--- a/devtools/client/jar.mn
+++ b/devtools/client/jar.mn
@@ -148,16 +148,17 @@ devtools.jar:
 %   skin devtools classic/1.0 %skin/
     skin/devtools-browser.css (themes/devtools-browser.css)
     skin/common.css (themes/common.css)
     skin/splitters.css (themes/splitters.css)
     skin/dark-theme.css (themes/dark-theme.css)
     skin/light-theme.css (themes/light-theme.css)
     skin/firebug-theme.css (themes/firebug-theme.css)
     skin/toolbars.css (themes/toolbars.css)
+    skin/tooltips.css (themes/tooltips.css)
     skin/variables.css (themes/variables.css)
     skin/images/add.svg (themes/images/add.svg)
     skin/images/filters.svg (themes/images/filters.svg)
     skin/images/filter-swatch.svg (themes/images/filter-swatch.svg)
     skin/images/angle-swatch.svg (themes/images/angle-swatch.svg)
     skin/images/pseudo-class.svg (themes/images/pseudo-class.svg)
     skin/images/controls.png (themes/images/controls.png)
     skin/images/controls@2x.png (themes/images/controls@2x.png)

--- a/devtools/client/shared/test/browser_html_tooltip-01.js
+++ b/devtools/client/shared/test/browser_html_tooltip-01.js
@@ -6,17 +6,17 @@
 
 /**
  * Test the HTMLTooltip show & hide methods.
  */
 
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 const TEST_URI = `data:text/xml;charset=UTF-8,<?xml version="1.0"?>
   <?xml-stylesheet href="chrome://global/skin/global.css"?>
-  <?xml-stylesheet href="chrome://devtools/skin/common.css"?>
+  <?xml-stylesheet href="chrome://devtools/skin/tooltips.css"?>
   <window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
    title="Tooltip test">
     <vbox flex="1">
       <hbox id="box1" flex="1">test1</hbox>
       <hbox id="box2" flex="1">test2</hbox>
       <hbox id="box3" flex="1">test3</hbox>
       <hbox id="box4" flex="1">test4</hbox>
     </vbox>

--- a/devtools/client/shared/test/browser_html_tooltip-02.js
+++ b/devtools/client/shared/test/browser_html_tooltip-02.js
@@ -6,17 +6,17 @@
 
 /**
  * Test the HTMLTooltip is closed when clicking outside of its container.
  */
 
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 const TEST_URI = `data:text/xml;charset=UTF-8,<?xml version="1.0"?>
   <?xml-stylesheet href="chrome://global/skin/global.css"?>
-  <?xml-stylesheet href="chrome://devtools/skin/common.css"?>
+  <?xml-stylesheet href="chrome://devtools/skin/tooltips.css"?>
   <window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
    title="Tooltip test">
     <vbox flex="1">
       <hbox id="box1" flex="1">test1</hbox>
       <hbox id="box2" flex="1">test2</hbox>
       <hbox id="box3" flex="1">test3</hbox>
       <hbox id="box4" flex="1">test4</hbox>
     </vbox>

--- a/devtools/client/shared/test/browser_html_tooltip-03.js
+++ b/devtools/client/shared/test/browser_html_tooltip-03.js
@@ -6,17 +6,17 @@
 
 /**
  * Test the HTMLTooltip autofocus configuration option.
  */
 
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 const TEST_URI = `data:text/xml;charset=UTF-8,<?xml version="1.0"?>
   <?xml-stylesheet href="chrome://global/skin/global.css"?>
-  <?xml-stylesheet href="chrome://devtools/skin/common.css"?>
+  <?xml-stylesheet href="chrome://devtools/skin/tooltips.css"?>
   <window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
    title="Tooltip test">
     <vbox flex="1">
       <hbox id="box1" flex="1">test1</hbox>
       <hbox id="box2" flex="1">test2</hbox>
       <hbox id="box3" flex="1">
         <textbox id="box3-input"></textbox>
       </hbox>

