Improve static resources directory structure

src/static/css/main.css

@@ -0,0 +1,31 @@
+body {
+    margin: 0;
+}
+
+header {
+    text-align: center;
+}
+
+header h1 {
+    margin-bottom: 0;
+}
+
+form {
+    display: flex;
+    justify-content: center;
+    margin-top: 20px;
+    width: 100%;
+}
+
+form button{
+    margin-left: 10px;
+}
+
+form input{
+    width: 80%;
+}
+
+footer{
+    text-align: center;
+    margin-top: 20px;
+}