diff --git a/README.md b/README.md
index 6d896ac..80a2650 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # preview.nvim
 
-**Universal previewer for Neovim**
+**Universal document previewer for Neovim**
 
 An extensible framework for compiling and previewing _any_ documents (LaTeX,
 Typst, Markdown, etc.)—diagnostics included.
@@ -81,8 +81,3 @@ vim.g.preview = {
   typst = { open = { 'sioyek', '--new-instance' } },
 }
 ```
-
-**Q: How do I set up SyncTeX (forward/inverse search)?**
-
-See `:help preview-synctex` for full recipes covering Zathura, Sioyek, and
-Okular.
diff --git a/doc/preview.txt b/doc/preview.txt
index 3912a41..383a8f5 100644
--- a/doc/preview.txt
+++ b/doc/preview.txt
@@ -22,12 +22,10 @@ CONTENTS                                                   *preview-contents*
   3. Install ............................................... |preview-install|
   4. Configuration ........................................... |preview-config|
   5. Presets ............................................... |preview-presets|
-     - Math rendering ....................................... |preview-math|
   6. Commands ............................................. |preview-commands|
   7. Lua API ................................................... |preview-api|
   8. Events ............................................... |preview-events|
   9. Health ............................................... |preview-health|
-  10. SyncTeX ............................................. |preview-synctex|
 
 ==============================================================================
 REQUIREMENTS                                           *preview-requirements*
@@ -70,10 +68,6 @@ Provider fields: ~
                                         receives a |preview.Context| and
                                         returns a string[].
 
-  {extra_args}       (string[]|function) Appended to {args} after evaluation.
-                                        Useful for adding flags to a preset
-                                        without replacing its defaults.
-
   {cwd}              (string|function)  Working directory. If a function,
                                         receives a |preview.Context|.
                                         Default: git root or file directory.
@@ -190,33 +184,6 @@ override individual fields by passing a table instead: >lua
   `mermaid`            mmdc → SVG (Mermaid diagrams, `.mmd`)
   `quarto`             quarto render → HTML (scientific publishing)
 
-Math rendering (pandoc presets): ~
-                                                        *preview-math*
-
-The `markdown` and `github` presets use `--mathml` by default, which converts
-TeX math to native MathML markup rendered by the browser. This is the only
-math option compatible with `--embed-resources` (self-contained HTML).
-
-`--mathjax` and `--katex` insert `<script>` tags that load JavaScript and
-fonts from a CDN at runtime. Pandoc's `--embed-resources` cannot inline these
-dynamic dependencies, so math fails to render in the output.
-
-To use KaTeX or MathJax instead, override `args` to drop `--embed-resources`
-(the output will require internet access): >lua
-
-    vim.g.preview = {
-      github = {
-        args = function(ctx)
-          return {
-            '-f', 'gfm', ctx.file, '-s', '--katex',
-            '--css', 'https://cdn.jsdelivr.net/gh/pixelbrackets/gfm-stylesheet@master/dist/gfm.css',
-            '-o', ctx.output,
-          }
-        end,
-      },
-    }
-<
-
 ==============================================================================
 COMMANDS                                                  *preview-commands*
 
@@ -305,116 +272,5 @@ Checks: ~
 - Each configured provider's binary is executable
 - Each configured provider's opener binary (if any) is executable
 
-==============================================================================
-SYNCTEX                                                    *preview-synctex*
-
-SyncTeX enables bidirectional navigation between LaTeX source and the
-compiled PDF. The `latex` preset compiles with `-synctex=1` by default.
-
-Forward search (editor -> viewer) requires caching the output path.
-Inverse search (viewer -> editor) requires a fixed Neovim server socket.
-
-The following configs leverage the below basic setup: ~
-
->lua
-    vim.fn.serverstart('/tmp/nvim-preview.sock')
-
-    local synctex_pdf = {}
-    vim.api.nvim_create_autocmd('User', {
-      pattern = 'PreviewCompileSuccess',
-      callback = function(args)
-        synctex_pdf[args.data.bufnr] = args.data.output
-      end,
-    })
-<
-
-The recipes below bind `<leader>s` for forward search. To scroll the PDF
-automatically on cursor movement, call the forward search function from a
-|CursorMoved| or |CursorHold| autocmd instead.
-
-Viewer-specific recipes: ~
-
-                                                    *preview-synctex-zathura*
-Zathura ~
-
-Inverse search: Ctrl+click.
-
->lua
-    vim.keymap.set('n', '<leader>s', function()
-      local pdf = synctex_pdf[vim.api.nvim_get_current_buf()]
-      if pdf then
-        vim.fn.jobstart({
-          'zathura', '--synctex-forward',
-          vim.fn.line('.') .. ':0:' .. vim.fn.expand('%:p'), pdf,
-        })
-      end
-    end)
-
-    vim.g.preview = {
-      latex = {
-        open = {
-          'zathura',
-          '--synctex-editor-command',
-          'nvim --server /tmp/nvim-preview.sock'
-            .. [[ --remote-expr "execute('b +%{line} %{input}')"]],
-        },
-      },
-    }
-<
-
-                                                     *preview-synctex-sioyek*
-Sioyek ~
-
-Inverse search: right-click with synctex mode active.
