diff --git a/src/App.js b/src/App.js
index 50778b5..0043513 100644
--- a/src/App.js
+++ b/src/App.js
@@ -21,6 +21,7 @@ class App extends Component {
             search_text: null,
             flow_render_key: +new Date(),
             token: localStorage['TOKEN']||null,
+            darkmode: window.matchMedia('(prefers-color-scheme: dark)').matches,
         };
         this.show_sidebar_bound=this.show_sidebar.bind(this);
         this.set_mode_bound=this.set_mode.bind(this);
@@ -30,6 +31,28 @@ class App extends Component {
         this.inpku_flag=window[atob('ZG9jdW1lbnQ')][atob('Y29va2ll')].indexOf(atob('cGt1X2lwX2ZsYWc9eWVz'))!==-1;
     }
 
+    componentDidMount() {
+        this.update_color_scheme();
+        window.matchMedia('(prefers-color-scheme: dark)').addListener((e)=>{
+            this.setState({
+                darkmode: e.matches,
+            });
+        });
+    }
+
+    componentDidUpdate(prevProps,prevState) {
+        if(this.state.darkmode!==prevState.darkmode)
+            this.update_color_scheme();
+    }
+
+    update_color_scheme() {
+        if(this.state.darkmode)
+            document.body.classList.add('root-dark-mode');
+        else
+            document.body.classList.remove('root-dark-mode');
+    }
+
+
     on_pressure() {
         if(this.state.sidebar_title!==null)
             this.setState((prevState)=>({
diff --git a/src/Common.css b/src/Common.css
index b1ca4eb..2448f61 100644
--- a/src/Common.css
+++ b/src/Common.css
@@ -7,6 +7,10 @@
     height: 100%;
 }
 
+.root-dark-mode .bg-img {
+    opacity: .6;
+}
+
 .black-outline {
     text-shadow: /* also change .flow-item-row-with-prompt:hover::before */
         -1px -1px 0 rgba(0,0,0,.6),
@@ -22,6 +26,23 @@
     font-weight: bold;
 }
 
+.root-dark-mode .search-query-highlight {
+    border-bottom: 1px solid white;
+}
+
 .url-pid-link {
     opacity: .6;
+}
+
+:root {
+    --coloredspan-bgcolor-light: white;
+    --coloredspan-bgcolor-dark: black;
+}
+
+.colored-span {
+    background-color: var(--coloredspan-bgcolor-light);
+}
+
+.root-dark-mode .colored-span {
+    background-color: var(--coloredspan-bgcolor-dark);
 }
\ No newline at end of file
diff --git a/src/Common.js b/src/Common.js
index 0c01710..fe53dac 100644
--- a/src/Common.js
+++ b/src/Common.js
@@ -17,6 +17,15 @@ export function build_highlight_re(txt,split) {
     return txt ? new RegExp(`(${txt.split(split).filter((x)=>!!x).map(escape_regex).join('|')})`,'g') : /^$/g;
 }
 
+function ColoredSpan(props) {
+    return (
+        <span className="colored-span" style={{
+            '--coloredspan-bgcolor-light': props.colors[0],
+            '--coloredspan-bgcolor-dark': props.colors[1],
+        }}>{props.children}</span>
+    )
+}
+
 export class HighlightedText extends PureComponent {
     render() {
         function normalize_url(url) {
@@ -31,7 +40,7 @@ export class HighlightedText extends PureComponent {
                             rule==='url_pid' ? <span className="url-pid-link" title={p}>/hole/##</span> :
                             rule==='url' ? <a href={normalize_url(p)} target="_blank" rel="noopener">{p}</a> :
                             rule==='pid' ? <a href={'##'+p} onClick={(e)=>{e.preventDefault(); this.props.show_pid(p);}}>{p}</a> :
-                            rule==='nickname' ? <span style={{backgroundColor: this.props.color_picker.get(p)}}>{p}</span> :
+                            rule==='nickname' ? <ColoredSpan colors={this.props.color_picker.get(p)}>{p}</ColoredSpan> :
                             rule==='search' ? <span className="search-query-highlight">{p}</span> :
                             p
                         }</span>
diff --git a/src/Flows.css b/src/Flows.css
index 9de99fb..c8f7908 100644
--- a/src/Flows.css
+++ b/src/Flows.css
@@ -1,11 +1,27 @@
+:root {
+    --box-bgcolor-light: hsl(0,0%,97%);
+    --box-bgcolor-dark: hsl(0,0%,20%);
+    --foreground-dark: hsl(0,0%,93%)
+}
+
 .box {
-    background-color: hsl(0,0%,97%);
+    background-color: var(--box-bgcolor-light);
+    color: black;
     border-radius: 5px;
     margin: 1em 0;
     padding: .5em;
     box-shadow: 0 2px 5px rgba(0,0,0,.4);
 }
 
