💄 style: add codeblock background colours

sass/main.scss

@@ -65,6 +65,8 @@
     --quote-color: #355f62;
     --border-color: #727272;
     --meta-color: #5b5b65;
+    --codeblock-bg: #272430;
+    --codeblock-highlight: #433e52;
 
     --theme-switcher-svg: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 512 512'%3E%3Cpath d='M283.211 512c78.962 0 151.079-35.925 198.857-94.792 7.068-8.708-.639-21.43-11.562-19.35-124.203 23.654-238.262-71.576-238.262-196.954 0-72.222 38.662-138.635 101.498-174.394 9.686-5.512 7.25-20.197-3.756-22.23A258.156 258.156 0 0 0 283.211 0c-141.309 0-256 114.511-256 256 0 141.309 114.511 256 256 256z'/%3E%3C/svg%3E%0A");
 }
@@ -83,6 +85,8 @@
     --quote-color: #a9c5c7;
     --border-color: black;
     --meta-color: #B0B0B0;
+    --codeblock-bg: #151515;
+    --codeblock-highlight: #292929;
 
     --theme-switcher-svg: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 96 960 960' %3E%3Cpath d='M480 776q-83 0-141.5-58.5T280 576q0-83 58.5-141.5T480 376q83 0 141.5 58.5T680 576q0 83-58.5 141.5T480 776ZM80 616q-17 0-28.5-11.5T40 576q0-17 11.5-28.5T80 536h80q17 0 28.5 11.5T200 576q0 17-11.5 28.5T160 616H80Zm720 0q-17 0-28.5-11.5T760 576q0-17 11.5-28.5T800 536h80q17 0 28.5 11.5T920 576q0 17-11.5 28.5T880 616h-80ZM480 296q-17 0-28.5-11.5T440 256v-80q0-17 11.5-28.5T480 136q17 0 28.5 11.5T520 176v80q0 17-11.5 28.5T480 296Zm0 720q-17 0-28.5-11.5T440 976v-80q0-17 11.5-28.5T480 856q17 0 28.5 11.5T520 896v80q0 17-11.5 28.5T480 1016ZM226 378l-43-42q-12-11-11.5-28t11.5-29q12-12 29-12t28 12l42 43q11 12 11 28t-11 28q-11 12-27.5 11.5T226 378Zm494 495-42-43q-11-12-11-28.5t11-27.5q11-12 27.5-11.5T734 774l43 42q12 11 11.5 28T777 873q-12 12-29 12t-28-12Zm-42-495q-12-11-11.5-27.5T678 322l42-43q11-12 28-11.5t29 11.5q12 12 12 29t-12 28l-43 42q-12 11-28 11t-28-11ZM183 873q-12-12-12-29t12-28l43-42q12-11 28.5-11t27.5 11q12 11 11.5 27.5T282 830l-42 43q-11 12-28 11.5T183 873Z'/%3E%3C/svg%3E");