-
-Add to `~/.config/sioyek/prefs_user.config`: >
-    inverse_search_command nvim --server /tmp/nvim-preview.sock --remote-expr "execute('b +%2 %1')"
-<
-
->lua
-    vim.keymap.set('n', '<leader>s', function()
-      local pdf = synctex_pdf[vim.api.nvim_get_current_buf()]
-      if pdf then
-        vim.fn.jobstart({
-          'sioyek',
-          '--instance-name', 'preview',
-          '--forward-search-file', vim.fn.expand('%:p'),
-          '--forward-search-line', tostring(vim.fn.line('.')),
-          pdf,
-        })
-      end
-    end)
-
-    vim.g.preview = {
-      latex = {
-        open = { 'sioyek', '--instance-name', 'preview' },
-      },
-    }
-<
-
-                                                     *preview-synctex-okular*
-Okular ~
-
-Inverse search (Shift+click): one-time GUI setup via
-Settings -> Configure Okular -> Editor -> Custom Text Editor: >
-    nvim --server /tmp/nvim-preview.sock --remote-expr "execute('b +%l %f')"
-<
-
->lua
-    vim.keymap.set('n', '<leader>s', function()
-      local pdf = synctex_pdf[vim.api.nvim_get_current_buf()]
-      if pdf then
-        vim.fn.jobstart({
-          'okular', '--unique',
-          ('%s#src:%d:%s'):format(pdf, vim.fn.line('.'), vim.fn.expand('%:p')),
-        })
-      end
-    end)
-
-    vim.g.preview = {
-      latex = { open = { 'okular', '--unique' } },
-    }
-<
-
 ==============================================================================
  vim:tw=78:ts=8:ft=help:norl:
diff --git a/flake.nix b/flake.nix
index 539840f..636f4d0 100644
--- a/flake.nix
+++ b/flake.nix
@@ -19,8 +19,7 @@
     {
       formatter = forEachSystem (pkgs: pkgs.nixfmt-tree);
 
-      devShells = forEachSystem (
-        pkgs:
+      devShells = forEachSystem (pkgs:
         let
           devTools = [
             (pkgs.luajit.withPackages (
@@ -49,11 +48,8 @@
               pkgs.quarto
               pkgs.plantuml
               pkgs.mermaid-cli
-              pkgs.zathura
-              pkgs.sioyek
             ];
           };
-        }
-      );
+        });
     };
 }
diff --git a/lua/preview/compiler.lua b/lua/preview/compiler.lua
index 5480d57..a193ad2 100644
--- a/lua/preview/compiler.lua
+++ b/lua/preview/compiler.lua
@@ -3,102 +3,45 @@ local M = {}
 local diagnostic = require('preview.diagnostic')
 local log = require('preview.log')
 
----@class preview.BufState
----@field watching boolean
----@field process? table
----@field is_reload? boolean
----@field provider? string
----@field output? string
----@field viewer? table
----@field viewer_open? boolean
----@field open_watcher? uv.uv_fs_event_t
----@field debounce? uv.uv_timer_t
----@field bwp_autocmd? integer
----@field unload_autocmd? integer
+---@type table<integer, preview.Process>
+local active = {}
 
----@type table<integer, preview.BufState>
-local state = {}
+---@type table<integer, integer>
+local watching = {}
+
+---@type table<integer, true>
+local opened = {}
+
+---@type table<integer, string>
+local last_output = {}
+
+---@type table<integer, table>
+local viewer_procs = {}
+
+---@type table<integer, uv.uv_fs_event_t>
+local open_watchers = {}
+
+local debounce_timers = {}
 
 local DEBOUNCE_MS = 500
 
----@param bufnr integer
----@return preview.BufState
-local function get_state(bufnr)
-  if not state[bufnr] then
-    state[bufnr] = { watching = false }
-  end
-  return state[bufnr]
-end
-
 ---@param bufnr integer
 local function stop_open_watcher(bufnr)
-  local s = state[bufnr]
-  if not (s and s.open_watcher) then
-    return
+  local w = open_watchers[bufnr]
+  if w then
+    w:stop()
+    w:close()
+    open_watchers[bufnr] = nil
   end
-  s.open_watcher:stop()
-  s.open_watcher:close()
-  s.open_watcher = nil
 end
 
 ---@param bufnr integer
 local function close_viewer(bufnr)
-  local s = state[bufnr]
-  if not (s and s.viewer) then
-    return
-  end
-  s.viewer:kill('sigterm')
-  s.viewer = nil
-end
-
----@param bufnr integer
----@param name string
----@param provider preview.ProviderConfig
----@param ctx preview.Context
----@param output string
-local function handle_errors(bufnr, name, provider, ctx, output)
-  local errors_mode = provider.errors
-  if errors_mode == nil then
-    errors_mode = 'diagnostic'
-  end
-  if not (provider.error_parser and errors_mode) then
-    return
-  end
-  if errors_mode == 'diagnostic' then
-    diagnostic.set(bufnr, name, provider.error_parser, output, ctx)
-  elseif errors_mode == 'quickfix' then
-    local ok, diags = pcall(provider.error_parser, output, ctx)
-    if ok and diags and #diags > 0 then
-      local items = {}
-      for _, d in ipairs(diags) do
-        table.insert(items, {
-          bufnr = bufnr,
-          lnum = d.lnum + 1,
-          col = d.col + 1,
-          text = d.message,
-          type = d.severity == vim.diagnostic.severity.WARN and 'W' or 'E',
