diff --git a/app/controllers/overlays_controller.rb b/app/controllers/overlays_controller.rb
index f5ffb91..d31b5fc 100644
--- a/app/controllers/overlays_controller.rb
+++ b/app/controllers/overlays_controller.rb
@@ -1,46 +1,77 @@
 class OverlaysController < ApplicationController
   before_action :set_overlay, only: [ :destroy ]
-  before_action :set_server_template, only: [ :create ]
+  before_action :set_server_template, only: [ :create, :destroy ]
 
   def index
     @system_overlays = Overlay.system_overlays
     @custom_overlays = current_user.overlays.custom_overlays.order(:name)
   end
 
+  def new
+    @overlay = current_user.overlays.build
+  end
+
   def create
-    @server_template = current_user.server_templates.find(params[:server_template_id])
-    @overlay = Overlay.find(params[:overlay_id])
+    if @server_template.present?
+      # Attach existing overlay to a template
+      @overlay = Overlay.find(params[:overlay_id])
 
-    position = @server_template.template_overlays.maximum(:position).to_i + 1
-    @template_overlay = @server_template.template_overlays.build(overlay_id: @overlay.id, position: position)
+      position = @server_template.template_overlays.maximum(:position).to_i + 1
+      @template_overlay = @server_template.template_overlays.build(overlay_id: @overlay.id, position: position)
 
-    if @template_overlay.save
-      Activity.log(current_user, "added_overlay", "ServerTemplate", @server_template.id, { overlay: @overlay.name })
-      redirect_to @server_template, notice: "Overlay added successfully!"
+      if @template_overlay.save
+        Activity.log(current_user, "added_overlay", "ServerTemplate", @server_template.id, { overlay: @overlay.name })
+        redirect_to @server_template, notice: "Overlay added successfully!"
+      else
+        redirect_to @server_template, alert: "Failed to add overlay"
+      end
     else
-      redirect_to @server_template, alert: "Failed to add overlay"
+      # Create a new custom overlay for the current user
+      @overlay = current_user.overlays.build(overlay_params.merge(overlay_type: "custom"))
+
+      if @overlay.save
+        Activity.log(current_user, "created_overlay", "Overlay", @overlay.id, { name: @overlay.name, slug: @overlay.slug })
+        redirect_to overlays_path, notice: "Overlay created"
+      else
+        render :new, status: :unprocessable_entity
+      end
     end
   end
 
   def destroy
-    authorize_user!
-    server_template = @overlay.server_templates.find(params[:server_template_id])
-    @overlay.template_overlays.where(server_template_id: server_template.id).destroy_all
-    Activity.log(current_user, "removed_overlay", "ServerTemplate", server_template.id, { overlay: @overlay.name })
-    redirect_to server_template, notice: "Overlay removed successfully!"
+    if @server_template.present?
+      authorize_user_for_template_overlay!
+      @overlay.template_overlays.where(server_template_id: @server_template.id).destroy_all
+      Activity.log(current_user, "removed_overlay", "ServerTemplate", @server_template.id, { overlay: @overlay.name })
+      redirect_to @server_template, notice: "Overlay removed successfully!"
+    else
+      authorize_owner!
+      name = @overlay.name
+      @overlay.destroy
+      redirect_to overlays_path, notice: "Overlay '#{name}' deleted"
+    end
   end
 
   private
 
   def set_overlay
-    @overlay = Overlay.find(params[:id])
+    @overlay = Overlay.find(params[:id]) if params[:id].present?
   end
 
   def set_server_template
+    return unless params[:server_template_id].present?
     @server_template = current_user.server_templates.find(params[:server_template_id])
   end
 
-  def authorize_user!
+  def overlay_params
+    params.require(:overlay).permit(:name, :slug)
+  end
+
+  def authorize_user_for_template_overlay!
     redirect_to dashboard_path, alert: "Not authorized" unless @overlay.user_id.nil? || @overlay.user_id == current_user.id
   end
+
+  def authorize_owner!
+    redirect_to overlays_path, alert: "Not authorized" unless @overlay.user_id == current_user.id
+  end
 end
diff --git a/app/models/config_option.rb b/app/models/config_option.rb
index bebda14..16ccfbd 100644
--- a/app/models/config_option.rb
+++ b/app/models/config_option.rb
@@ -1,6 +1,6 @@
 class ConfigOption < ApplicationRecord
   belongs_to :server_template
 
-  validates :config_key, :config_value, presence: true
+  validates :config_key, presence: true
   validates :config_key, uniqueness: { scope: :server_template_id }
 end
diff --git a/app/models/overlay.rb b/app/models/overlay.rb
index de6542e..bb299d4 100644
--- a/app/models/overlay.rb
+++ b/app/models/overlay.rb
@@ -3,11 +3,37 @@ class Overlay < ApplicationRecord
   has_many :template_overlays, dependent: :destroy
   has_many :server_templates, through: :template_overlays
 
