feat(plotly): implement bar-stacked (#6134)

## Implementation: `bar-stacked` - python/plotly

Implements the **python/plotly** version of `bar-stacked`.

**File:** `plots/bar-stacked/implementations/python/plotly.py`

**Parent Issue:** #1947

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/anyplot/actions/runs/25594734391)*

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Markus Neusinger <2921697+MarkusNeusinger@users.noreply.github.com>

Author: github-actions[bot]

plots/bar-stacked/implementations/python/plotly.py

@@ -1,113 +1,138 @@
-""" pyplots.ai
+""" anyplot.ai
 bar-stacked: Stacked Bar Chart
-Library: plotly 6.5.0 | Python 3.13.11
-Quality: 97/100 | Created: 2025-12-26
+Library: plotly 6.7.0 | Python 3.13.13
+Quality: 93/100 | Updated: 2026-05-09
 """
 
+import os
+
 import plotly.graph_objects as go
 
 
+# Theme 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(26,26,23,0.08)" if THEME == "light" else "rgba(240,239,232,0.08)"
+GRID_SUBTLE = "rgba(26,26,23,0.04)" if THEME == "light" else "rgba(240,239,232,0.04)"
+
+# Okabe-Ito palette (first series always #009E73)
+COLORS = ["#009E73", "#D55E00", "#0072B2", "#CC79A7"]
+
 # Data - Quarterly revenue by product category
 quarters = ["Q1 2024", "Q2 2024", "Q3 2024", "Q4 2024"]
+categories = ["Software", "Hardware", "Services", "Support"]
 
 # Revenue in thousands USD for each product category
 software = [120, 145, 160, 180]
 hardware = [80, 75, 90, 95]
 services = [45, 55, 65, 75]
 support = [25, 30, 35, 40]
 
-# Calculate totals for annotation
+all_data = [software, hardware, services, support]
+
+# Calculate totals and per-component percentages for storytelling
 totals = [s + h + sv + sp for s, h, sv, sp in zip(software, hardware, services, support, strict=True)]
 
-# Create figure
+# Create figure with enhanced styling
 fig = go.Figure()
 
-# Add stacked bars (bottom to top)
-fig.add_trace(
-    go.Bar(
-        name="Software",
-        x=quarters,
-        y=software,
-        marker_color="#306998",
-        text=software,
-        textposition="inside",
-        textfont={"size": 18, "color": "white"},
-    )
-)
+# Add stacked bars with custom hover templates for better storytelling
+for category, data, color in zip(categories, all_data, COLORS, strict=True):
+    percentages = [f"{v / total * 100:.0f}%" for v, total in zip(data, totals, strict=True)]
 
-fig.add_trace(
-    go.Bar(
-        name="Hardware",
-        x=quarters,
-        y=hardware,
-        marker_color="#FFD43B",
-        text=hardware,
-        textposition="inside",
-        textfont={"size": 18, "color": "#333"},
-    )
-)
+    custom_hover = [
+        f"<b>{category}</b><br>" + f"Quarter: {q}<br>" + f"Revenue: ${v}K<br>" + f"% of Total: {pct}<extra></extra>"
+        for q, v, pct in zip(quarters, data, percentages, strict=True)
+    ]
 
-fig.add_trace(
-    go.Bar(
-        name="Services",
-        x=quarters,
-        y=services,
-        marker_color="#4ECDC4",
-        text=services,
-        textposition="inside",
-        textfont={"size": 18, "color": "white"},
+    fig.add_trace(
+        go.Bar(
+            name=category,
+            x=quarters,
+            y=data,
+            marker=dict(color=color, line=dict(color=ELEVATED_BG, width=0.5)),
+            text=data,
+            textposition="inside",
+            textfont={"size": 18, "color": "white"},
+            customdata=custom_hover,
+            hovertemplate="%{customdata}",
+        )
     )
-)
 