-        })
-      end
-      vim.fn.setqflist(items, 'r')
-      local win = vim.fn.win_getid()
-      vim.cmd.cwindow()
-      vim.fn.win_gotoid(win)
-    end
-  end
-end
-
----@param bufnr integer
----@param provider preview.ProviderConfig
-local function clear_errors(bufnr, provider)
-  local errors_mode = provider.errors
-  if errors_mode == nil then
-    errors_mode = 'diagnostic'
-  end
-  if errors_mode == 'diagnostic' then
-    diagnostic.clear(bufnr)
-  elseif errors_mode == 'quickfix' then
-    vim.fn.setqflist({}, 'r')
-    vim.cmd.cwindow()
+  local obj = viewer_procs[bufnr]
+  if obj then
+    local kill = obj.kill
+    kill(obj, 'sigterm')
+    viewer_procs[bufnr] = nil
   end
 end
 
@@ -111,23 +54,7 @@ local function do_open(bufnr, output_file, open_config)
   elseif type(open_config) == 'table' then
     local open_cmd = vim.list_extend({}, open_config)
     table.insert(open_cmd, output_file)
-    log.dbg('opening viewer for buffer %d: %s', bufnr, table.concat(open_cmd, ' '))
-    local proc
-    proc = vim.system(
-      open_cmd,
-      {},
-      vim.schedule_wrap(function()
-        local s = state[bufnr]
-        if s and s.viewer == proc then
-          log.dbg('viewer exited for buffer %d, resetting viewer_open', bufnr)
-          s.viewer = nil
-          s.viewer_open = nil
-        else
-          log.dbg('viewer exited for buffer %d (stale proc, ignoring)', bufnr)
-        end
-      end)
-    )
-    get_state(bufnr).viewer = proc
+    viewer_procs[bufnr] = vim.system(open_cmd)
   end
 end
 
@@ -163,30 +90,10 @@ local function resolve_reload_cmd(provider, ctx)
   return nil
 end
 
----@param bufnr integer
----@param s preview.BufState
-local function stop_watching(bufnr, s)
-  s.watching = false
-  M.stop(bufnr)
-  stop_open_watcher(bufnr)
-  close_viewer(bufnr)
-  s.viewer_open = nil
-  if s.bwp_autocmd then
-    vim.api.nvim_del_autocmd(s.bwp_autocmd)
-    s.bwp_autocmd = nil
-  end
-  if s.debounce then
-    s.debounce:stop()
-    s.debounce:close()
-    s.debounce = nil
-  end
-end
-
 ---@param bufnr integer
 ---@param name string
 ---@param provider preview.ProviderConfig
 ---@param ctx preview.Context
----@param opts? {oneshot?: boolean}
 function M.compile(bufnr, name, provider, ctx, opts)
   opts = opts or {}
 
@@ -202,9 +109,7 @@ function M.compile(bufnr, name, provider, ctx, opts)
     vim.cmd('silent! update')
   end
 
-  local s = get_state(bufnr)
-
-  if s.process then
+  if active[bufnr] then
     log.dbg('killing existing process for buffer %d before recompile', bufnr)
     M.stop(bufnr)
   end
@@ -222,7 +127,7 @@ function M.compile(bufnr, name, provider, ctx, opts)
   end
 
   if output_file ~= '' then
-    s.output = output_file
+    last_output[bufnr] = output_file
   end
 
   local reload_cmd
@@ -250,20 +155,74 @@ function M.compile(bufnr, name, provider, ctx, opts)
             return
           end
           stderr_acc[#stderr_acc + 1] = data
-          handle_errors(bufnr, name, provider, ctx, table.concat(stderr_acc))
+          local errors_mode = provider.errors
+          if errors_mode == nil then
+            errors_mode = 'diagnostic'
+          end
+          if provider.error_parser and errors_mode then
+            local output = table.concat(stderr_acc)
+            if errors_mode == 'diagnostic' then
+              diagnostic.set(bufnr, name, provider.error_parser, output, ctx)
+            elseif errors_mode == 'quickfix' then
+              local ok, diags = pcall(provider.error_parser, output, ctx)
+              if ok and diags and #diags > 0 then
+                local items = {}
+                for _, d in ipairs(diags) do
+                  table.insert(items, {
+                    bufnr = bufnr,
+                    lnum = d.lnum + 1,
+                    col = d.col + 1,
+                    text = d.message,
+                    type = d.severity == vim.diagnostic.severity.WARN and 'W' or 'E',
+                  })
+                end
+                vim.fn.setqflist(items, 'r')
+                local win = vim.fn.win_getid()
+                vim.cmd.cwindow()
+                vim.fn.win_gotoid(win)
+              end
+            end
+          end
         end),
       },
       vim.schedule_wrap(function(result)
-        local cs = state[bufnr]
-        if cs and cs.process == obj then
-          cs.process = nil
+        if active[bufnr] and active[bufnr].obj == obj then
+          active[bufnr] = nil
         end
         if not vim.api.nvim_buf_is_valid(bufnr) then
           return
         end
+
         if result.code ~= 0 then
           log.dbg('long-running process failed for buffer %d (exit code %d)', bufnr, result.code)
-          handle_errors(bufnr, name, provider, ctx, (result.stdout or '') .. (result.stderr or ''))
