diff --git a/source/code/ui.js b/source/code/ui.js
new file mode 100644
index 0000000..0fc9338
--- /dev/null
+++ b/source/code/ui.js
@@ -0,0 +1,77 @@
+let introDelay = 6;
+let hintDelay = 1;
+
+const intro = {
+	element: document.getElementById('intro'),
+	delay: introDelay * 1000,
+	show() {
+		if (typeof this.timeoutId === 'number') {
+			this.cancel();
+		}
+
+		console.info("Intro begin.");
+		this.element.classList.replace('op_hide', 'op_show');
+
+		this.timeoutId = setTimeout(
+			() => {
+				this.dismiss();
+			},
+			this.delay
+		)
+	},
+	dismiss() {
+		this.element.classList.replace('op_show', 'op_hide');
+		this.timeoutId = undefined;
+
+		this.element.addEventListener('transitionend', () => {
+			console.info("Intro fin.");
+			agree();
+		});
+	},
+	cancel() {
+		clearTimeout(this.timeoutId);
+	}
+};
+const agreement = document.getElementById('agreement');
+const hint = {
+	element: document.getElementById('hint'),
+	delay: hintDelay * 1000,
+	show() {
+		if (typeof this.timeoutId === 'number') {
+			this.cancel();
+		}
+
+		this.element.classList.remove('di_none');
+
+		this.timeoutId = setTimeout(
+			() => {
+				this.dismiss();
+			},
+			this.delay
+		);
+	},
+	dismiss() {
+		this.element.classList.add('di_none');
+		this.timeoutId = undefined;
+	},
+	cancel() {
+		clearTimeout(this.timeoutId);
+	}
+};
+
+window.addEventListener('click', () => hint.show());
+window.addEventListener('keydown', () => hint.show());
+
+if (intro.element) intro.show();
+
+function agree() {
+	if (agreement) {
+		console.info("Agreement show.");
+		agreement.classList.replace('op_hide', 'op_show');
+
+		setTimeout(() => {
+			agreement.classList.replace('op_show', 'op_hide');
+			console.info("Agreement closed.");
+		}, introDelay * 1000)
+	}
+}
diff --git a/source/screens/demo/examples/ui/index.njk b/source/screens/demo/examples/ui/index.njk
new file mode 100644
index 0000000..46c2827
--- /dev/null
+++ b/source/screens/demo/examples/ui/index.njk
@@ -0,0 +1,73 @@
+---
+title: Init
+tags: 
+  - demoExample
+  - index
+  - ui
+---
+{% set pageId = "init" %}
+{% set pageClass = "html_ui" %}
+
+{% extends "demo/_app.njk" %}
+
+{% block title %}{{ title }}
+{% endblock %}
+
+{% block links %}
+		<link href="{{ pageBase }}css/ui.css" media="all" rel="stylesheet"/>
+{% endblock %}
+
+{% block head %}
+		{{ super() }}
+{% endblock %}
+
+{% block body %}
+		<div id="hint" class="toast di_none" role="alert" aria-live="assertive" aria-atomic="true">
+			<p>Hold <kbd>space</kbd> to skip.</p>
+		</div>
+		<div id="intro" class="op_hide">
+			<div class="brand">
+				{# <img src="" alt="Brand logo"> #}
+				<svg
+					width="128"
+					height="128"
+					viewBox="0 0 128 128"
+					version="1.1"
+					xmlns="http://www.w3.org/2000/svg"
+					xmlns:svg="http://www.w3.org/2000/svg">
+					<g>
+						<rect
+							style="display:inline;fill:none;stroke:#ffffff;stroke-width:2;stroke-linecap:round;stroke-dasharray:none"
+							width="126"
+							height="126"
+							x="1"
+							y="1" />
+						<circle
+							style="fill:none;stroke:#ffffff;stroke-width:2;stroke-linecap:round;stroke-linejoin:bevel;stroke-dasharray:none"
