diff --git a/scripts/assets/figures.css b/scripts/assets/figures.css
new file mode 100644
index 000000000..2ea2a465f
--- /dev/null
+++ b/scripts/assets/figures.css
@@ -0,0 +1,14 @@
+/* Center figures: standalone images (paragraphs containing only an <img>)
+   and their italic captions ("*Figure: ...*" renders as <em>) */
+.md-content p > img:only-child {
+  display: block;
+  margin-left: auto;
+  margin-right: auto;
+}
+
+/* Center the caption paragraph that follows an image.
+   The Lua filter emits "*Figure: caption*" which renders as <p><em>...</em></p> */
+.md-content p:has(> img:only-child) + p > em:only-child {
+  display: block;
+  text-align: center;
+}
diff --git a/scripts/convert.py b/scripts/convert.py
index fc04d99ab..127cbfa9c 100644
--- a/scripts/convert.py
+++ b/scripts/convert.py
@@ -578,7 +578,7 @@ def generate_zensical_config(
         {"path": "https://cdnjs.cloudflare.com/ajax/libs/mathjax/3.2.2/es5/tex-mml-chtml.js", "async": True},
         {"path": "assets/eq-tooltips.js"},
     ]
-    project["extra_css"] = ["assets/eq-tooltips.css"]
+    project["extra_css"] = ["assets/eq-tooltips.css", "assets/figures.css"]
 
     config_path = output_dir / "zensical.toml"
     config_path.write_text(tomli_w.dumps(config))