Rework header spacing

Realign some of the spacing in the main-header to look more like a title
and button group. Also removes padding from gr-dropdown button trigger.

Change-Id: I12dfc07e1fc2a9c1dcf48ab900e87fd0f0684d5f

polygerrit-ui/app/elements/core/gr-account-dropdown/gr-account-dropdown.html

@@ -24,11 +24,8 @@ limitations under the License.
 <dom-module id="gr-account-dropdown">
   <template>
     <style include="shared-styles">
-      button {
-        background: none;
-        border: none;
-        font: inherit;
-        padding: .3em 0;
+      gr-dropdown {
+        padding: .5em;
       }
       gr-avatar {
         height: 2em;

polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.html

@@ -57,6 +57,7 @@ limitations under the License.
       }
       ul {
         list-style: none;
+        padding-left: 1em;
       }
       .links > li {
         cursor: default;
@@ -89,10 +90,10 @@ limitations under the License.
         max-width: 500px;
       }
       gr-dropdown {
-        padding: 0.5em;
+        padding: 1em .5em;
       }
       .browse {
-        padding: 1em;
+        margin: .5em;
         text-decoration: none;
       }
       .accountContainer:not(.loggedIn):not(.loggedOut) .loginButton,
@@ -104,7 +105,7 @@ limitations under the License.
       .accountContainer {
         align-items: center;
         display: flex;
-        margin: 0 -0.5em 0 0.5em;
+        margin: 0 -.5em 0 .5em;
         white-space: nowrap;
         overflow: hidden;
         text-overflow: ellipsis;

polygerrit-ui/app/elements/shared/gr-dropdown/gr-dropdown.html

@@ -48,9 +48,6 @@ limitations under the License.
         width: 2em;
         vertical-align: middle;
       }
-      gr-button[link] {
-        padding: 0.5em;
-      }
       gr-button[link]:focus {
         outline: 5px auto -webkit-focus-ring-color;
       }