added error highlighting.

init.lua

@@ -54,17 +54,59 @@ opt.mouse = ""
 opt.shortmess:append("atI")
 opt.hidden = true
 opt.termguicolors = true -- Important for modern LSPs/UI
+opt.updatetime = 300    -- Faster response for diagnostics
 
 -- =============================================================================
 -- 4. DIAGNOSTICS (Error display)
 -- =============================================================================
 vim.diagnostic.config({
-    virtual_text = false, -- No text noise in the line
+    virtual_text = {
+        prefix = "●", -- Subtle dot for error messages
+    },
     underline = true,     -- Errors are underlined
-    signs = false,        -- No icons on the edge (less noise)
+    signs = true,        -- Enable icons in the gutter
     update_in_insert = false,
+    severity_sort = true,
 })
 
+-- Show error message in a floating window on hover
+vim.api.nvim_create_autocmd("CursorHold", {
+    callback = function()
+        vim.diagnostic.open_float(nil, { focusable = false, border = "rounded" })
+    end,
+})
+
+-- Custom icons for diagnostics
+local signs = { Error = " ", Warn = " ", Hint = " ", Info = " " }
+for type, icon in pairs(signs) do
+    local hl = "DiagnosticSign" .. type
+    vim.fn.sign_define(hl, { text = icon, texthl = hl, numhl = hl })
+end
+
+-- =============================================================================
+-- 4.5 TREESITTER (Syntax & Error Highlighting)
+-- =============================================================================
+vim.schedule(function()
+    local ok_ts, ts = pcall(require, "nvim-treesitter.configs")
+    if ok_ts then
+        ts.setup({
+            ensure_installed = { "lua", "python", "rust" },
+            highlight = {
+                enable = true,
+                additional_vim_regex_highlighting = false,
+            },
+        })
+    end
+end)
+
+-- =============================================================================
+-- 4.6 HIGHLIGHTS (Visibility)
+-- =============================================================================
+vim.api.nvim_set_hl(0, "DiagnosticUnderlineError", { undercurl = true, sp = "red", bold = true })
+vim.api.nvim_set_hl(0, "DiagnosticUnderlineWarn", { undercurl = true, sp = "orange" })
+vim.api.nvim_set_hl(0, "DiagnosticError", { fg = "red" })
+vim.api.nvim_set_hl(0, "DiagnosticWarn", { fg = "orange" })
+
 -- =============================================================================
 -- 5. KEYMAPS (Leader: Space)
 -- =============================================================================