--- a/devtools/client/shared/test/browser_html_tooltip-04.js
+++ b/devtools/client/shared/test/browser_html_tooltip-04.js
@@ -7,17 +7,17 @@
 /**
  * Test the HTMLTooltip positioning for a small tooltip element (should aways
  * find a way to fit).
  */
 
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 const TEST_URI = `data:text/xml;charset=UTF-8,<?xml version="1.0"?>
   <?xml-stylesheet href="chrome://global/skin/global.css"?>
-  <?xml-stylesheet href="chrome://devtools/skin/common.css"?>
+  <?xml-stylesheet href="chrome://devtools/skin/tooltips.css"?>
   <window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
    title="Tooltip test">
     <vbox flex="1">
       <hbox style="height: 10px">spacer</hbox>
       <hbox id="box1" style="height: 50px">test1</hbox>
       <hbox id="box2" style="height: 50px">test2</hbox>
       <hbox flex="1">MIDDLE</hbox>
       <hbox id="box3" style="height: 50px">test3</hbox>

--- a/devtools/client/shared/test/browser_html_tooltip-05.js
+++ b/devtools/client/shared/test/browser_html_tooltip-05.js
@@ -7,17 +7,17 @@
 /**
  * Test the HTMLTooltip positioning for a huge tooltip element (can not fit in
  * the viewport).
  */
 
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 const TEST_URI = `data:text/xml;charset=UTF-8,<?xml version="1.0"?>
   <?xml-stylesheet href="chrome://global/skin/global.css"?>
-  <?xml-stylesheet href="chrome://devtools/skin/common.css"?>
+  <?xml-stylesheet href="chrome://devtools/skin/tooltips.css"?>
   <window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
    title="Tooltip test">
     <vbox flex="1">
       <hbox id="box1" style="height: 50px">test1</hbox>
       <hbox id="box2" style="height: 50px">test2</hbox>
       <hbox id="box3" style="height: 50px">test3</hbox>
       <hbox id="box4" style="height: 50px">test4</hbox>
     </vbox>

--- a/devtools/client/shared/test/browser_html_tooltip_arrow-01.js
+++ b/devtools/client/shared/test/browser_html_tooltip_arrow-01.js
@@ -15,17 +15,16 @@ const getAnchor = function (position) {
                                           height: 10px;
                                           position: absolute;
                                           background: red;
                                           ${position}"></html:div>`;
 };
 
 const TEST_URI = `data:text/xml;charset=UTF-8,<?xml version="1.0"?>
   <?xml-stylesheet href="chrome://global/skin/global.css"?>
-  <?xml-stylesheet href="chrome://devtools/skin/common.css"?>
   <?xml-stylesheet href="chrome://devtools/skin/light-theme.css"?>
 
   <window class="theme-light"
           xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
           xmlns:html="http://www.w3.org/1999/xhtml"
           title="Tooltip test">
     <vbox flex="1" style="position: relative">
       ${getAnchor("top: 0; left: 0;")}

--- a/devtools/client/shared/test/browser_html_tooltip_arrow-02.js
+++ b/devtools/client/shared/test/browser_html_tooltip_arrow-02.js
@@ -14,17 +14,16 @@ const getAnchor = function (position) {
   return `<html:div class="anchor" style="height: 5px;
                                           position: absolute;
                                           background: red;
                                           ${position}"></html:div>`;
 };
 
 const TEST_URI = `data:text/xml;charset=UTF-8,<?xml version="1.0"?>
   <?xml-stylesheet href="chrome://global/skin/global.css"?>
-  <?xml-stylesheet href="chrome://devtools/skin/common.css"?>
   <?xml-stylesheet href="chrome://devtools/skin/light-theme.css"?>
 
   <window class="theme-light"
           xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
           xmlns:html="http://www.w3.org/1999/xhtml"
           title="Tooltip test">
     <vbox flex="1" style="position: relative">
       ${getAnchor("top:    0; left: 0; width: 50px;")}

--- a/devtools/client/themes/common.css
+++ b/devtools/client/themes/common.css
@@ -146,195 +146,16 @@
   color: #222;
 }
 
