diff --git a/src/rp/cli.py b/src/rp/cli.py
index 318dfe1..844d70b 100644
--- a/src/rp/cli.py
+++ b/src/rp/cli.py
@@ -20,22 +20,6 @@ app = typer.Typer(
     rich_markup_mode="rich",
 )
 
-_THEMES = [
-    "monokai",
-    "github-dark",
-    "one-dark",
-    "vim",
-    "vs",
-    "nord",
-    "dracula",
-    "solarized-dark",
-    "solarized-light",
-    "default",
-    "friendly",
-    "native",
-    "emacs",
-]
-
 
 def version_callback(value: bool) -> None:
     if value:
diff --git a/src/rp/detect.py b/src/rp/detect.py
index 19c2f50..ca5e811 100644
--- a/src/rp/detect.py
+++ b/src/rp/detect.py
@@ -73,10 +73,12 @@ def detect_type(
             return EXTENSION_MAP[suffix]
 
     if content is not None:
-        try:
-            json.loads(content[:1000])
-            return "json"
-        except (json.JSONDecodeError, ValueError):
-            pass
+        stripped = content.lstrip()
+        if stripped and stripped[0] in ("{", "["):
+            try:
+                json.loads(stripped[:1000])
+                return "json"
+            except (json.JSONDecodeError, ValueError):
+                pass
 
     return "text"
diff --git a/src/rp/render.py b/src/rp/render.py
index d4ae8f3..09e9aa8 100644
--- a/src/rp/render.py
+++ b/src/rp/render.py
@@ -44,9 +44,14 @@ def render(
                 content, "json", theme=options.theme, line_numbers=line_numbers
             )
     else:
-        renderable = Syntax(
-            content, file_type, theme=options.theme, line_numbers=line_numbers
-        )
+        try:
+            renderable = Syntax(
+                content, file_type, theme=options.theme, line_numbers=line_numbers
+            )
+        except Exception:
+            renderable = Syntax(
+                content, "text", theme=options.theme, line_numbers=line_numbers
+            )
 
     if use_pager:
         with console.pager(styles=True):