Improve css of wiki page

frontend/config/webpack.config.dev.js.template

@@ -94,7 +94,7 @@ module.exports = {
     // for React Native Web.
     extensions: ['.web.js', '.mjs', '.js', '.json', '.web.jsx', '.jsx'],
     alias: {
-      
+
       // Support React Native Web
       // https://www.smashingmagazine.com/2016/08/a-glimpse-into-the-future-with-react-native-for-web/
       'react-native': 'react-native-web',
@@ -125,7 +125,7 @@ module.exports = {
             options: {
               formatter: eslintFormatter,
               eslintPath: require.resolve('eslint'),
-              
+
             },
             loader: require.resolve('eslint-loader'),
           },
@@ -154,7 +154,7 @@ module.exports = {
             include: paths.appSrc,
             loader: require.resolve('babel-loader'),
             options: {
-              
+
               // This is a feature of `babel-loader` for webpack (not Babel itself).
               // It enables caching results in ./node_modules/.cache/babel-loader/
               // directory for faster rebuilds.
@@ -169,11 +169,17 @@ module.exports = {
           {
             test: /\.css$/,
             use: [
-              require.resolve('style-loader'),
+              {
+                loader: require.resolve('style-loader'),
+                options: {
+                  insertAt: 'top',
+                },
+              },
               {
                 loader: require.resolve('css-loader'),
                 options: {
                   importLoaders: 1,
+                  insertAt: 'top',
                 },
               },
               {
@@ -286,7 +292,7 @@ module.exports = {
       "Access-Control-Allow-Methods": "GET, POST, PUT, DELETE, PATCH, OPTIONS",
       "Access-Control-Allow-Headers": "X-Requested-With, content-type, Authorization"
     },
-    
+
     // watchOptions: {
     //   aggregateTimeout: 1000,
     //   poll: 5000,

frontend/src/components/MainPanel.js

@@ -34,7 +34,7 @@ class MainPanel extends Component {
         <div className="main-panel-top panel-top">
           <span className="sf2-icon-menu side-nav-toggle hidden-md-up d-md-none" title="Side Nav Menu" onClick={this.onMenuClick}></span>
            <div className={`wiki-page-ops ${this.props.permission === 'rw' ? '' : 'hide'}`}>
-              <a className="sf-btn-link btn-white" onClick={this.onEditClick}>Edit Page</a>
+              <a className="btn btn-secondary btn-topbar" onClick={this.onEditClick}>Edit Page</a>
            </div>
           <div className="common-toolbar">
             <Search />

frontend/src/css/wiki.css

@@ -87,3 +87,7 @@
     font-size:12px;
     color: #666;
 }
+
+.wiki-md-viewer-rendered-content.article h1 {
+  margin-top: 0;
+}

media/css/seahub_react.css

@@ -82,6 +82,13 @@ a:hover { color:#eb8205; }
 
 /* common elements */
 
+/**** topbar button ****/
+.btn-topbar {
+  padding: 0.25rem 0.5rem;
+  line-height: 1.6;
+  font-weight: normal;
+}
+
 /**** caret ****/
 .outer-caret,
 .inner-caret {