update Login/Register Container style & fix OnlyGuest Mixin

browser/styles/main/containers/LoginContainer.styl

@@ -4,6 +4,8 @@
   box-sizing border-box
   color inactiveTextColor
   .logo
+    width 215px
+    height 215px
     display block
     margin 0 auto
   .authNavigator
@@ -20,13 +22,16 @@
     p
       margin-bottom 25px
     .facebookBtn, .githubBtn
-      padding 20px
       margin 0 45px
+      width 75px
+      height 75px
+      line-height 75px
+      font-size 35px
+      text-align center
       background-image none
-      font-size 25px
       color white
       border none
-      circle()
+      border-radius 37.5px
       cursor pointer
     .facebookBtn
       background-color facebookColor
@@ -34,6 +39,7 @@
         background-color lighten(facebookColor, 25%)
     .githubBtn
       background-color githubBtn
+      font-size 42px
       &:hover, &.hover
         background-color lighten(githubBtn, 25%)
   .divider
@@ -53,3 +59,9 @@
         display block
         width 200px
         margin 0 auto
+        &.hover, &:hover
+          background-color brandColor
+          color white
+  p.alert
+    text-align center
+    font-size 0.8em

browser/styles/main/index.styl

@@ -52,6 +52,7 @@ button
   font-size 1em
   height 33px
   box-sizing border-box
+  transition 0.1s
   &:focus, &.focus
     border-bottom 1px solid brandBorderColor
     outline none