Minor arc-green color tweaks (#25175) (#25205)

Backport #25175 by @silverwind

Some minor color tweaks

<img width="1271" alt="Screenshot 2023-06-09 at 13 29 25"
src="https://github.com/go-gitea/gitea/assets/115237/b7b34995-5d34-461f-8d19-4f5755a98109">
<img width="1272" alt="Screenshot 2023-06-09 at 13 31 20"
src="https://github.com/go-gitea/gitea/assets/115237/63c866b4-797e-46ed-ba28-b1162ccd3e15">
<img width="1276" alt="Screenshot 2023-06-09 at 13 32 21"
src="https://github.com/go-gitea/gitea/assets/115237/de7ee02e-d0c7-4979-a8aa-0fd03e8db491">

Co-authored-by: silverwind <me@silverwind.io>

Author: GiteaBot

web_src/css/base.css

@@ -188,7 +188,7 @@
   --color-text-light-3: #a0a0a0;
   --color-box-header: #f7f7f7;
   --color-box-body: #ffffff;
-  --color-box-body-highlight: #f8f8f8;
+  --color-box-body-highlight: #fafafa;
   --color-footer: #ffffff;
   --color-timeline: #ececec;
   --color-input-text: #212121;

web_src/css/themes/theme-arc-green.css

@@ -165,36 +165,36 @@
   --color-git: #f05133;
   /* target-based colors */
   --color-body: #2e323e;
-  --color-box-header: #333743;
-  --color-box-body: #252a36;
-  --color-box-body-highlight: #303440;
+  --color-box-header: #303340;
+  --color-box-body: #222733;
+  --color-box-body-highlight: #262b36;
   --color-text-dark: #dbe0ea;
   --color-text: #cbd0da;
   --color-text-light: #bbbfca;
   --color-text-light-1: #aaafb9;
   --color-text-light-2: #9a9ea9;
   --color-text-light-3: #8a8e99;
-  --color-footer: #262b36;
+  --color-footer: #232834;
   --color-timeline: #4c525e;
   --color-input-text: #dfe3ec;
-  --color-input-background: #262b36;
+  --color-input-background: #1e252e;
   --color-input-toggle-background: #454a57;
   --color-input-border: var(--color-secondary);
   --color-input-border-hover: var(--color-secondary-dark-1);
-  --color-header-wrapper: #212531;
-  --color-header-wrapper-transparent: #21253100;
+  --color-header-wrapper: #202430;
+  --color-header-wrapper-transparent: #20243000;
   --color-light: #00000028;
   --color-light-mimic-enabled: rgba(0, 0, 0, calc(40 / 255 * 222 / 255 / var(--opacity-disabled)));
   --color-light-border: #ffffff28;
   --color-hover: #ffffff19;
   --color-active: #ffffff24;
-  --color-menu: #262b36;
-  --color-card: #262b36;
+  --color-menu: #1e252e;
+  --color-card: #1e252e;
   --color-markup-table-row: #ffffff06;
   --color-markup-code-block: #ffffff16;
-  --color-button: #262b36;
+  --color-button: #1e252e;
   --color-code-bg: #222733;
-  --color-code-sidebar-bg: #252a36;
+  --color-code-sidebar-bg: #232834;
   --color-shadow: #00000060;
   --color-secondary-bg: #2a2e3a;
   --color-text-focus: #fff;
@@ -208,8 +208,8 @@
   --color-reaction-active-bg: var(--color-primary-light-5);
   --color-tooltip-text: #ffffff;
   --color-tooltip-bg: #000000f0;
-  --color-nav-bg: #2e323e;
-  --color-nav-hover-bg: #434651;
+  --color-nav-bg: #232834;
+  --color-nav-hover-bg: #383c47;
   --color-label-text: #dfe3ec;
   --color-label-bg: #7c84974b;
   --color-label-hover-bg: #7c8497a0;