Add animated matrix background effect to home page.

public/matrix.js

@@ -0,0 +1,27 @@
+const canvas = document.getElementById("matrix-canvas");
+const ctx = canvas.getContext("2d");
+canvas.width = window.innerWidth;
+canvas.height = window.innerHeight;
+const letters = "アァイィウヴエェオカキクケコサシスセソタチツテトナニヌネノハヒフヘホマミムメモヤユヨラリルレロワヲンABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".split("");
+const fontSize = 16;
+const columns = Math.floor(canvas.width / fontSize);
+const drops = new Array(columns).fill(1);
+function drawMatrix() {
+    ctx.fillStyle = "rgba(0, 0, 0, 0.2)";
+    ctx.fillRect(0, 0, canvas.width, canvas.height);
+    ctx.fillStyle = "#39FF14";
+    ctx.font = fontSize + "px monospace";
+    for (let i = 0; i < drops.length; i++) {
+        const text = letters[Math.floor(Math.random() * letters.length)];
+        ctx.fillText(text, i * fontSize, drops[i] * fontSize);
+        if (drops[i] * fontSize > canvas.height || Math.random() > 0.975) {
+            drops[i] = 0;
+        }
+        drops[i]++;
+    }
+}
+setInterval(drawMatrix, 50);
+window.addEventListener("resize", () => {
+    canvas.width = window.innerWidth;
+    canvas.height = window.innerHeight;
+});