diff --git a/lib/pressa/config/loader.rb b/lib/pressa/config/loader.rb
index bc56b15..bf11540 100644
--- a/lib/pressa/config/loader.rb
+++ b/lib/pressa/config/loader.rb
@@ -141,10 +141,18 @@ module Pressa
         entries.map.with_index do |item, index|
           case item
           when String
+            validate_asset_path!(
+              item,
+              context: "#{context}[#{index}]"
+            )
             Script.new(src: item, defer: true)
           when Hash
             src = item["src"]
             raise ValidationError, "Expected #{context}[#{index}].src to be a String" unless src.is_a?(String) && !src.empty?
+            validate_asset_path!(
+              src,
+              context: "#{context}[#{index}].src"
+            )
 
             defer = item.key?("defer") ? item["defer"] : true
             unless [true, false].include?(defer)
@@ -164,10 +172,18 @@ module Pressa
         entries.map.with_index do |item, index|
           case item
           when String
+            validate_asset_path!(
+              item,
+              context: "#{context}[#{index}]"
+            )
             Stylesheet.new(href: item)
           when Hash
             href = item["href"]
             raise ValidationError, "Expected #{context}[#{index}].href to be a String" unless href.is_a?(String) && !href.empty?
+            validate_asset_path!(
+              href,
+              context: "#{context}[#{index}].href"
+            )
 
             Stylesheet.new(href:)
           else
@@ -190,6 +206,12 @@ module Pressa
         normalized = value.start_with?("/") ? value : "/#{value}"
         "#{site_url}#{normalized}"
       end
+
+      def validate_asset_path!(value, context:)
+        return if value.start_with?("/", "http://", "https://")
+
+        raise ValidationError, "Expected #{context} to start with / or use http(s) scheme"
+      end
     end
   end
 end
diff --git a/lib/pressa/posts/models.rb b/lib/pressa/posts/models.rb
index 2e90959..d95d63e 100644
--- a/lib/pressa/posts/models.rb
+++ b/lib/pressa/posts/models.rb
@@ -86,6 +86,10 @@ module Pressa
       def recent_posts(limit = 10)
         all_posts.take(limit)
       end
+
+      def earliest_year
+        by_year.keys.min
+      end
     end
   end
 end
diff --git a/lib/pressa/site.rb b/lib/pressa/site.rb
index 8020965..99899d4 100644
--- a/lib/pressa/site.rb
+++ b/lib/pressa/site.rb
@@ -21,6 +21,7 @@ module Pressa
     attribute :description, Types::String
     attribute :url, Types::String
     attribute :image_url, Types::String.optional.default(nil)
+    attribute :copyright_start_year, Types::Integer.optional.default(nil)
     attribute :scripts, Types::Array.of(Script).default([].freeze)
     attribute :styles, Types::Array.of(Stylesheet).default([].freeze)
     attribute :plugins, Types::Array.default([].freeze)
diff --git a/lib/pressa/site_generator.rb b/lib/pressa/site_generator.rb
index 77b9d79..bc7aa6b 100644
--- a/lib/pressa/site_generator.rb
+++ b/lib/pressa/site_generator.rb
@@ -15,8 +15,10 @@ module Pressa
       FileUtils.rm_rf(target_path)
       FileUtils.mkdir_p(target_path)
 
-      site.plugins.each { |plugin| plugin.setup(site:, source_path:) }
+      setup_site = site
+      setup_site.plugins.each { |plugin| plugin.setup(site: setup_site, source_path:) }
 
+      @site = site_with_copyright_start_year(setup_site)
       site.plugins.each { |plugin| plugin.render(site:, target_path:) }
 
       copy_static_files(source_path, target_path)
@@ -99,5 +101,23 @@ module Pressa
       basename = File.basename(source_file)
       basename.start_with?(".")
     end
+
+    def site_with_copyright_start_year(base_site)
+      start_year = find_copyright_start_year(base_site)
+      Site.new(**base_site.to_h.merge(copyright_start_year: start_year))
+    end
+
+    def find_copyright_start_year(base_site)
+      years = base_site.plugins.filter_map do |plugin|
+        next unless plugin.respond_to?(:posts_by_year)
+
+        posts_by_year = plugin.posts_by_year
+        next unless posts_by_year.respond_to?(:earliest_year)
+
+        posts_by_year.earliest_year
+      end
+
+      years.min || Time.now.year
+    end
   end
 end
diff --git a/lib/pressa/views/layout.rb b/lib/pressa/views/layout.rb
index 40a1069..28dddcd 100644
--- a/lib/pressa/views/layout.rb
+++ b/lib/pressa/views/layout.rb
@@ -4,8 +4,6 @@ require "pressa/views/icons"
 module Pressa
   module Views
     class Layout < Phlex::HTML
-      START_YEAR = 2006
-
       attr_reader :site,
         :page_subtitle,
         :page_description,
@@ -34,10 +32,6 @@ module Pressa
         @content = content
       end
 
