diff --git a/lib/prawn/svg/color.rb b/lib/prawn/svg/color.rb
index 0a744f5..8c2fe70 100644
--- a/lib/prawn/svg/color.rb
+++ b/lib/prawn/svg/color.rb
@@ -211,6 +211,43 @@ def parse(color_string, gradients = nil, color_mode = :rgb)
       result.compact
     end
 
+    def parse_color(value)
+      case value
+      in ['rgb', args]
+        return unless args.length == 3
+
+        rgb =
+          args.map do |arg|
+            number = to_float(arg, 2.55) or break
+            format('%02x', number.round.clamp(0, 255))
+          end
+
+        rgb && RGB.new(rgb.join)
+
+      in ['device-cmyk', args]
+        return unless args.length == 4
+
+        cymk =
+          args.map do |arg|
+            number = to_float(arg, 0.01) or break
+            (number * 100).clamp(0, 100)
+          end
+
+        cymk && CMYK.new(cymk)
+
+      in /\A#([0-9a-f])([0-9a-f])([0-9a-f])\z/i
+        RGB.new("#{$1 * 2}#{$2 * 2}#{$3 * 2}")
+
+      in /\A#[0-9a-f]{6}\z/i
+        RGB.new(value[1..])
+
+      in String => color
+        if (hex = HTML_COLORS[color.downcase])
+          hex_color(hex, nil) # TODO : color mode
+        end
+      end
+    end
+
     def css_color_to_prawn_color(color)
       parse(color).detect { |value| value.is_a?(RGB) || value.is_a?(CMYK) }&.value
     end
@@ -221,6 +258,15 @@ def default_color(color_mode)
 
     private
 
+    def to_float(string, percentage_multiplier)
+      if string[-1] == '%'
+        number = Float(string[0..-2], exception: false)
+        number && (number * percentage_multiplier)
+      else
+        Float(string, exception: false)
+      end
+    end
+
     def hex_color(hex, color_mode)
       if color_mode == :cmyk
         r, g, b = [hex[0..1], hex[2..3], hex[4..5]].map { |h| h.to_i(16) / 255.0 }
diff --git a/lib/prawn/svg/elements/base.rb b/lib/prawn/svg/elements/base.rb
index 7f4c7eb..6c29c25 100644
--- a/lib/prawn/svg/elements/base.rb
+++ b/lib/prawn/svg/elements/base.rb
@@ -182,7 +182,7 @@ def apply_colors
 
       next if [nil, 'inherit', 'none'].include?(color)
 
-      color = computed_properties.color if color == 'currentColor'
+      color = computed_properties.color if color == 'currentcolor'
 
       results = Prawn::SVG::Color.parse(color, document.gradients, document.color_mode)
 
diff --git a/lib/prawn/svg/elements/root.rb b/lib/prawn/svg/elements/root.rb
index 1cec90a..db5fd4c 100644
--- a/lib/prawn/svg/elements/root.rb
+++ b/lib/prawn/svg/elements/root.rb
@@ -8,7 +8,7 @@ def parse
   end
 
   def apply
-    if [nil, 'inherit', 'none', 'currentColor'].include?(properties.fill)
+    if [nil, 'inherit', 'none', 'currentcolor'].include?(properties.fill)
       add_call 'fill_color', Prawn::SVG::Color.default_color(@document.color_mode).value
     end
 
diff --git a/lib/prawn/svg/properties.rb b/lib/prawn/svg/properties.rb
index f83ab60..7976813 100644
--- a/lib/prawn/svg/properties.rb
+++ b/lib/prawn/svg/properties.rb
@@ -1,5 +1,5 @@
 class Prawn::SVG::Properties
-  Config = Struct.new(:default, :inheritable?, :keywords, :keyword_restricted?, :attr, :ivar)
+  Config = Struct.new(:default, :inheritable?, :valid_values, :attr, :ivar)
 
   EM = 16
   FONT_SIZES = {
@@ -13,35 +13,35 @@ class Prawn::SVG::Properties
   }.freeze
 
