Create skeleton of main activities view UI in client

client/styles.css

@@ -0,0 +1,25 @@
+.card-container {
+	background-color: mix(@theme_base_color, @theme_bg_color, 0.7);
+	padding: 6px;
+}
+
+.card {
+	border: 1px solid alpha(@theme_fg_color, 0.2);
+	box-shadow: 0 1px 2px alpha(black, 0.15);
+	background-color: @theme_bg_color;
+	padding: 12px 16px;
+}
+
+.activity-subject {
+	font-weight: bold;
+}
+
+/*
+ * The visual center (i.e. the center of the clock) of the
+ * "appointment-new-symbolic" icon is slightly displaced from the
+ * center of the actual image, so tweak it here.
+ */
+.log-session-button image {
+	margin-top: -2px;
+	margin-left: 3px;
+}