diff --git a/lib/mmmd/renderers/html.rb b/lib/mmmd/renderers/html.rb
index 72d98c5..45f4ab9 100644
--- a/lib/mmmd/renderers/html.rb
+++ b/lib/mmmd/renderers/html.rb
@@ -128,11 +128,10 @@ module MMMD
 
         def initialize(overrides)
           @mapping = self.class.mapping
-          if overrides["mapping"]
-            overrides["mapping"].each do |key, value|
-              next unless @mapping[key]
-              @mapping[key] = @mapping[key].merge(value)
-            end
+          overrides["mapping"]&.each do |key, value|
+            next unless @mapping[key]
+
+            @mapping[key] = @mapping[key].merge(value)
           end
         end
 
diff --git a/lib/mmmd/renderers/plainterm.rb b/lib/mmmd/renderers/plainterm.rb
index 95279a8..5e36a21 100644
--- a/lib/mmmd/renderers/plainterm.rb
+++ b/lib/mmmd/renderers/plainterm.rb
@@ -381,7 +381,11 @@ module MMMD
         def initialize(overrides)
           @style = self.class.style
           @effect_priority = self.class.effect_priority
-          @style = @style.merge(overrides["style"]) if overrides["style"]
+          overrides["style"]&.each do |key, value|
+            next unless @style[key]
+
+            @style[key] = @style[key].merge(value)
+          end
         end
 
