Fix options page CSS in Firefox

The options page CSS didn't work correctly in Firefox, since it was
using styles originally developed by the Chromium team for Chrome. This
CL fixes this by using CSS properties also available in Firefox.

This CL also sets explicitly a font family and size, since this makes
the options page look better in Firefox (specially the experiments
page).

Fixed: twpowertools:119
Change-Id: I49c7a52c02b9ddd462d95da4148ebd893c87234f
diff --git a/src/static/options/chrome_style/chrome_style.css b/src/static/options/chrome_style/chrome_style.css
index 3f8b076..cfcb771 100644
--- a/src/static/options/chrome_style/chrome_style.css
+++ b/src/static/options/chrome_style/chrome_style.css
@@ -46,7 +46,7 @@
 h1,
 h2,
 h3 {
-  -webkit-user-select: none;
+  user-select: none;
   font-weight: normal;
   /* Makes the vertical size of the text the same for all fonts. */
   line-height: 1;
@@ -78,13 +78,13 @@
 
 /* Default state **************************************************************/
 
-:-webkit-any(button,
+:is(button,
              input[type='button'],
              input[type='submit']),
 select,
 input[type='checkbox'],
 input[type='radio'] {
-  -webkit-user-select: none;
+  user-select: none;
   background-image: linear-gradient(#ededed, #ededed 38%, #dedede);
   border: 1px solid rgba(0, 0, 0, 0.25);
   border-radius: 2px;
@@ -100,10 +100,10 @@
 select,
 input[type='checkbox']:not(:indeterminate),
 input[type='radio'] {
-  -webkit-appearance: none;
+  appearance: none;
 }
 
-:-webkit-any(button,
+:is(button,
              input[type='button'],
              input[type='submit']),
 select {
@@ -111,17 +111,17 @@
   min-width: 4em;
 }
 
-:-webkit-any(button,
+:is(button,
              input[type='button'],
              input[type='submit']) {
-  -webkit-padding-end: 10px;
-  -webkit-padding-start: 10px;
+  padding-inline-end: 10px;
+  padding-inline-start: 10px;
 }
 
 select {
-  -webkit-appearance: none;
-  -webkit-padding-end: 20px;
-  -webkit-padding-start: 6px;
+  appearance: none;
+  padding-inline-end: 20px;
+  padding-inline-start: 6px;
   /* OVERRIDE */
   background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABMAAAAICAQAAACxSAwfAAAAUUlEQVR4AWP4TxREZkYxpKHAKKzKEhOZvyG4zN8SE7Eq+6+wYCHbTwiT7eeChf8VsFsKVQhTxIDDbVCFfF8ginApgyp82wRShEcZVJIVzoJDAGqrgIJGRl20AAAAAElFTkSuQmCC),
       linear-gradient(#ededed, #ededed 38%, #dedede);
@@ -170,7 +170,7 @@
 }
 
 input[type='search'] {
-  -webkit-appearance: textfield;
+  appearance: textfield;
   /* NOTE: Keep a relatively high min-width for this so we don't obscure the end
    * of the default text in relatively spacious languages (i.e. German). */
   min-width: 160px;
@@ -179,7 +179,7 @@
 /* Checked ********************************************************************/
 
 input[type='checkbox']:checked:not(:indeterminate)::before {
-  -webkit-user-select: none;
+  user-select: none;
   background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAsAAAALCAQAAAADpb+tAAAAZ0lEQVR4AWNAA2xAiAXEM8xiMEAXVGJYz7AZCFEkmBi6wYKtEC4/gxqY9gILrmYQhwiXMWxkiAVyVoOFfSCCpkAmCK4Fk+1QA4GqekECUAMkka0KY9gIFvZDd5oawwyGBqACdIDqOwAQzBnTWnnU+gAAAABJRU5ErkJggg==);
   background-size: 100% 100%;
   content: '';
@@ -202,11 +202,11 @@
 
 /* Hover **********************************************************************/
 
-:enabled:hover:-webkit-any(
+:enabled:hover:is(
     select,
     input[type='checkbox'],
     input[type='radio'],
-    :-webkit-any(
+    :is(
         button,
         input[type='button'],
         input[type='submit'])) {
@@ -217,19 +217,19 @@
   color: black;
 }
 
