diff --git a/app.py b/app.py
index 7ed69f8..4633487 100644
--- a/app.py
+++ b/app.py
@@ -17,6 +17,25 @@ def hex_to_rgba(hex_color: str, alpha: float = 0.1) -> str:
     return f"rgba({r}, {g}, {b}, {alpha})"
 
 
+def add_milestone_line(fig, x, color: str, text: str, xref: str = "x"):
+    """用 shape + annotation 手动添加竖线，绕过 Plotly add_vline 对 datetime.date 的 bug。"""
+    fig.add_shape(
+        type="line",
+        x0=x, x1=x, y0=0, y1=1,
+        xref=xref, yref="paper",
+        line=dict(color=color, width=1.5, dash="dot"),
+    )
+    fig.add_annotation(
+        x=x, y=1.02,
+        xref=xref, yref="paper",
+        text=text,
+        showarrow=False,
+        font=dict(color=color, size=10),
+        bgcolor="rgba(255,255,255,0.8)",
+        borderpad=2,
+    )
+
+
 # ─── Page Config ────────────────────────────────────────────────────────────
 st.set_page_config(
     page_title="麦麦智农",
@@ -289,13 +308,9 @@ with chart_left:
         # 添加生育期标记
         ms = summary.get("milestones", {})
         if "flowering" in ms:
-            fig_lai.add_vline(x=ms["flowering"], line=dict(color="#d4a574", width=1.5, dash="dot"),
-                              annotation_text="开花", annotation_font_color="#7c5e42",
-                              annotation_position="top left")
+            add_milestone_line(fig_lai, x=ms["flowering"], color="#d4a574", text="开花")
         if "maturity" in ms:
-            fig_lai.add_vline(x=ms["maturity"], line=dict(color="#7c5e42", width=1.5, dash="dash"),
-                              annotation_text="成熟", annotation_font_color="#7c5e42",
-                              annotation_position="top right")
+            add_milestone_line(fig_lai, x=ms["maturity"], color="#7c5e42", text="成熟")
         fig_lai.update_layout(
             xaxis=dict(title="日期", color="#5a5a5a", gridcolor="rgba(0,0,0,0.06)"),
             yaxis=dict(title="LAI", color="#5a5a5a", gridcolor="rgba(0,0,0,0.06)"),
@@ -327,9 +342,9 @@ with chart_right:
             ))
         ms = summary.get("milestones", {})
         if "flowering" in ms:
-            fig_bio.add_vline(x=ms["flowering"], line=dict(color="#d4a574", width=1.5, dash="dot"))
+            add_milestone_line(fig_bio, x=ms["flowering"], color="#d4a574", text="开花")
         if "maturity" in ms:
-            fig_bio.add_vline(x=ms["maturity"], line=dict(color="#7c5e42", width=1.5, dash="dash"))
+            add_milestone_line(fig_bio, x=ms["maturity"], color="#7c5e42", text="成熟")
         fig_bio.update_layout(
             xaxis=dict(title="日期", color="#5a5a5a", gridcolor="rgba(0,0,0,0.06)"),
             yaxis=dict(title="干物质 (kg/ha)", color="#5a5a5a", gridcolor="rgba(0,0,0,0.06)"),