ui: Minor visual refresh

The focus is on:
1. Increasing information density
2. Decreasing visual noise / increasing consistency
It's by no means done but it's a step in the right direction.

For 1. we:
- Decrease font size
- Remove excessive padding
- Reduce topbar height
- Reduce sidebar width
- Reduce the minimum track height
- Reduce the thread state track

For 2. we:
- Reduce the number of typefaces
- Reduce the number of weights in use
- Reduce the number of non-semantic colors
- Use the same border-radius everywhere
- Replace some custom buttons with with the button widget

Before/after for the various surfaces:

- Welcome:
  - https://screenshot.googleplex.com/5Vg3Dcckjq2h8Rf
  - https://screenshot.googleplex.com/6Wop2quyztZ7Nno
- Timeline:
  - https://screenshot.googleplex.com/5sahBHEhqaB7F8X
  - https://screenshot.googleplex.com/382giTGsEnga33T
- Query:
  - https://screenshot.googleplex.com/5ozS5m5Jzo3rrtn
  - https://screenshot.googleplex.com/9fTHeyVyG4XHmN8
- Metrics:
  - https://screenshot.googleplex.com/mGsFtDLJeC6BVGy
  - https://screenshot.googleplex.com/VsowCEdrBYUHCJR
- Flags:
  - https://screenshot.googleplex.com/BjtWjNpg969Y8YZ
  - https://screenshot.googleplex.com/ZAkfSzD3kCNbLDg
- RecordingV2:
  - https://screenshot.googleplex.com/3jUgxhmpLGoF3YV
  - https://screenshot.googleplex.com/9HDoY7kEnkZ9C5S
- Recording:
  - https://screenshot.googleplex.com/3C5RB3U3rdQusNb
  - https://screenshot.googleplex.com/9U7bYTxfeWgtP43
- Tabs:
  - https://screenshot.googleplex.com/C8BoNPFr9DLiYy8
  - https://screenshot.googleplex.com/5y2g9tAi6L59Djb

Change-Id: I8e22bdc694b8e0846e839daf9aaab4e447414885
diff --git a/ui/src/assets/sidebar.scss b/ui/src/assets/sidebar.scss
index b0a7092..6fedf61 100644
--- a/ui/src/assets/sidebar.scss
+++ b/ui/src/assets/sidebar.scss
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+@import "widgets/theme";
+
 .sidebar {
   --sidebar-padding-bottom: 40px;
   --sidebar-timing: 0.15s;
@@ -38,11 +40,11 @@
     height: var(--topbar-height);
     line-height: var(--topbar-height);
     vertical-align: middle;
-    padding: 0 20px;
+    padding: 0 12px;
     color: #fff;
     overflow: visible;
     .brand {
-      height: 40px;
+      height: 36px;
       margin-top: 4px;
     }
     &::before {
@@ -54,7 +56,7 @@
       position: absolute;
       font-size: 10px;
       line-height: 10px;
-      font-family: "Raleway", sans-serif;
+      font-family: "Roboto", sans-serif;
       left: 155px;
       top: 7px;
     }
@@ -121,17 +123,15 @@
           cursor: pointer;
           > h1,
           > h2 {
-            font-family: "Raleway", sans-serif;
             letter-spacing: 0.25px;
             overflow: hidden;
             text-overflow: ellipsis;
             white-space: nowrap;
-            margin: 0 24px;
+            margin: 0 12px;
           }
           > h1 {
             color: #fff;
             font-size: 15px;
-            font-weight: 500;
           }
           > h2 {
             @include transition();
@@ -189,10 +189,8 @@
           a {
             line-height: 24px;
             font-size: 14px;
-            font-weight: 400;
-            font-family: "Raleway", sans-serif;
             letter-spacing: 0.5px;
-            padding: 5px 24px;
+            padding: 4px 12px;
             text-decoration: none;
             display: block;
             &.pending {
@@ -225,6 +223,7 @@
           }
           .material-icons {
             margin-right: 10px;
+            font-size: 20px
           }
           &:hover {
             background-color: #373f4b;
@@ -265,13 +264,19 @@
     }
 
     > .dbg-info-square {
+      font-family: "Roboto Condensed", sans-serif;
       width: 24px;
-      height: 22px;
-      line-height: 22px;
+      height: 24px;
+      line-height: 24px;
+      display: flex;
+      justify-content: center;
+      flex-direction: column;
+      align-items: center;
+
       margin: 1px 0;
       background: #12161b;
       color: #4e71b3;
-      border-radius: 5px;
+      border-radius: $pf-border-radius;
       font-size: 12px;
       text-align: center;
       &.green {