Anonymous Pens can't be embedded.
Edit on CodePen
{"__browser":{"device":"unknown_device","mobile":false,"name":"unknown browser","platform":"unknown_platform","version":"0"},"__constants":{},"__CPDATA":{"domain_iframe":"https://cdpn.io","environment":"production","host":"codepen.io","iframe_allow":"accelerometer; ambient-light-sensor; camera; display-capture; encrypted-media; geolocation; gyroscope; microphone; midi; payment; web-share; vr","iframe_sandbox":"allow-forms allow-modals allow-pointer-lock allow-popups allow-same-origin allow-scripts allow-top-navigation-by-user-activation allow-downloads allow-presentation"},"__graphql":{"data":{"data":null,"errors":[{"message":"Cannot return null for non-nullable field Query.sessionUser"}]},"url":"https://codepen.io/graphql","api":"cprails","cpedata":{"action":"show","controller":"embed"}},"__pay_stripe_public_key":"pk_live_2GndomDfiklqpSNQn8FrGuwZSMIMzha7DkLJqlYe7IR0ihKAlKdiHg68JJc5eVPt68rzAjzAAVXcUwjySHRCsgjQQ00gtRBUFNH","__pay_braintree_env":"production","__boomboom":{"serve_url":"https://cdpn.io/cpe/boomboom","store_url":"https://codepen.io/cpe/boomboom/store"},"__pageType":"embed","__item":"{\"editor_settings\":{\"auto_run\":true,\"auto_save\":true,\"format_on_save\":false,\"indent_with\":\"spaces\",\"tab_size\":2,\"id\":\"VoDkNZ\",\"autocomplete\":false,\"code_folding\":true,\"css_pre_processor\":\"none\",\"css_prefix\":\"neither\",\"css_starter\":\"neither\",\"emmet_active\":true,\"font_size\":14,\"font_type\":\"system\",\"html_pre_processor\":\"none\",\"js_pre_processor\":\"none\",\"key_bindings\":\"normal\",\"line_numbers\":true,\"line_wrapping\":true,\"match_brackets\":true,\"snippets\":{\"markupSnippets\":{},\"stylesheetSnippets\":{}},\"theme\":\"twilight\"},\"hashid\":\"RPoLRJ\",\"itemType\":\"pen\",\"resources\":[],\"tags\":[],\"id\":3897783,\"user_id\":1,\"html\":\"<h1>Collapsing Child Margins</h1>\\n\\n<div class=\\\"red\\\">\\n <div class=\\\"orange\\\">\\n <div class=\\\"yellow\\\">\\n <div class=\\\"green\\\">\\n <div class=\\\"blue\\\">\\n <div class=\\\"purple\\\">Collapsed</div>\\n </div>\\n </div>\\n </div>\\n </div>\\n</div>\\n\\n<div class=\\\"padding red\\\">\\n <div class=\\\"padding orange\\\">\\n <div class=\\\"padding yellow\\\">\\n <div class=\\\"padding green\\\">\\n <div class=\\\"padding blue\\\">\\n <div class=\\\"padding purple\\\">Not Collapsed</div>\\n </div>\\n </div>\\n </div>\\n </div>\\n</div>\",\"css\":\"/* PRESENTATIONAL STYLES */\\n\\nhtml {\\n font-size: 16px;\\n}\\n\\nbody {\\n background-color: #333;\\n color: #fff;\\n font-family: Helvetica;\\n padding: 25px;\\n text-align: center;\\n}\\n\\nh1 {\\n font-size: 2em;\\n font-weight: 800;\\n}\\n\\n/* DEMO STYLES */\\n\\n/* Parent */\\ndiv {\\n margin: 15px 0;\\n}\\n\\n/* Add padding to the parent */\\n.padding::before,\\n.padding::after {\\n content: ' ';\\n margin: -1px 0;\\n display: block;\\n height: 2px;\\n}\\n\\n/* Here come the children */\\n.red {\\n background-color: #ff6b6b;\\n}\\n\\n.orange {\\n background-color: #ff9e2c;\\n}\\n\\n.yellow {\\n background-color: #eeee78;\\n}\\n\\n.green {\\n background-color: #4ecd9d;\\n}\\n\\n.blue {\\n background-color: #4e97cd;\\n}\\n\\n.purple {\\n background-color: #6c4ecd;\\n}\",\"js\":\"\",\"html_pre_processor\":\"none\",\"css_pre_processor\":\"none\",\"js_pre_processor\":\"none\",\"html_classes\":\"\",\"css_starter\":\"reset\",\"js_library\":null,\"created_at\":\"2015-05-26T13:41:09.000Z\",\"updated_at\":\"2015-05-26T13:41:09.000Z\",\"title\":\"Collapsing Margins: Parents and Children Comparison\",\"description\":\"\\n\\nForked from [CSS-Tricks](http://codepen.io/team/css-tricks/)'s Pen [Collapsing Margins: Vertical](http://codepen.io/team/css-tricks/pen/pJyxQa/).\",\"slug_hash\":\"RPoLRJ\",\"head\":\"\",\"private\":false,\"has_animation\":false,\"team_id\":0,\"css_prefix\":\"neither\",\"template\":false,\"parent_id\":null,\"comments_count\":0,\"custom_screenshot_filename\":null,\"loves_count\":0,\"pick\":false,\"popularity_score\":0,\"views_count\":0,\"pick_visible_at\":\"2022-11-08T22:42:57.485Z\",\"pen_hash\":null}","__jwt":"eyJhbGciOiJIUzI1NiJ9.eyJjbGFpbXMiOnsidXNlcl9pZCI6MX0sImV4cCI6MTY3NTI2Mzg4OX0.Alvijbjmzt3wImMwQ5sLlws2RzWuA7OR8TITrmX4PuY","__processorsMap":{"autoprefixer":"autoprefixer-10","babel":"babel-7","coffeescript":"coffeescript-2","format-1":"format-1","flutter":"flutter-1","haml":"haml-4","less":"less-3","lint-1":"lint-1","livescript":"livescript-1","markdown":"markdown-11","postcss":"postcss-7","pug":"pug-2","sass":"sass-1","scss":"sass-1","sass-ruby-3":"sass-ruby-3","sass-ruby-compass-3":"sass-ruby-compass-3","slim":"slim-3","stylus":"stylus-0","typescript":"typescript-4","vue":"vue-2","vue3":"vue-3"},"__favicon_mask_icon":"https://cpwebassets.codepen.io/assets/favicon/logo-pin-8f3771b1072e3c38bd662872f6b673a722f4b3ca2421637d5596661b4e2132cc.svg","__favicon_shortcut_icon":"https://cpwebassets.codepen.io/assets/favicon/favicon-aec34940fbc1a6e787974dcd360f2c6b63348d4b1f4e06c77743096d55480f33.ico","__path_to_iframe_console_runner":"https://cpwebassets.codepen.io/assets/editor/iframe/iframeConsoleRunner-6bce046e7128ddf9391ccf7acbecbf7ce0cbd7b6defbeb2e217a867f51485d25.js","__path_to_iframe_refresh_css":"https://cpwebassets.codepen.io/assets/editor/iframe/iframeRefreshCSS-550eae0ce567d3d9182e33cee4e187761056020161aa87e3ef74dc467972c555.js","__path_to_iframe_runtime_errors":"https://cpwebassets.codepen.io/assets/editor/iframe/iframeRuntimeErrors-4f205f2c14e769b448bcf477de2938c681660d5038bc464e3700256713ebe261.js","__path_to_processor_worker":"https://cpwebassets.codepen.io/assets/packs/router.js","__path_to_stop_execution_on_timeout":"https://cpwebassets.codepen.io/assets/common/stopExecutionOnTimeout-2c7831bb44f98c1391d6a4ffda0e1fd302503391ca806e7fcc7b9b87197aec26.js","__pen_normalize_css_url":"https://cdnjs.cloudflare.com/ajax/libs/normalize/5.0.0/normalize.min.css","__pen_prefix_free_url":"https://cdnjs.cloudflare.com/ajax/libs/prefixfree/1.0.7/prefixfree.min.js","__pen_reset_css_url":"https://cdnjs.cloudflare.com/ajax/libs/meyer-reset/2.0/reset.min.css"}