diff --git a/src/lang/en.json b/src/lang/en.json
index 8ff6198..c962383 100644
--- a/src/lang/en.json
+++ b/src/lang/en.json
@@ -3,6 +3,7 @@
 	"company_name": "AYO inc.",
 	"address_one_line": "Tokyo Itabashi Akatsukashinmachi 3-chōme-33-3",
 	"email_contact": "contact@ayo.tokyo",
+	"inferno_credit": "Website built with ",
 	"flow1": "From repetitive tasks done by human",
 	"flow2": "With the help of data gathered",
 	"flow3": "To automated systems"
diff --git a/src/lang/jp.json b/src/lang/jp.json
index 3fb2b0f..730be3d 100644
--- a/src/lang/jp.json
+++ b/src/lang/jp.json
@@ -3,6 +3,7 @@
 	"company_name": "AYO\u200b合同会社",
 	"address_one_line": "東京\u200b都板橋区\u200b赤塚新町\u200b三丁目３３番３ｰ１０２号",
 	"email_contact": "contact@ayo.tokyo",
+	"inferno_credit": "Website built with ",
 	"flow1": "人によって\u200b繰り返される\u200b作業",
 	"flow2": "収集された\u200bデータ\u200b（の助け）\u200bによって",
 	"flow3": "システム\u200bを自動化するため"
diff --git a/src/main.css b/src/main.css
index 944d6f7..21d2b90 100644
--- a/src/main.css
+++ b/src/main.css
@@ -3,6 +3,11 @@
    box-sizing: border-box;
 }
 
+a, a:visited
+{
+   color: inherit;
+}
+
 body
 {
    background-color: var(--main-bg-color);
@@ -62,17 +67,26 @@ body
    }
 }
 
-footer
+footer > section
 {
    display: flex;
    justify-content: center;
    align-items: center;
+   margin: 0 10px;
+}
+
+footer .legal div
+{
    padding: 10px;
 }
 
-footer > div
+footer .credit
+{
+   font-size: 0.8rem;
+}
+
+footer > section > div
 {
-   margin: 0 10px;
    word-break: keep-all;
 }
 
diff --git a/src/main.jsx b/src/main.jsx
index 8c20910..1abf837 100644
--- a/src/main.jsx
+++ b/src/main.jsx
@@ -1,5 +1,5 @@
 `use strict`
-import { Component } from 'inferno'
+import { Component, version } from 'inferno'
 import { connect } from 'inferno-redux'
 
 import { changeTheme, fetchLang } from './actions'
@@ -78,9 +78,19 @@ class MainComponent extends Component
 					</div>
 				</div>
 				<footer>
-					<div>{this.props.strings.company_name}</div>
-					<div>{this.props.strings.address_one_line}</div>
-					<div>{this.props.strings.email_contact}</div>
+					<section className="legal">
+						<div>{this.props.strings.company_name}</div>
+						<div>{this.props.strings.address_one_line}</div>
+						<div>{this.props.strings.email_contact}</div>
+					</section>
+					<section className="credit">
+						<div>
+							{this.props.strings.inferno_credit}
+							<a target="_blank" rel="noopener noreferrer" href="https://infernojs.org/">
+								{`Inferno ` + version}
+							</a>
+						</div>
+					</section>
 				</footer>
 			</main>)
 	 }
diff --git a/webpack.dev.js b/webpack.dev.js
index 0f6f528..9e08df6 100644
--- a/webpack.dev.js
+++ b/webpack.dev.js
@@ -33,6 +33,7 @@ module.exports = Object.assign(
 			}),
 			new CopyPlugin([
 				{from: 'index.html'},
+				{from: 'robot.txt'},
 				{from: 'src/lang', to: 'lang'},
 				{from: 'assets/public', to: 'assets'}
 			]),
@@ -40,7 +41,8 @@ module.exports = Object.assign(
 			{
 				filename: "[path].gz[query]",
 				algorithm: "gzip",
-				test: /\.js/
+				test: [/\.js/, /^assets\.*/],
+				threshold: 1000
 			})
 		],
 		// webpack-dev-server configuration
diff --git a/webpack.prod.js b/webpack.prod.js
index 182b1ec..03a8d01 100644
--- a/webpack.prod.js
+++ b/webpack.prod.js
@@ -29,7 +29,8 @@ module.exports = Object.assign(
 			{
 				filename: "[path].gz[query]",
 				algorithm: "gzip",
-				test: [/\.js/, /^assets\.*/]
+				test: [/\.js/, /^assets\.*/],
+				threshold: 1000
 			})
 		]
 	}