   PROPERTIES = {
-    'clip-path'         => Config.new('none', false, %w[inherit none]),
-    'color'             => Config.new('', true),
-    'display'           => Config.new('inline', false, %w[inherit inline none], true),
-    'fill'              => Config.new('black', true, %w[inherit none currentColor]),
-    'fill-opacity'      => Config.new('1', true),
-    'fill-rule'         => Config.new('nonzero', true, %w[inherit nonzero evenodd]),
-    'font-family'       => Config.new('sans-serif', true),
+    'clip-path'         => Config.new('none', false, ['none', :funciri]),
+    'color'             => Config.new('', true, [:color]),
+    'display'           => Config.new('inline', false, %w[inline none]),
+    'fill'              => Config.new('black', true, ['none', 'currentcolor', :paint]),
+    'fill-opacity'      => Config.new('1', true, [:number]),
+    'fill-rule'         => Config.new('nonzero', true, %w[nonzero evenodd]),
+    'font-family'       => Config.new('sans-serif', true, [:any]),
     'font-size'         => Config.new('medium', true,
-      %w[inherit xx-small x-small small medium large x-large xx-large larger smaller]),
-    'font-style'        => Config.new('normal', true, %w[inherit normal italic oblique], true),
-    'font-variant'      => Config.new('normal', true, %w[inherit normal small-caps], true),
-    'font-weight'       => Config.new('normal', true, %w[inherit normal bold 100 200 300 400 500 600 700 800 900], true), # bolder/lighter not supported
-    'letter-spacing'    => Config.new('normal', true, %w[inherit normal]),
-    'marker-end'        => Config.new('none', true, %w[inherit none]),
-    'marker-mid'        => Config.new('none', true, %w[inherit none]),
-    'marker-start'      => Config.new('none', true, %w[inherit none]),
-    'opacity'           => Config.new('1', false),
-    'overflow'          => Config.new('visible', false, %w[inherit visible hidden scroll auto], true),
-    'stop-color'        => Config.new('black', false, %w[inherit none currentColor]),
-    'stop-opacity'      => Config.new('1', false),
-    'stroke'            => Config.new('none', true, %w[inherit none currentColor]),
-    'stroke-dasharray'  => Config.new('none', true, %w[inherit none]),
-    'stroke-linecap'    => Config.new('butt', true, %w[inherit butt round square], true),
-    'stroke-linejoin'   => Config.new('miter', true, %w[inherit miter round bevel], true),
-    'stroke-opacity'    => Config.new('1', true),
-    'stroke-width'      => Config.new('1', true),
-    'text-anchor'       => Config.new('start', true, %w[inherit start middle end], true),
-    'text-decoration'   => Config.new('none', true, %w[inherit none underline], true),
-    'dominant-baseline' => Config.new('auto', true, %w[inherit auto middle], true)
+      [:positive_length, :positive_percentage, 'xx-small', 'x-small', 'small', 'medium', 'large', 'x-large', 'xx-large', 'larger', 'smaller']),
+    'font-style'        => Config.new('normal', true, %w[normal italic oblique]),
+    'font-variant'      => Config.new('normal', true, %w[normal small-caps]),
+    'font-weight'       => Config.new('normal', true, %w[normal bold 100 200 300 400 500 600 700 800 900]), # bolder/lighter not supported
+    'letter-spacing'    => Config.new('normal', true, [:length, 'normal']),
+    'marker-end'        => Config.new('none', true, [:funciri, 'none']),
+    'marker-mid'        => Config.new('none', true, [:funciri, 'none']),
+    'marker-start'      => Config.new('none', true, [:funciri, 'none']),
+    'opacity'           => Config.new('1', false, [:number]),
+    'overflow'          => Config.new('visible', false, %w[visible hidden scroll auto]),
+    'stop-color'        => Config.new('black', false, [:color_with_lcc, 'currentcolor']),
+    'stop-opacity'      => Config.new('1', false, [:number]),
+    'stroke'            => Config.new('none', true, ['none', 'currentcolor', :paint]),
+    'stroke-dasharray'  => Config.new('none', true, [:dasharray, 'none']),
+    'stroke-linecap'    => Config.new('butt', true, %w[butt round square]),
+    'stroke-linejoin'   => Config.new('miter', true, %w[miter round bevel]),
+    'stroke-opacity'    => Config.new('1', true, [:number]),
+    'stroke-width'      => Config.new('1', true, [:positive_length, :positive_percentage]),
+    'text-anchor'       => Config.new('start', true, %w[start middle end]),
+    'text-decoration'   => Config.new('none', true, %w[none underline]),
+    'dominant-baseline' => Config.new('auto', true, %w[auto middle])
   }.freeze
 
   PROPERTIES.each do |name, value|
@@ -64,17 +64,7 @@ def load_default_stylesheet
   end
 
