feat(plotly): implement dumbbell-basic (#5417)

## Implementation: `dumbbell-basic` - python/plotly

Implements the **python/plotly** version of `dumbbell-basic`.

**File:** `plots/dumbbell-basic/implementations/python/plotly.py`

**Parent Issue:** #945

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/anyplot/actions/runs/24944963786)*

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: github-actions[bot]

plots/dumbbell-basic/implementations/python/plotly.py

@@ -1,13 +1,29 @@
-""" pyplots.ai
+""" anyplot.ai
 dumbbell-basic: Basic Dumbbell Chart
-Library: plotly 6.5.0 | Python 3.13.11
-Quality: 93/100 | Created: 2025-12-23
+Library: plotly 6.7.0 | Python 3.14.4
+Quality: 87/100 | Updated: 2026-04-26
 """
 
+import os
+
 import plotly.graph_objects as go
 
 
-# Data - Employee satisfaction scores before and after policy changes
+# Theme-adaptive chrome tokens
+THEME = os.getenv("ANYPLOT_THEME", "light")
+PAGE_BG = "#FAF8F1" if THEME == "light" else "#1A1A17"
+ELEVATED_BG = "#FFFDF6" if THEME == "light" else "#242420"
+INK = "#1A1A17" if THEME == "light" else "#F0EFE8"
+INK_SOFT = "#4A4A44" if THEME == "light" else "#B8B7B0"
+GRID = "rgba(26,26,23,0.10)" if THEME == "light" else "rgba(240,239,232,0.10)"
+
+# Okabe-Ito palette (theme-independent data colors)
+BEFORE_COLOR = "#009E73"  # position 1 — first categorical series
+AFTER_COLOR = "#D55E00"  # position 2 — second series
+
+# Data — Employee satisfaction scores before and after policy changes.
+# Deterministic, hand-picked values (no RNG): one department (Legal) shows a
+# slight regression to demonstrate full data range including negative change.
 categories = [
     "Engineering",
     "Sales",
@@ -17,77 +33,97 @@
     "Human Resources",
     "Operations",
     "Product",
+    "Legal",
 ]
-before = [62, 71, 58, 45, 68, 52, 64, 73]  # Before policy changes
-after = [78, 82, 75, 69, 74, 71, 79, 85]  # After policy changes
+before = [62, 71, 58, 45, 68, 52, 64, 73, 70]
+after = [78, 82, 75, 69, 74, 71, 79, 85, 67]
 
-# Sort by difference (largest improvement at top of chart)
+# Sort by difference (largest improvement at top, regression at bottom)
 data = sorted(zip(categories, before, after, strict=True), key=lambda x: x[2] - x[1])
 categories = [d[0] for d in data]
 before = [d[1] for d in data]
 after = [d[2] for d in data]
 
-# Create figure
 fig = go.Figure()
 
-# Add connecting lines (one per category)
+# Connecting lines (one per category)
 for i, cat in enumerate(categories):
     fig.add_trace(
         go.Scatter(
             x=[before[i], after[i]],
             y=[cat, cat],
             mode="lines",
-            line={"color": "#999999", "width": 2},
+            line={"color": INK_SOFT, "width": 2},
             showlegend=False,
             hoverinfo="skip",
         )
     )
 
-# Add "Before" dots (Python Blue)
+# "Before" markers — Okabe-Ito green (brand)
 fig.add_trace(
     go.Scatter(
         x=before,
         y=categories,
         mode="markers",
-        marker={"size": 18, "color": "#306998"},
+        marker={"size": 18, "color": BEFORE_COLOR, "line": {"color": PAGE_BG, "width": 2}},
         name="Before",
-        hovertemplate="<b>%{y}</b><br>Before: %{x}<extra></extra>",
+        hovertemplate="<b>%{y}</b><br>Before: %{x}/100<extra></extra>",
     )
 )
 
-# Add "After" dots (Python Yellow)
+# "After" markers — Okabe-Ito vermillion
 fig.add_trace(
     go.Scatter(
         x=after,
         y=categories,
         mode="markers",
-        marker={"size": 18, "color": "#FFD43B"},
+        marker={"size": 18, "color": AFTER_COLOR, "line": {"color": PAGE_BG, "width": 2}},
         name="After",
-        hovertemplate="<b>%{y}</b><br>After: %{x}<extra></extra>",
+        hovertemplate="<b>%{y}</b><br>After: %{x}/100<extra></extra>",
     )
 )
 
-# Layout
 fig.update_layout(
     title={
         "text": "Employee Satisfaction · dumbbell-basic · plotly · pyplots.ai",
-        "font": {"size": 28},
+        "font": {"size": 28, "color": INK},
         "x": 0.5,
         "xanchor": "center",
     },
     xaxis={
-        "title": {"text": "Satisfaction Score", "font": {"size": 22}},
-        "tickfont": {"size": 18},
+        "title": {"text": "Satisfaction Score (out of 100)", "font": {"size": 22, "color": INK}},
+        "tickfont": {"size": 18, "color": INK_SOFT},
         "range": [35, 95],
-        "gridcolor": "rgba(0,0,0,0.1)",
+        "gridcolor": GRID,
+        "gridwidth": 1,
+        "linecolor": INK_SOFT,
+        "zerolinecolor": INK_SOFT,
+    },
+    yaxis={
+        "title": {"text": "Department", "font": {"size": 22, "color": INK}},
+        "tickfont": {"size": 18, "color": INK_SOFT},
+        "gridcolor": GRID,
         "gridwidth": 1,
+        "linecolor": INK_SOFT,
+        "zerolinecolor": INK_SOFT,
+        "showgrid": True,
+    },
+    paper_bgcolor=PAGE_BG,
+    plot_bgcolor=PAGE_BG,
+    font={"color": INK},
+    legend={
+        "orientation": "h",
+        "yanchor": "bottom",
+        "y": 1.02,
+        "xanchor": "center",
+        "x": 0.5,
+        "font": {"size": 16, "color": INK_SOFT},
+        "bgcolor": ELEVATED_BG,
+        "bordercolor": INK_SOFT,
+        "borderwidth": 1,
     },
-    yaxis={"title": {"text": "Department", "font": {"size": 22}}, "tickfont": {"size": 18}},
-    template="plotly_white",
-    legend={"orientation": "h", "yanchor": "bottom", "y": 1.02, "xanchor": "center", "x": 0.5, "font": {"size": 18}},
-    margin={"l": 150, "r": 50, "t": 100, "b": 80},
+    margin={"l": 170, "r": 60, "t": 110, "b": 90},
 )
 
-# Save
-fig.write_image("plot.png", width=1600, height=900, scale=3)
-fig.write_html("plot.html", include_plotlyjs="cdn")
+fig.write_image(f"plot-{THEME}.png", width=1600, height=900, scale=3)
+fig.write_html(f"plot-{THEME}.html", include_plotlyjs="cdn")