-      def format_output?
-        true
-      end
-
       def view_template
         doctype
 
@@ -172,7 +166,7 @@ module Pressa
 
       def render_footer
         footer do
-          plain "© #{START_YEAR} - #{Time.now.year} "
+          plain "© #{footer_years} "
           a(href: site.url_for("/about")) { site.author }
         end
       end
@@ -201,6 +195,14 @@ module Pressa
         normalized = path.start_with?("/") ? path : "/#{path}"
         site.url_for(normalized)
       end
+
+      def footer_years
+        current_year = Time.now.year
+        start_year = site.copyright_start_year || current_year
+        return current_year.to_s if start_year >= current_year
+
+        "#{start_year} - #{current_year}"
+      end
     end
   end
 end
diff --git a/site.toml b/site.toml
index b9b751d..6c906e3 100644
--- a/site.toml
+++ b/site.toml
@@ -5,14 +5,14 @@ description = "Sami Samhuri's blog about programming, mainly about iOS and Ruby
 url = "https://samhuri.net"
 image_url = "/images/me.jpg"
 scripts = []
-styles = ["css/normalize.css", "css/style.css", "css/syntax.css"]
+styles = ["/css/normalize.css", "/css/style.css", "/css/syntax.css"]
 plugins = ["posts", "projects"]
 
 [projects_plugin]
 scripts = [
   "https://ajax.googleapis.com/ajax/libs/prototype/1.6.1.0/prototype.js",
-  "js/gitter.js",
-  "js/store.js",
-  "js/projects.js"
+  "/js/gitter.js",
+  "/js/store.js",
+  "/js/projects.js"
 ]
 styles = []
diff --git a/spec/config/loader_test.rb b/spec/config/loader_test.rb
index ec60aa5..4a4df45 100644
--- a/spec/config/loader_test.rb
+++ b/spec/config/loader_test.rb
@@ -11,11 +11,11 @@ class Pressa::Config::LoaderTest < Minitest::Test
       assert_equal("Sami Samhuri", site.author)
       assert_equal("https://samhuri.net", site.url)
       assert_equal("https://samhuri.net/images/me.jpg", site.image_url)
-      assert_equal(["css/style.css"], site.styles.map(&:href))
+      assert_equal(["/css/style.css"], site.styles.map(&:href))
 
       projects_plugin = site.plugins.find { |plugin| plugin.is_a?(Pressa::Projects::Plugin) }
       refute_nil(projects_plugin)
-      assert_equal(["js/projects.js"], projects_plugin.scripts.map(&:src))
+      assert_equal(["/js/projects.js"], projects_plugin.scripts.map(&:src))
     end
   end
 
@@ -338,6 +338,25 @@ class Pressa::Config::LoaderTest < Minitest::Test
     end
   end
 
+  def test_build_site_rejects_non_absolute_local_asset_paths
+    Dir.mktmpdir do |dir|
+      File.write(File.join(dir, "site.toml"), <<~TOML)
+        author = "Sami Samhuri"
+        email = "sami@samhuri.net"
+        title = "samhuri.net"
+        description = "blog"
+        url = "https://samhuri.net"
+        scripts = ["js/site.js"]
+        styles = ["css/site.css"]
+      TOML
+      File.write(File.join(dir, "projects.toml"), "")
+
+      loader = Pressa::Config::Loader.new(source_path: dir)
+      error = assert_raises(Pressa::Config::ValidationError) { loader.build_site }
+      assert_match(%r{start with / or use http\(s\) scheme}, error.message)
+    end
+  end
+
   private
 
   def with_temp_config
@@ -350,11 +369,11 @@ class Pressa::Config::LoaderTest < Minitest::Test
         url = "https://samhuri.net"
         image_url = "/images/me.jpg"
         scripts = []
-        styles = ["css/style.css"]
+        styles = ["/css/style.css"]
         plugins = ["posts", "projects"]
 
         [projects_plugin]
-        scripts = ["js/projects.js"]
+        scripts = ["/js/projects.js"]
         styles = []
       TOML
 
diff --git a/spec/posts/models_test.rb b/spec/posts/models_test.rb
index fca5f6f..9acc302 100644
--- a/spec/posts/models_test.rb
+++ b/spec/posts/models_test.rb
@@ -70,7 +70,13 @@ class Pressa::Posts::ModelsTest < Minitest::Test
     assert_equal([11, 10], year_2025.sorted_months.map { |mp| mp.month.number })
     assert_equal([regular_post, link_post], year_2025.all_posts)
     assert_equal([2025, 2024], posts_by_year.sorted_years)
+    assert_equal(2024, posts_by_year.earliest_year)
     assert_equal(3, posts_by_year.all_posts.length)
     assert_equal([regular_post], posts_by_year.recent_posts(1))
   end
+
+  def test_posts_by_year_earliest_year_is_nil_for_empty_collection
+    posts_by_year = Pressa::Posts::PostsByYear.new(by_year: {})
+    assert_nil(posts_by_year.earliest_year)
+  end
 end
diff --git a/spec/site_generator_rendering_test.rb b/spec/site_generator_rendering_test.rb
index 6e14044..14af007 100644
--- a/spec/site_generator_rendering_test.rb
+++ b/spec/site_generator_rendering_test.rb
@@ -20,6 +20,20 @@ class Pressa::SiteGeneratorRenderingTest < Minitest::Test
     end
   end
 
