remove/reorganize some css

scss/sections/_main.scss

@@ -1,3 +0,0 @@
-section {
-  margin-bottom: 10rem;
-}

scss/sections/_sidenav.scss

@@ -1,94 +0,0 @@
-.sidenav {
-  @include grid-pad;
-  @include panel-margin;
-  width: 100%;
-  flex-shrink: 0;
-
-  @include media($large-screen) {
-    width: 21rem;
-  }
-
-  @include media($xlarge-screen) {
-    width: 30rem;
-  }
-
-  .sidenav__link {
-    display: block;
-    border-top: 1px solid $color-black;
-    padding: $gap ($gap * 2);
-    color: $color-black;
-    text-decoration: none;
-
-    &:hover {
-      background-color: $color-white;
-      color: $color-primary;
-    }
-
-    &.sidenav__link--disabled {
-      color: $color-shadow;
-      pointer-events: none;
-    }
-
-    &.sidenav__link--active {
-      @include h4;
-      background-color: $color-white;
-      color: $color-primary;
-      box-shadow: inset .4rem 0 0 0 $color-primary;
-
-      + ul {
-        background-color: $color-white;
-
-        .sidenav__link {
-          &--active {
-            @include h5;
-            box-shadow: none;
-          }
-        }
-      }
-    }
-
-    + ul {
-      li {
-        .sidenav__link {
-          padding: ($gap * .75) ($gap * 3);
-          border: 0;
-          @include h5;
-          font-weight: normal;
-        }
-
-        &:last-child {
-          .sidenav__link {
-            padding-bottom: $gap * 1.5;
-          }
-        }
-      }
-    }
-  }
-
-  ul {
-    list-style: none;
-    margin: 0;
-    padding: 0;
-
-     li {
-      margin: 0;
-      display: block;
-    }
-  }
-
-  > ul {
-    @include panel-margin;
-
-    &:last-child {
-      margin: 0;
-    }
-
-    > li {
-      &:last-child {
-        > .sidenav__link {
-          border-bottom: 1px solid $color-black;
-        }
-      }
-    }
-  }
-}

scss/sections/_topbar.scss

@@ -1,54 +0,0 @@
-.topbar {
-  background-color: $color-white;
-  height: $topbar-height;
-  border-bottom: 1px solid $color-black;
-
-  .topbar__navigation {
-    display: flex;
-    flex-direction: row;
-    align-items: stretch;
-    justify-content: flex-end;
-
-    > .topbar__link {
-      @include h5;
-      color: $color-primary;
-      display: inline-block;
-      height: $topbar-height;
-      line-height: $topbar-height;
-      padding: 0 ($gap * 2);
-      text-decoration: none;
-
-      > span {
-        display: inline-block;
-        height: $topbar-height;
-        line-height: $topbar-height;
-      }
-
-      &.topbar__link--primary {
-        margin-right: auto;
-        > span {
-          @include nav-border;
-        }
-
-        &:hover {
-          color: $color-white;
-          background-color: $color-primary-darkest;
-        }
-      }
-
-      &.topbar__link--secondary {
-        font-weight: normal;
-        > span {
-          @include nav-border;
-          border-bottom-width: 0;
-        }
-
-        &:hover {
-          > span {
-            @include nav-border;
-          }
-        }
-      }
-    }
-  }
-}