Enhance tables canvas reading states

docs/tables_frontend_overhaul_implementation_plan.md

@@ -65,6 +65,7 @@ It is intentionally implementation-focused:
 | 2026-03-21 | P3.2 | Completed | Replaced the floating table picker with a permanent left-rail layout, converted the old selector component into a real page header, and kept the current selection flow intact inside the new reference frame. |
 | 2026-03-21 | P3.3 | Completed | Added rail search, family filters, pinned and recent sections, curated status chips, and keyboard up/down plus Enter handling on top of the new permanent table index rail. |
 | 2026-03-21 | P3.4 | Completed | Added a sticky context bar with reference-mode tabs, variant and severity selectors, roll-jump state, and active filter chips, then wired those controls into page state and canvas filtering. |
+| 2026-03-21 | P3.5 | Completed | Reworked the canvas with sticky headers, a sticky roll-band column, row and column emphasis driven by selection and roll-jump state, selected-cell treatment, and a comfortable/dense density toggle. |
 
 ### Lessons Learned
 
@@ -99,6 +100,7 @@ It is intentionally implementation-focused:
 - The `Tables` navigation model needs its own persistent geometry before advanced behaviors land. Converting the selector to a real rail first keeps later search and keyboard work from being tangled up with another structural rewrite.
 - Rail keyboard behavior is easiest to maintain when it works from one deduplicated option order, even if the UI shows multiple sections. Keeping one internal option list avoids separate arrow-key state per section.
 - The context bar controls should own one shared view-state model before the canvas gets more visual treatment. Wiring the filters into the host page now avoids a second refactor when row, column, and cell emphasis land.
+- Canvas emphasis becomes maintainable once selection, roll-jump, and density are all fed through one explicit state model. That lets the grid respond to context without hiding selection logic inside CSS-only heuristics.
 
 ## Target Outcomes
 
@@ -463,7 +465,7 @@ Build the shared interaction infrastructure needed by multiple destinations befo
 | `P3.2` | Completed | The old dropdown picker is gone; `/tables` now uses a permanent left rail and a real page header while keeping the current selection flow intact. |
 | `P3.3` | Completed | The rail now supports search-as-you-type, family filters, pinned and recent sections, curated status chips, and a deduplicated arrow/Enter keyboard path. |
 | `P3.4` | Completed | The table surface now has a sticky context bar with mode tabs, variant/severity focus, roll-jump state, and active filter chips wired into host-page view state. |
-| `P3.5` | Pending | Rework the canvas for sticky headers, sticky roll bands, stronger reading emphasis, and density control. |
+| `P3.5` | Completed | The canvas now supports sticky headers and roll bands, row and column emphasis from selection and roll-jump state, selected-cell treatment, and a comfortable/dense density toggle. |
 | `P3.6` | Pending | Remove visible resting-state action stacks from non-selected cells. |
 | `P3.7` | Pending | Add the desktop selection-driven inspector. |
 | `P3.8` | Pending | Add the mobile bottom-sheet inspector variant. |

src/RolemasterDb.App/Components/Pages/Tables.razor

@@ -61,17 +61,23 @@
                             SelectedGroupKey="selectedGroupKey"
                             SelectedColumnKey="selectedColumnKey"
                             RollJumpValue="rollJumpValue"
+                            DensityMode="densityMode"
                             OnTogglePin="TogglePinnedTableAsync"
                             OnModeChanged="UpdateReferenceModeAsync"
                             OnGroupChanged="UpdateSelectedGroupAsync"
                             OnColumnChanged="UpdateSelectedColumnAsync"
-                            OnRollJumpChanged="UpdateRollJumpAsync" />
+                            OnRollJumpChanged="UpdateRollJumpAsync"
+                            OnDensityChanged="UpdateDensityModeAsync" />
 
                         <TablesCanvas
                             Detail="detail"
                             CurrentMode="referenceMode"
                             SelectedGroupKey="selectedGroupKey"
                             SelectedColumnKey="selectedColumnKey"
+                            RollJumpValue="rollJumpValue"
+                            DensityMode="densityMode"
+                            SelectedCell="selectedCell"
+                            OnSelectCell="SelectCell"
                             OnOpenCuration="OpenCellCurationAsync"
                             OnOpenEditor="OpenCellEditorAsync" />
                     </div>
@@ -150,6 +156,8 @@
     private string selectedGroupKey = string.Empty;
     private string selectedColumnKey = string.Empty;
     private string rollJumpValue = string.Empty;
+    private string densityMode = TablesDensityMode.Comfortable;
+    private TablesCellSelection? selectedCell;
     private bool hasResolvedStoredTableSelection;
     private CriticalTableReference? SelectedTableReference =>
         referenceData?.CriticalTables.FirstOrDefault(item => string.Equals(item.Key, selectedTableSlug, StringComparison.OrdinalIgnoreCase));
@@ -664,6 +672,23 @@
         return Task.CompletedTask;
     }
 