-  validates :name, :overlay_type, :path, presence: true
+  validates :name, :overlay_type, :slug, presence: true
   validates :overlay_type, inclusion: { in: %w[system custom] }
   validates :name, uniqueness: { scope: :user_id, message: "must be unique per user" }
+  validate :slug_is_single_directory
+
+  before_validation :normalize_slug
 
   scope :system_overlays, -> { where(overlay_type: "system").where(user_id: nil) }
   scope :custom_overlays, -> { where(overlay_type: "custom") }
   scope :for_user, ->(user) { where("user_id IS NULL OR user_id = ?", user.id) }
+
+  private
+
+  def normalize_slug
+    return if slug.blank? && name.blank?
+
+    # Use provided slug or derive from name
+    source = slug.presence || name
+    self.slug = source.to_s.strip
+                      .downcase
+                      .gsub(%r{[^\w\-.]}, "_")  # Replace non-word chars (except - and .) with underscore
+                      .gsub(%r{_+}, "_")        # Collapse multiple underscores
+                      .sub(%r{^_+}, "")         # Strip leading underscores
+                      .sub(%r{_+$}, "")         # Strip trailing underscores
+  end
+
+  def slug_is_single_directory
+    return if slug.blank?
+
+    if slug.match?(%r{[\\/]})
+      errors.add(:slug, "must be a single directory name (no slashes)")
+    end
+  end
 end
diff --git a/app/models/startup_param.rb b/app/models/startup_param.rb
index a30e065..bf223bd 100644
--- a/app/models/startup_param.rb
+++ b/app/models/startup_param.rb
@@ -1,6 +1,6 @@
 class StartupParam < ApplicationRecord
   belongs_to :server_template
 
-  validates :param_key, :param_value, presence: true
+  validates :param_key, presence: true
   validates :param_key, uniqueness: { scope: :server_template_id }
 end
diff --git a/app/views/layouts/application.html.erb b/app/views/layouts/application.html.erb
new file mode 100644
index 0000000..4bbdc0f
--- /dev/null
+++ b/app/views/layouts/application.html.erb
@@ -0,0 +1,44 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title><%= content_for(:title) || "L4d Tools" %></title>
+    <meta name="viewport" content="width=device-width,initial-scale=1">
+    <meta name="apple-mobile-web-app-capable" content="yes">
+    <meta name="application-name" content="L4d Tools">
+    <meta name="mobile-web-app-capable" content="yes">
+    <%= csrf_meta_tags %>
+    <%= csp_meta_tag %>
+
+    <%= yield :head %>
+
+    <%# Enable PWA manifest for installable apps (make sure to enable in config/routes.rb too!) %>
+    <%#= tag.link rel: "manifest", href: pwa_manifest_path(format: :json) %>
+
+    <link rel="icon" href="/icon.png" type="image/png">
+    <link rel="icon" href="/icon.svg" type="image/svg+xml">
+    <link rel="apple-touch-icon" href="/icon.png">
+
+    <%# Includes all stylesheet files in app/assets/stylesheets %>
+    <%= stylesheet_link_tag :app, "data-turbo-track": "reload" %>
+    <%= javascript_importmap_tags %>
+  </head>
+
+  <body>
+    <header class="nav-bar" style="display:flex;gap:12px;align-items:center;padding:10px 16px;border-bottom:1px solid #ddd;margin-bottom:16px;">
+      <%= link_to "L4D.tools", dashboard_path, style: "font-weight:bold;" %>
+      <%= link_to "Servers", servers_path %>
+      <%= link_to "Templates", server_templates_path %>
+      <%= link_to "Overlays", overlays_path %>
+      <span style="margin-left:auto;"><%= link_to "Logout", logout_path %></span>
+    </header>
+
+    <% if flash.any? %>
+      <div class="flash-messages">
+        <% flash.each do |type, message| %>
+          <div class="flash flash-<%= type %>"><%= message %></div>
+        <% end %>
+      </div>
+    <% end %>
+    <%= yield %>
+  </body>
+</html>
diff --git a/app/views/overlays/index.html.slim b/app/views/overlays/index.html.slim
new file mode 100644
index 0000000..bcbc94b
--- /dev/null
+++ b/app/views/overlays/index.html.slim
@@ -0,0 +1,24 @@
+.overlays
+  h2 Overlays
+  = link_to "New Overlay", new_overlay_path, class: "btn btn--primary"
+
+  - all_overlays = (@system_overlays + @custom_overlays).sort_by(&:name)
+  - if all_overlays.any?
+    table
+      thead
+        tr
+          th Name
+          th Dir (slug)
+          th Type
+          th Actions
+      tbody
+        - all_overlays.each do |overlay|
+          tr
+            td = overlay.name
+            td = overlay.slug
+            td = overlay.overlay_type.humanize
+            td
+              - if overlay.overlay_type == "custom" && overlay.user_id == current_user.id
+                = link_to "Delete", overlay_path(overlay), method: :delete, data: { confirm: "Delete this overlay?" }, class: "btn btn--small btn--danger"
+  - else
+    p No overlays available.
diff --git a/app/views/overlays/new.html.slim b/app/views/overlays/new.html.slim
new file mode 100644
index 0000000..c62c4e6
--- /dev/null
+++ b/app/views/overlays/new.html.slim
@@ -0,0 +1,22 @@
+.overlay_form
+  h2 New Overlay
+
+  = form_with model: @overlay, url: overlays_path, local: true do |f|
+    - if @overlay.errors.any?
+      .alert.alert--error
+        h4 = pluralize(@overlay.errors.count, "error")
+        ul
+          - @overlay.errors.full_messages.each do |msg|
+            li = msg
+
+    .form-group
+      = f.label :name
+      = f.text_field :name, placeholder: "e.g., custom_addons"
+
+    .form-group
+      = f.label :slug, "Directory slug (optional, auto-derived from name)"
+      = f.text_field :slug, placeholder: "Leave blank to auto-generate"
+
+    .form-actions
+      = f.submit "Create Overlay", class: "btn btn--primary"
+      = link_to "Cancel", overlays_path, class: "btn"
diff --git a/app/views/server_templates/show.html.slim b/app/views/server_templates/show.html.slim
index e90d247..bde03e3 100644
--- a/app/views/server_templates/show.html.slim
+++ b/app/views/server_templates/show.html.slim
@@ -18,6 +18,8 @@
         - @server_template.template_overlays.ordered.each do |to|
           li
             = to.overlay.name
+            span.small
+              | (dir: /opt/l4d2/overlays/#{to.overlay.slug})
             = link_to "Remove", server_template_overlay_path(@server_template, to.overlay), method: :delete, data: { confirm: "Sure?" }, class: "btn btn--small btn--danger"
     - else
       p No overlays selected.
diff --git a/config/routes.rb b/config/routes.rb
index db7e0a2..e3d41ac 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -17,7 +17,7 @@ Rails.application.routes.draw do
     resources :startup_params, only: [ :create, :destroy ]
   end
 