 .devtools-autocomplete-listbox.firebug-theme > richlistitem > label,
 .devtools-autocomplete-listbox.light-theme > richlistitem > label {
   color: #666;
 }
 
-/* Tooltip widget (see devtools/client/shared/widgets/Tooltip.js) */
-
-.devtools-tooltip .panel-arrowcontent {
-  padding: 4px;
-}
-
-.devtools-tooltip .panel-arrowcontainer {
-  /* Reseting the transition used when panels are shown */
-  transition: none;
-  /* Panels slide up/down/left/right when they appear using a transform.
-  Since we want to remove the transition, we don't need to transform anymore
-  plus it can interfeer by causing mouseleave events on the underlying nodes */
-  transform: none;
-}
-
-.devtools-tooltip[clamped-dimensions] {
-  min-height: 100px;
-  max-height: 400px;
-  min-width: 100px;
-  max-width: 400px;
-}
-.devtools-tooltip[clamped-dimensions-no-min-height] {
-  min-height: 0;
-  max-height: 400px;
-  min-width: 100px;
-  max-width: 400px;
-}
-.devtools-tooltip[clamped-dimensions-no-max-or-min-height] {
-  min-width: 400px;
-  max-width: 400px;
-}
-.devtools-tooltip[clamped-dimensions] .panel-arrowcontent,
-.devtools-tooltip[clamped-dimensions-no-min-height] .panel-arrowcontent,
-.devtools-tooltip[clamped-dimensions-no-max-or-min-height] .panel-arrowcontent {
-  overflow: hidden;
-}
-.devtools-tooltip[wide] {
-  max-width: 600px;
-}
-
-/* Tooltip: Simple Text */
-
-.devtools-tooltip-simple-text {
-  max-width: 400px;
-  margin: 0 -4px; /* Compensate for the .panel-arrowcontent padding. */
-  padding: 8px 12px;
-  white-space: pre-wrap;
-}
-
-.devtools-tooltip-simple-text:first-child {
-  margin-top: -4px;
-}
-
-.devtools-tooltip-simple-text:last-child {
-  margin-bottom: -4px;
-}
-
-/* Tooltip: Alert Icon */
-
-.devtools-tooltip-alert-icon {
-  width: 32px;
-  height: 32px;
-  margin: 6px;
-  margin-inline-end: 20px;
-}
-
-.devtools-tooltip-alert-icon {
-  list-style-image: url("chrome://global/skin/icons/warning-32.png");
-}
-
-/* Tooltip: Variables View */
-
-.devtools-tooltip-variables-view-box {
-  margin: -4px; /* Compensate for the .panel-arrowcontent padding. */
-}
-
-.devtools-tooltip-variables-view-box .variable-or-property > .title {
-  padding-inline-end: 6px;
-}
-
-/* Tooltip: Tiles */
-
-.devtools-tooltip-tiles {
-  background-color: #eee;
-  background-image: linear-gradient(45deg, #ccc 25%, transparent 25%, transparent 75%, #ccc 75%, #ccc),
-    linear-gradient(45deg, #ccc 25%, transparent 25%, transparent 75%, #ccc 75%, #ccc);
-  background-size: 20px 20px;
-  background-position: 0 0, 10px 10px;
-}
-
-.devtools-tooltip-iframe {
-  border: none;
-  background: transparent;
-}
-
-.tooltip-container {
-  display: none;
-  position: fixed;
-  z-index: 9999;
-  display: none;
-  background: transparent;
-}
-
-.tooltip-panel{
-  background-color: var(--theme-tooltip-background);
-}
-
-.tooltip-visible {
-  display: block;
-}
-
-.tooltip-container[type="normal"] > .tooltip-panel {
-  height: 100%;
-  width: 100%;
-}
-
-/* Tooltip : arrow style */
-
-.tooltip-container[type="arrow"] {
-  filter: drop-shadow(0 3px 4px var(--theme-tooltip-shadow));
-}
-
-.tooltip-container[type="arrow"] > .tooltip-panel {
-  position: absolute;
-  box-sizing: border-box;
-  height: calc(100% - 13px);
-  width: 100%;
-
-  border: 3px solid var(--theme-tooltip-border);
-  border-radius: 5px;
-}
-
-.tooltip-top[type="arrow"] .tooltip-panel {
-  top: 0;
-}
-
-.tooltip-bottom[type="arrow"] .tooltip-panel {
-  bottom: 0;
-}
-
-.tooltip-arrow {
-  position: absolute;
-  height: 16px;
-  width: 32px;
-  overflow: hidden;
-}
-
-.tooltip-top .tooltip-arrow {
-  bottom: 0;
-}
-
-.tooltip-bottom .tooltip-arrow {
-  top: 0;
-}
-
-.tooltip-arrow:before {
-  content: "";
-  position: absolute;
-  width: 21px;
-  height: 21px;
-  margin-left: 4px;
-  background: linear-gradient(-45deg,
-    var(--theme-tooltip-background) 50%, transparent 50%);
-  border-color: var(--theme-tooltip-border);
-  border-style: solid;
-  border-width: 0px 3px 3px 0px;
-  border-radius: 3px;
-}
-
-.tooltip-bottom .tooltip-arrow:before {
-  margin-top: 4px;
-  transform: rotate(225deg);
-}
-
-.tooltip-top .tooltip-arrow:before {
-  margin-top: -12px;
-  transform: rotate(45deg);
-}
-
 /* links to source code, like displaying `myfile.js:45` */
 