+.root-dark-mode .box {
+    background-color: var(--box-bgcolor-dark);
+    color: var(--foreground-dark);
+}
+
+.root-dark-mode .sidebar .box {
+    --box-bgcolor-dark: hsl(0,0%,25%);
+}
+
 .box-tip {
     min-width: 100px;
     z-index: 1;
@@ -18,6 +34,11 @@
     text-shadow: 0 0 3px black;
 }
 
+.root-dark-mode .box-danger {
+    background-color: #d44;
+    color: var(--foreground-dark);
+}
+
 .left-container .flow-item {
     display: inline-block;
     width: 600px;
@@ -139,6 +160,10 @@
     max-height: 80vh;
 }
 
+.root-dark-mode .flow-item-row p.img img {
+    filter: brightness(.8);
+}
+
 .box-header-badge {
     float: right;
     margin: 0 .5em;
@@ -157,6 +182,10 @@
     display: none;
 }
 
+.root-dark-mode .flow-item-dot {
+    background-color: #eebb66;
+}
+
 .left-container .flow-item-dot {
     display: block;
 }
@@ -174,6 +203,10 @@
     color: #666666;
 }
 
+.root-dark-mode .box-id {
+    color: #bbbbbb;
+}
+
 .box-id a:hover::before {
     content: "复制全文";
     position: relative;
@@ -224,4 +257,8 @@
     border-radius: 3px;
     margin-right: .25em;
     padding: 0 .25em;
+}
+
+.root-dark-mode .box-header-tag {
+    background-color: #00a;
 }
\ No newline at end of file
diff --git a/src/Flows.js b/src/Flows.js
index ed4341f..0fe639e 100644
--- a/src/Flows.js
+++ b/src/Flows.js
@@ -80,7 +80,8 @@ class Reply extends PureComponent {
         ]);
         return (
             <div className={'flow-reply box'} style={this.props.info._display_color ? {
-                backgroundColor: this.props.info._display_color,
+                '--box-bgcolor-light': this.props.info._display_color[0],
+                '--box-bgcolor-dark': this.props.info._display_color[1],
             } : null}>
                 <div className="box-header">
                     <code className="box-id">#{this.props.info.cid}</code>
diff --git a/src/Sidebar.css b/src/Sidebar.css
index 017dd8d..40b1cba 100644
--- a/src/Sidebar.css
+++ b/src/Sidebar.css
@@ -20,6 +20,13 @@
     transition: unset;
 }
 
+.root-dark-mode .sidebar-on .sidebar-shadow {
+    opacity: .5;
+}
+.root-dark-mode .sidebar-on .sidebar-shadow:active {
+    opacity: .3;
+}
+
 .sidebar {
     user-select: text;
     position: fixed;
@@ -32,6 +39,10 @@
     backdrop-filter: blur(10px);
 }
 
