diff --git a/.config/nvim/init.lua b/.config/nvim/init.lua
index 422b8b6..ece59b0 100644
--- a/.config/nvim/init.lua
+++ b/.config/nvim/init.lua
@@ -65,11 +65,18 @@ vim.o.undodir = vim.env.XDG_CACHE_HOME .. "/vim/undo"
 vim.g.python_host_prog = '/usr/bin/python2'
 vim.g.python3_host_prog = '/usr/bin/python3'
 
--- append
+-- display certain invisible chars
 vim.opt.list = true
 vim.opt.listchars:append "space:·"
 vim.opt.listchars:append "eol:"
 
+-- folding
+vim.o.foldcolumn = '0'
+vim.o.foldlevel = 99
+vim.o.foldlevelstart = 99
+vim.o.foldenable = true
+
+
 -- set filetypes correctly by extension
 require('autocmd')
 
diff --git a/.config/nvim/lua/loadplugins.lua b/.config/nvim/lua/loadplugins.lua
index de5816d..139d8f0 100644
--- a/.config/nvim/lua/loadplugins.lua
+++ b/.config/nvim/lua/loadplugins.lua
@@ -104,6 +104,10 @@ return require("packer").startup(function(use)
     requires = { 'nvim-treesitter/nvim-treesitter' }
   }
 
+  -- folding improvements
+  use { 'kevinhwang91/nvim-ufo',
+    requires = 'kevinhwang91/promise-async' }
+
   -- colorful brackets
   use { 'luochen1990/rainbow' }
 
diff --git a/.config/nvim/plugin/colorscheme.lua b/.config/nvim/plugin/colorscheme.lua
index fe97ec8..4497d03 100644
--- a/.config/nvim/plugin/colorscheme.lua
+++ b/.config/nvim/plugin/colorscheme.lua
@@ -1,4 +1,3 @@
 -- tiyn/vim-tccs
 vim.cmd('colorscheme tccs')
 vim.api.nvim_set_hl(0, 'colorcolumn', { bg = '#772222' })
-
diff --git a/.config/nvim/plugin/lualine.lua b/.config/nvim/plugin/lualine.lua
index e7053f1..f243eec 100644
--- a/.config/nvim/plugin/lualine.lua
+++ b/.config/nvim/plugin/lualine.lua
@@ -2,6 +2,12 @@
 require('lualine').setup {
   options = {
     icons_enabled = true,
+    symbols = {
+      error = '',
+      warn = '',
+      hint = '',
+      info = '',
+  },
     theme = 'tccs',
     component_separators = { left = '', right = '' },
     section_separators = { left = '', right = '' },
diff --git a/.config/nvim/plugin/nvim-cmp.lua b/.config/nvim/plugin/nvim-cmp.lua
index 006d2e2..d652ae2 100644
--- a/.config/nvim/plugin/nvim-cmp.lua
+++ b/.config/nvim/plugin/nvim-cmp.lua
@@ -144,10 +144,16 @@ local attach_func = function(client, bufnr)
   navbuddy.attach(client, bufnr)
 end
 
+local capabilities = cmp_nvim_lsp.default_capabilities()
+capabilities.textDocument.foldingRange = {
+    dynamicRegistration = false,
+    lineFoldingOnly = true
+}
+
 for _, lsp in ipairs(servers) do
   nvim_lsp[lsp].setup {
     on_attach = attach_func,
-    capabilities = cmp_nvim_lsp.default_capabilities(),
+    capabilities = capabilities,
     flags = {
       debounce_text_changes = 150
     }
@@ -156,6 +162,7 @@ end
 
 require 'lspconfig'.jdtls.setup {
   on_attach = attach_func,
+  capabilities = capabilities,
   flags = {
     debounce_text_changes = 150
   },
@@ -164,6 +171,7 @@ require 'lspconfig'.jdtls.setup {
 
 require 'lspconfig'.lua_ls.setup {
   on_attach = attach_func,
+  capabilities = capabilities,
   settings = {
     Lua = {
       runtime = { version = 'LuaJIT' },
@@ -173,3 +181,22 @@ require 'lspconfig'.lua_ls.setup {
     },
   },
 }
+
+require('ufo').setup()
+
+vim.fn.sign_define(
+  "DiagnosticSignError",
+  { texthl = "DiagnosticSignError", text = "", numhl = "DiagnosticSignError" }
+)
+vim.fn.sign_define(
+  "DiagnosticSignWarn",
+  { texthl = "DiagnosticSignWarn", text = "", numhl = "DiagnosticSignWarn" }
+)
+vim.fn.sign_define(
+  "DiagnosticSignInfo",
+  { texthl = "DiagnosticSignInfo", text = "", numhl = "DiagnosticSignInfo" }
+)
+vim.fn.sign_define(
+  "DiagnosticSignHint",
+  { texthl = "DiagnosticSignHint", text = "", numhl = "DiagnosticSignHint" }
+)
diff --git a/.config/nvim/plugin/todo-comments.lua b/.config/nvim/plugin/todo-comments.lua
index fe06b51..4cddcc0 100644
--- a/.config/nvim/plugin/todo-comments.lua
+++ b/.config/nvim/plugin/todo-comments.lua
@@ -5,12 +5,13 @@ require 'todo-comments'.setup {
   sign_priority = 8, -- sign priority
   -- keywords recognized as todo comments
   keywords = {
-    ERRO = { icon = " ", color = "error" },
-    TODO = { icon = " ", color = "info" },
-    HACK = { icon = " ", color = "warning" },
+    ERRO = { icon = " ", color = "error" },
+    TODO = { icon = " ", color = "info" },
     WARN = { icon = " ", color = "warning" },
-    PERF = { icon = " ", color = "default" },
-    NOTE = { icon = " ", color = "hint" },
+    HACK = { icon = " ", color = "warning" },
+    PERF = { icon = " ", color = "perfect" },
+    HINT = { icon = " ", color = "hint" },
+    INFO = { icon = " ", color = "hint", alt = { "NOTE" } },
     TEST = { icon = " ", color = "test" },
   },
   gui_style = {
@@ -37,11 +38,11 @@ require 'todo-comments'.setup {
   -- list of named colors where we try to extract the guifg from the
   -- list of highlight groups or use the hex color if hl not found as a fallback
   colors = {
-    error = { "DiagnosticError", "ErrorMsg", "#DC2626" },
-    warning = { "WarningMsg", "DiagnosticWarn", "#FBBF24" },
-    info = { "Constant", "#2563EB" },
-    hint = { "Comment", "#10B981" },
-    default = { "Operator", "#7C3AED" },
+    error = { "DiagnosticSignError", "ErrorMsg", "#DC2626" },
+    warning = { "DiagnosticSignWarn", "WarningMsg", "#FBBF24" },
+    info = { "Comment", "#2563EB" },
+    hint = { "Constant", "#10B981" },
+    perfect = { "Operator", "#7C3AED" },
     test = { "Function", "#FF00FF" }
   },
   search = {