Center conversation tile in the main pane

Also fixes a visual bug with debug log and other overlays which wouldn't
cover the right edge of a very wide window.

// FREEBIE

stylesheets/_conversation.scss

@@ -15,8 +15,9 @@
 }
 
 .conversation {
+  max-width: 950px;
   background-color: #ffffff;
-  margin: 10px;
+  margin: 10px auto;
   padding: 20px 20px 10px;
   border-radius: 10px;
   height: calc(100% - 20px);

stylesheets/_global.scss

@@ -29,7 +29,6 @@ body {
 }
 
 #header {
-  max-width: 1300px;
   position: fixed;
   top: 1px;
   width: calc(100% - 2px);
@@ -92,8 +91,6 @@ button.back {
   position: relative;
   float: right;
   height: 36px;
-  padding-right: 8px;
-
 
   .hamburger {
     width: $header-height;

stylesheets/_index.scss

@@ -50,8 +50,7 @@
 }
 
 .conversation-stack {
-  padding-left: 300px;
-  padding-top: $header-height;
+  padding: $header-height 10px 0px 310px;
   .conversation {
     display: none;
   }
@@ -163,7 +162,6 @@ input.search {
 }
 
 .index {
-  max-width: 1300px;
   color: $grey_d;
   background: #2eace0;
 

stylesheets/manifest.css

@@ -38,7 +38,6 @@ body {
   display: none; }
 
 #header {
-  max-width: 1300px;
   position: fixed;
   top: 1px;
   width: calc(100% - 2px);
@@ -86,8 +85,7 @@ button.back {
 .menu {
   position: relative;
   float: right;
-  height: 36px;
-  padding-right: 8px; }
+  height: 36px; }
   .menu .hamburger {
     width: 36px;
     height: 36px;
@@ -433,8 +431,7 @@ img.emoji {
     background: url("/images/error_red.png") no-repeat left center; }
 
 .conversation-stack {
-  padding-left: 300px;
-  padding-top: 36px; }
+  padding: 36px 10px 0px 310px; }
   .conversation-stack .conversation {
     display: none; }
   .conversation-stack .conversation:first-child {
@@ -516,7 +513,6 @@ input.search {
     opacity: 1; }
 
 .index {
-  max-width: 1300px;
   color: #454545;
   background: #2eace0; }
   .index .gutter .new-group-update-form {
@@ -626,8 +622,9 @@ input.search {
   color: #999; }
 
 .conversation {
+  max-width: 950px;
   background-color: #ffffff;
-  margin: 10px;
+  margin: 10px auto;
   padding: 20px 20px 10px;
   border-radius: 10px;
   height: calc(100% - 20px);