theme: Remove unnecessary !important rules

Using !important is a bad practice and should be avoided wherever
possible to make styling and debugging easier. See:

https://developer.mozilla.org/en-US/docs/Web/CSS/Specificity#The_!important_exception

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/957

data/theme/gnome-shell-sass/_drawing.scss

@@ -137,7 +137,7 @@
   // normal button
   @if $t==normal {
     color: $tc;
-    background-color: lighten($c, 3%) !important;
+    background-color: lighten($c, 3%);
     border-color: draw_border_color($c);
     @include draw_shadows($button_shadow);
     // box-shadow: 0 1px 1px 0 rgba(0,0,0,0.1);
@@ -157,7 +157,7 @@
   // hover button
   @else if $t==hover {
     color: $tc;
-    background-color: lighten($c, if($variant == 'light', 8%, 5%)) !important;
+    background-color: lighten($c, if($variant == 'light', 8%, 5%));
     border-color: if($variant == 'light', draw_border_color(lighten($c, 7%)), draw_border_color($c));
     @include draw_shadows($button_shadow);
     text-shadow: 0 1px $text_shadow_color;
@@ -167,7 +167,7 @@
   // active button
   @else if $t==active {
     color: $tc;
-    background-color: darken($c,3%) !important;
+    background-color: darken($c,3%);
     border-color: draw_border_color(if($variant == 'light', $c, darken($c,7%)));
     text-shadow: none;
     icon-shadow: none;
@@ -178,7 +178,7 @@
   @else if $t==insensitive {
     color: $insensitive_fg_color;
     border-color: $insensitive_borders_color;
-    background-color: $insensitive_bg_color !important;
+    background-color: $insensitive_bg_color;
     box-shadow: none;
     text-shadow: none;
     icon-shadow: none;

data/theme/gnome-shell-sass/widgets/_app-grid.scss

@@ -37,7 +37,7 @@ $app_grid_fg_color: #fff;
 
   .overview-icon {
     @extend %icon_tile;
-    color: $app_grid_fg_color !important;
+    color: $app_grid_fg_color;
   }
 
   &:selected {
@@ -203,13 +203,12 @@ $app_grid_fg_color: #fff;
 
 // buttons
 .app-view-control {
-
   padding: 4px 32px;
   margin: 0 4px;
+
   &, &:hover, &:checked {
     @include button(undecorated);
     color: darken($osd_fg_color, 25%);
-    background-color: transparent !important;
   }
 
   &:hover {

data/theme/gnome-shell-sass/widgets/_calendar.scss

@@ -49,9 +49,9 @@
   // calendar
   .calendar {
     @extend %notification_bubble;
-    margin:$base_margin !important;
+    margin: $base_margin;
-    margin-bottom: $base_padding + $base_margin !important;
+    margin-bottom: $base_padding + $base_margin;
-    padding:$base_padding !important;
+    padding: $base_padding;
 
     // more below for sub-elements
   }
@@ -68,7 +68,7 @@
     .world-clocks-button,
     .weather-button {
       @extend %notification_bubble;
-      padding:$base_padding !important;
+      padding: $base_padding;
     }
   }
 }

data/theme/gnome-shell-sass/widgets/_dash.scss

@@ -9,12 +9,11 @@ $dash_border_radius: $modal_radius * 1.5;
   @include fontsize($base_font_size - 2);
   padding: ($dash_spacing / 2) 0;
 
-  //fixme: can't have non uniform borders :(
   border-radius: 0 $dash_border_radius $dash_border_radius 0; 
-  border-left-width: 0 !important;
+  border-left-width: 0;
   &:rtl {
     border-radius: $dash_border_radius 0 0 $dash_border_radius;
-    border-right-width: 0 !important;
+    border-right-width: 0;
   }
 
   .placeholder {

data/theme/gnome-shell-sass/widgets/_keyboard.scss

@@ -10,7 +10,7 @@ $default_key_bg_color: if($variant=='light', darken($osd_bg_color, 11%), lighten
 // draw keys using button function
 #keyboard {
   background-color: transparentize(if($variant=='light', darken($bg_color, 5%), darken($bg_color, 8%)), 0.1);
-  box-shadow: inset 0 1px 0 0 $osd_outer_borders_color !important;
+  box-shadow: inset 0 1px 0 0 $osd_outer_borders_color;
 
   .page-indicator {
     padding: $base_padding;

data/theme/gnome-shell-sass/widgets/_popovers.scss

@@ -87,7 +87,6 @@ $popover_arrow_height: 12px;
   height: 1px; //not really the whole box
   margin: 6px 64px;
   background-color: lighten($borders_color, 2%);
-  border: none !important;
 }
 
 // desktop background menu

data/theme/gnome-shell-sass/widgets/_search-results.scss

@@ -8,8 +8,6 @@
 // search results sections "the boxes"
 .search-section {
   spacing: $base_margin * 2;
-  padding:0 !important;
-  margin:0 !important;
   background-color:transparent;
   box-shadow:none;
   border:none;
@@ -118,7 +116,7 @@
   padding: $base_padding;
   color: $osd_fg_color;
 
-  border-radius: $base_border_radius + 2px !important;
+  border-radius: $base_border_radius + 2px;
 
   &:focus,
   &:selected,

data/theme/gnome-shell-sass/widgets/_workspace-switcher.scss

@@ -45,11 +45,11 @@
   padding: $base_padding;
 
   border-radius: $modal_radius 0 0 $modal_radius;
-  border-right-width: 0 !important;
+  border-right-width: 0;
 
   &:rtl {
     border-radius: 0 $modal_radius $modal_radius 0; 
-    border-left-width: 0 !important;
+    border-left-width: 0;
   }
 
   // drag and drop indicator