-fig.add_trace(
-    go.Bar(
-        name="Support",
-        x=quarters,
-        y=support,
-        marker_color="#FF6B6B",
-        text=support,
-        textposition="inside",
-        textfont={"size": 18, "color": "white"},
-    )
-)
+# Enhanced total annotations with visual emphasis
+for idx, (quarter, total) in enumerate(zip(quarters, totals, strict=True)):
+    growth_rate = ""
+    if idx > 0:
+        growth = ((total - totals[idx - 1]) / totals[idx - 1]) * 100
+        growth_rate = f"<br><span style='font-size:14px;'>+{growth:.1f}% QoQ</span>"
 
-# Add total annotations above each bar
-for quarter, total in zip(quarters, totals, strict=True):
     fig.add_annotation(
         x=quarter,
-        y=total + 10,
-        text=f"${total}K",
+        y=total + 12,
+        text=f"<b>${total}K</b>{growth_rate}",
         showarrow=False,
-        font={"size": 20, "color": "#333", "weight": "bold"},
+        font={"size": 20, "color": INK},
+        bgcolor=ELEVATED_BG,
+        bordercolor=INK_SOFT,
+        borderwidth=1,
     )
 
-# Update layout
+# Update layout with sophisticated design refinements
 fig.update_layout(
-    title={"text": "bar-stacked · plotly · pyplots.ai", "font": {"size": 32}, "x": 0.5, "xanchor": "center"},
-    xaxis={"title": {"text": "Quarter", "font": {"size": 24}}, "tickfont": {"size": 20}},
-    yaxis={
-        "title": {"text": "Revenue (Thousands USD)", "font": {"size": 24}},
-        "tickfont": {"size": 20},
-        "gridcolor": "rgba(0,0,0,0.1)",
-        "gridwidth": 1,
-    },
-    barmode="stack",
-    bargap=0.3,
-    template="plotly_white",
-    legend={
-        "orientation": "h",
-        "yanchor": "bottom",
-        "y": 1.02,
-        "xanchor": "center",
+    title={
+        "text": "bar-stacked · plotly · anyplot.ai",
+        "font": {"size": 28, "color": INK},
         "x": 0.5,
-        "font": {"size": 20},
-        "traceorder": "normal",
+        "xanchor": "center",
+        "y": 0.98,
+        "yanchor": "top",
     },
-    margin={"l": 100, "r": 60, "t": 120, "b": 80},
+    xaxis=dict(
+        title={"text": "Quarter", "font": {"size": 22, "color": INK}},
+        tickfont={"size": 18, "color": INK_SOFT},
+        showgrid=False,
+        showline=True,
+        linewidth=1.5,
+        linecolor=INK_SOFT,
+        mirror=False,
+    ),
+    yaxis=dict(
+        title={"text": "Revenue (Thousands USD)", "font": {"size": 22, "color": INK}},
+        tickfont={"size": 18, "color": INK_SOFT},
+        gridcolor=GRID_SUBTLE,
+        gridwidth=0.5,
+        showline=True,
+        linewidth=1.5,
+        linecolor=INK_SOFT,
+        mirror=False,
+    ),
+    barmode="stack",
+    bargap=0.35,
+    bargroupgap=0.1,
+    paper_bgcolor=PAGE_BG,
+    plot_bgcolor=PAGE_BG,
+    font={"color": INK, "family": "system-ui, -apple-system, sans-serif"},
+    legend=dict(
+        orientation="v",
+        yanchor="top",
+        y=0.99,
+        xanchor="right",
+        x=0.99,
+        font={"size": 18, "color": INK},
+        bgcolor="rgba(255,253,246,0.95)" if THEME == "light" else "rgba(36,36,32,0.95)",
+        bordercolor=INK_SOFT,
+        borderwidth=1.5,
+    ),
+    margin={"l": 110, "r": 70, "t": 120, "b": 90},
+    width=1600,
+    height=900,
 )
 
 # Save as PNG (4800 x 2700 px)
-fig.write_image("plot.png", width=1600, height=900, scale=3)
+fig.write_image(f"plot-{THEME}.png", width=1600, height=900, scale=3)
 
 # Save as HTML for interactivity
-fig.write_html("plot.html", include_plotlyjs="cdn")
+fig.write_html(f"plot-{THEME}.html", include_plotlyjs="cdn")