diff --git a/lighthouse-core/report/html/renderer/report-renderer.js b/lighthouse-core/report/html/renderer/report-renderer.js
index 3c7e61051669..86559958f4b6 100644
--- a/lighthouse-core/report/html/renderer/report-renderer.js
+++ b/lighthouse-core/report/html/renderer/report-renderer.js
@@ -91,17 +91,6 @@ class ReportRenderer {
     return el;
   }
 
-  /**
-   * @return {Element}
-   */
-  _renderReportShortHeader() {
-    const shortHeaderContainer = this._dom.createElement('div', 'lh-header-container');
-    const wrapper = this._dom.cloneTemplate('#tmpl-lh-scores-wrapper', this._templateContext);
-    shortHeaderContainer.appendChild(wrapper);
-    return shortHeaderContainer;
-  }
-
-
   /**
    * @param {LH.ReportResult} report
    * @return {DocumentFragment}
@@ -195,16 +184,8 @@ class ReportRenderer {
    * @return {DocumentFragment}
    */
   _renderReport(report) {
-    let header;
     const headerContainer = this._dom.createElement('div');
-    if (this._dom.isDevTools()) {
-      headerContainer.classList.add('lh-header-plain');
-      header = this._renderReportShortHeader();
-    } else {
-      headerContainer.classList.add('lh-header-sticky');
-      header = this._renderReportHeader();
-    }
-    headerContainer.appendChild(header);
+    headerContainer.appendChild(this._renderReportHeader());
 
     const container = this._dom.createElement('div', 'lh-container');
     const reportSection = container.appendChild(this._dom.createElement('div', 'lh-report'));
@@ -242,38 +223,27 @@ class ReportRenderer {
       wrapper.appendChild(renderer.render(category, report.categoryGroups));
     }
 
+    const reportFragment = this._dom.createFragment();
+    const topbarDocumentFragment = this._renderReportTopbar(report);
+    reportFragment.appendChild(topbarDocumentFragment);
+
     if (scoreHeader) {
-      const scoreGauges =
-        this._renderScoreGauges(report, categoryRenderer, specificCategoryRenderers);
-      scoreHeader.append(...scoreGauges);
       const scoreScale = this._dom.cloneTemplate('#tmpl-lh-scorescale', this._templateContext);
       const scoresContainer = this._dom.find('.lh-scores-container', headerContainer);
+      scoreHeader.append(
+        ...this._renderScoreGauges(report, categoryRenderer, specificCategoryRenderers));
       scoresContainer.appendChild(scoreHeader);
       scoresContainer.appendChild(scoreScale);
-    }
-
-    reportSection.appendChild(this._renderReportFooter(report));
-
-    const reportFragment = this._dom.createFragment();
 
-    if (!this._dom.isDevTools()) {
-      const topbarDocumentFragment = this._renderReportTopbar(report);
-      reportFragment.appendChild(topbarDocumentFragment);
-    }
-
-    if (scoreHeader && !this._dom.isDevTools()) {
       const stickyHeader = this._dom.createElement('div', 'lh-sticky-header');
-      this._dom.createChildOf(stickyHeader, 'div', 'lh-highlighter');
-
-      const scoreGauges =
-        this._renderScoreGauges(report, categoryRenderer, specificCategoryRenderers);
-      stickyHeader.append(...scoreGauges);
-
+      stickyHeader.append(
+        ...this._renderScoreGauges(report, categoryRenderer, specificCategoryRenderers));
       reportFragment.appendChild(stickyHeader);
     }
 
     reportFragment.appendChild(headerContainer);
     reportFragment.appendChild(container);
+    reportSection.appendChild(this._renderReportFooter(report));
 
