diff --git a/index.html b/index.html
index 6ab821c..33310c3 100644
--- a/index.html
+++ b/index.html
@@ -3,17 +3,51 @@
   <head>
     <meta charset="UTF-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-    <title>Document</title>
+    <title>Group Randomizer</title>
+    <link rel="stylesheet" href="style.css" />
   </head>
   <body>
-    <form id="file-form">
-      <input type="file" id="input-file" />
-      <input type="submit" value="Upload" />
-    </form>
+    <section class="container">
+      <div class="heading-container">
+        <h2 class="heading">Group Randomizer</h2>
+      </div>
+      <label for="input-file" class="drop-container" id="dropcontainer">
+        <span class="drop-title">Drop files here</span>
+        or
+        <input type="file" id="input-file" required />
+      </label>
+      <button class="random-btn" id="random-btn">Random Group</button>
+    </section>
+    <script>
+      const dropContainer = document.getElementById("dropcontainer");
+      const fileInput = document.getElementById("input-file");
+
+      dropContainer.addEventListener(
+        "dragover",
+        (e) => {
+          // prevent default to allow drop
+          e.preventDefault();
+        },
+        false
+      );
+
+      dropContainer.addEventListener("dragenter", () => {
+        dropContainer.classList.add("drag-active");
+      });
+
+      dropContainer.addEventListener("dragleave", () => {
+        dropContainer.classList.remove("drag-active");
+      });
+
+      dropContainer.addEventListener("drop", (e) => {
+        e.preventDefault();
+        dropContainer.classList.remove("drag-active");
+        fileInput.files = e.dataTransfer.files;
+      });
+    </script>
     <script type="module">
       import * as xlsx from "./xlsx.mjs";
 
-      // TODO: add only one sex day
       const GROUP = 13;
       const DAY = 6;
       let member = 0;
@@ -44,9 +78,7 @@
         },
       ];
 
-      async function processForm(e) {
-        if (e.preventDefault) e.preventDefault();
-
+      async function processForm() {
         console.log("File uploaded");
 
         const file_form = document.getElementById("input-file");
@@ -103,7 +135,7 @@
       }
 
       /**
-       *
+       * Create new xlsx worksheet for group assign
        * @param {xlsx.WorkBook} wb
        */
       function create_group_assign_sheet(wb) {
@@ -255,8 +287,6 @@
           total_error += error_for_day;
         }
         const R = Math.sqrt(total_error / 10000);
-        mx = Math.max(R, mx);
-        mn = Math.min(R, mn);
         return R;
       }
 
@@ -448,12 +478,11 @@
         });
       }
 
-      const form = document.getElementById("file-form");
-      if (form.attachEvent) {
-        form.AttachEvent("submit", processForm);
-      } else {
-        form.addEventListener("submit", processForm);
-      }
+      const randomBtn = document.getElementById("random-btn");
+      randomBtn.addEventListener("click", () => {
+        console.log(fileInput.files[0]);
+        processForm();
+      });
     </script>
   </body>
 </html>
diff --git a/style.css b/style.css
new file mode 100644
index 0000000..f560a5f
--- /dev/null
+++ b/style.css
@@ -0,0 +1,143 @@
+@import url("https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;700&family=Rubik+Bubbles&display=swap");
+
+body {
+  font-family: "Poppins", sans-serif;
+  margin: 0;
+  padding: 0;
+  box-sizing: border-box;
+}
+
+.container {
+  color: #fff;
+  display: flex;
+  flex-direction: column;
+  justify-content: center;
+  align-items: center;
+  gap: 5%;
+  width: 100vw;
+  height: 100vh;
+  overflow: hidden;
+  background: rgba(152, 140, 241, 0.5);
+}
+
+.heading-container {
+  font-family: "Rubik Bubbles", sans-serif;
+  display: flex;
+  flex-direction: column;
+  justify-content: center;
+  align-items: center;
+}
+
+.heading {
+  color: #455eb5;
+  font-size: 4rem;
+  font-weight: bold;
+}
+
+.drop-container {
+  position: relative;
+  display: flex;
+  gap: 10px;
+  flex-direction: column;
+  justify-content: center;
+  align-items: center;
+  height: 200px;
+  padding: 20px;
+  border-radius: 10px;
+  border: 2px dashed #555;
+  color: #444;
+  cursor: pointer;
+  background-color: #fff;
+  transition: background 0.2s ease-in-out, border 0.2s ease-in-out;
+}
+
+.drop-container:hover,
+.drop-container.drag-active {
+  background: #eee;
+  border-color: #111;
+}
+
+.drop-container:hover .drop-title,
+.drop-container.drag-active .drop-title {
+  color: #222;
+}
+
+.drop-title {
+  color: #444;
+  font-size: 20px;
+  font-weight: bold;
+  text-align: center;
+  transition: color 0.2s ease-in-out;
+}
+
+input[type="file"] {
+  width: 350px;
+  max-width: 100%;
+  color: #444;
+  padding: 5px;
+  background: #ffffff;
+  border-radius: 10px;
+  font-family: inherit;
+  border: 1px solid #555;
+}
+
+input[type="file"]::file-selector-button {
+  margin-right: 20px;
+  border: none;
+  background: #455eb5;
+  padding: 10px 20px;
+  border-radius: 10px;
+  color: #fff;
+  cursor: pointer;
+  font-family: inherit;
+  transition: background 0.2s ease-in-out;
+}
+
+input[type="file"]::file-selector-button:hover {
+  background: #0d45a5;
+}
+
+/* CSS */
+.random-btn {
+  background-image: linear-gradient(
+    92.88deg,
+    #455eb5 9.16%,
+    #5643cc 43.89%,
+    #673fd7 64.72%
+  );
+  border-radius: 8px;
+  border-style: none;
+  box-sizing: border-box;
+  color: #ffffff;
+  cursor: pointer;
+  flex-shrink: 0;
+  font-family: inherit;
+  font-size: 16px;
+  font-weight: 500;
+  height: 4rem;
+  text-align: center;
+  text-shadow: rgba(0, 0, 0, 0.25) 0 3px 8px;
+  transition: all 0.5s;
+  user-select: none;
+  -webkit-user-select: none;
+  touch-action: manipulation;
+  padding: 0 2.6rem;
+}
+
+.random-btn:hover {
+  box-shadow: rgba(80, 63, 205, 0.5) 0 1px 30px;
+  transition-duration: 0.1s;
+}
+
+.random-btn:active {
+  transform: scale(0.95);
+}
+
+@media (max-width: 768px) {
+  .heading {
+    font-size: 1rem;
+  }
+  .random-btn {
+    padding: 0 1.6rem;
+  }
+}
