Unify border-radius behavior (#26770)

## Changes
- no more hardcoded `border-radius`es (apart from `0`)
- no more value inconsistencies
- no more guessing what pixel value you should use
- two new variables:
- `--border-radius-medium` (for elements where the normal border radius
does not suffice)
  - `--border-radius-circle` (for displaying circles)

---------

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

Author: delvh

web_src/css/base.css

@@ -16,7 +16,9 @@
   --checkbox-mask-indeterminate: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16" width="16" height="16"><path fill-rule="evenodd" d="M2 7.75A.75.75 0 012.75 7h10a.75.75 0 010 1.5h-10A.75.75 0 012 7.75z"></path></svg>');
   --octicon-chevron-right: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16" width="16" height="16"><path d="M6.22 3.22a.75.75 0 0 1 1.06 0l4.25 4.25a.75.75 0 0 1 0 1.06l-4.25 4.25a.751.751 0 0 1-1.042-.018.751.751 0 0 1-.018-1.042L9.94 8 6.22 4.28a.75.75 0 0 1 0-1.06Z"></path></svg>');
   /* non-color variables */
-  --border-radius: 0.28571429rem;
+  --border-radius: 4px;
+  --border-radius-medium: 6px;
+  --border-radius-circle: 100%;
   --opacity-disabled: 0.55;
   --height-loading: 16rem;
   --tab-size: 4;
@@ -309,7 +311,7 @@ details summary > * {
 
 progress {
   background: var(--color-secondary-dark-1);
-  border-radius: 6px;
+  border-radius: var(--border-radius);
   border: none;
   overflow: hidden;
 }
@@ -339,7 +341,7 @@ progress::-moz-progress-bar {
 ::-webkit-scrollbar-thumb {
   box-shadow: inset 0 0 0 6px var(--color-primary);
   border: 2px solid transparent;
-  border-radius: 5px !important;
+  border-radius: var(--border-radius);
 }
 
 ::-webkit-scrollbar-thumb:window-inactive {
@@ -454,7 +456,7 @@ a.label,
 
 .issue-title code {
   padding: 2px 4px;
-  border-radius: 6px;
+  border-radius: var(--border-radius-medium);
   background-color: var(--color-markup-code-block);
 }
 
@@ -1510,7 +1512,7 @@ img.ui.avatar,
   margin-left: 0.4em;
   height: 0.67em;
   width: 0.67em;
-  border-radius: 0.15em;
+  border-radius: var(--border-radius);
 }
 
 .attention-icon {
@@ -2013,7 +2015,7 @@ a.ui.basic.label:hover {
 
 .color-icon {
   display: inline-block;
-  border-radius: 100%;
+  border-radius: var(--border-radius-circle);
   height: 14px;
   width: 14px;
 }

web_src/css/dashboard.css

@@ -98,7 +98,7 @@
 
 .feeds code {
   padding: 2px 4px;
-  border-radius: 3px;
+  border-radius: var(--border-radius);
   background-color: var(--color-markup-code-block);
   word-break: break-all;
 }

web_src/css/editor/combomarkdowneditor.css

@@ -83,7 +83,7 @@ text-expander .suggestions {
   margin-top: 24px;
   list-style: none;
   background: var(--color-box-body);
-  border-radius: 5px;
+  border-radius: var(--border-radius);
   border: 1px solid var(--color-secondary);
   box-shadow: 0 .5rem 1rem var(--color-shadow);
 }
@@ -101,15 +101,15 @@ text-expander .suggestions li + li {
 }
 
 text-expander .suggestions li:first-child {
-  border-radius: 4px 4px 0 0;
+  border-radius: var(--border-radius) var(--border-radius) 0 0;
 }
 
 text-expander .suggestions li:last-child {
-  border-radius: 0 0 4px 4px;
+  border-radius: 0 0 var(--border-radius) var(--border-radius);
 }
 
 text-expander .suggestions li:only-child {
-  border-radius: 4px;
+  border-radius: var(--border-radius);
 }
 
 text-expander .suggestions li:hover {

web_src/css/features/codeeditor.css

@@ -44,5 +44,5 @@
   position: absolute !important;
   resize: none !important;
   overflow: hidden !important;
-  border-radius: 4px !important;
+  border-radius: var(--border-radius-medium) !important;
 }

web_src/css/features/console.css

@@ -4,7 +4,7 @@
   background: var(--color-console-bg);
   color: var(--color-console-fg);
   font-family: var(--fonts-monospace);
-  border-radius: 5px;
+  border-radius: var(--border-radius);
   word-break: break-word;
   overflow-wrap: break-word;
 }

web_src/css/features/dropzone.css

@@ -3,7 +3,7 @@
   background: none;
   box-shadow: none;
   padding: 0;
-  border-radius: 4px;
+  border-radius: var(--border-radius-medium);
   min-height: 0;
 }
 

web_src/css/features/tribute.css

@@ -2,7 +2,7 @@
 
 .tribute-container {
   box-shadow: 0 0.25rem 0.5rem rgba(0, 0, 0, 0.25);
-  border-radius: 0.25rem;
+  border-radius: var(--border-radius);
 }
 
 .tribute-container ul {

web_src/css/form.css

@@ -221,7 +221,7 @@ textarea:focus,
   }
   .g-recaptcha-style iframe,
   .h-captcha-style iframe {
-    border-radius: 5px !important;
+    border-radius: var(--border-radius) !important;
     width: 302px !important;
     height: 76px !important;
   }

web_src/css/markup/content.css

@@ -180,7 +180,7 @@
   appearance: none;
   position: relative;
   border: 1px solid var(--color-secondary);
-  border-radius: 2px;
+  border-radius: var(--border-radius);
   background: var(--color-input-background);
   height: 14px;
   width: 14px;
@@ -433,7 +433,7 @@
   font-size: 85%;
   white-space: break-spaces;
   background-color: var(--color-markup-code-block);
-  border-radius: 4px;
+  border-radius: var(--border-radius);
 }
 
 .markup code br,
@@ -466,7 +466,7 @@
   font-size: 85%;
   line-height: 1.45;
   background-color: var(--color-markup-code-block);
-  border-radius: 4px;
+  border-radius: var(--border-radius);
 }
 
 .markup .highlight pre {
@@ -504,7 +504,7 @@
   vertical-align: middle;
   background-color: var(--color-markup-code-block);
   border: 1px solid var(--color-secondary);
-  border-radius: 3px;
+  border-radius: var(--border-radius);
   box-shadow: inset 0 -1px 0 var(--color-secondary);
 }
 

web_src/css/modules/animations.css

@@ -26,7 +26,7 @@
   border-width: 4px;
   border-style: solid;
   border-color: var(--color-secondary) var(--color-secondary) var(--color-secondary-dark-8) var(--color-secondary-dark-8);
-  border-radius: 100%;
+  border-radius: var(--border-radius-circle);
 }
 
 .is-loading.small-loading-icon::after {