+.root-dark-mode .sidebar {
+    background-color: hsla(0,0%,5%,.7);
+}
+
 .sidebar, .sidebar-title {
     will-change: left;
     left: 100%;
@@ -56,6 +67,13 @@
     backdrop-filter: blur(10px);
     box-shadow: 0 3px 5px rgba(0,0,0,.2);
 }
+
+.root-dark-mode .sidebar-title {
+    background-color: hsla(0,0%,20%,.6);
+    color: var(--foreground-dark);
+    text-shadow: 0 0 3px black;
+}
+
 .sidebar-title a {
     pointer-events: initial;
 }
diff --git a/src/Title.css b/src/Title.css
index 31c7335..5e8f926 100644
--- a/src/Title.css
+++ b/src/Title.css
@@ -1,3 +1,11 @@
+/* overriding infrastructure/widget.css */
+.root-dark-mode .title-line {
+    color: var(--foreground-dark);
+}
+.root-dark-mode .title-line::before, .root-dark-mode .title-line::after {
+    background-color: var(--foreground-dark);
+}
+
 .title-bar {
     z-index: 10;
     position: sticky;
@@ -11,6 +19,10 @@
     backdrop-filter: blur(10px);
 }
 
+.root-dark-mode .title-bar {
+    background-color: hsla(0,0%,80%,.7);
+}
+
 .control-bar {
     display: flex;
     margin-top: .5em;
@@ -36,13 +48,17 @@
 .control-search {
     flex: auto;
     color: black;
-    background-color: rgba(255,255,255,.3);
+    background-color: rgba(255,255,255,.3) !important;
     margin: 0 .5em;
     min-width: 8em;
 }
 
 .control-search:focus {
-    background-color: white;
+    background-color: white !important;
+}
+
+.root-dark-mode .control-search:focus {
+    background-color: hsl(0,0%,90%) !important;
 }
 
 .list-menu {
diff --git a/src/color_picker.js b/src/color_picker.js
index ca4f2e9..cff6ead 100644
--- a/src/color_picker.js
+++ b/src/color_picker.js
@@ -11,14 +11,17 @@ export class ColorPicker {
     get(name) {
         name=name.toLowerCase();
         if(name==='洞主')
-            return 'hsl(0,0%,97%)';
+            return ['hsl(0,0%,97%)','hsl(0,0%,25%)'];
         if(!window.config.color_picker)
-            return 'hsl(0,0%,87%)';
+            return ['hsl(0,0%,87%)','hsl(0,0%,13%)'];
 
         if(!this.names[name]) {
             this.current_h+=golden_ratio_conjugate;
             this.current_h%=1;
-            this.names[name]=`hsl(${this.current_h*360}, 50%, 90%)`;
+            this.names[name]=[
+                `hsl(${this.current_h*360}, 50%, 90%)`,
+                `hsl(${this.current_h*360}, 60%, 25%)`,
+            ];
         }
         return this.names[name];
     }
diff --git a/src/index.css b/src/index.css
index 0335be4..ffdd16c 100644
--- a/src/index.css
+++ b/src/index.css
@@ -4,6 +4,10 @@ body {
     background-color: #333;
 }
 
+body.root-dark-mode {
+    background-color: black;
+}
+
 html::-webkit-scrollbar {
     display: none;
 }
@@ -15,6 +19,10 @@ a {
     color: #00c;
 }
 
+.root-dark-mode .left-container a, .root-dark-mode .sidebar a, .root-dark-mode .sidebar-title a {
+    color: #9bf;
+}
+
 input, textarea {
     border-radius: 5px;
     border: 1px solid black;
@@ -39,6 +47,10 @@ button, .button {
     margin: 0 .5rem;
 }
 
+.root-dark-mode button, .root-dark-mode .button {
+    background-color: rgba(255,255,255,.6);
+}
+
 button:hover, .button:hover {
     background-color: rgba(255,255,255,.7);
 }
@@ -46,3 +58,7 @@ button:hover, .button:hover {
 button:disabled, .button:disabled {
     background-color: rgba(128,128,128,.5);
 }
+
+.root-dark-mode input:not([type=file]), .root-dark-mode textarea {
+    background-color: hsl(0,0%,80%);
+}
\ No newline at end of file