Refine theme toggle appearance

style.css

@@ -358,7 +358,7 @@ html {
 /* THEME TOGGLE */
 
 .theme-toggle {
-  position: fixed;
+  position: absolute;
   top: 16px;
   right: 18px;
   z-index: 1000;
@@ -366,19 +366,21 @@ html {
   display: inline-flex;
   align-items: center;
   justify-content: center;
-  min-width: 104px;
 
-  padding: 9px 13px;
+  width: 42px;
+  height: 42px;
+  padding: 0;
+
   border: 1px solid rgba(23, 32, 51, .22);
-  border-radius: 999px;
+  border-radius: 50%;
 
   color: #172033;
   background: rgba(255, 255, 255, .94);
   box-shadow: 0 5px 18px rgba(0, 0, 0, .15);
 
   font: inherit;
-  font-size: .86rem;
-  font-weight: 700;
+  font-size: 1.25rem;
+  line-height: 1;
   cursor: pointer;
 
   transition:
@@ -420,8 +422,8 @@ html[data-theme="night"] .theme-toggle {
   .theme-toggle {
     top: 10px;
     right: 10px;
-    min-width: 92px;
-    padding: 8px 11px;
-    font-size: .8rem;
+    width: 38px;
+    height: 38px;
+    font-size: 1.1rem;
   }
 }