diff --git a/Gemfile b/Gemfile
index 06bf9a1..4b06d65 100644
--- a/Gemfile
+++ b/Gemfile
@@ -47,6 +47,10 @@ gem "ferrum"
 
 # Math markup conversion (OMML ↔ MathML ↔ LaTeX ↔ AsciiMath)
 gem "plurimath", github: "jcasimir/plurimath", branch: "main"
+# Pin plurimath's own markup dependencies: newer releases restructure APIs
+# (e.g. mml drops `mml/configuration`) that this plurimath revision requires.
+gem "mml", "= 2.0.3"
+gem "lutaml-model", "= 0.7.7"
 
 group :development, :test do
   # See https://guides.rubyonrails.org/debugging_rails_applications.html#debugging-with-the-debug-gem
diff --git a/Gemfile.lock b/Gemfile.lock
index 455c9b7..942c879 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -15,7 +15,7 @@ GIT
 GEM
   remote: https://rubygems.org/
   specs:
-    action_text-trix (2.1.17)
+    action_text-trix (2.1.19)
       railties
     actioncable (8.1.3)
       actionpack (= 8.1.3)
@@ -89,7 +89,7 @@ GEM
       securerandom (>= 0.3)
       tzinfo (~> 2.0, >= 2.0.5)
       uri (>= 0.13.1)
-    addressable (2.8.9)
+    addressable (2.9.0)
       public_suffix (>= 2.0.2, < 8.0)
     ast (2.4.3)
     base64 (0.3.0)
@@ -105,7 +105,7 @@ GEM
     bundler-audit (0.9.3)
       bundler (>= 1.2.0)
       thor (~> 1.0)
-    concurrent-ruby (1.3.7)
+    concurrent-ruby (1.3.8)
     connection_pool (3.0.2)
     crass (1.0.7)
     date (3.5.1)
@@ -122,7 +122,7 @@ GEM
       sxp (~> 2.0)
       unicode-types (~> 1.8)
     ed25519 (1.4.0)
-    erb (6.0.5)
+    erb (6.0.6)
     erubi (1.13.1)
     et-orbi (1.4.0)
       tzinfo
@@ -203,8 +203,8 @@ GEM
       lutaml-model
       moxml
     moxml (0.1.10)
-    msgpack (1.8.1)
-    net-imap (0.6.3)
+    msgpack (1.8.3)
+    net-imap (0.6.4.1)
       date
       net-protocol
     net-pop (0.1.2)
@@ -256,7 +256,7 @@ GEM
       activesupport (>= 7.0.0)
       rack
     public_suffix (7.0.5)
-    puma (7.2.0)
+    puma (8.0.2)
       nio4r (~> 2.0)
     raabro (1.4.0)
     racc (1.8.1)
@@ -428,7 +428,7 @@ GEM
       bindex (>= 0.4.0)
       railties (>= 8.0.0)
     webrick (1.9.2)
-    websocket-driver (0.8.0)
+    websocket-driver (0.8.2)
       base64
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.5)
@@ -455,6 +455,8 @@ DEPENDENCIES
   importmap-rails
   jbuilder
   kamal
+  lutaml-model (= 0.7.7)
+  mml (= 2.0.3)
   pg (~> 1.1)
   plurimath!
   propshaft
diff --git a/config/routes.rb b/config/routes.rb
index 85e0c7b..00ef916 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -3,10 +3,10 @@
 
   root "grades#index"
 
-  resources :grades, only: [:show] do
-    resources :content_modules, only: [:show], path: "modules" do
-      resources :topics, only: [:show] do
-        resources :lessons, only: [:show]
+  resources :grades, only: [ :show ] do
+    resources :content_modules, only: [ :show ], path: "modules" do
+      resources :topics, only: [ :show ] do
+        resources :lessons, only: [ :show ]
       end
     end
   end
diff --git a/db/migrate/20260324160002_create_modules.rb b/db/migrate/20260324160002_create_modules.rb
index 47c5d7c..3a39c4f 100644
--- a/db/migrate/20260324160002_create_modules.rb
+++ b/db/migrate/20260324160002_create_modules.rb
@@ -10,7 +10,7 @@ def change
       t.timestamps
     end
 
