diff --git a/lua/codewindow/highlight.lua b/lua/codewindow/highlight.lua
index 535b43d..ef7f75b 100644
--- a/lua/codewindow/highlight.lua
+++ b/lua/codewindow/highlight.lua
@@ -3,7 +3,6 @@ local M = {}
 local config = require("codewindow.config").get()
 local utils = require("codewindow.utils")
 local highlighter
-local ts_utils
 
 local hl_namespace
 local screenbounds_namespace
@@ -99,13 +98,22 @@ local function extract_highlighting(buffer, lines)
       if hl then
         local c = query._query.captures[capture]
         if c ~= nil then
-          local start_row, start_col, end_row, end_col =
-            ts_utils.get_vim_range({ vim.treesitter.get_node_range(node) }, buffer)
+          -- vim.treesitter.get_node_range returns 0-indexed rows and columns
+          -- Rows: 0-indexed inclusive -> 1-indexed inclusive
+          -- Cols: 0-indexed with end exclusive [start_col, end_col) -> 1-indexed inclusive
+          local start_row, start_col, end_row, end_col = vim.treesitter.get_node_range(node)
+          start_row = start_row + 1
+          end_row = end_row + 1
+          start_col = start_col + 1
+          -- end_col is already "one past" in 0-based; in 1-based it's the inclusive end
 
           for y = start_row, end_row do
             for x = start_col, math.min(end_col, minimap_char_width) do
               local minimap_x, minimap_y = utils.buf_to_minimap(x, y)
-              highlights[minimap_y][minimap_x][c] = (highlights[minimap_y][minimap_x][c] or 0) + 1
+              if minimap_y >= 1 and minimap_y <= minimap_height
+                 and minimap_x >= 1 and minimap_x <= minimap_width then
+                highlights[minimap_y][minimap_x][c] = (highlights[minimap_y][minimap_x][c] or 0) + 1
+              end
             end
           end
         end
@@ -124,7 +132,6 @@ end
 
 if config.use_treesitter then
   highlighter = require("vim.treesitter.highlighter")
-  ts_utils = require("nvim-treesitter.ts_utils")
   M.extract_highlighting = extract_highlighting
 else
   M.extract_highlighting = function() end