margin: 0 0 0.75rem 0;
+    font-weight: 600;
+}
+
+.empty-dashboard-state p, .error-state p {
+    color: rgba(255, 255, 255, 0.45);
+    font-size: 0.88rem;
+    line-height: 1.5;
+    margin: 0 0 2rem 0;
+}
+
+/* Workspace Panels */
+.workspace-empty {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    flex-grow: 1;
+    padding: 3rem;
+    text-align: center;
+    color: rgba(255, 255, 255, 0.4);
+}
+
+.empty-glowing-brain {
+    width: 80px;
+    height: 80px;
+    border-radius: 50%;
+    background: rgba(0, 243, 255, 0.04);
+    border: 1px solid rgba(0, 243, 255, 0.1);
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    margin-bottom: 1.5rem;
+    box-shadow: 0 0 20px rgba(0, 243, 255, 0.05);
+}
+
+.workspace-empty h4 {
+    margin: 0 0 0.75rem 0;
+    color: #fff;
+    font-size: 1.1rem;
+    font-weight: 600;
+}
+
+.workspace-empty p {
+    font-size: 0.85rem;
+    line-height: 1.5;
+    max-width: 320px;
+    margin: 0;
+}
+
+.workspace-content {
+    display: flex;
+    flex-direction: column;
+    height: 100%;
+}
+
+.workspace-header {
+    padding: 1.5rem;
+    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
+}
+
+.node-meta {
+    display: flex;
+    align-items: center;
+    gap: 0.75rem;
+    margin-bottom: 0.5rem;
+}
+
+.node-id {
+    font-family: 'Outfit', sans-serif;
+    font-size: 0.75rem;
+    font-weight: 700;
+    letter-spacing: 0.08em;
+    color: var(--nexus-neon);
+}
+
+.badge {
+    font-size: 0.7rem;
+    padding: 0.2rem 0.55rem;
+    border-radius: 12px;
+    font-weight: 500;
+    display: inline-flex;
+    align-items: center;
+    gap: 0.25rem;
+}
+
+.badge-unlocked {
+    background: rgba(0, 243, 255, 0.08);
+    color: var(--nexus-neon);
+    border: 1px solid rgba(0, 243, 255, 0.2);
+}
+
+.badge-locked {
+    background: rgba(255, 255, 255, 0.05);
+    color: rgba(255, 255, 255, 0.4);
+    border: 1px solid rgba(255, 255, 255, 0.05);
+}
+
+.workspace-title {
+    margin: 0;
+    font-size: 1.4rem;
+    font-weight: 700;
+    color: #fff;
+}
+
+.workspace-body {
+    flex-grow: 1;
+    overflow-y: auto;
+    padding: 1.5rem;
+    display: flex;
+    flex-direction: column;
+    gap: 1.5rem;
+}
+
+/* Scrollbar customization for workspace body */
+.workspace-body::-webkit-scrollbar {
+    width: 6px;
+}
+.workspace-body::-webkit-scrollbar-track {
+    background: transparent;
+}
+.workspace-body::-webkit-scrollbar-thumb {
+    background: rgba(255, 255, 255, 0.08);
+    border-radius: 3px;
+}
+.workspace-body::-webkit-scrollbar-thumb:hover {
+    background: var(--nexus-neon);
+}
+
+.locked-warning {
+    display: flex;
+    flex-direction: row;
+    gap: 1rem;
+    background: rgba(255, 171, 0, 0.04);
+    border: 1px solid rgba(255, 171, 0, 0.15);
+    border-radius: 8px;
+    padding: 1rem;
+    color: rgba(255, 255, 255, 0.85);
+}
+
+.lock-warning-icon {
+    color: #ffab00;
+    flex-shrink: 0;
+    margin-top: 0.1rem;
+}
+
+.locked-warning strong {
+    font-size: 0.85rem;
+    color: #ffab00;
+    display: block;
+    margin-bottom: 0.25rem;
+}
+
+.locked-warning p {
+    margin: 0;
+    font-size: 0.8rem;
+    line-height: 1.4;
+    color: rgba(255, 255, 255, 0.55);
+}
+
+.metadata-section h4 {
+    margin: 0 0 0.5rem 0;
+    font-size: 0.85rem;
+    font-weight: 600;
+    color: #aaa;
+    display: flex;
+    align-items: center;
+    gap: 0.35rem;
+    text-transform: uppercase;
+    letter-spacing: 0.05em;
+}
+
+.section-text {
+    margin: 0;
+    font-size: 0.88rem;
+    line-height: 1.6;
+    color: rgba(255, 255, 255, 0.7);
+}
+
+.summary-box {
+    background: rgba(255, 255, 255, 0.02);
+    border-left: 3px solid var(--nexus-neon);
+    border-radius: 0 8px 8px 0;
+    padding: 1rem;
+    margin-top: 0.25rem;
+}
+
+.key-terms-grid {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 0.5rem;
+    margin-top: 0.5rem;
+}
+
+.term-pill {
+    font-size: 0.75rem;
+    background: rgba(255, 255, 255, 0.03);
+    border: 1px solid rgba(255, 255, 255, 0.05);
+    color: rgba(255, 255, 255, 0.6);
+    padding: 0.3rem 0.75rem;
+    border-radius: 20px;
+    font-weight: 500;
+    transition: all 0.2s ease;
+}
+
+.term-pill:hover {
+    border-color: rgba(0, 243, 255, 0.2);
+    color: var(--nexus-neon);
+    background: rgba(0, 243, 255, 0.03);
+}
+
+.workspace-footer {
+    padding: 1.25rem 1.5rem;
+    border-top: 1px solid rgba(255, 255, 255, 0.05);
+}
+
+.nexus-btn.primary-neon {
+    background: linear-gradient(135deg, var(--nexus-neon), #00b8cc);
+    color: #000;
+    border: none;
+    font-weight: 600;
+    letter-spacing: 0.03em;
+    padding: 0.75rem 1.5rem;
+    border-radius: 8px;
+    cursor: pointer;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    gap: 0.5rem;
+    width: 100%;
+    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
+    box-shadow: 0 4px 15px rgba(0, 243, 255, 0.2);
+}
+
+.nexus-btn.primary-neon:hover {
+    box-shadow: 0 6px 25px rgba(0, 243, 255, 0.4);
+    transform: translateY(-1px);
+}
+
+.nexus-btn.secondary-neon {
+    background: transparent;
+    color: #fff;
+    border: 1px solid rgba(255, 255, 255, 0.1);
+    font-weight: 600;
+    padding: 0.75rem 1.5rem;
+    border-radius: 8px;
+    cursor: pointer;
+    display: inline-flex;
+    align-items: center;
+    gap: 0.5rem;
+    transition: all 0.2s ease;
+}
+
+.nexus-btn.secondary-neon:hover {
+    border-color: var(--nexus-neon);
+    color: var(--nexus-neon);
+    box-shadow: 0 0 10px rgba(0, 243, 255, 0.1);
+}
+
+@media (max-width: 1024px) {
+    .concepts-dashboard {
+        grid-template-columns: 1fr;
+        height: auto;
+    }
+    .concepts-dashboard-container {
+        padding: 1rem;
+    }
+    .dashboard-header {
+        grid-template-columns: 1fr;
+        text-align: center;
+        gap: 1rem;
+    }
+    .header-back, .header-actions {
+        display: flex;
+        justify-content: center;
+    }
+}