 .devtools-source-link {
   font-family: var(--monospace-font-family);
   color: var(--theme-highlight-blue);
   cursor: pointer;
   white-space: nowrap;
   display: flex;

--- a/devtools/client/themes/dark-theme.css
+++ b/devtools/client/themes/dark-theme.css
@@ -1,16 +1,17 @@
 /* vim:set ts=2 sw=2 sts=2 et: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 @import url(variables.css);
 @import url(common.css);
 @import url(toolbars.css);
+@import url(tooltips.css);
 
 body {
   margin: 0;
 }
 
 .theme-body {
   background: var(--theme-body-background);
   color: var(--theme-body-color);

--- a/devtools/client/themes/light-theme.css
+++ b/devtools/client/themes/light-theme.css
@@ -1,16 +1,17 @@
 /* vim:set ts=2 sw=2 sts=2 et: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 @import url(variables.css);
 @import url(common.css);
 @import url(toolbars.css);
+@import url(tooltips.css);
 
 body {
   margin: 0;
 }
 
 .theme-body {
   background: var(--theme-body-background);
   color: var(--theme-body-color);

new file mode 100644
--- /dev/null
+++ b/devtools/client/themes/tooltips.css
@@ -0,0 +1,184 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+
+/* Tooltip widget (see devtools/client/shared/widgets/Tooltip.js) */
+
+.devtools-tooltip .panel-arrowcontent {
+  padding: 4px;
+}
+
+.devtools-tooltip .panel-arrowcontainer {
+  /* Reseting the transition used when panels are shown */
+  transition: none;
+  /* Panels slide up/down/left/right when they appear using a transform.
+  Since we want to remove the transition, we don't need to transform anymore
+  plus it can interfeer by causing mouseleave events on the underlying nodes */
+  transform: none;
+}
+
+.devtools-tooltip[clamped-dimensions] {
+  min-height: 100px;
+  max-height: 400px;
+  min-width: 100px;
+  max-width: 400px;
+}
+.devtools-tooltip[clamped-dimensions-no-min-height] {
+  min-height: 0;
+  max-height: 400px;
+  min-width: 100px;
+  max-width: 400px;
+}
+.devtools-tooltip[clamped-dimensions-no-max-or-min-height] {
+  min-width: 400px;
+  max-width: 400px;
+}
+.devtools-tooltip[clamped-dimensions] .panel-arrowcontent,
+.devtools-tooltip[clamped-dimensions-no-min-height] .panel-arrowcontent,
+.devtools-tooltip[clamped-dimensions-no-max-or-min-height] .panel-arrowcontent {
+  overflow: hidden;
+}
+.devtools-tooltip[wide] {
+  max-width: 600px;
+}
+
+/* Tooltip: Simple Text */
+
+.devtools-tooltip-simple-text {
+  max-width: 400px;
+  margin: 0 -4px; /* Compensate for the .panel-arrowcontent padding. */
+  padding: 8px 12px;
+  white-space: pre-wrap;
+}
+
+.devtools-tooltip-simple-text:first-child {
