Material UI: upgrade modals

Also clean up the Create Torrent page, delete some redundant CSS, prevent click-and-drag inside a TextField from moving the whole window, and make all label and input fonts  a consistent 14px size.

static/main.css

@@ -265,14 +265,9 @@ table {
   font-weight: bold;
 }
 
-.open-torrent-address-modal input {
-  width: 100%;
-}
-
 .create-torrent {
   padding: 10px 25px;
   overflow: hidden;
-  font: 16px/24px BlinkMacSystemFont, "Helvetica Neue", Helvetica, sans-serif;
 }
 
 .create-torrent .torrent-attribute {
@@ -323,6 +318,15 @@ i:not(.disabled):hover { /* Show they're clickable without pointer: cursor */
   text-align: center;
 }
 
+/*
+ * INPUTS
+ */
+input,
+textarea,
+.control {
+  font-size: 14px !important;
+}
+
 /*
  * TORRENT LIST
  */