src/NexusReader.Web/Program.cs

@@ -7,6 +7,7 @@ using NexusReader.Application.Abstractions.Services;
 using NexusReader.Application.Queries.User;
 using NexusReader.Application.Commands.Library;
 using NexusReader.Application.Queries.Library;
+using NexusReader.Application.Queries.Concepts;
 using MediatR;
 using NexusReader.Web.Client.Services;
 using NexusReader.UI.Shared.Services;
@@ -369,6 +370,28 @@ app.MapGet("/api/library/books", async (ClaimsPrincipal user, IMediator mediator
     return Results.BadRequest(errorMsg);
 }).RequireAuthorization();
 
+app.MapGet("/api/book/{bookId:guid}/concepts-map", async (
+    Guid bookId,
+    ClaimsPrincipal user,
+    IMediator mediator) =>
+{
+    var userId = user.FindFirstValue(ClaimTypes.NameIdentifier);
+    var tenantId = user.FindFirstValue("TenantId") ?? "global";
+
+    if (string.IsNullOrEmpty(userId))
+    {
+        return Results.Unauthorized();
+    }
+
+    var result = await mediator.Send(new GetBookConceptsMapQuery(bookId, userId, tenantId));
+    if (result.IsFailed)
+    {
+        return Results.BadRequest(result.Errors.FirstOrDefault()?.Message ?? "Failed to fetch concepts map.");
+    }
+
+    return Results.Ok(result.Value);
+}).RequireAuthorization();
+
 app.MapPost("/api/StripeWebhook", async (
     HttpContext context, 
     UserManager<NexusUser> userManager,