split up layout and global file and clean up markup

assets/stylesheets/layout/grid-lists.css

@@ -0,0 +1,29 @@
+.grid-list {
+  display: flex;
+  flex-wrap: wrap;
+  justify-content: space-between;
+  margin: 0 calc(var(--grid-gutter) / 2 * -1);
+
+  & > * {
+    box-sizing: border-box;
+    margin: 0 calc(var(--grid-gutter) / 2) var(--grid-gutter);
+    flex: 0 0 calc(50% - var(--grid-gutter));
+
+    @media (--breakpoint-desktop) {
+      flex: 0 0 calc(33% - var(--grid-gutter));
+    }
+  }
+}
+
+.grid-list-small {
+  display: flex;
+  flex-wrap: wrap;
+  justify-content: space-between;
+  margin: 0 calc(var(--grid-gutter) / 2 * -1);
+
+  & > * {
+    box-sizing: border-box;
+    margin: 0 calc(var(--grid-gutter) / 2) var(--grid-gutter);
+    flex: 0 0 calc(50% - var(--grid-gutter));
+  }
+}

assets/stylesheets/layout/index.css

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+@import 'layout-centered';
+@import 'layout-sidebar';
+@import 'grid-lists';

assets/stylesheets/layout/layout-centered.css

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+@block layout-centered {
+  max-width: var(--content-max-width);
+  margin: 0 auto;
+  padding: 0 2vw;
+}

assets/stylesheets/layout/layout-sidebar.css

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+@block layout-sidebar {
+  padding: 0 2vw;
+  max-width: var(--content-max-width);
+  margin: 0 auto;
+
+  @media (--breakpoint-desktop) {
+    display: flex;
+    align-items: flex-start;
+  }
+
+  @element sidebar {
+    @media (--breakpoint-desktop) {
+      flex: 0 0 220px;
+      border-radius: 7px;
+      box-shadow: var(--card-box-shadow);
+    }
+  }
+
+  @element sidebar-header {
+    padding: var(--grid-gutter);
+    border-bottom: 1px solid var(--color-sidebar-seperator);
+  }
+
+  @element sidebar-title {
+    font-size: 1.25em;
+    margin: 0;
+  }
+
+  @element sidebar-content {
+    background: var(--color-sidebar-bg);
+    padding: var(--grid-gutter);
+  }
+
+  @element content {
+    padding: var(--grid-gutter) 0;
+
+    @media (--breakpoint-desktop) {
+      flex: 1 1 auto;
+      margin-left: var(--grid-gutter);
+      overflow: hidden;
+    }
+  }
+}