         attr_reader :style, :effect_priority
diff --git a/wiki/renderers/HTML.md b/wiki/renderers/HTML.md
new file mode 100644
index 0000000..9751ce8
--- /dev/null
+++ b/wiki/renderers/HTML.md
@@ -0,0 +1,82 @@
+HTML renderer
+=============
+
+HTML renderer does exactly what it says on the tin - renders markdown to HTML.
+It offers the ability to modify the way output is generated, as well as tags
+which are used for every block.
+
+Global options
+--------------
+
+Global options are applied to the root of the configuration hash for the
+renderer. They can be applied using the following pattern via command
+line:
+
+```
+$ mmmdpp -o '"nameOfGlobalOption": <value, in JSON element form>' ...
+
+# i.e.
+$ mmmdpp -o '"linewrap": 65' ...
+```
+
+Following global options can be provided:
+
+- `linewrap` - line wrapping, in number of text columns (80 by default)
+- `init_level` - initial indent level of generated text (2 by default)
+- `indent` - number of spaces per indent (2 by default)
+- `nowrap` - do not output wrapping code, only direct translations of
+   markdown elements (false by default)
+- `head` - array of head elements to add to the default template
+  output ([] by default)
+- `preambule` - text contents to embed before the translation output
+  (part of template containing head element by default)
+- `postambule` - text contents to embed after the translation output
+  (part of template by default)
+
+Per-class overrides
+-------------------
+
+Applying a per-class override via command line options works like this:
+```
+# see the following paragraph for all known block classes
+$ mmmdpp -o '"mapping"."Block::ClassName".override: <value, in JSON element form>' ...
+
+# i.e.
+$ mmmdpp -o '"mapping"."PointBlank::DOM::Paragraph".inline: true' ...
+```
+
+For library usage, these options roughly translate to the following hash, passed
+as the second argument to object initializer:
+```
+{
+    "mapping" => {
+        "PointBlank::DOM::Paragraph" => {
+            inline: true
+        }
+    }
+}
+```
+
+Following options can be applied to every class element:
+
+- `tag` - name of the tag this class should be mapped to. (i.e.
+  'PointBlank::DOM::Paragraph' => 'p', 'PointBlank::DOM::InlineEmphasis' =>
+  'em')      
+- `sanitize` - sanitize entities in text. shouldn't really be used anywhere
+  outside of text
+- `inline` - the tag should be considered self-closing
+- `codeblock` - special case. disables wordwrap, makes the block uninlined
+  regardless of containing tags.
+- `figcaption` - wrap tag into a `<figure>` tag. text contained in the tag is
+  copied into a caption.
+- `outer` - hash of parameters for an outer wrapping tag. can be defined
+  recursively. all options in this list apply.
+- `href` - add a href attribute. works only on links and classes containing
+  a `:uri` attribute
+- `title` - add a title attribute. works only on classes that have a
+  `:title` attribute
+- `style` - define an inline CSS style to embed into the tag.
+- `src` - add an src attribute. works only on images and classes containing
+  a `:uri` attribute
+- `alt` - add an alt attribute. works only on classes that have a
+  `:title` attribute
diff --git a/wiki/renderers/Plainterm.md b/wiki/renderers/Plainterm.md
new file mode 100644
index 0000000..bd0b760
--- /dev/null
+++ b/wiki/renderers/Plainterm.md
@@ -0,0 +1,131 @@
+Plainterm renderer
+==================
+
+Plainterm renderer renders markdown documents into a prettier format for reading
+in the terminal. It uses certain control codes to make it work. Styles applied
+to various elements can be changed.
+
+Applicable global options
+-------------------------
+
+Global options are applied to the root of the configuration hash for the
+renderer. They can be applied using the following pattern via command
+line:
+
+```
+$ mmmdpp -o '"nameOfGlobalOption": <value, in JSON element form>' ...
+
+# i.e.
+$ mmmdpp -o '"hsize": 65' ...
+```
+
+- `style` - override the style of certain elements. See "Style overrides"
+- `hsize` - horizontal size to align the contents to. Automatically
+   set to the width of the current terminal by default, or, if unavailable,
+   to 80 columns.
+
+Style overrides
+---------------
+
+Style overrides provide per-class overrides for element style. It's essentially
+a stylesheet applied to the element.
+
+Applying a style override via command line options works like this:
+```
+# see the following paragraph for all known block classes
+$ mmmdpp -o '"style"."Block::ClassName".override: <value, in JSON element form>' ...
+
+# i.e.
+$ mmmdpp -o '"style"."PointBlank::DOM::Paragraph".indent: false' ...
+```
+
+For library usage, these options roughly translate to the following hash, passed
+as the second argument to object initializer:
+```
+{
+    "style" => {
+        "PointBlank::DOM::Paragraph" => {
+            indent: false
+        }
+    }
+}
+```
+
+Applicable style overrides:
+- `indent` (boolean) - increase indentation
+- `increase_level` (boolean) - decrease horizontal space occupied (needed with
+  indent)
+- `center` (boolean) - center text
+- `bold` (boolean) - render text in bold
+- `italics` (boolean) - render text in italics
+- `strikethrough` (boolean) - render text with strikethrough
+- `bg` (text, #RGB) - set color background
+- `fg` (text, #RGB) - set color foreground
+- `box` (boolean) - render contents in an ascii box
+- `rjust` (boolean) - right-justify text
+- `extra_newlines` (boolean) - add extra newlines around the text block
+- `underline_block` (boolean) - underline text block, from left visual boundary
+  of text to right visual boundary of text
+- `underline_full_block` (boolean) - underline text block, from left border to
+  right border
+- `bullet` (boolean) - add bullet to block, used for bullet lists
+- `numbered` (boolean) - add numbered point to block, used for ordered lists
+- `leftline` (boolean) - draw a line on the left side of the block, top to
+  bottom
+
+Style defaults
+--------------
+
+These are the defaults applied to each class of text block
+
+- `PointBlank::DOM::Paragraph`:
+  - `indent`
+  - `increase_level`
+- `PointBlank::DOM::Text`:
+  - none applied by default
+- `PointBlank::DOM::SetextHeading1` (underline style of heading in markdown,
+  level 1)
+  - `center`
+  - `bold`
+  - `extra_newlines`
+  - `underline_full_block`
+- `PointBlank::DOM::SetextHeading2` (underline style of heading in markdown,
+  level 2)
+  - `center`
+  - `underline_block`
+- `PointBlank::DOM::ATXHeading1` (hash-symbol prefix style of heading,
+  level 1)
+  - (same as SetextHeading1)
+- `PointBlank::DOM::ATXHeading2` (hash-symbol heading, level 2)
+  - (same as SetextHeading2)
+- `PointBlank::DOM::ATXHeading3` (hash-symbol heading, level 3)
+  - `underline`
+  - `bold`
+- `PointBlank::DOM::ATXHeading4` (hash-symbol heading, level 4)
+  - `bold`
+  - `underline`
+- `PointBlank::DOM::ATXHeading5` (hash-symbol heading, level 5)
+  - `underline`
+- `PointBlank::DOM::ATXHeading6` (hash-symbol heading, level 6)
+  - `underline`
+- `PointBlank::DOM::InlineImage` (image link)
+  - `underline`
+- `PointBlank::DOM::InlineLink` (link)
+  - `underline`
+- `PointBlank::DOM::InlinePre` (inline code)
+  - none by default
+- `PointBlank::DOM::InlineEmphasis`
+  - `italics`
+- `PointBlank::DOM::InlineStrong` (strong emphasis)
+  - `bold`
+- `PointBlank::DOM::ULListElement` (element of an unordered list)
+  - `bullet`
+  - `increase_level`
+- `PointBlank::DOM::OLListElement` (element of an ordered list)
+  - `numbered`
+  - `increase_level`
+- `PointBlank::DOM::QuoteBlock`
+  - `leftline`
+  - `increase_level`
+- `PointBlank::DOM::HorizontalRule`
+  - `hrule`