+          local errors_mode = provider.errors
+          if errors_mode == nil then
+            errors_mode = 'diagnostic'
+          end
+          if provider.error_parser and errors_mode then
+            local output = (result.stdout or '') .. (result.stderr or '')
+            if errors_mode == 'diagnostic' then
+              diagnostic.set(bufnr, name, provider.error_parser, output, ctx)
+            elseif errors_mode == 'quickfix' then
+              local ok, diagnostics = pcall(provider.error_parser, output, ctx)
+              if ok and diagnostics and #diagnostics > 0 then
+                local items = {}
+                for _, d in ipairs(diagnostics) do
+                  table.insert(items, {
+                    bufnr = bufnr,
+                    lnum = d.lnum + 1,
+                    col = d.col + 1,
+                    text = d.message,
+                    type = d.severity == vim.diagnostic.severity.WARN and 'W' or 'E',
+                  })
+                end
+                vim.fn.setqflist(items, 'r')
+                local win = vim.fn.win_getid()
+                vim.cmd.cwindow()
+                vim.fn.win_gotoid(win)
+              end
+            end
+          end
           vim.api.nvim_exec_autocmds('User', {
             pattern = 'PreviewCompileFailed',
             data = {
@@ -277,7 +236,7 @@ function M.compile(bufnr, name, provider, ctx, opts)
       end)
     )
 
-    if provider.open and not opts.oneshot and not s.viewer_open and output_file ~= '' then
+    if provider.open and not opts.oneshot and not opened[bufnr] and output_file ~= '' then
       local pre_stat = vim.uv.fs_stat(output_file)
       local pre_mtime = pre_stat and pre_stat.mtime.sec or 0
       local out_dir = vim.fn.fnamemodify(output_file, ':h')
@@ -285,7 +244,7 @@ function M.compile(bufnr, name, provider, ctx, opts)
       stop_open_watcher(bufnr)
       local watcher = vim.uv.new_fs_event()
       if watcher then
-        s.open_watcher = watcher
+        open_watchers[bufnr] = watcher
         watcher:start(
           out_dir,
           {},
@@ -293,12 +252,8 @@ function M.compile(bufnr, name, provider, ctx, opts)
             if err or vim.fn.fnamemodify(filename or '', ':t') ~= out_name then
               return
             end
-            local cs = state[bufnr]
-            if not cs then
-              return
-            end
-            if cs.viewer_open then
-              log.dbg('watcher fired for buffer %d but viewer already open', bufnr)
+            if opened[bufnr] then
+              stop_open_watcher(bufnr)
               return
             end
             if not vim.api.nvim_buf_is_valid(bufnr) then
@@ -307,27 +262,41 @@ function M.compile(bufnr, name, provider, ctx, opts)
             end
             local new_stat = vim.uv.fs_stat(output_file)
             if not (new_stat and new_stat.mtime.sec > pre_mtime) then
-              log.dbg(
-                'watcher fired for buffer %d but mtime not newer (%d <= %d)',
-                bufnr,
-                new_stat and new_stat.mtime.sec or 0,
-                pre_mtime
-              )
               return
             end
-            log.dbg('watcher opening viewer for buffer %d', bufnr)
-            cs.viewer_open = true
+            stop_open_watcher(bufnr)
             stderr_acc = {}
-            clear_errors(bufnr, provider)
+            local errors_mode = provider.errors
+            if errors_mode == nil then
+              errors_mode = 'diagnostic'
+            end
+            if errors_mode == 'diagnostic' then
+              diagnostic.clear(bufnr)
+            elseif errors_mode == 'quickfix' then
+              vim.fn.setqflist({}, 'r')
+              vim.cmd.cwindow()
+            end
             do_open(bufnr, output_file, provider.open)
+            opened[bufnr] = true
           end)
         )
       end
     end
 
-    s.process = obj
-    s.provider = name
-    s.is_reload = true
+    active[bufnr] = { obj = obj, provider = name, output_file = output_file, is_reload = true }
+
+    vim.api.nvim_create_autocmd('BufUnload', {
+      buffer = bufnr,
+      once = true,
+      callback = function()
+        M.stop(bufnr)
+        stop_open_watcher(bufnr)
+        if not provider.detach then
+          close_viewer(bufnr)
+        end
+        last_output[bufnr] = nil
+      end,
+    })
 
     vim.api.nvim_exec_autocmds('User', {
       pattern = 'PreviewCompileStarted',
@@ -340,27 +309,37 @@ function M.compile(bufnr, name, provider, ctx, opts)
   if provider.args then
     vim.list_extend(cmd, eval_list(provider.args, resolved_ctx))
   end
-  if provider.extra_args then
-    vim.list_extend(cmd, eval_list(provider.extra_args, resolved_ctx))
-  end
 
   log.dbg('compiling buffer %d with provider "%s": %s', bufnr, name, table.concat(cmd, ' '))
 
