diff --git a/spec/support/capybara.rb b/spec/support/capybara.rb
index 38f60402..8855eb76 100644
--- a/spec/support/capybara.rb
+++ b/spec/support/capybara.rb
@@ -1,8 +1,12 @@
+require "timeout"
+
 require "selenium/webdriver"
 
 Capybara.register_driver :headless_chrome do |app|
+  # `--disable-dev-shm-usage` keeps Chrome off the small `/dev/shm` of CI
+  # runners and containers, where exhausting it crashes the renderer.
   options = Selenium::WebDriver::Chrome::Options.new(
-    args: %w[--no-sandbox --headless],
+    args: %w[--no-sandbox --headless --disable-dev-shm-usage],
   )
 
   # Point Selenium at a specific Chrome binary, e.g. inside a container
@@ -23,3 +27,11 @@
 
 Capybara.server = :webrick
 Capybara.javascript_driver = :headless_chrome
+
+RSpec.configure do |config|
+  # A crashed browser can leave the driver waiting forever: fail the example
+  # with a backtrace instead of eating the job's runtime cap.
+  config.around(:each, :js) do |example|
+    Timeout.timeout(300) { example.run }
+  end
+end