feat: change filter styles according to spec

Author: bmikkelsen22

src/Assets/Styles/advanced-filter.less

@@ -8,6 +8,8 @@
   border-top: 1px solid @grey-border-color;
   box-shadow: @box-shadow;
   flex-basis: 300px;
+  padding: 0;
+  overflow: hidden;
 
   *:not(span) {
     font-family: inherit;
@@ -18,7 +20,7 @@
   display: flex;
   flex-direction: column;
   width: 100%;
-  background-color: @background-color-base;
+  background-color: @sb-white;
 }
 
 div.adv-filter-group {
@@ -27,6 +29,9 @@ div.adv-filter-group {
   width: 100%;
   z-index: 1;
   background-color: @sb-white;
+  padding: @spacing-unit @spacing-unit 0 @spacing-unit;
+  background-color: @background-color-base;
+  border-bottom: 1px solid @grey-border-color;
 }
 
 div.filter-title-container {
@@ -136,5 +141,4 @@ div.filter-btn-group > button.btn {
   max-height: 30vh;
   flex-basis: 150px;
   align-content: flex-start;
-
 }