Added primitive search mechanism in backend.

Began implementing search mechanism for frontend.

Props/assets/styles/site.scss

@@ -17,10 +17,11 @@ header > nav {
         &.active {
             @include themer.themed {
                 color: themer.color-of("navbar-active");
-                border-color: themer.color-of("navbar-active");
+                border-bottom-color: themer.color-of("navbar-active");
             }
+            padding-bottom: 2px;
             border-bottom-style: solid;
-            border-bottom-width: 1px;
+            border-bottom-width: 2px;
         }
     }
 
@@ -82,26 +83,32 @@ footer {
 }
 
 .concise {
+    @extend .container;
     max-width: 630px;
     width: inherit;
 }
 
 .less-concise {
+    @extend .container;
     max-width: 720px;
     width: inherit;
 }
 
-hr.concise {
-    @extend .my-3;
-    @include themer.themed {
-        color: themer.color-of("special");
+hr {
+    &.concise {
+        @extend .my-2;
+        width: 15%;
+        max-width: 160px;
+        min-width: 32px;
+        height: 2px;
+    }
+    &.less-concise {
+        @extend .my-2;
+        width: 30%;
+        max-width: 270px;
+        min-width: 32px;
+        height: 2px;
     }
-    width: 15%;
-    max-width: 160px;
-    min-width: 32px;
-    margin-left: auto;
-    margin-right: auto;
-    height: 2px;
 }
 
 html {
@@ -118,4 +125,62 @@ body {
         background-color: themer.color-of("background");
         color: themer.color-of("text");
     }
-}
+}
+
+.text-muted {
+    @include themer.themed {
+        color: themer.color-of("muted") !important;
+    }
+}
+
+.multipage {
+    display: flex;
+    flex-direction: column;
+    flex-grow: 1;
+
+    .multipage-slides, .multipage-slides > .multipage-slide.active {
+        display: flex;
+        flex-direction: column;
+        flex-grow: 1;
+    }
+
+    .multipage-slide {
+        .multipage-content {
+            @extend .container;
+            flex-grow: 1;
+            display: flex;
+            flex-direction: column;
+        }
+
+        .multipage-title {
+            @extend .less-concise;
+            text-align: center;
+        }
+    }
+
+    .nav-pills.selectors {
+        display: flex;
+        justify-content: center;
+        margin-bottom: 1rem;
+        button[type="button"] {
+            margin-right: 5px;
+            margin-left: 5px;
+            opacity: 0.4;
+            border-style: none;
+            font-size: 1.5rem;
+            min-width: 30px;
+            width: auto;
+            height: auto;
+            background-color: transparent;
+            background-clip: border-box;
+            @include themer.themed {
+                border-bottom: 2px solid themer.color-of("text");
+            }
+            border-bottom-style: none;
+
+            &.active {
+                opacity: 1;
+            }
+        }
+    }
+}