+    private Task UpdateDensityModeAsync(string mode)
+    {
+        densityMode = NormalizeDensityMode(mode);
+        return Task.CompletedTask;
+    }
+
+    private void SelectCell(TablesCellSelection selection)
+    {
+        if (tableDetail?.Cells.Any(cell => cell.ResultId == selection.ResultId) != true)
+        {
+            selectedCell = null;
+            return;
+        }
+
+        selectedCell = selection;
+    }
+
     private void NormalizeViewStateForCurrentDetail()
     {
         referenceMode = NormalizeMode(referenceMode);
@@ -673,6 +698,8 @@
             selectedGroupKey = string.Empty;
             selectedColumnKey = string.Empty;
             rollJumpValue = string.Empty;
+            densityMode = NormalizeDensityMode(densityMode);
+            selectedCell = null;
             return;
         }
 
@@ -687,6 +714,12 @@
         }
 
         rollJumpValue = NormalizeRollInput(rollJumpValue);
+        densityMode = NormalizeDensityMode(densityMode);
+
+        if (selectedCell is not null && tableDetail.Cells.All(cell => cell.ResultId != selectedCell.ResultId))
+        {
+            selectedCell = null;
+        }
     }
 
     private static string NormalizeMode(string? mode) =>
@@ -700,6 +733,11 @@
     private static string NormalizeOptionalFilter(string? value) =>
         string.IsNullOrWhiteSpace(value) ? string.Empty : value.Trim();
 
+    private static string NormalizeDensityMode(string? mode) =>
+        string.Equals(mode, TablesDensityMode.Dense, StringComparison.Ordinal)
+            ? TablesDensityMode.Dense
+            : TablesDensityMode.Comfortable;
+
     private static string NormalizeRollInput(string? value)
     {
         if (string.IsNullOrWhiteSpace(value))

src/RolemasterDb.App/Components/Tables/TablesCanvas.razor

@@ -1,12 +1,12 @@
 <div class="table-scroll">
-    <div class="critical-table-grid" role="group" aria-label="@Detail.DisplayName" style="@gridTemplateStyle">
+    <div class="critical-table-grid @BuildGridCssClass()" role="group" aria-label="@Detail.DisplayName" style="@gridTemplateStyle">
         @if (Detail.Groups.Count > 0)
         {
             <div class="critical-table-grid-header-cell critical-table-grid-corner" aria-hidden="true"></div>
             @foreach (var group in visibleGroups)
             {
                 <div
-                    class="critical-table-grid-header-cell critical-table-grid-group-header"
+                    class="@BuildGroupHeaderCssClass(group.Key)"
                     style="@BuildColumnSpanStyle(visibleColumns.Count)">
                     <span>@group.Label</span>
                 </div>
@@ -16,14 +16,14 @@
         <div class="critical-table-grid-header-cell critical-table-grid-roll-band-header" aria-hidden="true"></div>
         @foreach (var displayColumn in displayColumns)
         {
-            <div class="critical-table-grid-header-cell critical-table-grid-column-header">
+            <div class="@BuildColumnHeaderCssClass(displayColumn.GroupKey, displayColumn.ColumnKey)">
                 <span>@displayColumn.ColumnLabel</span>
             </div>
         }
 
         @foreach (var rollBand in Detail.RollBands)
         {
-            <div class="critical-table-grid-header-cell critical-table-grid-roll-band">@rollBand.Label</div>
+            <div class="@BuildRollBandCssClass(rollBand.Label)">@rollBand.Label</div>
             @foreach (var displayColumn in displayColumns)
             {
                 if (TryGetCell(rollBand.Label, displayColumn.GroupKey, displayColumn.ColumnKey, out var resolvedCell) && resolvedCell is not null)
@@ -32,7 +32,7 @@
 
