Add `.warning` class for doc author use

This is designed to be compatible with rustdoc's version, in
https://github.com/rust-lang/rust/pull/106561

1 files changed, 23 insertions, 0 deletions

diff --git a/src/theme/css/general.css b/src/theme/css/general.css
index 7e746d27..e7d20da7 100644
--- a/src/theme/css/general.css
+++ b/src/theme/css/general.css
@@ -156,6 +156,29 @@ blockquote {
     border-block-end: .1em solid var(--quote-border);
 }
 
+.warning {
+    margin: 20px;
+    padding: 0 20px;
+    border-inline-start: 2px solid var(--warning-border);
+}
+
+.warning:before {
+    position: absolute;
+    width: 3rem;
+    height: 3rem;
+    margin-inline-start: calc(-1.5rem - 21px);
+    content: "ⓘ";
+    text-align: center;
+    background-color: var(--bg);
+    color: var(--warning-border);
+    font-weight: bold;
+    font-size: 2rem;
+}
+
+blockquote .warning:before {
+    background-color: var(--quote-bg);
+}
+
 kbd {
     background-color: var(--table-border-color);
     border-radius: 4px;