check $.style

src/plot.py

@@ -266,8 +266,34 @@ def check(graphs: Any):
                 p, f"graph {name}", point_fields, sub_path=["points", str(j)]
             )
 
-        # TODO: check style
-        info(f"the style of graph {name} won't be checked")
+        if "style" in g:
+            info(f"checking the `$.style` of graph {name}")
+            _check_extra_class_fields(
+                g["style"], name, __get_class_fields(Style), sub_path=["style"]
+            )
+
+            if "line" in g["style"]:
+                _check_extra_class_fields(
+                    g["style"]["line"],
+                    name,
+                    __get_class_fields(LineStyle),
+                    sub_path=["style", "line"]
+                )
+                if "marker" in g["style"]["line"]:
+                    _check_extra_class_fields(
+                        g["style"]["line"]["marker"],
+                        name,
+                        __get_class_fields(MarkerStyle),
+                        sub_path=["style", "line", "marker"]
+                    )
+
+            if "error" in g["style"]:
+                _check_extra_class_fields(
+                    g["style"]["error"],
+                    name,
+                    __get_class_fields(ErrorStyle),
+                    sub_path=["style", "error"]
+                )
 
 
 # see [`HELP`]