-:enabled:hover:-webkit-any(select) {
+:enabled:hover:is(select) {
   /* OVERRIDE */
   background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABMAAAAICAQAAACxSAwfAAAAUUlEQVR4AWP4TxREZkYxpKHAKKzKEhOZvyG4zN8SE7Eq+6+wYCHbTwiT7eeChf8VsFsKVQhTxIDDbVCFfF8ginApgyp82wRShEcZVJIVzoJDAGqrgIJGRl20AAAAAElFTkSuQmCC),
-      linear-gradient(#f0f0f0, #f0f0f0 38%, #e0e0e0);
+      linear-gradient(#f0f0f0, #f0f0f0 38%, #e0e0e0)!important;
 }
 
 /* Active *********************************************************************/
 
-:enabled:active:-webkit-any(
+:enabled:active:is(
     select,
     input[type='checkbox'],
     input[type='radio'],
-    :-webkit-any(
+    :is(
         button,
         input[type='button'],
         input[type='submit'])) {
@@ -238,7 +238,7 @@
   text-shadow: none;
 }
 
-:enabled:active:-webkit-any(select) {
+:enabled:active:is(select) {
   /* OVERRIDE */
   background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABMAAAAICAQAAACxSAwfAAAAUUlEQVR4AWP4TxREZkYxpKHAKKzKEhOZvyG4zN8SE7Eq+6+wYCHbTwiT7eeChf8VsFsKVQhTxIDDbVCFfF8ginApgyp82wRShEcZVJIVzoJDAGqrgIJGRl20AAAAAElFTkSuQmCC),
       linear-gradient(#e7e7e7, #e7e7e7 38%, #d7d7d7);
@@ -246,7 +246,7 @@
 
 /* Disabled *******************************************************************/
 
-:disabled:-webkit-any(
+:disabled:is(
     button,
     input[type='button'],
     input[type='submit']),
@@ -264,12 +264,12 @@
       linear-gradient(#f1f1f1, #f1f1f1 38%, #e6e6e6);
 }
 
-input:disabled:-webkit-any([type='checkbox'],
+input:disabled:is([type='checkbox'],
                            [type='radio']) {
   opacity: .75;
 }
 
-input:disabled:-webkit-any([type='password'],
+input:disabled:is([type='password'],
                            [type='search'],
                            [type='text'],
                            [type='url'],
@@ -279,7 +279,7 @@
 
 /* Focus **********************************************************************/
 
-:enabled:focus:-webkit-any(
+:enabled:focus:is(
     select,
     input[type='checkbox'],
     input[type='number'],
@@ -289,12 +289,12 @@
     input[type='text'],
     input[type='url'],
     input:not([type]),
-    :-webkit-any(
+    :is(
          button,
          input[type='button'],
          input[type='submit'])) {
   /* OVERRIDE */
-  -webkit-transition: border-color 200ms;
+  transition: border-color 200ms;
   /* We use border color because it follows the border radius (unlike outline).
    * This is particularly noticeable on mac. */
   border-color: rgb(77, 144, 254);
@@ -314,7 +314,7 @@
  *   </div>
  */
 
-:-webkit-any(.checkbox, .radio) label {
+:is(.checkbox, .radio) label {
   /* Don't expand horizontally: <http://crbug.com/112091>. */
   align-items: center;
   display: inline-flex;
@@ -322,20 +322,20 @@
   padding-top: 7px;
 }
 
-:-webkit-any(.checkbox, .radio) label input {
+:is(.checkbox, .radio) label input {
   flex-shrink: 0;
 }
 
-:-webkit-any(.checkbox, .radio) label input ~ span {
-  -webkit-margin-start: 0.6em;
+:is(.checkbox, .radio) label input ~ span {
+  margin-inline-start: 0.6em;
   /* Make sure long spans wrap at the same horizontal position they start. */
   display: block;
 }
 
-:-webkit-any(.checkbox, .radio) label:hover {
+:is(.checkbox, .radio) label:hover {
   color: black;
 }
 
-label > input:disabled:-webkit-any([type='checkbox'], [type='radio']) ~ span {
+label > input:disabled:is([type='checkbox'], [type='radio']) ~ span {
   color: #999;
 }
diff --git a/src/static/options/options.css b/src/static/options/options.css
index 68057ce..39783ef 100644
--- a/src/static/options/options.css
+++ b/src/static/options/options.css
@@ -1,5 +1,7 @@
 body {
   padding-top: 16px;
+  font-family: 'Roboto', -apple-system, BlinkMacSystemFont, 'Segoe UI Adjusted', 'Segoe UI', 'Liberation Sans', sans-serif;
+  font-size: 13px;
 }
 
 main {