   local obj
   obj = vim.system(
     cmd,
-    { cwd = cwd, env = provider.env },
+    {
+      cwd = cwd,
+      env = provider.env,
+    },
     vim.schedule_wrap(function(result)
-      local cs = state[bufnr]
-      if cs and cs.process == obj then
-        cs.process = nil
+      if active[bufnr] and active[bufnr].obj == obj then
+        active[bufnr] = nil
       end
       if not vim.api.nvim_buf_is_valid(bufnr) then
         return
       end
+
+      local errors_mode = provider.errors
+      if errors_mode == nil then
+        errors_mode = 'diagnostic'
+      end
+
       if result.code == 0 then
         log.dbg('compilation succeeded for buffer %d', bufnr)
-        clear_errors(bufnr, provider)
+        if errors_mode == 'diagnostic' then
+          diagnostic.clear(bufnr)
+        elseif errors_mode == 'quickfix' then
+          vim.fn.setqflist({}, 'r')
+          vim.cmd.cwindow()
+        end
         vim.api.nvim_exec_autocmds('User', {
           pattern = 'PreviewCompileSuccess',
           data = { bufnr = bufnr, provider = name, output = output_file },
@@ -371,21 +350,42 @@ function M.compile(bufnr, name, provider, ctx, opts)
           r.inject(output_file)
           r.broadcast()
         end
-        cs = state[bufnr]
         if
           provider.open
           and not opts.oneshot
-          and cs
-          and not cs.viewer_open
+          and not opened[bufnr]
           and output_file ~= ''
           and vim.uv.fs_stat(output_file)
         then
-          cs.viewer_open = true
           do_open(bufnr, output_file, provider.open)
+          opened[bufnr] = true
         end
       else
         log.dbg('compilation failed for buffer %d (exit code %d)', bufnr, result.code)
-        handle_errors(bufnr, name, provider, ctx, (result.stdout or '') .. (result.stderr or ''))
+        if provider.error_parser and errors_mode then
+          local output = (result.stdout or '') .. (result.stderr or '')
+          if errors_mode == 'diagnostic' then
+            diagnostic.set(bufnr, name, provider.error_parser, output, ctx)
+          elseif errors_mode == 'quickfix' then
+            local ok, diagnostics = pcall(provider.error_parser, output, ctx)
+            if ok and diagnostics and #diagnostics > 0 then
+              local items = {}
+              for _, d in ipairs(diagnostics) do
+                table.insert(items, {
+                  bufnr = bufnr,
+                  lnum = d.lnum + 1,
+                  col = d.col + 1,
+                  text = d.message,
+                  type = d.severity == vim.diagnostic.severity.WARN and 'W' or 'E',
+                })
+              end
+              vim.fn.setqflist(items, 'r')
+              local win = vim.fn.win_getid()
+              vim.cmd.cwindow()
+              vim.fn.win_gotoid(win)
+            end
+          end
+        end
         vim.api.nvim_exec_autocmds('User', {
           pattern = 'PreviewCompileFailed',
           data = {
@@ -399,9 +399,19 @@ function M.compile(bufnr, name, provider, ctx, opts)
     end)
   )
 
-  s.process = obj
-  s.provider = name
-  s.is_reload = false
+  active[bufnr] = { obj = obj, provider = name, output_file = output_file }
+
+  vim.api.nvim_create_autocmd('BufUnload', {
+    buffer = bufnr,
+    once = true,
+    callback = function()
+      M.stop(bufnr)
+      if not provider.detach then
+        close_viewer(bufnr)
+      end
+      last_output[bufnr] = nil
+    end,
+  })
 
   vim.api.nvim_exec_autocmds('User', {
     pattern = 'PreviewCompileStarted',
@@ -411,37 +421,39 @@ end
 
 ---@param bufnr integer
 function M.stop(bufnr)
-  local s = state[bufnr]
-  if not s then
-    return
-  end
-  local obj = s.process
-  if not obj then
+  local proc = active[bufnr]
+  if not proc then
     return
   end
   log.dbg('stopping process for buffer %d', bufnr)
-  obj:kill('sigterm')
+  ---@type fun(self: table, signal: string|integer)
+  local kill = proc.obj.kill
+  kill(proc.obj, 'sigterm')
 
   local timer = vim.uv.new_timer()
   if timer then
     timer:start(5000, 0, function()
       timer:close()
-      local cs = state[bufnr]
-      if cs and cs.process == obj then
-        obj:kill('sigkill')
-        cs.process = nil
+      if active[bufnr] and active[bufnr].obj == proc.obj then
+        kill(proc.obj, 'sigkill')
+        active[bufnr] = nil
       end
     end)
   end
 end
 
 function M.stop_all()
-  for bufnr, s in pairs(state) do
-    stop_watching(bufnr, s)
-    if s.unload_autocmd then
-      vim.api.nvim_del_autocmd(s.unload_autocmd)
-    end
-    state[bufnr] = nil
+  for bufnr, _ in pairs(active) do
+    M.stop(bufnr)
+  end
+  for bufnr, _ in pairs(watching) do
+    M.unwatch(bufnr)
+  end
+  for bufnr, _ in pairs(open_watchers) do
+    stop_open_watcher(bufnr)
+  end
+  for bufnr, _ in pairs(viewer_procs) do
