fix(nvim): fix black float backgrounds and guarantee abook 24-line height

- Add winhighlight=Normal:Normal to all floats so they inherit the
  colorscheme background instead of showing NormalFloat (black)
- Pin abook to min 24 lines; mail/calendar split the remaining height

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

nvim/init.lua

@@ -179,14 +179,15 @@ end
 local function _pim_float(row, col, height, width, border)
     local buf = vim.api.nvim_create_buf(false, true)
     vim.api.nvim_open_win(buf, true, {
-        relative = "editor",
-        row      = row,
-        col      = col,
-        height   = math.max(1, height),
-        width    = math.max(1, width),
-        style    = "minimal",
-        border   = border or "none",
-        zindex   = 50,
+        relative    = "editor",
+        row         = row,
+        col         = col,
+        height      = math.max(1, height),
+        width       = math.max(1, width),
+        style       = "minimal",
+        border      = border or "none",
+        zindex      = 50,
+        winhighlight = "Normal:Normal,NormalNC:Normal",
     })
     return vim.api.nvim_get_current_win()
 end
@@ -232,10 +233,11 @@ local function toggle_pim()
     local H     = vim.o.lines - 2
     local col_w = math.min(vim.o.columns, math.max(90, math.floor(vim.o.columns * 0.45)))
 
-    -- divide column height: mail 40%, calendar 30%, abook remainder (≥ 10)
-    local mail_h = math.max(1, math.floor(H * 0.40))
-    local cal_h  = math.max(1, math.floor(H * 0.30))
-    local ab_h   = math.max(1, H - mail_h - cal_h)
+    -- abook gets a fixed 24-line minimum; mail/calendar split the rest 57/43
+    local ab_h   = math.max(24, math.floor(H * 0.30))
+    local rest   = math.max(2,  H - ab_h)
+    local mail_h = math.max(1,  math.floor(rest * 0.57))
+    local cal_h  = math.max(1,  rest - mail_h)
 
     local w1 = _pim_float(0,               0, mail_h, col_w)
     local ok, err = pcall(vim.cmd, "terminal alot")