     return reportFragment;
   }
diff --git a/lighthouse-core/report/html/renderer/report-ui-features.js b/lighthouse-core/report/html/renderer/report-ui-features.js
index 8a2db2697921..b403805b5610 100644
--- a/lighthouse-core/report/html/renderer/report-ui-features.js
+++ b/lighthouse-core/report/html/renderer/report-ui-features.js
@@ -44,6 +44,8 @@ class ReportUIFeatures {
     this._dom = dom;
     /** @type {Document} */
     this._document = this._dom.document();
+    /** @type {ParentNode} */
+    this._templateContext = this._dom.document();
     /** @type {boolean} */
     this._copyAttempt = false;
     /** @type {HTMLElement} */
@@ -76,9 +78,8 @@ class ReportUIFeatures {
    * @param {LH.Result} report
    */
   initFeatures(report) {
-    if (this._dom.isDevTools()) return;
-
     this.json = report;
+
     this._setupMediaQueryListeners();
     this._setupExportButton();
     this._setupThirdPartyFilter();
@@ -86,6 +87,7 @@ class ReportUIFeatures {
     this._resetUIState();
     this._document.addEventListener('keyup', this.onKeyUp);
     this._document.addEventListener('copy', this.onCopy);
+
     const topbarLogo = this._dom.find('.lh-topbar__logo', this._document);
     topbarLogo.addEventListener('click', () => this._toggleDarkTheme());
 
@@ -98,13 +100,9 @@ class ReportUIFeatures {
     const scoresAll100 = Object.values(report.categories).every(cat => cat.score === 1);
     const hasAllCoreCategories =
       Object.keys(report.categories).filter(id => !Util.isPluginCategory(id)).length >= 5;
-    if (!this._dom.isDevTools() && scoresAll100 && hasAllCoreCategories) {
+    if (scoresAll100 && hasAllCoreCategories) {
       turnOffTheLights = true;
-      const scoresContainer = this._dom.find('.lh-scores-container', this._document);
-      scoresContainer.classList.add('score100');
-      scoresContainer.addEventListener('click', _ => {
-        scoresContainer.classList.toggle('fireworks-paused');
-      });
+      this._enableFireworks();
     }
 
     if (turnOffTheLights) {
@@ -114,8 +112,21 @@ class ReportUIFeatures {
     // There is only a sticky header when at least 2 categories are present.
     if (Object.keys(this.json.categories).length >= 2) {
       this._setupStickyHeaderElements();
-      this._document.addEventListener('scroll', this._updateStickyHeaderOnScroll);
-      window.addEventListener('resize', this._updateStickyHeaderOnScroll);
+      const containerEl = this._dom.find('.lh-container', this._document);
+      const elToAddScrollListener = this._getScrollParent(containerEl);
+      elToAddScrollListener.addEventListener('scroll', this._updateStickyHeaderOnScroll);
+
+      // Use ResizeObserver where available.
+      // TODO: there is an issue with incorrect position numbers and, as a result, performance
+      // issues due to layout thrashing.
+      // See https://github.com/GoogleChrome/lighthouse/pull/9023/files#r288822287 for details.
+      // For now, limit to DevTools.
+      if (this._dom.isDevTools()) {
+        const resizeObserver = new window.ResizeObserver(this._updateStickyHeaderOnScroll);
+        resizeObserver.observe(containerEl);
+      } else {
+        window.addEventListener('resize', this._updateStickyHeaderOnScroll);
+      }
     }
 
     // Show the metric descriptions by default when there is an error.
@@ -128,6 +139,43 @@ class ReportUIFeatures {
     }
   }
 