-    add_index :content_modules, [:grade_id, :number], unique: true
-    add_index :content_modules, [:grade_id, :position]
+    add_index :content_modules, [ :grade_id, :number ], unique: true
+    add_index :content_modules, [ :grade_id, :position ]
   end
 end
diff --git a/db/migrate/20260324160003_create_topics.rb b/db/migrate/20260324160003_create_topics.rb
index 32eb0e8..3cd3a82 100644
--- a/db/migrate/20260324160003_create_topics.rb
+++ b/db/migrate/20260324160003_create_topics.rb
@@ -10,7 +10,7 @@ def change
       t.timestamps
     end
 
-    add_index :topics, [:content_module_id, :letter], unique: true
-    add_index :topics, [:content_module_id, :position]
+    add_index :topics, [ :content_module_id, :letter ], unique: true
+    add_index :topics, [ :content_module_id, :position ]
   end
 end
diff --git a/db/migrate/20260324160004_create_lessons.rb b/db/migrate/20260324160004_create_lessons.rb
index 4df5aec..8df15c2 100644
--- a/db/migrate/20260324160004_create_lessons.rb
+++ b/db/migrate/20260324160004_create_lessons.rb
@@ -9,7 +9,7 @@ def change
       t.timestamps
     end
 
-    add_index :lessons, [:topic_id, :number], unique: true
-    add_index :lessons, [:topic_id, :position]
+    add_index :lessons, [ :topic_id, :number ], unique: true
+    add_index :lessons, [ :topic_id, :position ]
   end
 end
diff --git a/db/migrate/20260324160009_create_assessments.rb b/db/migrate/20260324160009_create_assessments.rb
index d8761ca..9a51936 100644
--- a/db/migrate/20260324160009_create_assessments.rb
+++ b/db/migrate/20260324160009_create_assessments.rb
@@ -10,6 +10,6 @@ def change
       t.timestamps
     end
 
-    add_index :assessments, [:content_module_id, :assessment_type], unique: true
+    add_index :assessments, [ :content_module_id, :assessment_type ], unique: true
   end
 end
diff --git a/db/migrate/20260324160010_create_problems.rb b/db/migrate/20260324160010_create_problems.rb
index 044cce4..21ffba8 100644
--- a/db/migrate/20260324160010_create_problems.rb
+++ b/db/migrate/20260324160010_create_problems.rb
@@ -10,6 +10,6 @@ def change
       t.timestamps
     end
 
-    add_index :problems, [:source_type, :source_id, :position], unique: true
+    add_index :problems, [ :source_type, :source_id, :position ], unique: true
   end
 end
diff --git a/db/migrate/20260324160012_create_standard_taggings.rb b/db/migrate/20260324160012_create_standard_taggings.rb
index 2d1e005..5ab52de 100644
--- a/db/migrate/20260324160012_create_standard_taggings.rb
+++ b/db/migrate/20260324160012_create_standard_taggings.rb
@@ -7,7 +7,7 @@ def change
       t.timestamps
     end
 
-    add_index :standard_taggings, [:standard_id, :taggable_type, :taggable_id],
+    add_index :standard_taggings, [ :standard_id, :taggable_type, :taggable_id ],
               unique: true, name: "idx_standard_taggings_uniqueness"
   end
 end
diff --git a/db/migrate/20260324223010_create_supplemental_resources.rb b/db/migrate/20260324223010_create_supplemental_resources.rb
index ef76598..fd81960 100644
--- a/db/migrate/20260324223010_create_supplemental_resources.rb
+++ b/db/migrate/20260324223010_create_supplemental_resources.rb
@@ -14,7 +14,7 @@ def change
     end
 
     add_index :supplemental_resources,
-              [:resourceable_type, :resourceable_id, :resource_type],
+              [ :resourceable_type, :resourceable_id, :resource_type ],
               name: "idx_supplemental_resources_lookup"
     add_index :supplemental_resources, :resource_type
     add_index :supplemental_resources, :source
diff --git a/db/migrate/20260325120001_create_expressions.rb b/db/migrate/20260325120001_create_expressions.rb
index 277f786..720020e 100644
--- a/db/migrate/20260325120001_create_expressions.rb
+++ b/db/migrate/20260325120001_create_expressions.rb
@@ -15,7 +15,7 @@ def change
       t.timestamps
     end
 