                     @if (MatchesModeFilter(cell))
                     {
-                        <div class="@GetCellCssClass(cell)">
+                        <div class="@GetCellCssClass(cell, displayColumn.GroupKey)" @onclick="() => SelectCell(cell)">
                             <div class="critical-table-cell-shell">
                                 <div class="critical-table-cell-actions">
                                     @if (cell.IsCurated)
@@ -45,6 +45,7 @@
                                             type="button"
                                             class="critical-cell-action-button is-curation"
                                             title="Open the curation preview for this cell."
+                                            @onclick:stopPropagation="true"
                                             @onclick="() => OnOpenCuration.InvokeAsync(cell.ResultId)">
                                             Needs Curation
                                         </button>
@@ -54,6 +55,7 @@
                                         type="button"
                                         class="critical-cell-action-button is-edit"
                                         title="Open the full editor for this cell."
+                                        @onclick:stopPropagation="true"
                                         @onclick="() => OnOpenEditor.InvokeAsync(cell.ResultId)">
                                         Edit
                                     </button>
@@ -105,6 +107,18 @@
     [Parameter]
     public string SelectedColumnKey { get; set; } = string.Empty;
 
+    [Parameter]
+    public string RollJumpValue { get; set; } = string.Empty;
+
+    [Parameter]
+    public string DensityMode { get; set; } = TablesDensityMode.Comfortable;
+
+    [Parameter]
+    public TablesCellSelection? SelectedCell { get; set; }
+
+    [Parameter]
+    public EventCallback<TablesCellSelection> OnSelectCell { get; set; }
+
     [Parameter]
     public EventCallback<int> OnOpenCuration { get; set; }
 
@@ -175,10 +189,133 @@
             _ => true
         };
 
-    private static string BuildColumnSpanStyle(int span) => $"grid-column: span {span};";
+    private string? ActiveRollBand =>
+        !string.IsNullOrWhiteSpace(SelectedCell?.RollBand)
+            ? SelectedCell.RollBand
+            : ResolveRollJumpBandLabel();
 
-    private static string GetCellCssClass(CriticalTableCellDetail cell) =>
+    private string? ActiveColumnKey =>
-        cell.IsCurated
+        !string.IsNullOrWhiteSpace(SelectedCell?.ColumnKey)
-            ? "critical-table-cell is-curated"
+            ? SelectedCell.ColumnKey
-            : "critical-table-cell needs-curation";
+            : (!string.IsNullOrWhiteSpace(SelectedColumnKey) ? SelectedColumnKey : null);
+
+    private string? ActiveGroupKey =>
+        !string.IsNullOrWhiteSpace(SelectedCell?.GroupKey)
+            ? SelectedCell.GroupKey
+            : (!string.IsNullOrWhiteSpace(SelectedGroupKey) ? SelectedGroupKey : null);
+
+    private string BuildGridCssClass() =>
+        string.Equals(DensityMode, TablesDensityMode.Dense, StringComparison.Ordinal)
+            ? "is-dense"
+            : "is-comfortable";
+
+    private string BuildGroupHeaderCssClass(string groupKey)
+    {
+        var classes = new List<string> { "critical-table-grid-header-cell", "critical-table-grid-group-header" };
+        if (string.Equals(groupKey, ActiveGroupKey, StringComparison.OrdinalIgnoreCase))
+        {
+            classes.Add("is-active-group");
+        }
+
+        return string.Join(' ', classes);
+    }
+
+    private string BuildColumnHeaderCssClass(string? groupKey, string columnKey)
+    {
+        var classes = new List<string> { "critical-table-grid-header-cell", "critical-table-grid-column-header" };
+
+        if (string.Equals(columnKey, ActiveColumnKey, StringComparison.OrdinalIgnoreCase))
+        {
+            classes.Add("is-active-column");
+        }
+
+        if (!string.IsNullOrWhiteSpace(groupKey) &&
+            string.Equals(groupKey, ActiveGroupKey, StringComparison.OrdinalIgnoreCase))
+        {
+            classes.Add("is-active-group");
+        }
+
+        return string.Join(' ', classes);
+    }
+
+    private string BuildRollBandCssClass(string rollBandLabel)
+    {
+        var classes = new List<string> { "critical-table-grid-header-cell", "critical-table-grid-roll-band" };
+        if (string.Equals(rollBandLabel, ActiveRollBand, StringComparison.OrdinalIgnoreCase))
+        {
+            classes.Add("is-active-row");
+        }
+
+        if (string.Equals(rollBandLabel, ResolveRollJumpBandLabel(), StringComparison.OrdinalIgnoreCase))
+        {
+            classes.Add("is-roll-target");
+        }
+
+        return string.Join(' ', classes);
+    }
+
+    private string GetCellCssClass(CriticalTableCellDetail cell, string? groupKey)
+    {
+        var classes = new List<string>
+        {
+            "critical-table-cell",
+            cell.IsCurated ? "is-curated" : "needs-curation"
+        };
+
+        if (string.Equals(cell.RollBand, ActiveRollBand, StringComparison.OrdinalIgnoreCase))
+        {
+            classes.Add("is-active-row");
+        }
+
+        if (string.Equals(cell.ColumnKey, ActiveColumnKey, StringComparison.OrdinalIgnoreCase))
+        {
+            classes.Add("is-active-column");
+        }
+
+        if (!string.IsNullOrWhiteSpace(groupKey) &&
+            string.Equals(groupKey, ActiveGroupKey, StringComparison.OrdinalIgnoreCase))
+        {
+            classes.Add("is-active-group");
+        }
+
+        if (SelectedCell is not null && cell.ResultId == SelectedCell.ResultId)
+        {
+            classes.Add("is-selected-cell");
+        }
+
+        if (string.Equals(cell.RollBand, ResolveRollJumpBandLabel(), StringComparison.OrdinalIgnoreCase))
+        {
+            classes.Add("is-roll-target");
+        }
+
+        return string.Join(' ', classes);
+    }
+
+    private string? ResolveRollJumpBandLabel()
+    {
+        if (!int.TryParse(RollJumpValue, out var targetRoll))
+        {
+            return null;
+        }
+
+        foreach (var rollBand in Detail.RollBands)
+        {
+            if (targetRoll < rollBand.MinRoll)
+            {
+                continue;
+            }
+
+            if (rollBand.MaxRoll is null || targetRoll <= rollBand.MaxRoll.Value)
+            {
+                return rollBand.Label;
+            }
+        }
+
+        return null;
+    }
+
+    private Task SelectCell(CriticalTableCellDetail cell) =>
+        OnSelectCell.InvokeAsync(new TablesCellSelection(cell.ResultId, cell.RollBand, cell.ColumnKey, cell.GroupKey));
+
+    private static string BuildColumnSpanStyle(int span) => $"grid-column: span {span};";
 }