+  /**
+   * Define a custom element for <templates> to be extracted from. For example:
+   *     this.setTemplateContext(new DOMParser().parseFromString(htmlStr, 'text/html'))
+   * @param {ParentNode} context
+   */
+  setTemplateContext(context) {
+    this._templateContext = context;
+  }
+
+  /**
+   * Finds the first scrollable ancestor of `element`. Falls back to the document.
+   * @param {HTMLElement} element
+   * @return {Node}
+   */
+  _getScrollParent(element) {
+    const {overflowY} = window.getComputedStyle(element);
+    const isScrollable = overflowY !== 'visible' && overflowY !== 'hidden';
+
+    if (isScrollable) {
+      return element;
+    }
+
+    if (element.parentElement) {
+      return this._getScrollParent(element.parentElement);
+    }
+
+    return document;
+  }
+
+  _enableFireworks() {
+    const scoresContainer = this._dom.find('.lh-scores-container', this._document);
+    scoresContainer.classList.add('score100');
+    scoresContainer.addEventListener('click', _ => {
+      scoresContainer.classList.toggle('fireworks-paused');
+    });
+  }
+
   /**
    * Fires a custom DOM event on target.
    * @param {string} name Name of the event.
@@ -188,13 +236,13 @@ class ReportUIFeatures {
       if (thirdPartyRows.size === urlItems.length || !thirdPartyRows.size) return;
 
       // create input box
-      const filterTemplate = this._dom.cloneTemplate('#tmpl-lh-3p-filter', this._document);
+      const filterTemplate = this._dom.cloneTemplate('#tmpl-lh-3p-filter', this._templateContext);
       const filterInput = this._dom.find('input', filterTemplate);
       const id = `lh-3p-filter-label--${index}`;
 
       filterInput.id = id;
       filterInput.addEventListener('change', e => {
-        // Remove rows from the dom and keep track of them to readd on uncheck.
+        // Remove rows from the dom and keep track of them to re-add on uncheck.
         // Why removing instead of hiding? To keep nth-child(even) background-colors working.
         if (e.target instanceof HTMLInputElement && !e.target.checked) {
           for (const row of thirdPartyRows.values()) {
@@ -263,7 +311,10 @@ class ReportUIFeatures {
     this.topbarEl = this._dom.find('.lh-topbar', this._document);
     this.scoreScaleEl = this._dom.find('.lh-scorescale', this._document);
     this.stickyHeaderEl = this._dom.find('.lh-sticky-header', this._document);
-    this.highlightEl = this._dom.find('.lh-highlighter', this._document);
+
+    // Position highlighter at first gauge; will be transformed on scroll.
+    const firstGauge = this._dom.find('.lh-gauge__wrapper', this.stickyHeaderEl);
+    this.highlightEl = this._dom.createChildOf(firstGauge, 'div', 'lh-highlighter');
   }
 
   /**
@@ -554,7 +605,15 @@ class ReportUIFeatures {
    * @param {boolean} [force]
    */
   _toggleDarkTheme(force) {
-    this._document.body.classList.toggle('dark', force);
+    const el = this._dom.find('.lh-vars', this._document);
+    // This seems unnecessary, but in DevTools, passing "undefined" as the second
+    // parameter acts like passing "false".
+    // https://github.com/ChromeDevTools/devtools-frontend/blob/dd6a6d4153647c2a4203c327c595692c5e0a4256/front_end/dom_extension/DOMExtension.js#L809-L819
+    if (typeof force === 'undefined') {
+      el.classList.toggle('dark');
+    } else {
+      el.classList.toggle('dark', force);
+    }
   }
 
   _updateStickyHeaderOnScroll() {
@@ -574,11 +633,12 @@ class ReportUIFeatures {
     // Category order matches gauge order in sticky header.
     const gaugeWrapperEls = this.stickyHeaderEl.querySelectorAll('.lh-gauge__wrapper');
     const gaugeToHighlight = gaugeWrapperEls[highlightIndex];
-    const offset = gaugeToHighlight.getBoundingClientRect().left + 'px';
+    const origin = gaugeWrapperEls[0].getBoundingClientRect().left;
+    const offset = gaugeToHighlight.getBoundingClientRect().left - origin;
 