-    add_index :expressions, [:source_type, :source_id, :position], unique: true,
+    add_index :expressions, [ :source_type, :source_id, :position ], unique: true,
               name: "idx_expressions_source_position"
     add_index :expressions, :conversion_status
   end
diff --git a/lib/engageny/html_parser.rb b/lib/engageny/html_parser.rb
index a15e9d5..a25713d 100644
--- a/lib/engageny/html_parser.rb
+++ b/lib/engageny/html_parser.rb
@@ -62,7 +62,7 @@ def self.wrap_section(head_html, section_html)
     def split_document
       # Find the boundary between head and body content
       body_match = @html.match(/\A(.*?<body[^>]*>)(.*)\z/m)
-      return ["", [], ""] unless body_match
+      return [ "", [], "" ] unless body_match
 
       head = body_match[1]
       body = body_match[2]
@@ -77,7 +77,7 @@ def split_document
       body_close = body.index("</body>") || body.length
 
       if section_starts.empty?
-        return [head + body[0...body_close], [], body[body_close..]]
+        return [ head + body[0...body_close], [], body[body_close..] ]
       end
 
       # Head includes everything up to and including the first section's start
@@ -92,7 +92,7 @@ def split_document
 
       tail = body[body_close..]
 
-      [full_head, sections, tail]
+      [ full_head, sections, tail ]
     end
 
     def find_student_section_indices
diff --git a/lib/engageny/math_converter.rb b/lib/engageny/math_converter.rb
index 682e58a..e217453 100644
--- a/lib/engageny/math_converter.rb
+++ b/lib/engageny/math_converter.rb
@@ -101,7 +101,7 @@ def manifest_summary
     # We keep only the final (inserted) content and discard deletions.
     def try_strip_track_changes(xml)
       # Check for ins/del in either namespace
-      return [xml, nil] unless xml.match?(/(?:<[mw]:ins\b|<[mw]:del\b)/)
+      return [ xml, nil ] unless xml.match?(/(?:<[mw]:ins\b|<[mw]:del\b)/)
 
       doc = Nokogiri::XML(xml)
       word_ns = "http://schemas.openxmlformats.org/wordprocessingml/2006/main"
@@ -110,7 +110,7 @@ def try_strip_track_changes(xml)
       changed = false
 
       # Remove <w:del> and <m:del> elements entirely (deleted content)
-      [["w", word_ns], ["m", math_ns]].each do |prefix, ns|
+      [ [ "w", word_ns ], [ "m", math_ns ] ].each do |prefix, ns|
         doc.xpath("//#{prefix}:del", prefix => ns).each do |del|
           del.remove
           changed = true
@@ -118,7 +118,7 @@ def try_strip_track_changes(xml)
       end
 
       # Unwrap <w:ins> and <m:ins> elements (keep children, remove wrapper)
-      [["w", word_ns], ["m", math_ns]].each do |prefix, ns|
+      [ [ "w", word_ns ], [ "m", math_ns ] ].each do |prefix, ns|
         doc.xpath("//#{prefix}:ins", prefix => ns).each do |ins|
           ins.children.each { |child| ins.add_previous_sibling(child) }
           ins.remove
@@ -126,7 +126,7 @@ def try_strip_track_changes(xml)
         end
       end
 
-      [doc.root.to_xml, changed ? FIXES[:strip_track_changes] : nil]
+      [ doc.root.to_xml, changed ? FIXES[:strip_track_changes] : nil ]
     end
 
     # Fix: Convert <m:sym> special symbol references to Unicode.
@@ -148,12 +148,12 @@ def try_strip_track_changes(xml)
       "Symbol:F070" => "\u03C0",    # pi π
       "Symbol:F071" => "\u03B8",    # theta θ
       "Symbol:F044" => "\u0394",    # Delta Δ
-      "Symbol:F053" => "\u03A3",    # Sigma Σ
+      "Symbol:F053" => "\u03A3"    # Sigma Σ
     }.freeze
 
     def try_sym_to_unicode(xml)
       # <w:sym> lives in the Word namespace, not math namespace
-      return [xml, nil] unless xml.match?(/(?:<[mw]:sym\b)/)
+      return [ xml, nil ] unless xml.match?(/(?:<[mw]:sym\b)/)
 
       doc = Nokogiri::XML(xml)
       changed = false
@@ -184,7 +184,7 @@ def try_sym_to_unicode(xml)
         end
       end
 
