improve: add production stage

src/components/Footer.js

@@ -0,0 +1,78 @@
+import React from "react";
+import "./Footer.css";
+
+const Footer = () => {
+    const [isExpanded, setIsExpanded] = React.useState(false);
+    const [isVisible, setIsVisible] = React.useState(false);
+    const toggleExpand = () => {
+        if(!isExpanded) {
+            setIsVisible(true);
+        }
+        setIsExpanded((prev) => !prev);
+    };
+    const onTransitionEnd = () => {
+        if(!isExpanded) {
+            setIsVisible(false);
+        }
+    };
+    return (
+        <footer className={`footer ${isExpanded ? "expanded" : ""}`}>
+            <button
+                className="toggle-button"
+                onClick={toggleExpand}
+                type="button"
+            >
+                {isExpanded ? "↓" : "↑"}
+            </button>
+            <div className={`footer-content`}>
+                <p>&copy; {new Date().getFullYear()} Hangman Lab. All rights reserved.</p>
+                {
+                    isVisible && (
+                        <div
+                            className={`footer-details ${isExpanded ? "expanded" : ""}`}
+                            onTransitionEnd={onTransitionEnd}
+                        >
+                            <div className="footer-icons">
+                                <a
+                                    href="https://www.linkedin.com/in/zhhrozhh/"
+                                    target="_blank"
+                                    rel="noopener noreferrer"
+                                >
+                                    <img
+                                        src="/icons/linkedin.png"
+                                        alt="LinkedIn"
+                                        className="footer-icon"
+                                    />
+                                    LinkedIn
+                                </a>
+                                <a
+                                    href="https://git.hangman-lab.top/hzhang/HangmanLab"
+                                    target="_blank"
+                                    rel="noopener noreferrer"
+                                >
+                                    <img
+                                        src="/icons/git.png"
+                                        alt="GitHub"
+                                        className="footer-icon"
+                                    />
+                                    GitHub
+                                </a>
+                                <a href="mailto:hzhang@hangman-lab.top">
+                                    <img
+                                        src="/icons/email.png"
+                                        alt="Email"
+                                        className="footer-icon"
+                                    />
+                                    Email
+                                </a>
+                            </div>
+                        </div>
+                    )
+                }
+            </div>
+
+        </footer>
+    );
+};
+
+export default Footer;