src/RolemasterDb.App/Components/Tables/TablesCellSelection.cs

@@ -0,0 +1,7 @@
+namespace RolemasterDb.App.Components.Tables;
+
+public sealed record TablesCellSelection(
+    int ResultId,
+    string RollBand,
+    string ColumnKey,
+    string? GroupKey);

src/RolemasterDb.App/Components/Tables/TablesContextBar.razor

@@ -13,6 +13,7 @@
     </div>
 
     <div class="tables-context-controls">
+        <div class="tables-context-tab-row">
             <SegmentedTabs
                 Items="modeTabs"
                 SelectedValue="CurrentMode"
@@ -20,6 +21,14 @@
                 AriaLabel="Reference mode"
                 CssClass="tables-context-mode-tabs" />
 
+            <SegmentedTabs
+                Items="densityTabs"
+                SelectedValue="DensityMode"
+                SelectedValueChanged="OnDensityChanged"
+                AriaLabel="Table density"
+                CssClass="tables-context-density-tabs" />
+        </div>
+
         <div class="tables-context-fields">
             @if (Detail.Groups.Count > 1)
             {
@@ -104,6 +113,12 @@
         new(TablesReferenceMode.Curated, "Curated")
     ];
 
+    private readonly IReadOnlyList<SegmentedTabItem> densityTabs =
+    [
+        new(TablesDensityMode.Comfortable, "Comfortable"),
+        new(TablesDensityMode.Dense, "Dense")
+    ];
+
     [Parameter, EditorRequired]
     public CriticalTableDetail Detail { get; set; } = default!;
 
@@ -122,6 +137,9 @@
     [Parameter]
     public string RollJumpValue { get; set; } = string.Empty;
 
+    [Parameter]
+    public string DensityMode { get; set; } = TablesDensityMode.Comfortable;
+
     [Parameter]
     public EventCallback OnTogglePin { get; set; }
 
@@ -137,6 +155,9 @@
     [Parameter]
     public EventCallback<string> OnRollJumpChanged { get; set; }
 
+    [Parameter]
+    public EventCallback<string> OnDensityChanged { get; set; }
+
     private string GetReadingHint() =>
         Detail.Groups.Count > 0
             ? "Find the roll band on the left, then read across to the group and severity you need."

src/RolemasterDb.App/Components/Tables/TablesDensityMode.cs

@@ -0,0 +1,7 @@
+namespace RolemasterDb.App.Components.Tables;
+
+public static class TablesDensityMode
+{
+    public const string Comfortable = "comfortable";
+    public const string Dense = "dense";
+}

src/RolemasterDb.App/wwwroot/app.css

@@ -1382,10 +1382,21 @@ pre,
     margin-top: 0.85rem;
 }
 
+.tables-context-tab-row {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 0.75rem;
+    align-items: center;
+}
+
 .tables-context-mode-tabs {
     width: fit-content;
 }
 
