implemented also atom feed via template

web/planet-mars/planet.css

@@ -0,0 +1,59 @@
+p, h1, h2, h3, h4, h5, h6, small {
+  max-width: 48em;
+}
+
+h1 a, h2 a, h3 a, h4 a, h5 a, h6 a {
+    color: inherit !important;
+    text-decoration: none;
+}
+
+ul, ol {
+  /* account for the 1em -webkit-margin-start for the list icon */
+  max-width: 45em;
+}
+
+ul,ol,dl, p {
+  line-height: 1.4;
+}
+
+body {
+  margin-top: 1em;
+  margin-bottom: 1em;
+}
+
+#maincontainer {
+    display: flex;
+    max-width: 80em;
+}
+
+#maincontainer main {
+    max-width: 50em;
+}
+
+#maincontainer main * {
+    max-width: 50em;
+}
+
+#maincontainer aside {
+    margin-left: 5em;
+    max-width: 25em;
+}
+
+article > h2.entry_header {
+    margin-bottom: 3px;
+}
+
+.entry_meta {
+    border: 1px thin;
+    padding: 3px 0;
+    background-color: LightBlue;
+}
+
+hr.entry_sep {
+   border: none;
+}
+hr.entry_sep::before {
+  content: '* * *';
+  display: block;
+  text-align: center;
+}