feat(plotnine): implement errorbar-basic (#5387)

## Implementation: `errorbar-basic` - python/plotnine

Implements the **python/plotnine** version of `errorbar-basic`.

**File:** `plots/errorbar-basic/implementations/python/plotnine.py`

**Parent Issue:** #973

---
:robot: *[impl-generate
workflow](https://github.com/MarkusNeusinger/anyplot/actions/runs/24927208728)*

---------

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/errorbar-basic/implementations/python/plotnine.py

@@ -1,42 +1,122 @@
-""" pyplots.ai
+""" anyplot.ai
 errorbar-basic: Basic Error Bar Plot
-Library: plotnine 0.15.2 | Python 3.13.11
-Quality: 91/100 | Created: 2025-12-23
+Library: plotnine 0.15.3 | Python 3.14.4
+Quality: 85/100 | Updated: 2026-04-25
 """
 
+import os
+
 import pandas as pd
-from plotnine import aes, element_text, geom_errorbar, geom_point, ggplot, labs, theme, theme_minimal
+from plotnine import (
+    aes,
+    element_blank,
+    element_line,
+    element_rect,
+    element_text,
+    geom_errorbar,
+    geom_point,
+    ggplot,
+    labs,
+    position_dodge,
+    scale_color_manual,
+    theme,
+    theme_minimal,
+)
+
 
+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"
 
-# Data - Lab measurements with measurement uncertainty
+OKABE_ITO = ["#009E73", "#D55E00", "#0072B2"]
+
+# Data — three lab methods measured across six samples
 data = pd.DataFrame(
     {
-        "experiment": ["Sample A", "Sample B", "Sample C", "Sample D", "Sample E", "Sample F"],
-        "measurement": [42.5, 38.2, 55.1, 47.8, 33.6, 51.3],
-        "error": [3.2, 4.1, 2.8, 5.5, 3.8, 4.2],
+        "sample": [
+            "Sample A",
+            "Sample B",
+            "Sample C",
+            "Sample D",
+            "Sample E",
+            "Sample F",
+            "Sample A",
+            "Sample B",
+            "Sample C",
+            "Sample D",
+            "Sample E",
+            "Sample F",
+            "Sample A",
+            "Sample B",
+            "Sample C",
+            "Sample D",
+            "Sample E",
+            "Sample F",
+        ],
+        "method": (["Method A"] * 6 + ["Method B"] * 6 + ["Method C"] * 6),
+        "measurement": [
+            42.5,
+            38.2,
+            55.1,
+            47.8,
+            33.6,
+            51.3,
+            44.8,
+            40.1,
+            53.6,
+            49.2,
+            35.9,
+            52.7,
+            41.2,
+            39.5,
+            56.3,
+            46.4,
+            34.8,
+            50.1,
+        ],
+        "error": [3.2, 4.1, 2.8, 5.5, 3.8, 4.2, 2.6, 3.4, 3.1, 4.2, 3.0, 3.6, 3.9, 4.5, 2.5, 5.1, 4.3, 4.0],
     }
 )
 
-# Calculate error bar positions
 data["ymin"] = data["measurement"] - data["error"]
 data["ymax"] = data["measurement"] + data["error"]
 
-# Plot
+# Order samples by mean measurement to create visual hierarchy
+sample_order = data.groupby("sample")["measurement"].mean().sort_values().index.tolist()
+data["sample"] = pd.Categorical(data["sample"], categories=sample_order, ordered=True)
+
+dodge = position_dodge(width=0.55)
+
 plot = (
-    ggplot(data, aes(x="experiment", y="measurement"))
-    + geom_errorbar(aes(ymin="ymin", ymax="ymax"), width=0.3, size=1.5, color="#306998")
-    + geom_point(size=6, color="#306998")
-    + labs(x="Experiment", y="Measurement Value", title="errorbar-basic · plotnine · pyplots.ai")
+    ggplot(data, aes(x="sample", y="measurement", color="method", group="method"))
+    + geom_errorbar(aes(ymin="ymin", ymax="ymax"), width=0.35, size=1.4, position=dodge)
+    + geom_point(size=5, position=dodge)
+    + scale_color_manual(values=OKABE_ITO, name="Method")
+    + labs(x="Experimental Sample", y="Measurement Value (mg/L)", title="errorbar-basic · plotnine · anyplot.ai")
     + theme_minimal()
     + theme(
         figure_size=(16, 9),
-        text=element_text(size=14),
-        axis_title=element_text(size=20),
-        axis_text=element_text(size=16),
-        plot_title=element_text(size=24),
-        axis_text_x=element_text(size=16),
+        text=element_text(size=14, color=INK_SOFT),
+        plot_background=element_rect(fill=PAGE_BG, color=PAGE_BG),
+        panel_background=element_rect(fill=PAGE_BG, color=PAGE_BG),
+        panel_border=element_blank(),
+        panel_grid_major_x=element_blank(),
+        panel_grid_minor=element_blank(),
+        panel_grid_major_y=element_line(color=INK, size=0.3, alpha=0.10),
+        axis_line_x=element_line(color=INK_SOFT, size=0.6),
+        axis_line_y=element_blank(),
+        axis_ticks=element_blank(),
+        axis_title=element_text(size=20, color=INK),
+        axis_text=element_text(size=16, color=INK_SOFT),
+        plot_title=element_text(size=24, color=INK, weight="bold"),
+        legend_background=element_rect(fill=ELEVATED_BG, color=ELEVATED_BG),
+        legend_key=element_rect(fill=PAGE_BG, color=PAGE_BG),
+        legend_text=element_text(size=16, color=INK_SOFT),
+        legend_title=element_text(size=16, color=INK),
+        legend_position="right",
     )
 )
 
-# Save
-plot.save("plot.png", dpi=300)
+plot.save(f"plot-{THEME}.png", dpi=300, width=16, height=9, verbose=False)