+.tables-context-density-tabs {
+    width: fit-content;
+}
+
 .tables-context-fields {
     display: flex;
     flex-wrap: wrap;
@@ -1452,6 +1463,9 @@ pre,
     font-size: 1.5rem;
     border-top: 1px solid rgba(127, 96, 55, 0.2);
     border-left: 1px solid rgba(127, 96, 55, 0.2);
+    isolation: isolate;
+    --tables-group-header-top: 0;
+    --tables-column-header-top: 3.2rem;
 }
 
 .critical-table-grid-header-cell {
@@ -1474,14 +1488,56 @@ pre,
     font-size: 2rem;
 }
 
+.critical-table-grid-group-header {
+    position: sticky;
+    top: var(--tables-group-header-top);
+    z-index: 3;
+}
+
+.critical-table-grid-column-header {
+    position: sticky;
+    top: var(--tables-column-header-top);
+    z-index: 3;
+}
+
+.critical-table-grid.is-dense {
+    font-size: 1.2rem;
+    --tables-column-header-top: 2.6rem;
+}
+
+.critical-table-grid.is-dense .critical-table-grid-header-cell {
+    padding: 0.25rem;
+}
+
+.critical-table-grid.is-dense .critical-table-cell {
+    padding: 0.35rem;
+}
+
 .critical-table-grid-corner,
 .critical-table-grid-roll-band-header {
     background: rgba(255, 247, 230, 0.52);
 }
 
+.critical-table-grid-corner {
+    position: sticky;
+    top: var(--tables-group-header-top);
+    left: 0;
+    z-index: 5;
+}
+
+.critical-table-grid-roll-band-header {
+    position: sticky;
+    top: var(--tables-column-header-top);
+    left: 0;
+    z-index: 5;
+}
+
 .critical-table-grid-roll-band {
     background: rgba(255, 247, 230, 0.52);
     font-size: 1.5rem;
+    position: sticky;
+    left: 0;
+    z-index: 2;
 }
 
 .critical-table-cell {
@@ -1492,6 +1548,8 @@ pre,
     border-right: 1px solid rgba(127, 96, 55, 0.2);
     border-bottom: 1px solid rgba(127, 96, 55, 0.2);
     box-sizing: border-box;
+    cursor: pointer;
+    transition: box-shadow 0.16s ease, background-color 0.16s ease, transform 0.16s ease;
 }
 
 .critical-table-cell.is-curated {
@@ -1506,6 +1564,40 @@ pre,
         rgba(255, 255, 255, 0.85);
 }
 
+.critical-table-cell.is-active-row,
+.critical-table-grid-roll-band.is-active-row {
+    background:
+        linear-gradient(180deg, rgba(13, 148, 136, 0.12), rgba(13, 148, 136, 0.04)),
+        rgba(255, 255, 255, 0.9);
+}
+
+.critical-table-grid-column-header.is-active-column,
+.critical-table-cell.is-active-column {
+    box-shadow: inset 0 0 0 999px rgba(13, 148, 136, 0.06);
+}
+
+.critical-table-grid-group-header.is-active-group,
+.critical-table-grid-column-header.is-active-group,
+.critical-table-cell.is-active-group {
+    box-shadow: inset 0 0 0 999px rgba(188, 117, 43, 0.05);
+}
+
+.critical-table-cell.is-selected-cell {
+    box-shadow: inset 0 0 0 2px rgba(13, 148, 136, 0.62);
+    background:
+        linear-gradient(135deg, rgba(13, 148, 136, 0.16), transparent 38%),
+        rgba(255, 255, 255, 0.96);
+}
+
+.critical-table-cell.is-roll-target::after,
+.critical-table-grid-roll-band.is-roll-target::after {
+    content: "";
+    position: absolute;
+    inset: 0;
+    border: 2px dashed rgba(13, 148, 136, 0.35);
+    pointer-events: none;
+}
+
 .critical-table-cell-shell {
     display: flex;
     flex-direction: column;
@@ -2256,6 +2348,11 @@ pre,
         min-width: 0;
     }
 
+    .tables-context-tab-row {
+        flex-direction: column;
+        align-items: stretch;
+    }
+
     .critical-editor-header,
     .critical-editor-footer {
         flex-direction: column;