diff --git a/options/options.css b/options/options.css
index a9280ca..6b440eb 100644
--- a/options/options.css
+++ b/options/options.css
@@ -1,9 +1,38 @@
+:root {
+    --c-text: #000;
+    --c-background: #fff;
+    --c-btn-background: #e7e7e7;
+
+    @media (prefers-color-scheme: dark) {
+        --c-text: #fff;
+        --c-background: #27272a;
+        --c-btn-background: #555;
+    }
+}
+
 html {
+    background-color: var(--c-background);
     font-family: sans-serif;
+    box-sizing: content-box;
+    margin: 0;
+    height: 100%;
+}
+
+body {
+    box-sizing: content-box;
+    margin: 0;
+    height: 100%;
+}
+
+form {
+    box-sizing: content-box;
+    height: 100%;
+    margin: 0;
 }
 
 button {
-    background-color: #e7e7e7;
+    color: var(--c-text);
+    background-color: var(--c-btn-background);
     border-radius: 5px;
     border: none;
     padding: 5px 10px;
@@ -16,6 +45,7 @@ button {
 }
 
 #spaces {
+    color: var(--c-text);
     width: 100%;
     border-collapse: collapse;
 }
@@ -41,7 +71,9 @@ button {
 }
 
 #spaces tbody input {
+    background-color: var(--c-background);
     border: none;
+    color: var(--c-text);
     height: 100%;
     width: 100%;
     font-size: inherit;