+							cx="64"
+							cy="64"
+							r="63" />
+						<path
+							style="fill:none;stroke:#ffffff;stroke-width:2;stroke-linecap:round;stroke-linejoin:bevel;stroke-dasharray:none"
+							d="m 9.3926879,32.472455 109.2146221,-2e-6 -54.607309,94.582637 z" />
+					</g>
+				</svg>
+				<h1>Brand name</h1>
+			</div>
+			<p>Powered by</p>
+			<ul class="tech-stack">
+				<li>Vendor</li>
+				<li>IDE</li>
+				<li>Engine</li>
+			</ul>
+		</div>
+		<div id="agreement" class="op_hide">
+				<div class="hello">Hello World!</div>
+				<p class="hello">Only left mouse click or any key</p>
+		</div>
+{% endblock %}
+
+{%- block script %}
+		{{ super() }}
+		<script src="{{ pageBase }}js/ui.js"></script>
+{% endblock %}
\ No newline at end of file
diff --git a/source/style/ui.scss b/source/style/ui.scss
index d088323..ee5186b 100644
--- a/source/style/ui.scss
+++ b/source/style/ui.scss
@@ -1,6 +1,113 @@
+@use "sass:map";
+
 @import "demo_config";
 @import "hippie-style/hippie";
 
+$z-indexes: (
+	"default": 0,
+	"content-bottom": 1,
+	"content-low": 2,
+	"content-med": 3,
+	"content-high": 4,
+	"content-top": 10,
+	"modal-low": 11,
+	"modal-med": 12,
+	"modal-high": 13,
+	"toast": 100
+);
+
+.op_show {
+	transition: $transition_show;
+}
+
+.op_hide {
+	transition: $transition_hide;
+}
+
+.html_ui {
+	height: 100%;
+
+	body {
+		position: relative;
+		min-height: 100%;
+		background-color: black;
+	}
+}
+
+#intro {
+	@extend %full_parent;
+
+	z-index: map.get($z-indexes, "content-top");
+	overflow: hidden;
+	display: flex;
+	flex-direction: column;
+	align-items: center;
+	justify-content: center;
+	background-color: black;
+
+	h1,
+	p,
+	li {
+		color: white;
+	}
+}
+
+.brand {
+	text-align: center;
+
+	img {
+		display: inline-block;
+		width: 128px;
+		height: 128px;
+		background-color: white;
+	}
+
+	*+h1 {
+		margin-top: $space_small;
+		margin-bottom: $space_large;
+	}
+}
+
+.tech-stack {
+	display: flex;
+	padding-left: 0;
+
+	li {
+		list-style: none;
+		padding-inline: $space_double;
+	}
+}
+
+#agreement {
+	display: flex;
+	align-items: center;
+	justify-content: center;
+	height: 100vh;
+	background-color: $color_back_basic;
+}
+
+.toast {
+	z-index: map.get($z-indexes, "toast");
+	position: fixed;
+  right: $space_half;
+  bottom: $space_double;
+
+	p {
+		color: white;
+	}
+
+	kbd {
+		border-color: $color_brighter;
+		color: $color_back_io;
+	}
+}
+
+.hello {
+	flex: 0 1 auto;
+	padding: 1em 2em;
+	background-color: rgba(black, .25);
+}
+
 @import "modules/ui/new_module";
 @import "modules/ui/settings_module";
-@import "modules/ui/drag_module";
+@import "modules/ui/drag_module";
\ No newline at end of file
diff --git a/source/templates/hippie/partials/_body_nav.njk b/source/templates/hippie/partials/_body_nav.njk
index db7ea52..58fed6d 100644
--- a/source/templates/hippie/partials/_body_nav.njk
+++ b/source/templates/hippie/partials/_body_nav.njk
@@ -1,6 +1,6 @@
 <!-- body_nav.partial -->
 <div class="pos_rel">
-  <nav class="nav_page_meta js_">
+  <nav class="nav_page_meta">
     <ul>
       <li class="js_scrolltop di_none">
         <a href="#begin" class="a_button_meta">