(update) themes' footer default colors

apps/block_scout_web/assets/css/theme/_ethereum_classic_variables.scss

@@ -1,3 +1,8 @@
 $primary:       #1b1b39;
 $secondary:     #4beba0;
 $tertiary:      #4beba0;
+
+$footer-background-color: $primary;
+$footer-title-color: #fff;
+$footer-text-color: #fff;
+$footer-item-disc-color: $secondary;

apps/block_scout_web/assets/css/theme/_goerli_variables.scss

@@ -1,3 +1,8 @@
 $primary:       #20201A;
 $secondary:     #F0D96B;
 $tertiary:      #4A443A;
+
+$footer-background-color: $primary;
+$footer-title-color: #fff;
+$footer-text-color: #fff;
+$footer-item-disc-color: $secondary;

apps/block_scout_web/assets/css/theme/_kovan_variables.scss

@@ -1,3 +1,8 @@
 $primary: #28aca4;
 $secondary: #89edda;
 $tertiary: #997fdc;
+
+$footer-background-color: $primary;
+$footer-title-color: #fff;
+$footer-text-color: #fff;
+$footer-item-disc-color: $secondary;

apps/block_scout_web/assets/css/theme/_pirl_variables.scss

@@ -1,3 +1,8 @@
 $primary:       #343434;
 $secondary:     #A2D729;
 $tertiary:      #7F7F7F;
+
+$footer-background-color: $primary;
+$footer-title-color: #fff;
+$footer-text-color: #fff;
+$footer-item-disc-color: $secondary;

apps/block_scout_web/assets/css/theme/_poa_variables.scss

@@ -4,3 +4,8 @@ $tertiary:      #997fdc;
 
 $header-links-color-active: #333;
 $button-secondary-color: $primary;
+
+$footer-background-color: $primary;
+$footer-title-color: #fff;
+$footer-text-color: #fff;
+$footer-item-disc-color: $secondary;

apps/block_scout_web/assets/css/theme/_ropsten_variables.scss

@@ -1,3 +1,8 @@
 $primary:  #2fa8f8;
 $secondary: #a2daff;
 $tertiary:  #006aa7;
+
+$footer-background-color: $primary;
+$footer-title-color: #fff;
+$footer-text-color: #fff;
+$footer-item-disc-color: $secondary;

apps/block_scout_web/assets/css/theme/_social_variables.scss

@@ -1,3 +1,8 @@
 $primary:       #A375FF;
 $secondary:     #00F0BD;
 $tertiary:      #53A9FF;
+
+$footer-background-color: $primary;
+$footer-title-color: #fff;
+$footer-text-color: #fff;
+$footer-item-disc-color: $secondary;

apps/block_scout_web/assets/css/theme/_sokol_variables.scss

@@ -1,3 +1,8 @@
 $primary:       #559387;
 $secondary:     #add7cf;
 $tertiary:      #38533d;
+
+$footer-background-color: $primary;
+$footer-title-color: #fff;
+$footer-text-color: #fff;
+$footer-item-disc-color: $secondary;

apps/block_scout_web/assets/css/theme/_tobalaba_variables.scss

@@ -1,3 +1,8 @@
 $primary:       #633D99;
 $secondary:     #6CC04A;
 $tertiary:      #A566FF;
+
+$footer-background-color: $primary;
+$footer-title-color: #fff;
+$footer-text-color: #fff;
+$footer-item-disc-color: $secondary;

apps/block_scout_web/assets/css/theme/_variables.scss

@@ -2,12 +2,20 @@
 // @import "dai_variables";
 // @import "ethereum_classic_variables";
 // @import "ethereum_variables";
+// @import "expanse_variables";
+// @import "gochain_variables";
 // @import "goerli_variables";
+// @import "kovan_variables";
+// @import "musicoin_variables";
+// @import "pirl_variables";
 // @import "poa_variables";
 @import "posdao_variables";
 // @import "rinkeby_variables";
 // @import "ropsten_variables";
+// @import "social_variables";
 // @import "sokol_variables";
+// @import "tobalaba_variables";
+// @import "tomochain_variables";
 @import "theme/base_variables";
 
 // responsive breakpoints