Add shadows to question blocks

- increase contrast of light theme
- prepares upcoming color themes

customize.dist/src/less2/include/colortheme.less

@@ -299,7 +299,7 @@
 @cp_usergrid-selected-fg: @cryptpad_color_white;
 
 // Other
-@cp_shadow-color: fade(@cryptpad_color_black, 40%);
+@cp_shadow-color: fade(@cryptpad_color_black, 30%);
 
 // Apps
 @cp_app-bg: @cryptpad_color_grey_100;
@@ -428,8 +428,8 @@
 @cp_calendar-now-fg: @cryptpad_color_grey_200;
 
 // Forms
-@cp_form-bg1: @cryptpad_color_grey_200;
+@cp_form-bg1: @cryptpad_color_grey_50;
-@cp_form-bg2: @cryptpad_color_grey_100;
+@cp_form-bg2: @cryptpad_color_grey_200;
 @cp_form-border: @cryptpad_color_grey_200;
 @cp_form-poll-color: @cryptpad_color_grey_800;
 @cp_form-poll-no: fade(@cryptpad_color_light_red, 75%);

www/form/app-form.less

@@ -341,6 +341,7 @@
                 .cp-form-block {
                     background: @cp_form-bg1;
                     padding: 10px;
+                    box-shadow: 0px 0px 15px @cp_shadow-color;
                     &:not(:last-child) {
                         margin-bottom: 20px;
                     }
@@ -699,7 +700,7 @@
             margin-top: -10px;
             margin-right: -10px;
             i { margin-right: 5px; }
-            background: fade(@cryptpad_text_col, 15%);
+            background: fade(@cryptpad_text_col, 10%);
         }
     }