Added css for the main page, added user panel

Created src/main.css that contains src/main.html css design
Updated login.html for clearer actions
Changed main.html for to a new layout for the css, added watching user panel

src/login.html

@@ -12,8 +12,8 @@
       <h1> Login To Watch-Together Server</h1>
         <div class="form">
           <form action="/login" method="post" class="login-form">
-            <input type="text" placeholder="username" name="username"/>
-            <input type="password" placeholder="password" name="password"/>
+            <input type="text" placeholder="your username" name="username"/>
+            <input type="password" placeholder="server password" name="password"/>
             <button>login</button>
           </form>
         </div>