     // Mutate at end to avoid layout thrashing.
+    this.highlightEl.style.transform = `translate(${offset}px)`;
     this.stickyHeaderEl.classList.toggle('lh-sticky-header--visible', showStickyHeader);
-    this.highlightEl.style.left = offset;
   }
 }
 
diff --git a/lighthouse-core/report/html/report-styles.css b/lighthouse-core/report/html/report-styles.css
index 8be7d1206f03..c4c4faaeeed5 100644
--- a/lighthouse-core/report/html/report-styles.css
+++ b/lighthouse-core/report/html/report-styles.css
@@ -261,6 +261,24 @@
   --audit-indent: 16px;
   --expandable-indent: 16px;
 
+  --gauge-circle-size-big: 72px;
+  --gauge-circle-size: 64px;
+
+  --audits-margin-bottom: 20px;
+  --env-name-min-width: 120px;
+  --header-padding: 16px 0 16px 0;
+  --plugin-icon-size: 75%;
+  --pwa-icon-margin: 0 7px 0 -3px;
+  --score-container-width: 92px;
+  --score-number-font-size-big: 34px;
+  --score-number-font-size: 26px;
+  --score-shape-margin-left: 2px;
+  --score-shape-size: 10px;
+  --score-title-font-size-big: 22px;
+  --score-title-font-size: 14px;
+  --score-title-line-height-big: 26px;
+  --score-title-line-height: 20px;
+
   --lh-audit-vpadding: 4px;
   --lh-audit-hgap: 12px;
   --lh-audit-group-vpadding: 12px;
@@ -555,6 +573,9 @@
   .lh-column:first-of-type {
     margin-right: 0px;
   }
+  .lh-column:first-of-type .lh-metric:last-of-type {
+    border-bottom: 0;
+  }
 }
 
 
@@ -952,22 +973,6 @@
 }
 
 /* Report */
-
-.lh-header-sticky {
-  /** TODO: Redesigned report has a small sticky header.
-  For now, disable the current sticky behavior. */
-  /* position: -webkit-sticky;
-  position: sticky; */
-  top: 0;
-  width: 100%;
-  min-width: var(--report-min-width);
-  z-index: 2;
-  will-change: transform;
-}
-.lh-header-plain {
-  margin-top: var(--section-padding);
-}
-
 .lh-list > div:not(:last-child) {
   padding-bottom: 20px;
 }
diff --git a/lighthouse-core/report/html/templates.html b/lighthouse-core/report/html/templates.html
index 7032ea4b83c1..ee4b388c69af 100644
--- a/lighthouse-core/report/html/templates.html
+++ b/lighthouse-core/report/html/templates.html
@@ -159,7 +159,6 @@
     .lh-scores-container {
       display: flex;
       flex-direction: column;
-      margin-top: var(--topbar-height);
       padding: var(--header-padding);
       position: relative;
       width: 100%;
@@ -171,12 +170,12 @@
       --plugin-icon-size: 75%;
       --score-container-width: 60px;
       --score-number-font-size: 13px;
-      position: fixed;
+      position: sticky;
       left: 0;
       right: 0;
       top: var(--topbar-height);
       font-weight: 700;
-      display: flex;
+      display: none;
       justify-content: center;
       background-color: var(--color-sticky-header-bg);
       border-bottom: 1px solid var(--color-black-200);
@@ -184,12 +183,17 @@
       padding-bottom: 4px;
       z-index: 1;
       pointer-events: none;
-      opacity: 0;
     }
 
     .lh-sticky-header--visible {
+      display: flex;
       pointer-events: auto;
-      opacity: 1;
+    }
+
+    /* Disable the gauge arc animation for the sticky header, so toggling display: none
+       does not play the animation. */
+    .lh-sticky-header .lh-gauge-arc {
+      animation: none;
     }
 
