style: standardize quotes in CSS and improve formatting for range input styles

src/index.css

@@ -1,5 +1,5 @@
-@import "tailwindcss";
-@import "tw-animate-css";
+@import 'tailwindcss';
+@import 'tw-animate-css';
 
 @custom-variant dark (&:is(.dark *));
 
@@ -121,26 +121,26 @@
 
 @layer components {
   /* Custom slider styles for volume control */
-  input[type="range"] {
+  input[type='range'] {
     -webkit-appearance: none;
     background: transparent;
   }
 
-  input[type="range"]::-webkit-slider-track {
+  input[type='range']::-webkit-slider-track {
     @apply h-1 bg-muted rounded-lg;
   }
 
-  input[type="range"]::-webkit-slider-thumb {
+  input[type='range']::-webkit-slider-thumb {
     -webkit-appearance: none;
     @apply h-4 w-4 bg-primary rounded-full cursor-pointer;
     margin-top: -6px;
   }
 
-  input[type="range"]::-moz-range-track {
+  input[type='range']::-moz-range-track {
     @apply h-1 bg-muted rounded-lg border-0;
   }
 
-  input[type="range"]::-moz-range-thumb {
+  input[type='range']::-moz-range-thumb {
     @apply h-4 w-4 bg-primary rounded-full cursor-pointer border-0;
   }