+    close_viewer(bufnr)
   end
   require('preview.reload').stop()
 end
@@ -452,77 +464,76 @@ end
 ---@param ctx_builder fun(bufnr: integer): preview.Context
 function M.toggle(bufnr, name, provider, ctx_builder)
   local is_longrunning = type(provider.reload) == 'table' or type(provider.reload) == 'function'
-  local s = get_state(bufnr)
 
-  if s.watching then
-    local output = s.output
-    if not s.viewer_open and provider.open and output and vim.uv.fs_stat(output) then
-      log.dbg('toggle reopen viewer for buffer %d', bufnr)
-      s.viewer_open = true
-      do_open(bufnr, output, provider.open)
-    else
-      log.dbg('toggle off for buffer %d', bufnr)
-      stop_watching(bufnr, s)
+  if is_longrunning then
+    if active[bufnr] then
+      M.stop(bufnr)
       vim.notify('[preview.nvim]: watching stopped', vim.log.levels.INFO)
+    else
+      M.compile(bufnr, name, provider, ctx_builder(bufnr))
+      vim.notify('[preview.nvim]: watching with "' .. name .. '"', vim.log.levels.INFO)
     end
     return
   end
 
-  log.dbg('toggle on for buffer %d', bufnr)
-  s.watching = true
-
-  if s.unload_autocmd then
-    vim.api.nvim_del_autocmd(s.unload_autocmd)
+  if watching[bufnr] then
+    M.unwatch(bufnr)
+    vim.notify('[preview.nvim]: watching stopped', vim.log.levels.INFO)
+    return
   end
-  s.unload_autocmd = vim.api.nvim_create_autocmd('BufUnload', {
+
+  local au_id = vim.api.nvim_create_autocmd('BufWritePost', {
+    buffer = bufnr,
+    callback = function()
+      if debounce_timers[bufnr] then
+        debounce_timers[bufnr]:stop()
+      else
+        debounce_timers[bufnr] = vim.uv.new_timer()
+      end
+      debounce_timers[bufnr]:start(
+        DEBOUNCE_MS,
+        0,
+        vim.schedule_wrap(function()
+          local ctx = ctx_builder(bufnr)
+          M.compile(bufnr, name, provider, ctx)
+        end)
+      )
+    end,
+  })
+
+  watching[bufnr] = au_id
+  log.dbg('watching buffer %d with provider "%s"', bufnr, name)
+  vim.notify('[preview.nvim]: watching with "' .. name .. '"', vim.log.levels.INFO)
+
+  vim.api.nvim_create_autocmd('BufUnload', {
     buffer = bufnr,
     once = true,
     callback = function()
-      M.stop(bufnr)
+      M.unwatch(bufnr)
       stop_open_watcher(bufnr)
       if not provider.detach then
         close_viewer(bufnr)
       end
-      state[bufnr] = nil
+      opened[bufnr] = nil
     end,
   })
 
-  if not is_longrunning then
-    s.bwp_autocmd = vim.api.nvim_create_autocmd('BufWritePost', {
-      buffer = bufnr,
-      callback = function()
-        local ds = state[bufnr]
-        if not ds then
-          return
-        end
-        if ds.debounce then
-          ds.debounce:stop()
-        else
-          ds.debounce = vim.uv.new_timer()
-        end
-        ds.debounce:start(
-          DEBOUNCE_MS,
-          0,
-          vim.schedule_wrap(function()
-            M.compile(bufnr, name, provider, ctx_builder(bufnr))
-          end)
-        )
-      end,
-    })
-    log.dbg('watching buffer %d with provider "%s"', bufnr, name)
-  end
-
-  vim.notify('[preview.nvim]: watching with "' .. name .. '"', vim.log.levels.INFO)
   M.compile(bufnr, name, provider, ctx_builder(bufnr))
 end
 
 ---@param bufnr integer
 function M.unwatch(bufnr)
-  local s = state[bufnr]
-  if not s then
+  local au_id = watching[bufnr]
+  if not au_id then
     return
   end
-  stop_watching(bufnr, s)
+  vim.api.nvim_del_autocmd(au_id)
+  if debounce_timers[bufnr] then
+    debounce_timers[bufnr]:stop()
+    debounce_timers[bufnr]:close()
+    debounce_timers[bufnr] = nil
+  end
+  watching[bufnr] = nil
   log.dbg('unwatched buffer %d', bufnr)
 end
 
@@ -571,8 +582,7 @@ end
 ---@param bufnr integer
 ---@return boolean
 function M.open(bufnr, open_config)
-  local s = state[bufnr]
-  local output = s and s.output
+  local output = last_output[bufnr]
   if not output then
     log.dbg('no last output file for buffer %d', bufnr)
     return false
@@ -588,20 +598,26 @@ end
 ---@param bufnr integer
 ---@return preview.Status
 function M.status(bufnr)
-  local s = state[bufnr]
-  if not s then
-    return { compiling = false, watching = false }
+  local proc = active[bufnr]
+  if proc then
+    return {
+      compiling = not proc.is_reload,
+      watching = watching[bufnr] ~= nil or proc.is_reload == true,
+      provider = proc.provider,
+      output_file = proc.output_file,
+    }
   end
-  return {
-    compiling = s.process ~= nil and not s.is_reload,
-    watching = s.watching,
-    provider = s.provider,
-    output_file = s.output,
-  }
+  return { compiling = false, watching = watching[bufnr] ~= nil }
 end
 
 M._test = {
-  state = state,
+  active = active,
+  watching = watching,
+  opened = opened,
+  last_output = last_output,
+  debounce_timers = debounce_timers,
