add media queries

src/assets/css/_variables.scss

@@ -1,11 +1,39 @@
 // colors
 
-$card-dark: #08090C;
+$card-dark: #08090c;
 $red: #df4646;
 $blue: rgb(5, 80, 150);
 $green: rgb(67, 148, 67);
 $separator: #ffffff46;
 $pink: rgb(196, 58, 58);
 // sizes
-$small: .5em;
-$smaller: .25em;
+$small: 0.5em;
+$smaller: 0.25em;
+
+// media query mixins
+
+@mixin phone-only {
+  @media (max-width: 599px) {
+    @content;
+  }
+}
+@mixin tablet-portrait {
+  @media (max-width: 900px) {
+    @content;
+  }
+}
+@mixin tablet-landscape {
+  @media (max-width: 1200px) {
+    @content;
+  }
+}
+@mixin for-desktop-up {
+  @media (min-width: 1200px) {
+    @content;
+  }
+}
+@mixin for-big-desktop-up {
+  @media (min-width: 1800px) {
+    @content;
+  }
+}

src/assets/css/global.scss

@@ -136,14 +136,13 @@ button {
   width: 30em;
   position: relative;
   margin-bottom: 0.5em;
-}
 
-@media (max-width: 70em) {
-  .r-sidebar {
+  @include tablet-landscape {
     display: none;
   }
 }
 
+
 .image {
   background-position: center;
   background-repeat: no-repeat;
@@ -248,3 +247,5 @@ button {
   background-image: url(../../assets/icons/playing.webp);
   transition: all 0.3s ease-in-out;
 }
+
+