diff --git a/scripts/interface/Interface.js b/scripts/interface/Interface.js
index 84abbe3..20480c5 100644
--- a/scripts/interface/Interface.js
+++ b/scripts/interface/Interface.js
@@ -37,6 +37,7 @@ define([
 			}
 		});
 		code = code.replace(/[{}]/g, '');
+		code = 'headers fade\nterminators fade\n' + code;
 		return code;
 	}
 
diff --git a/scripts/main.js b/scripts/main.js
index f5d703e..b8cc12f 100644
--- a/scripts/main.js
+++ b/scripts/main.js
@@ -176,12 +176,12 @@
 			{
 				title: 'Title',
 				code: 'title {Title}',
-				preview: 'title Title\nA -> B',
+				preview: 'headers box\ntitle Title\nA -> B',
 			},
 			{
 				title: 'Chunky theme',
 				code: 'theme chunky',
-				preview: 'theme chunky\nA -> B',
+				preview: 'headers box\ntheme chunky\nA -> B',
 			},
 			{
 				title: 'Cross terminators',
diff --git a/scripts/sequence/CodeMirrorMode.js b/scripts/sequence/CodeMirrorMode.js
index 7a16b40..4112413 100644
--- a/scripts/sequence/CodeMirrorMode.js
+++ b/scripts/sequence/CodeMirrorMode.js
@@ -138,6 +138,13 @@ define(['core/ArrayUtilities'], (array) => {
 					},
 				},
 			}},
+			'headers': {type: 'keyword', suggest: true, then: {
+				'none': {type: 'keyword', suggest: true, then: {}},
+				'cross': {type: 'keyword', suggest: true, then: {}},
+				'box': {type: 'keyword', suggest: true, then: {}},
+				'fade': {type: 'keyword', suggest: true, then: {}},
+				'bar': {type: 'keyword', suggest: true, then: {}},
+			}},
 			'terminators': {type: 'keyword', suggest: true, then: {
 				'none': {type: 'keyword', suggest: true, then: {}},
 				'cross': {type: 'keyword', suggest: true, then: {}},
diff --git a/scripts/sequence/Generator.js b/scripts/sequence/Generator.js
index fc7dc02..48be6b3 100644
--- a/scripts/sequence/Generator.js
+++ b/scripts/sequence/Generator.js
@@ -146,6 +146,32 @@ define(['core/ArrayUtilities'], (array) => {
 		}
 	}
 
+	function swapBegin(stage, mode) {
+		if(stage.type === 'agent begin') {
+			stage.mode = mode;
+			return true;
+		}
+		if(stage.type === 'parallel') {
+			let any = false;
+			stage.stages.forEach((subStage) => {
+				if(subStage.type === 'agent begin') {
+					subStage.mode = mode;
+					any = true;
+				}
+			});
+			return any;
+		}
+		return false;
+	}
+
+	function swapFirstBegin(stages, mode) {
+		for(let i = 0; i < stages.length; ++ i) {
+			if(swapBegin(stages[i], mode)) {
+				break;
+			}
+		}
+	}
+
 	function addBounds(target, agentL, agentR, involvedAgents = null) {
 		array.remove(target, agentL, agentEqCheck);
 		array.remove(target, agentR, agentEqCheck);
@@ -585,6 +611,7 @@ define(['core/ArrayUtilities'], (array) => {
 				this.currentNest.rightAgent
 			);
 			optimiseStages(globals.stages);
+			swapFirstBegin(globals.stages, meta.headers || 'box');
 
 			return {
 				meta: {
diff --git a/scripts/sequence/Generator_spec.js b/scripts/sequence/Generator_spec.js
index c957fbe..23f5081 100644
--- a/scripts/sequence/Generator_spec.js
+++ b/scripts/sequence/Generator_spec.js
@@ -490,6 +490,25 @@ defineDescribe('Sequence Generator', ['./Generator'], (Generator) => {
 			]);
 		});
 
+		it('uses the header theme for the topmost begin statement', () => {
+			const sequence = generator.generate({
+				meta: {
+					headers: 'foo',
+				},
+				stages: [
+					PARSED.connect(['A', 'B']),
+					PARSED.connect(['B', 'C']),
+				],
+			});
+			expect(sequence.stages).toEqual([
+				GENERATED.beginAgents(['A', 'B'], {mode: 'foo'}),
+				jasmine.anything(),
+				GENERATED.beginAgents(['C'], {mode: 'box'}),
+				jasmine.anything(),
+				jasmine.anything(),
+			]);
+		});
+
 		it('removes duplicate end agents', () => {
 			const sequence = generator.generate({stages: [
 				PARSED.beginAgents(['A']),
diff --git a/scripts/sequence/Parser.js b/scripts/sequence/Parser.js
index cb3422d..c29194d 100644
--- a/scripts/sequence/Parser.js
+++ b/scripts/sequence/Parser.js
@@ -262,6 +262,19 @@ define([
 			return true;
 		},
 
+		(line, meta) => { // headers
+			if(tokenKeyword(line[0]) !== 'headers') {
+				return null;
+			}
+
+			const type = tokenKeyword(line[1]);
+			if(TERMINATOR_TYPES.indexOf(type) === -1) {
+				throw makeError('Unknown header "' + type + '"', line[1]);
+			}
+			meta.headers = type;
+			return true;
+		},
+
 		(line) => { // autolabel
 			if(tokenKeyword(line[0]) !== 'autolabel') {
 				return null;
@@ -439,6 +452,7 @@ define([
 					title: '',
 					theme: '',
 					terminators: 'none',
+					headers: 'box',
 				},
 				stages: [],
 			};
diff --git a/scripts/sequence/Parser_spec.js b/scripts/sequence/Parser_spec.js
index 9224627..06614fd 100644
--- a/scripts/sequence/Parser_spec.js
+++ b/scripts/sequence/Parser_spec.js
@@ -72,6 +72,7 @@ defineDescribe('Sequence Parser', ['./Parser'], (Parser) => {
 					title: '',
 					theme: '',
 					terminators: 'none',
+					headers: 'box',
 				},
 				stages: [],
 			});
@@ -92,6 +93,11 @@ defineDescribe('Sequence Parser', ['./Parser'], (Parser) => {
 			expect(parsed.meta.terminators).toEqual('bar');
 		});
 
+		it('reads headers metadata', () => {
+			const parsed = parser.parse('headers bar');
+			expect(parsed.meta.headers).toEqual('bar');
+		});
+
 		it('reads multiple tokens as one when reading values', () => {
 			const parsed = parser.parse('title foo bar');
 			expect(parsed.meta.title).toEqual('foo bar');
@@ -524,6 +530,12 @@ defineDescribe('Sequence Parser', ['./Parser'], (Parser) => {
 			));
 		});
 
+		it('rejects invalid headers', () => {
+			expect(() => parser.parse('headers foo')).toThrow(new Error(
+				'Unknown header "foo" at line 1, character 8'
+			));
+		});
+
 		it('rejects malformed notes', () => {
 			expect(() => parser.parse('note over A hello')).toThrow();
 		});