+  viewer_procs = viewer_procs,
+  open_watchers = open_watchers,
 }
 
 return M
diff --git a/lua/preview/init.lua b/lua/preview/init.lua
index 489679f..7cb982b 100644
--- a/lua/preview/init.lua
+++ b/lua/preview/init.lua
@@ -2,7 +2,6 @@
 ---@field ft? string
 ---@field cmd string[]
 ---@field args? string[]|fun(ctx: preview.Context): string[]
----@field extra_args? string[]|fun(ctx: preview.Context): string[]
 ---@field cwd? string|fun(ctx: preview.Context): string
 ---@field env? table<string, string>
 ---@field output? string|fun(ctx: preview.Context): string
@@ -95,7 +94,6 @@ function M.setup(opts)
     vim.validate(prefix .. '.cmd', provider.cmd, 'table')
     vim.validate(prefix .. '.cmd[1]', provider.cmd[1], 'string')
     vim.validate(prefix .. '.args', provider.args, { 'table', 'function' }, true)
-    vim.validate(prefix .. '.extra_args', provider.extra_args, { 'table', 'function' }, true)
     vim.validate(prefix .. '.cwd', provider.cwd, { 'string', 'function' }, true)
     vim.validate(prefix .. '.output', provider.output, { 'string', 'function' }, true)
     vim.validate(prefix .. '.error_parser', provider.error_parser, 'function', true)
diff --git a/lua/preview/presets.lua b/lua/preview/presets.lua
index 1f333bf..1b5333e 100644
--- a/lua/preview/presets.lua
+++ b/lua/preview/presets.lua
@@ -115,24 +115,6 @@ local function parse_asciidoctor(output)
   return diagnostics
 end
 
----@param output string
----@return preview.Diagnostic[]
-local function parse_mermaid(output)
-  local lnum = output:match('Parse error on line (%d+)')
-  if not lnum then
-    return {}
-  end
-  local msg = output:match('(Expecting .+)') or 'parse error'
-  return {
-    {
-      lnum = tonumber(lnum) - 1,
-      col = 0,
-      message = msg,
-      severity = vim.diagnostic.severity.ERROR,
-    },
-  }
-end
-
 ---@type preview.ProviderConfig
 M.typst = {
   ft = 'typst',
@@ -224,7 +206,7 @@ M.markdown = {
   ft = 'markdown',
   cmd = { 'pandoc' },
   args = function(ctx)
-    return { ctx.file, '-s', '--embed-resources', '--mathml', '-o', ctx.output }
+    return { ctx.file, '-s', '--embed-resources', '-o', ctx.output }
   end,
   output = function(ctx)
     return (ctx.file:gsub('%.md$', '.html'))
@@ -250,7 +232,6 @@ M.github = {
       ctx.file,
       '-s',
       '--embed-resources',
-      '--mathml',
       '--css',
       'https://cdn.jsdelivr.net/gh/pixelbrackets/gfm-stylesheet@master/dist/gfm.css',
       '-o',
@@ -332,7 +313,19 @@ M.mermaid = {
     return (ctx.file:gsub('%.mmd$', '.svg'))
   end,
   error_parser = function(output)
-    return parse_mermaid(output)
+    local diagnostics = {}
+    for line in output:gmatch('[^\r\n]+') do
+      local lnum = line:match('^%s*Parse error on line (%d+)')
+      if lnum then
+        table.insert(diagnostics, {
+          lnum = tonumber(lnum) - 1,
+          col = 0,
+          message = line,
+          severity = vim.diagnostic.severity.ERROR,
+        })
+      end
+    end
+    return diagnostics
   end,
   clean = function(ctx)
     return { 'rm', '-f', (ctx.file:gsub('%.mmd$', '.svg')) }
diff --git a/spec/compiler_spec.lua b/spec/compiler_spec.lua
index 5b12cfb..cd1dd9f 100644
--- a/spec/compiler_spec.lua
+++ b/spec/compiler_spec.lua
@@ -8,13 +8,8 @@ describe('compiler', function()
     compiler = require('preview.compiler')
   end)
 
-  local function process_done(bufnr)
-    local s = compiler._test.state[bufnr]
-    return not s or s.process == nil
-  end
-
   describe('compile', function()
-    it('spawns a process and tracks it in state', function()
+    it('spawns a process and tracks it in active table', function()
       local bufnr = helpers.create_buffer({ 'hello' }, 'text')
       vim.api.nvim_buf_set_name(bufnr, '/tmp/preview_test.txt')
       vim.bo[bufnr].modified = false
@@ -28,16 +23,15 @@ describe('compiler', function()
       }
 
       compiler.compile(bufnr, 'echo', provider, ctx)
-      local s = compiler._test.state[bufnr]
-      assert.is_not_nil(s)
-      assert.is_not_nil(s.process)
-      assert.are.equal('echo', s.provider)
+      local active = compiler._test.active
+      assert.is_not_nil(active[bufnr])
+      assert.are.equal('echo', active[bufnr].provider)
 
       vim.wait(2000, function()
-        return process_done(bufnr)
+        return active[bufnr] == nil
       end, 50)
 
-      assert.is_nil(compiler._test.state[bufnr].process)
+      assert.is_nil(active[bufnr])
       helpers.delete_buffer(bufnr)
     end)
 
@@ -67,7 +61,7 @@ describe('compiler', function()
       assert.is_true(fired)
 
       vim.wait(2000, function()
-        return process_done(bufnr)
+        return compiler._test.active[bufnr] == nil
       end, 50)
 
       helpers.delete_buffer(bufnr)
@@ -130,7 +124,7 @@ describe('compiler', function()
       vim.notify = orig
 
