Add design element(css)

+div
+{
+    width: 500px;
+    height:700px;
+    margin: 0 auto;
+    display:block;
+    background-color: white;
+}
+#tex1
+{
+  font-family: 'Nanum Gothic';
+  font-size:80px;
+  font-weight: bold;
+}
+#tex2
+{
+  font-family: 'Nanum Gothic';
+  font-size:30px;
+  font-weight: bold;
+}
+#btn
+{
+  position: relative;
+  top:40%;
+  width:100%;
+  height:12%;
+  font-family: 'Nanum Gothic';
+  font-size:large;
+  font-weight: bold;
+  color:white;
+  background-color: black;
+  text-align: center;
+  border-radius: 12px;
+
+}
+.box {
+	animation: fade-in 0.8s cubic-bezier(0.390, 0.575, 0.565, 1.000) both;
+}
+@keyframes fade-in {
+    0% {
+      opacity: 0;
+    }
+    100% {
+      opacity: 1;
+    }
+  }
+
+@keyframes spin {
+    100% {
+      transform: rotate(360deg);
+    }
+}
+.spinner 
+{
+  display: inline-block;
+  width: 50px;
+  height: 50px;
+  border: 5px solid black;
+  border-color: black transparent transparent;
+  border-radius: 50%;
+  animation: spin 1s linear infinite;
+}