+  margin-top: -4px;
+}
+
+.devtools-tooltip-simple-text:last-child {
+  margin-bottom: -4px;
+}
+
+/* Tooltip: Alert Icon */
+
+.devtools-tooltip-alert-icon {
+  width: 32px;
+  height: 32px;
+  margin: 6px;
+  margin-inline-end: 20px;
+}
+
+.devtools-tooltip-alert-icon {
+  list-style-image: url("chrome://global/skin/icons/warning-32.png");
+}
+
+/* Tooltip: Variables View */
+
+.devtools-tooltip-variables-view-box {
+  margin: -4px; /* Compensate for the .panel-arrowcontent padding. */
+}
+
+.devtools-tooltip-variables-view-box .variable-or-property > .title {
+  padding-inline-end: 6px;
+}
+
+/* Tooltip: Tiles */
+
+.devtools-tooltip-tiles {
+  background-color: #eee;
+  background-image: linear-gradient(45deg, #ccc 25%, transparent 25%, transparent 75%, #ccc 75%, #ccc),
+    linear-gradient(45deg, #ccc 25%, transparent 25%, transparent 75%, #ccc 75%, #ccc);
+  background-size: 20px 20px;
+  background-position: 0 0, 10px 10px;
+}
+
+.devtools-tooltip-iframe {
+  border: none;
+  background: transparent;
+}
+
+.tooltip-container {
+  display: none;
+  position: fixed;
+  z-index: 9999;
+  display: none;
+  background: transparent;
+}
+
+.tooltip-panel{
+  background-color: var(--theme-tooltip-background);
+}
+
+.tooltip-visible {
+  display: block;
+}
+
+.tooltip-container[type="normal"] > .tooltip-panel {
+  height: 100%;
+  width: 100%;
+}
+
+/* Tooltip : arrow style */
+
+.tooltip-container[type="arrow"] {
+  filter: drop-shadow(0 3px 4px var(--theme-tooltip-shadow));
+}
+
+.tooltip-container[type="arrow"] > .tooltip-panel {
+  position: absolute;
+  box-sizing: border-box;
+  height: calc(100% - 13px);
+  width: 100%;
+
+  border: 3px solid var(--theme-tooltip-border);
+  border-radius: 5px;
+}
+
+.tooltip-top[type="arrow"] .tooltip-panel {
+  top: 0;
+}
+
+.tooltip-bottom[type="arrow"] .tooltip-panel {
+  bottom: 0;
+}
+
+.tooltip-arrow {
+  position: absolute;
+  height: 16px;
+  width: 32px;
+  overflow: hidden;
+}
+
+.tooltip-top .tooltip-arrow {
+  bottom: 0;
+}
+
+.tooltip-bottom .tooltip-arrow {
+  top: 0;
+}
+
+.tooltip-arrow:before {
+  content: "";
+  position: absolute;
+  width: 21px;
+  height: 21px;
+  margin-left: 4px;
+  background: linear-gradient(-45deg,
+    var(--theme-tooltip-background) 50%, transparent 50%);
+  border-color: var(--theme-tooltip-border);
+  border-style: solid;
+  border-width: 0px 3px 3px 0px;
+  border-radius: 3px;
+}
+
+.tooltip-bottom .tooltip-arrow:before {
+  margin-top: 4px;
+  transform: rotate(225deg);
+}
+
+.tooltip-top .tooltip-arrow:before {
+  margin-top: -12px;
+  transform: rotate(45deg);
+}