Remove obsolete components.

assets/sass/components/inline-sibling/_inline-sibling.scss

@@ -1,31 +0,0 @@
-// stylelint-disable selector-max-compound-selectors
-
-// Inline sibling
-//
-// An element that needs to appear inline with the content that follows.
-
-.inline-sibling,
-%inline-sibling {
-  display: inline;
-  margin-right: 10px;
-
-  @include rtl() {
-    margin-right: 0;
-    margin-left: 10px;
-  }
-
-  // All of the children of the element need to be inline as well.
-  &__child,
-  * {
-    display: inline;
-  }
-
-  // The next element (and its first-child element, if the markup is nested)
-  // needs to be inline.
-  &__adjacent,
-  + *,
-  + * > :first-child,
-  + * > :first-child > :first-child {
-    display: inline;
-  }
-}

assets/sass/components/inverted-box/_inverted-box.scss

@@ -1,26 +0,0 @@
-// A inverted box style.
-
-.inverted-box,
-%inverted-box {
-  @include padding(.5);
-  background: var(--color-brand);
-  color: var(--color-text-bg);
-  border-radius: $m-radius;
-
-  :link,
-  :visited {
-    color: var(--color-text-bg);
-  }
-
-  p,
-  ul,
-  ol {
-    &:first-of-type {
-      margin-top: 0;
-    }
-
-    &:last-of-type {
-      margin-bottom: 0;
-    }
-  }
-}

assets/sass/components/monospace/_monospace.scss

@@ -1,10 +0,0 @@
-// Monospace
-
-.monospace,
-%monospace {
-  // Correct the inheritance and scaling of font size in all browsers.
-  // The font-family value ends with ", serif".
-  @include typeface(monospace);
-  // Correct the odd `em` font sizing in all browsers.
-  font-size: 1em;
-}

assets/sass/components/watermark/_watermark.scss

@@ -1,21 +0,0 @@
-// stylelint-disable color-function-notation, alpha-value-notation
-
-// Watermark
-//
-// Make the element appear beneath sibling elements, like a watermark.
-
-.watermark,
-%watermark {
-  @include typeface(compact);
-  display: block;
-  height: 0;
-  overflow: visible;
-  background-color: transparent;
-  color: var(--color-watermark);
-  font-size: 75px;
-  line-height: 1;
-  text-align: center;
-  // stylelint-disable no-color-literals
-  text-shadow: 0 0 1px rgba(0, 0, 0, .1);
-  word-wrap: break-word;
-}

assets/sass/components/wireframe/_wireframe.scss

@@ -1,34 +0,0 @@
-$with-wireframes: false !default;
-
-// Wireframe
-//
-// Add wireframes around main layout elements.
-// http://www.boxesandarrows.com/view/html_wireframes_and_prototypes_all_gain_and_no_pain
-// are useful when prototyping a website.
-//
-// This design is not applied to the site unless you set the following Sass
-// variable: `$with-wireframes: true;`
-
-@if $with-wireframes {
-  .wireframe,
-  %wireframe {
-    outline: 1px solid var(--color-border);
-  }
-
-  //
-  // Zen selectors.
-  //
-
-  .layout {
-    &__header,
-    &__footer,
-    &__main,
-    &__navigation,
-    &__first-sidebar,
-    &__second-sidebar,
-    &__page-top,
-    &__page-bottom {
-      @extend %wireframe;
-    }
-  }
-}