-  resources :overlays, only: [ :index ]
+  resources :overlays, only: [ :index, :new, :create, :destroy ]
 
   resources :servers do
     member do
diff --git a/db/migrate/20260118180000_rename_overlay_path_to_slug.rb b/db/migrate/20260118180000_rename_overlay_path_to_slug.rb
new file mode 100644
index 0000000..661ffc2
--- /dev/null
+++ b/db/migrate/20260118180000_rename_overlay_path_to_slug.rb
@@ -0,0 +1,5 @@
+class RenameOverlayPathToSlug < ActiveRecord::Migration[8.1]
+  def change
+    rename_column :overlays, :path, :slug
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 8724abb..de913cf 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.1].define(version: 2026_01_18_162630) do
+ActiveRecord::Schema[8.1].define(version: 2026_01_18_180000) do
   create_table "activities", force: :cascade do |t|
     t.string "action", null: false
     t.datetime "created_at", null: false
@@ -38,7 +38,7 @@ ActiveRecord::Schema[8.1].define(version: 2026_01_18_162630) do
     t.text "description"
     t.string "name", null: false
     t.string "overlay_type", default: "system", null: false
-    t.string "path", null: false
+    t.string "slug", null: false
     t.datetime "updated_at", null: false
     t.integer "user_id"
     t.index ["user_id", "name"], name: "index_overlays_on_user_id_and_name", unique: true
diff --git a/lib/l4d_server/launcher.rb b/lib/l4d_server/launcher.rb
index f4cd9d6..d961187 100644
--- a/lib/l4d_server/launcher.rb
+++ b/lib/l4d_server/launcher.rb
@@ -46,7 +46,7 @@ module L4dServer
 
     def mount_overlayfs
       server_dir = "/opt/l4d2/servers/#{@server.id}"
-      overlays = @template.template_overlays.ordered.map { |to| "/opt/l4d2/overlays/#{to.overlay.name}" }.join(":")
+      overlays = @template.template_overlays.ordered.map { |to| "/opt/l4d2/overlays/#{to.overlay.slug}" }.join(":")
       lower_dirs = "#{overlays}:/opt/l4d2/installation"
 
       mount_cmd = "fuse-overlayfs -o lowerdir=#{lower_dirs},upperdir=#{server_dir}/upper,workdir=#{server_dir}/work #{server_dir}/merged"