       assert.is_true(notified)
-      assert.is_true(process_done(bufnr))
+      assert.is_nil(compiler._test.active[bufnr])
       helpers.delete_buffer(bufnr)
     end)
 
@@ -192,7 +186,7 @@ describe('compiler', function()
       compiler.compile(bufnr, 'falsecmd', provider, ctx)
 
       vim.wait(2000, function()
-        return process_done(bufnr)
+        return compiler._test.active[bufnr] == nil
       end, 50)
 
       assert.is_false(parser_called)
@@ -224,7 +218,7 @@ describe('compiler', function()
       compiler.compile(bufnr, 'qfcmd', provider, ctx)
 
       vim.wait(2000, function()
-        return process_done(bufnr)
+        return compiler._test.active[bufnr] == nil
       end, 50)
 
       local qflist = vim.fn.getqflist()
@@ -261,7 +255,7 @@ describe('compiler', function()
       compiler.compile(bufnr, 'truecmd', provider, ctx)
 
       vim.wait(2000, function()
-        return process_done(bufnr)
+        return compiler._test.active[bufnr] == nil
       end, 50)
 
       assert.are.equal(0, #vim.fn.getqflist())
@@ -304,7 +298,7 @@ describe('compiler', function()
       compiler.stop(bufnr)
 
       vim.wait(2000, function()
-        return process_done(bufnr)
+        return compiler._test.active[bufnr] == nil
       end, 50)
 
       helpers.delete_buffer(bufnr)
@@ -335,12 +329,11 @@ describe('compiler', function()
       }
 
       compiler.compile(bufnr, 'testprov', provider, ctx)
-      local s = compiler._test.state[bufnr]
-      assert.is_not_nil(s)
-      assert.are.equal('/tmp/preview_test_open.pdf', s.output)
+      assert.is_not_nil(compiler._test.last_output[bufnr])
+      assert.are.equal('/tmp/preview_test_open.pdf', compiler._test.last_output[bufnr])
 
       vim.wait(2000, function()
-        return process_done(bufnr)
+        return compiler._test.active[bufnr] == nil
       end, 50)
 
       helpers.delete_buffer(bufnr)
@@ -348,7 +341,7 @@ describe('compiler', function()
   end)
 
   describe('toggle', function()
-    it('starts watching and sets watching flag', function()
+    it('registers autocmd and tracks in watching table', function()
       local bufnr = helpers.create_buffer({ 'hello' }, 'text')
       vim.api.nvim_buf_set_name(bufnr, '/tmp/preview_test_watch.txt')
 
@@ -358,7 +351,7 @@ describe('compiler', function()
       end
 
       compiler.toggle(bufnr, 'echo', provider, ctx_builder)
-      assert.is_true(compiler.status(bufnr).watching)
+      assert.is_not_nil(compiler._test.watching[bufnr])
 
       helpers.delete_buffer(bufnr)
     end)
@@ -373,10 +366,10 @@ describe('compiler', function()
       end
 
       compiler.toggle(bufnr, 'echo', provider, ctx_builder)
-      assert.is_true(compiler.status(bufnr).watching)
+      assert.is_not_nil(compiler._test.watching[bufnr])
 
       compiler.toggle(bufnr, 'echo', provider, ctx_builder)
-      assert.is_false(compiler.status(bufnr).watching)
+      assert.is_nil(compiler._test.watching[bufnr])
 
       helpers.delete_buffer(bufnr)
     end)
@@ -396,10 +389,10 @@ describe('compiler', function()
       end
 
       compiler.toggle(bufnr, 'echo', provider, ctx_builder)
-      assert.is_true(compiler.status(bufnr).watching)
+      assert.is_not_nil(compiler._test.watching[bufnr])
 
       compiler.stop_all()
-      assert.is_false(compiler.status(bufnr).watching)
+      assert.is_nil(compiler._test.watching[bufnr])
 
       helpers.delete_buffer(bufnr)
     end)
diff --git a/spec/presets_spec.lua b/spec/presets_spec.lua
index 573b1ef..2160dfa 100644
--- a/spec/presets_spec.lua
+++ b/spec/presets_spec.lua
@@ -294,11 +294,11 @@ describe('presets', function()
       assert.are.same({ 'pandoc' }, presets.markdown.cmd)
     end)
 
-    it('returns args with standalone, embed-resources, and mathml flags', function()
+    it('returns args with standalone and embed-resources flags', function()
       local args = presets.markdown.args(md_ctx)
       assert.is_table(args)
       assert.are.same(
-        { '/tmp/document.md', '-s', '--embed-resources', '--mathml', '-o', '/tmp/document.html' },
+        { '/tmp/document.md', '-s', '--embed-resources', '-o', '/tmp/document.html' },
         args
       )
     end)
@@ -382,7 +382,7 @@ describe('presets', function()
       assert.are.same({ 'pandoc' }, presets.github.cmd)
     end)
 
-    it('returns args with standalone, embed-resources, mathml, and css flags', function()
+    it('returns args with standalone, embed-resources, and css flags', function()
       local args = presets.github.args(md_ctx)
       assert.is_table(args)
       assert.are.same({
@@ -391,7 +391,6 @@ describe('presets', function()
         '/tmp/document.md',
         '-s',
         '--embed-resources',
-        '--mathml',
         '--css',
         'https://cdn.jsdelivr.net/gh/pixelbrackets/gfm-stylesheet@master/dist/gfm.css',
         '-o',