-      [doc.root.to_xml, changed ? FIXES[:sym_to_unicode] : nil]
+      [ doc.root.to_xml, changed ? FIXES[:sym_to_unicode] : nil ]
     end
 
     def extract_text(omml_xml)
diff --git a/lib/engageny/page_comparator.rb b/lib/engageny/page_comparator.rb
index 8fa0a92..f4f6df2 100644
--- a/lib/engageny/page_comparator.rb
+++ b/lib/engageny/page_comparator.rb
@@ -1,5 +1,6 @@
 require "ferrum"
 require "fileutils"
+require "zip"
 
 module Engageny
   class PageComparator
@@ -37,7 +38,7 @@ def screenshot_html
         browser_path: CHROME_PATH,
         headless: "new",
         timeout: 30,
-        window_size: [900, 1200]
+        window_size: [ 900, 1200 ]
       )
 
       begin
@@ -92,18 +93,14 @@ def find_original_pdf
       return nil unless zip_path.exist?
 
       # Find the PDF inside the ZIP
-      output = `unzip -l "#{zip_path}" 2>/dev/null | grep "#{pdf_name}" | grep -v Archived`
-      return nil if output.strip.empty?
-
-      # Extract the path from the unzip listing
-      zip_entry = output.strip.split(/\s+/, 4).last
+      zip_entry = Zip::File.open(zip_path.to_s) do |zip|
+        zip.glob("**/*#{pdf_name}").reject { |e| e.name.include?("Archived") }.first&.name
+      end
       return nil unless zip_entry
 
       dest = OUTPUT_DIR.join("original.pdf")
-      system("unzip", "-o", zip_path.to_s, zip_entry, "-d", OUTPUT_DIR.to_s)
+      Zip::File.open(zip_path.to_s) { |zip| zip.extract(zip_entry, dest.to_s) { true } }
 
-      extracted = OUTPUT_DIR.join(zip_entry)
-      FileUtils.cp(extracted, dest) if extracted.exist?
       dest.exist? ? dest : nil
     end
 
diff --git a/lib/tasks/engageny.rake b/lib/tasks/engageny.rake
index 268d3d8..22984c2 100644
--- a/lib/tasks/engageny.rake
+++ b/lib/tasks/engageny.rake
@@ -70,8 +70,8 @@ namespace :engageny do
         original.chars.each_with_index do |c, i|
           if reconstructed[i] != c
             puts "  First diff at byte #{i}"
-            puts "  Original:      #{original[[i - 30, 0].max..i + 30].inspect}"
-            puts "  Reconstructed: #{reconstructed[[i - 30, 0].max..i + 30].inspect}"
+            puts "  Original:      #{original[[ i - 30, 0 ].max..i + 30].inspect}"
+            puts "  Reconstructed: #{reconstructed[[ i - 30, 0 ].max..i + 30].inspect}"
             break
           end
         end
@@ -82,7 +82,7 @@ namespace :engageny do
   end
 
   desc "Visual comparison: screenshot HTML rendering and compare against original PDF"
-  task :compare, [:lesson_id] => :environment do |_t, args|
+  task :compare, [ :lesson_id ] => :environment do |_t, args|
     require_relative "../engageny/html_parser"
     require_relative "../engageny/html_normalizer"
     require "ferrum"
@@ -126,7 +126,7 @@ namespace :engageny do
       browser_path: "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome",
       headless: "new",
       timeout: 30,
-      window_size: [1000, 1400]
+      window_size: [ 1000, 1400 ]
     )
 
     browser.goto("data:text/html;charset=utf-8,#{ERB::Util.url_encode(html)}")
diff --git a/scripts/fetch_ccss_standards.rb b/scripts/fetch_ccss_standards.rb
index 672c31b..a3cb7f9 100644
--- a/scripts/fetch_ccss_standards.rb
+++ b/scripts/fetch_ccss_standards.rb
@@ -28,7 +28,7 @@
 }.freeze
 
 TARGET_GRADES = %w[04 05 06].freeze
-TARGET_GRADE_INTS = [4, 5, 6].freeze
+TARGET_GRADE_INTS = [ 4, 5, 6 ].freeze
 
 $stderr.puts "Fetching CCSS data from #{SOURCE_URL}..."
 raw = URI.open(SOURCE_URL).read
@@ -104,7 +104,7 @@
 end
 
 # Sort by grade, domain, then code
-standards.sort_by! { |s| [s[:grade_level], s[:domain_code], s[:code]] }
+standards.sort_by! { |s| [ s[:grade_level], s[:domain_code], s[:code] ] }
 
 output = {
   source: "Common Core State Standards via SirFizX/standards-data (GitHub)",