added help page (closes #15)

src/js/main.js

@@ -162,6 +162,22 @@
 		location.hash='menu';
 	};
 
+	// show help page
+	help=async () => {
+		stopGame();
+		let iframe=document.createElement('iframe');
+		iframe.src='help.html';
+		iframe.style.width='100%';
+		iframe.style.height='100%';
+		await new Popup(
+			"Help",
+			[iframe],
+			{ok: "OK"},
+			true
+		).display();
+		location.hash='menu';
+	};
+
 	// display the win popup
 	handleWin=async snek => {
 		// hide the HUD

src/less/help.less

@@ -0,0 +1,16 @@
+.help {
+	display: block;
+
+	article {
+		margin-bottom: 2ex;
+	}
+
+	section {
+		margin-bottom: 1ex;
+	}
+
+	ul {
+		margin-left: 2ex;
+		font-size: 1.6em;
+	}
+}

src/less/popup.less

@@ -48,6 +48,7 @@
 				flex-direction: column;
 				align-items: center;
 				overflow-y: auto;
+				flex: 1;
 
 				& > * {
 					margin: .5rem;

src/less/snek.less

@@ -31,6 +31,10 @@ h1, h2, h3, h4, h5, h6 {
 	margin-bottom: .1em;
 }
 
+p + p {
+	margin-top: 1em;
+}
+
 a {
 	text-decoration: inherit;
 	display: contents;
@@ -40,6 +44,11 @@ em {
 	font-style: italic;
 }
 
+code {
+	background: @accentbg;
+	font-weight: bold;
+}
+
 header, footer {
 	background: @accentbg;
 
@@ -131,3 +140,6 @@ p {
 
 // setup the hud
 @import 'hud';
+
+// setup the help file
+@import 'help';