+  class PostsPluginSpy < PluginSpy
+    attr_reader :posts_by_year, :render_site_year
+
+    def initialize(posts_by_year:)
+      super()
+      @posts_by_year = posts_by_year
+    end
+
+    def render(site:, target_path:)
+      @render_site_year = site.copyright_start_year
+      super
+    end
+  end
+
   class MarkdownRendererSpy
     attr_reader :calls
 
@@ -51,6 +65,27 @@ class Pressa::SiteGeneratorRenderingTest < Minitest::Test
     )
   end
 
+  def build_posts_by_year(year:)
+    post = Pressa::Posts::Post.new(
+      slug: "first-post",
+      title: "First Post",
+      author: "Sami Samhuri",
+      date: DateTime.parse("#{year}-02-01T10:00:00-08:00"),
+      formatted_date: "1st February, #{year}",
+      body: "<p>First post</p>",
+      excerpt: "First post...",
+      path: "/posts/#{year}/02/first-post"
+    )
+
+    month_posts = Pressa::Posts::MonthPosts.new(
+      month: Pressa::Posts::Month.new(name: "February", number: 2, padded: "02"),
+      posts: [post]
+    )
+
+    year_posts = Pressa::Posts::YearPosts.new(year:, by_month: {2 => month_posts})
+    Pressa::Posts::PostsByYear.new(by_year: {year => year_posts})
+  end
+
   def test_generate_runs_plugins_copies_static_files_and_renders_supported_files
     Dir.mktmpdir do |root|
       source_path = File.join(root, "source")
@@ -110,4 +145,20 @@ class Pressa::SiteGeneratorRenderingTest < Minitest::Test
       assert_empty(renderer.calls)
     end
   end
+
+  def test_generate_sets_copyright_start_year_from_earliest_post_year
+    Dir.mktmpdir do |root|
+      source_path = File.join(root, "source")
+      target_path = File.join(root, "target")
+      FileUtils.mkdir_p(source_path)
+
+      plugin = PostsPluginSpy.new(posts_by_year: build_posts_by_year(year: 2006))
+      renderer = MarkdownRendererSpy.new
+      site = build_site(plugin:, renderer:)
+
+      Pressa::SiteGenerator.new(site:).generate(source_path:, target_path:)
+
+      assert_equal(2006, plugin.render_site_year)
+    end
+  end
 end
diff --git a/spec/views/layout_test.rb b/spec/views/layout_test.rb
index 446a194..26cb724 100644
--- a/spec/views/layout_test.rb
+++ b/spec/views/layout_test.rb
@@ -21,6 +21,17 @@ class Pressa::Views::LayoutTest < Minitest::Test
     )
   end
 
+  def site_with_copyright_start_year(year)
+    Pressa::Site.new(
+      author: "Sami Samhuri",
+      email: "sami@samhuri.net",
+      title: "samhuri.net",
+      description: "blog",
+      url: "https://samhuri.net",
+      copyright_start_year: year
+    )
+  end
+
   def test_rendering_child_components_as_html_instead_of_escaped_text
     html = Pressa::Views::Layout.new(
       site:,
@@ -64,13 +75,25 @@ class Pressa::Views::LayoutTest < Minitest::Test
     assert_includes(html, %(<link rel="stylesheet" type="text/css" href="https://cdn.example.com/site.css">))
   end
 
-  def test_format_output_is_enabled
-    layout = Pressa::Views::Layout.new(
-      site:,
+  def test_footer_renders_year_range_using_copyright_start_year
+    html = Pressa::Views::Layout.new(
+      site: site_with_copyright_start_year(2006),
       canonical_url: "https://samhuri.net/posts/",
       content: content_view
-    )
+    ).call
 
-    assert(layout.format_output?)
+    assert_includes(html, "<footer>© 2006 - #{Time.now.year} <a href=\"https://samhuri.net/about\">Sami Samhuri</a></footer>")
+  end
+
+  def test_footer_renders_single_year_when_start_year_matches_current_year
+    current_year = Time.now.year
+    html = Pressa::Views::Layout.new(
+      site: site_with_copyright_start_year(current_year),
+      canonical_url: "https://samhuri.net/posts/",
+      content: content_view
+    ).call
+
+    assert_includes(html, "<footer>© #{current_year} <a href=\"https://samhuri.net/about\">Sami Samhuri</a></footer>")
+    refute_includes(html, "<footer>© #{current_year} - #{current_year} ")
   end
 end