Add background color and padding to content nav

src/_includes/main/content-nav.njk

@@ -1,6 +1,6 @@
 <aside class="right-sidebar">
     <nav class="content__nav sidebar--sticky">
-        <h2 class="content__nav--title">Content Index</h2>
+        <h2 class="content__nav--title">My Contents</h2>
         <ul class="content__nav--links">
             {% for archive in collections.archive %}
                 <li><a href="{{ archive.url }}">{{ archive.data.title }}</a></li>
@@ -15,7 +15,8 @@
 
 <style>
     .content__nav {
-        padding-left: 0.5em;
+        padding: 1.2em clamp(1em, 5%, 1.5em);
+        background-color: var(--clr-content-bg);
     }
 
     .content__nav--title {