     .lh-sticky-header .lh-gauge__label {
@@ -201,8 +205,11 @@
       height: 1px;
       background: var(--color-highlighter-bg);
       position: absolute;
-      bottom: -1px;
-      left: 0;
+      bottom: -5px;
+    }
+
+    .lh-gauge__wrapper:first-of-type {
+      contain: none;
     }
   </style>
   <div class="lh-scores-wrapper">
@@ -219,7 +226,7 @@
 <template id="tmpl-lh-topbar">
   <style>
     .lh-topbar {
-      position: fixed;
+      position: sticky;
       top: 0;
       left: 0;
       right: 0;
@@ -256,6 +263,15 @@
       cursor: pointer;
       margin-right: 5px;
     }
+    /*
+      Some features in the top right drop down menu don't work in the DevTools
+      client. They could with some tweaks, but currently they don't. For example:
+      Saving as HTML/JSON - does not bring up a file dialog, as one would expect in DevTools.
+                            also, it saves the AuditsPanel HTML, which is funky.
+    */
+    .lh-devtools .lh-export__button {
+      display: none;
+    }
     .lh-export__button svg {
       fill: var(--lh-export-icon-color);
     }
diff --git a/lighthouse-core/test/report/html/renderer/report-renderer-test.js b/lighthouse-core/test/report/html/renderer/report-renderer-test.js
index d961c9ad8976..477a984ce9eb 100644
--- a/lighthouse-core/test/report/html/renderer/report-renderer-test.js
+++ b/lighthouse-core/test/report/html/renderer/report-renderer-test.js
@@ -77,7 +77,7 @@ describe('ReportRenderer', () => {
     it('should render a report', () => {
       const container = renderer._dom._document.body;
       const output = renderer.renderReport(sampleResults, container);
-      assert.ok(output.querySelector('.lh-header-sticky'), 'has a header');
+      assert.ok(output.querySelector('.lh-header-container'), 'has a header');
       assert.ok(output.querySelector('.lh-report'), 'has report body');
       // 3 sets of gauges - one in sticky header, one in scores header, and one in each section.
       assert.equal(output.querySelectorAll('.lh-gauge__wrapper, .lh-gauge--pwa__wrapper').length,
diff --git a/lighthouse-viewer/tsconfig.json b/lighthouse-viewer/tsconfig.json
index 8996a9d996c9..9d5631bfd24a 100644
--- a/lighthouse-viewer/tsconfig.json
+++ b/lighthouse-viewer/tsconfig.json
@@ -2,7 +2,7 @@
   "extends": "../tsconfig",
   "compilerOptions": {
     "typeRoots": [
-      "@types",
+      "../node_modules/@types",
       "../types",
       "./types",
     ],
diff --git a/package.json b/package.json
index 0df74e94bf52..a1ad87657270 100644
--- a/package.json
+++ b/package.json
@@ -87,6 +87,7 @@
     "@types/node": "*",
     "@types/opn": "^3.0.28",
     "@types/raven": "^2.5.1",
+    "@types/resize-observer-browser": "^0.1.1",
     "@types/rimraf": "^2.0.2",
     "@types/semver": "^5.5.0",
     "@types/uglify-es": "^3.0.0",
@@ -183,7 +184,7 @@
     },
     {
       "path": "./dist/viewer/src/viewer.js",
-      "threshold": "70 Kb"
+      "threshold": "75 Kb"
     }
   ],
   "nyc": {
diff --git a/yarn.lock b/yarn.lock
index 4302fa1580c3..1546a5507ce0 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -585,6 +585,11 @@
     "@types/events" "*"
     "@types/node" "*"
 
+"@types/resize-observer-browser@^0.1.1":
+  version "0.1.1"
+  resolved "https://registry.yarnpkg.com/@types/resize-observer-browser/-/resize-observer-browser-0.1.1.tgz#9b7cdae9cdc8b1a7020ca7588018dac64c770866"
+  integrity sha512-5/bJS/uGB5kmpRrrAWXQnmyKlv+4TlPn4f+A2NBa93p+mt6Ht+YcNGkQKf8HMx28a9hox49ZXShtbGqZkk41Sw==
+
 "@types/rimraf@^2.0.2":
   version "2.0.2"
   resolved "https://registry.yarnpkg.com/@types/rimraf/-/rimraf-2.0.2.tgz#7f0fc3cf0ff0ad2a99bb723ae1764f30acaf8b6e"