diff --git a/src/check.rs b/src/check.rs
index 4fc811f..c4f3387 100644
--- a/src/check.rs
+++ b/src/check.rs
@@ -14,10 +14,13 @@ pub fn is_ascii_alphanumeric(c: char) -> bool {
 /// doesn't give an easy answer. Because of this, we're conservative in what we
 /// allow. This way, the output we produce should parse correctly in a wide
 /// range of circumstances while following the standard.
+///
+/// The `annotation-xml` MathML element requires us to allow dashes in tag
+/// names.
 pub fn is_valid_tag_name(name: &str) -> bool {
     !name.is_empty()
         && name.chars().take(1).all(is_ascii_alpha)
-        && name.chars().all(is_ascii_alphanumeric)
+        && name.chars().all(|c| is_ascii_alphanumeric(c) || c == '-')
 }
 
 /// <https://html.spec.whatwg.org/multipage/syntax.html#syntax-attribute-name>
diff --git a/src/element.rs b/src/element.rs
index 8da0968..e12112b 100644
--- a/src/element.rs
+++ b/src/element.rs
@@ -63,8 +63,13 @@ pub struct Element {
 
 impl Element {
     pub fn new(name: impl ToString, kind: ElementKind) -> Self {
+        let mut name = name.to_string();
+        if kind == ElementKind::Foreign {
+            name = name.to_ascii_lowercase()
+        }
+
         Self {
-            name: name.to_string().to_ascii_lowercase(),
+            name,
             kind,
             attributes: BTreeMap::new(),
             children: vec![],
diff --git a/src/elements.rs b/src/html.rs
similarity index 96%
rename from src/elements.rs
rename to src/html.rs
index 2e117e7..f518fbe 100644
--- a/src/elements.rs
+++ b/src/html.rs
@@ -112,9 +112,7 @@ element!(portal);
 element!(source, ElementKind::Void);
 
 // SVG and MathML
-// TODO Proper SVG and MathML support
-element!(svg, ElementKind::Foreign);
-element!(math, ElementKind::Foreign);
+// See corresponding modules
 
 // Scripting
 element!(canvas);
diff --git a/src/lib.rs b/src/lib.rs
index 7a186fd..3b157fb 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,14 +5,16 @@
 
 mod check;
 mod element;
-pub mod elements;
+pub mod html;
+pub mod mathml;
 mod render;
+pub mod svg;
 
-pub use self::{element::*, elements::*, render::*};
+pub use self::{element::*, render::*};
 
 #[cfg(test)]
 mod tests {
-    use crate::{elements::*, render::Render, Content, Element};
+    use crate::{html::*, Content, Element, Render};
 
     #[test]
     fn simple_website() {
diff --git a/src/mathml.rs b/src/mathml.rs
new file mode 100644
index 0000000..f9c091e
--- /dev/null
+++ b/src/mathml.rs
@@ -0,0 +1,50 @@
+//! Definitions for all non-deprecated MathML elements.
+//!
+//! <https://developer.mozilla.org/en-US/docs/Web/MathML/Element>
+
+use crate::{Element, ElementKind};
+
+macro_rules! element {
+    ( $name:ident ) => {
+        element!($name, stringify!($name));
+    };
+    ( $name:ident, $tag:expr ) => {
+        pub fn $name() -> Element {
+            Element::new($tag, ElementKind::Foreign)
+        }
+    };
+}
+
+// MathML elements A to Z
+
+// Deprecated and non-standard elements intentionally omitted.
+
+element!(annotation);
+element!(annotation_xml, "annotation-xml");
+element!(math);
+element!(merror);
+element!(mfrac);
+element!(mi);
+element!(mmultiscripts);
+element!(mn);
+element!(mo);
+element!(mover);
+element!(mpadded);
+element!(mphantom);
+element!(mprescripts);
+element!(mroot);
+element!(mrow);
+element!(ms);
+element!(mspace);
+element!(msqrt);
+element!(mstyle);
+element!(msub);
+element!(msubsup);
+element!(msup);
+element!(mtable);
+element!(mtd);
+element!(mtext);
+element!(mtr);
+element!(munder);
+element!(munderover);
+element!(semantics);
diff --git a/src/svg.rs b/src/svg.rs
new file mode 100644
index 0000000..bf450fe
--- /dev/null
+++ b/src/svg.rs
@@ -0,0 +1,84 @@
+//! Definitions for all non-deprecated SVG elements.
+//!
+//! <https://developer.mozilla.org/en-US/docs/Web/SVG/Element>
+
+use crate::{Element, ElementKind};
+
+macro_rules! element {
+    ( $name:ident ) => {
+        element!($name, stringify!($name));
+    };
+    ( $name:ident, $tag:expr ) => {
+        pub fn $name() -> Element {
+            Element::new($tag, ElementKind::Foreign)
+        }
+    };
+}
+
+// SVG elements A to Z
+
+// Deprecated elements intentionally omitted.
+
+element!(a);
+element!(animate);
+element!(animate_motion, "animateMotion");
+element!(animate_transform, "animateTransform");
+element!(circle);
+element!(clip_path, "clipPath");
+element!(defs);
+element!(desc);
+element!(ellipse);
+element!(fe_blend, "feBlend");
+element!(fe_color_matrix, "feColorMatrix");
+element!(fe_component_transfer, "feComponentTransfer");
+element!(fe_composite, "feComposite");
+element!(fe_convolve_matrix, "feConvolveMatrix");
+element!(fe_diffuse_lighting, "feDiffuseLighting");
+element!(fe_displacement_map, "feDisplacementMap");
+element!(fe_distant_light, "feDistantLight");
+element!(fe_drop_shadow, "feDropShadow");
+element!(fe_flood, "feFlood");
+element!(fe_func_a, "feFuncA");
+element!(fe_func_b, "feFuncB");
+element!(fe_func_g, "feFuncG");
+element!(fe_func_r, "feFuncR");
+element!(fe_gaussian_blue, "feGaussianBlur");
+element!(fe_image, "feImage");
+element!(fe_merge, "feMerge");
+element!(fe_merge_node, "feMergeNode");
+element!(fe_morphology, "feMorphology");
+element!(fe_offset, "feOffset");
+element!(fe_point_light, "fePointLight");
+element!(fe_specular_lighting, "feSpecularLighting");
+element!(fe_spot_light, "feSpotLight");
+element!(fe_tile, "feTile");
+element!(fe_turbulence, "feTurbulence");
+element!(filter);
+element!(foreign_object, "foreignObject");
+element!(g);
+element!(image);
+element!(line);
+element!(linear_gradient, "linearGradient");
+element!(marker);
+element!(mask);
+element!(metadata);
+element!(mpath);
+element!(path);
+element!(pattern);
+element!(polygon);
+element!(polyline);
+element!(radial_gradient, "radialGradient");
+element!(rect);
+element!(script);
+element!(set);
+element!(stop);
+element!(style);
+element!(svg);
+element!(switch);
+element!(symbol);
+element!(text);
+element!(text_path, "textPath");
+element!(title);
+element!(tspan);
+element!(r#use);
+element!(view);