fix(seaborn): address review feedback for line-retention-cohort

Attempt 2/3 - fixes based on AI review

Author: github-actions[bot]

plots/line-retention-cohort/implementations/seaborn.py

@@ -1,4 +1,4 @@
-""" pyplots.ai
+"""pyplots.ai
 line-retention-cohort: User Retention Curve by Cohort
 Library: seaborn 0.13.2 | Python 3.14.3
 Quality: 87/100 | Created: 2026-03-16
@@ -21,33 +21,43 @@
 decay_rates = [0.18, 0.16, 0.14, 0.12, 0.10]
 floors = [8, 10, 14, 18, 22]
 
+endpoint_values = {}
+
 for (cohort_label, cohort_size), decay, floor in zip(cohorts.items(), decay_rates, floors, strict=True):
     retention = 100 * np.exp(-decay * weeks) + floor * (1 - np.exp(-0.3 * weeks))
     retention[0] = 100.0
     retention = np.clip(retention, 0, 100)
     noise = np.random.normal(0, 0.8, len(weeks))
     noise[0] = 0
     retention = np.clip(retention + noise, 0, 100)
+    label = f"{cohort_label} (n={cohort_size:,})"
+    endpoint_values[label] = retention[-1]
     for w, r in zip(weeks, retention, strict=True):
-        records.append({"week": w, "retention": r, "cohort": f"{cohort_label} (n={cohort_size:,})"})
+        records.append({"week": w, "retention": r, "cohort": label})
 
 df = pd.DataFrame(records)
 
+# Custom palette starting with Python Blue
+palette = ["#306998", "#E8922A", "#3A9E78", "#D94F4F", "#8B6DB0"]
+
 # Plot - use seaborn style, context, and hue-based grouping
 sns.set_theme(
     style="whitegrid",
+    font="sans-serif",
     rc={
         "axes.spines.top": False,
         "axes.spines.right": False,
-        "grid.alpha": 0.15,
-        "grid.linewidth": 0.8,
+        "axes.spines.left": False,
+        "grid.alpha": 0.12,
+        "grid.linewidth": 0.6,
         "axes.grid.axis": "y",
+        "axes.facecolor": "#FAFAFA",
+        "figure.facecolor": "white",
+        "font.family": "sans-serif",
     },
 )
 sns.set_context("talk", font_scale=1.1)
 
-palette = sns.color_palette("colorblind", n_colors=5)
-
 fig, ax = plt.subplots(figsize=(16, 9))
 
 sns.lineplot(
@@ -64,28 +74,65 @@
     ax=ax,
 )
 
+# Progressive emphasis: older cohorts thinner/lighter, newer bolder
 cohort_labels = df["cohort"].unique()
 for i, line in enumerate(ax.lines[: len(cohort_labels)]):
-    weight = 1.5 + i * 0.4
+    weight = 1.5 + i * 0.5
     line.set_linewidth(weight)
     line.set_markersize(5 + i * 1.5)
-    line.set_alpha(0.5 + i * 0.12)
-
-ax.axhline(y=20, color="#888888", linestyle="--", linewidth=1.2, alpha=0.5, zorder=1)
-ax.text(12.3, 20, "20% target", fontsize=13, color="#888888", va="center", fontstyle="italic")
+    line.set_alpha(0.45 + i * 0.13)
+
+# 20% reference line
+ax.axhline(y=20, color="#AAAAAA", linestyle="--", linewidth=1.0, alpha=0.6, zorder=1)
+ax.text(12.3, 15, "20% target", fontsize=14, color="#999999", va="center", fontstyle="italic")
+
+# Endpoint annotations for data storytelling
+sorted_endpoints = sorted(endpoint_values.items(), key=lambda x: list(endpoint_values.keys()).index(x[0]))
+placed_positions = []
+for i, (_label, val) in enumerate(sorted_endpoints):
+    color = palette[i]
+    # Avoid overlap with other annotations by nudging
+    pos = val
+    for prev in placed_positions:
+        if abs(pos - prev) < 4:
+            pos = prev + 4 if pos >= prev else prev - 4
+    placed_positions.append(pos)
+    ax.annotate(
+        f"{val:.0f}%",
+        xy=(12, val),
+        xytext=(12.6, pos),
+        fontsize=13,
+        fontweight="bold",
+        color=color,
+        va="center",
+        ha="left",
+    )
 
 # Style
-ax.set_title("line-retention-cohort · seaborn · pyplots.ai", fontsize=24, fontweight="medium", pad=20)
-ax.set_xlabel("Weeks Since Signup", fontsize=20)
-ax.set_ylabel("Retained Users (%)", fontsize=20)
-ax.tick_params(axis="both", labelsize=16)
+ax.set_title("line-retention-cohort · seaborn · pyplots.ai", fontsize=24, fontweight="bold", pad=24, color="#333333")
+ax.set_xlabel("Weeks Since Signup", fontsize=20, color="#555555", labelpad=12)
+ax.set_ylabel("Retained Users (%)", fontsize=20, color="#555555", labelpad=12)
+ax.tick_params(axis="both", labelsize=16, colors="#666666")
 
-ax.set_xlim(-0.3, 12.5)
-ax.set_ylim(0, 105)
+ax.set_xlim(-0.3, 13.5)
+ax.set_ylim(0, 108)
 ax.set_xticks(weeks)
 
-legend = ax.legend(fontsize=14, frameon=False, loc="upper right", title="Signup Cohort", title_fontsize=15)
+# Use sns.despine for seaborn-idiomatic spine removal
+sns.despine(ax=ax, left=True, bottom=False)
+
+legend = ax.legend(
+    fontsize=13,
+    frameon=True,
+    fancybox=True,
+    framealpha=0.85,
+    edgecolor="#DDDDDD",
+    loc="upper right",
+    title="Signup Cohort",
+    title_fontsize=15,
+)
 legend.get_title().set_fontweight("semibold")
+legend.get_frame().set_linewidth(0.5)
 
 plt.tight_layout()
 plt.savefig("plot.png", dpi=300, bbox_inches="tight")