   def set(name, value)
-    if (config = PROPERTIES[name.to_s.downcase])
-      value = value.strip
-      keyword = value.downcase
-      keywords = config.keywords || ['inherit']
-
-      if keywords.include?(keyword)
-        value = keyword
-      elsif config.keyword_restricted?
-        value = config.default
-      end
-
+    if (config = PROPERTIES[name.to_s.downcase]) && (value = parse_value(config, value.strip))
       instance_variable_set(config.ivar, value)
     end
   end
@@ -125,4 +115,81 @@ def compute_font_size_property(value)
       FONT_SIZES[value] || value.to_f
     end
   end
+
+  def parse_value(config, value)
+    keyword = value.downcase
+
+    return 'inherit' if keyword == 'inherit'
+
+    config.valid_values.detect do |type|
+      result = parse_value_with_type(type, value, keyword)
+      break result if result
+    end
+  end
+
+  NUMBER_REGEXP = /\A[+-]?\d*(\.\d+)?\z/.freeze
+  LENGTH_REGEXP = /\A[+-]?\d*(\.\d+)?(em|ex|px|in|cm|mm|pt|pc)?\z/i.freeze
+  PERCENTAGE_REGEXP = /\A[+-]?\d*(\.\d+)?%\z/.freeze
+  POSITIVE_LENGTH_REGEXP = /\A+?\d*(\.\d+)?(em|ex|px|in|cm|mm|pt|pc)?\z/i.freeze
+  POSITIVE_PERCENTAGE_REGEXP = /\A+?\d*(\.\d+)?%\z/.freeze
+
+  def parse_value_with_type(type, value, keyword)
+    case type
+    when String
+      type == keyword ? keyword : nil
+    when :color
+      values = Prawn::SVG::CSS::ValuesParser.parse(value)
+      if values.length == 1
+        Prawn::SVG::Color.parse_color(values[0]) ? value : nil
+      end
+    when :funciri
+      case Prawn::SVG::CSS::ValuesParser.parse(value)
+      in [['url', [_url]]]
+        value
+      else
+        nil
+      end
+    when :paint
+      case Prawn::SVG::CSS::ValuesParser.parse(value)
+      in [['url', [_url]]]
+        value
+      in [['url', [_url]], other]
+        ['none', 'currentcolor'].include?(other.downcase) || Prawn::SVG::Color.parse_color(other) ? value : nil
+      in [['url', [_url]], other, ['icc-color', _args]] # rubocop:disable Lint/DuplicateBranch
+        ['none', 'currentcolor'].include?(other.downcase) || Prawn::SVG::Color.parse_color(other) ? value : nil
+      in [other, ['icc-color', _args]]
+        Prawn::SVG::Color.parse_color(other) ? value : nil
+      in [other] # rubocop:disable Lint/DuplicateBranch
+        Prawn::SVG::Color.parse_color(other) ? value : nil
+      else
+        nil
+      end
+    when :color_with_lcc
+      case Prawn::SVG::CSS::ValuesParser.parse(value)
+      in [other, ['icc-color', _args]]
+        Prawn::SVG::Color.parse_color(other) ? value : nil
+      in [other] # rubocop:disable Lint/DuplicateBranch
+        Prawn::SVG::Color.parse_color(other) ? value : nil
+      else
+        nil
+      end
+    when :dasharray
+      values = value.split(Prawn::SVG::Elements::COMMA_WSP_REGEXP)
+      values.all? { |value| value.match(POSITIVE_LENGTH_REGEXP) || value.match(POSITIVE_PERCENTAGE_REGEXP) } ? value : nil
+    when :number
+      value.match(NUMBER_REGEXP) ? value : nil
+    when :length
+      value.match(LENGTH_REGEXP) ? value : nil
+    when :percentage
+      value.match(PERCENTAGE_REGEXP) ? value : nil
+    when :positive_length
+      value.match(POSITIVE_LENGTH_REGEXP) ? value : nil
+    when :positive_percentage
+      value.match(POSITIVE_PERCENTAGE_REGEXP) ? value : nil
+    when :any
+      value
+    else
+      raise "Unknown valid value type: #{type}"
+    end
+  end
 end
diff --git a/spec/prawn/svg/elements/base_spec.rb b/spec/prawn/svg/elements/base_spec.rb
index 98452a8..b0ab34e 100644
--- a/spec/prawn/svg/elements/base_spec.rb
+++ b/spec/prawn/svg/elements/base_spec.rb
@@ -139,7 +139,7 @@
 
     it "uses the color attribute if 'currentColor' fill attribute provided" do
       expect(element).to receive(:add_call).with('fill_color', 'ff0000')
-      element.properties.fill = 'currentColor'
+      element.properties.fill = 'currentcolor'
       element.state.computed_properties.color = 'red'
       subject
     end
diff --git a/spec/prawn/svg/properties_spec.rb b/spec/prawn/svg/properties_spec.rb
index cc2f168..122f1a2 100644
--- a/spec/prawn/svg/properties_spec.rb
+++ b/spec/prawn/svg/properties_spec.rb
@@ -33,9 +33,13 @@
       expect(subject.color).to eq 'Red'
     end
 
-    it "sets a 'keyword restricted' property to its default if the value doesn't match a keyword" do
-      subject.set('stroke-linecap', 'invalid')
-      expect(subject.stroke_linecap).to eq 'butt'
+    it 'ignores invalid values, retaining any previously set value' do
+      subject.set('display', 'invalid')
+      expect(subject.display).to be nil
+      subject.set('display', 'none')
+      expect(subject.display).to eq 'none'
+      subject.set('display', 'invalid')
+      expect(subject.display).to eq 'none'
     end
   end