diff --git a/crates/shepherd-hud/src/app.rs b/crates/shepherd-hud/src/app.rs
index 13e5a16..13906c8 100644
--- a/crates/shepherd-hud/src/app.rs
+++ b/crates/shepherd-hud/src/app.rs
@@ -405,6 +405,8 @@ fn build_hud_content(state: SharedState) -> gtk4::Box {
                 entry_name,
                 warning_issued_at,
                 time_remaining_at_warning,
+                message,
+                severity,
                 ..
             } => {
                 app_label_clone.set_text(entry_name);
@@ -412,10 +414,28 @@ fn build_hud_content(state: SharedState) -> gtk4::Box {
                 let elapsed = warning_issued_at.elapsed().as_secs();
                 let remaining = time_remaining_at_warning.saturating_sub(elapsed);
                 time_display_clone.set_remaining(Some(remaining));
-                warning_label_clone.set_text(&format!(
-                    "Only {} seconds remaining!",
-                    remaining
-                ));
+                // Use configuration-defined message if present, otherwise show time-based message
+                let warning_text = message.clone().unwrap_or_else(|| {
+                    format!("Only {} seconds remaining!", remaining)
+                });
+                warning_label_clone.set_text(&warning_text);
+                
+                // Apply severity-based CSS classes
+                warning_box_clone.remove_css_class("warning-info");
+                warning_box_clone.remove_css_class("warning-warn");
+                warning_box_clone.remove_css_class("warning-critical");
+                match severity {
+                    shepherd_api::WarningSeverity::Info => {
+                        warning_box_clone.add_css_class("warning-info");
+                    }
+                    shepherd_api::WarningSeverity::Warn => {
+                        warning_box_clone.add_css_class("warning-warn");
+                    }
+                    shepherd_api::WarningSeverity::Critical => {
+                        warning_box_clone.add_css_class("warning-critical");
+                    }
+                }
+                
                 warning_box_clone.set_visible(true);
             }
             SessionState::Ending { reason, .. } => {
@@ -517,6 +537,31 @@ fn load_css() {
             padding: 4px 12px;
         }
 
+        .warning-banner.warning-info {
+            background-color: rgba(136, 192, 208, 0.2);
+        }
+
+        .warning-banner.warning-info .warning-text {
+            color: var(--color-info);
+        }
+
+        .warning-banner.warning-warn {
+            background-color: rgba(235, 203, 139, 0.2);
+        }
+
+        .warning-banner.warning-warn .warning-text {
+            color: var(--color-warning);
+        }
+
+        .warning-banner.warning-critical {
+            background-color: rgba(255, 107, 107, 0.2);
+            animation: blink 1s infinite;
+        }
+
+        .warning-banner.warning-critical .warning-text {
+            color: var(--color-critical);
+        }
+
         .warning-text {
             color: var(--color-warning);
             font-weight: bold;
diff --git a/crates/shepherd-hud/src/state.rs b/crates/shepherd-hud/src/state.rs
index 1d16a08..a36b91b 100644
--- a/crates/shepherd-hud/src/state.rs
+++ b/crates/shepherd-hud/src/state.rs
@@ -3,7 +3,7 @@
 //! The HUD subscribes to events from shepherdd and tracks session state.
 
 use chrono::Local;
-use shepherd_api::{Event, EventPayload, SessionEndReason, VolumeInfo, VolumeRestrictions};
+use shepherd_api::{Event, EventPayload, SessionEndReason, VolumeInfo, VolumeRestrictions, WarningSeverity};
 use shepherd_util::{EntryId, SessionId};
 use std::sync::Arc;
 use tokio::sync::watch;
@@ -31,6 +31,10 @@ pub enum SessionState {
         entry_name: String,
         warning_issued_at: std::time::Instant,
         time_remaining_at_warning: u64,
+        /// Optional custom message from configuration
+        message: Option<String>,
+        /// Severity level of the warning
+        severity: WarningSeverity,
     },
 
     /// Session is ending
@@ -210,9 +214,12 @@ impl SharedState {
             EventPayload::WarningIssued {
                 session_id,
                 time_remaining,
+                message,
+                severity,
                 ..
             } => {
                 self.session_tx.send_modify(|state| {
+                    // Handle transition from Active state
                     if let SessionState::Active {
                         session_id: sid,
                         entry_id,
@@ -227,6 +234,28 @@ impl SharedState {
                                 entry_name: entry_name.clone(),
                                 warning_issued_at: std::time::Instant::now(),
                                 time_remaining_at_warning: time_remaining.as_secs(),
+                                message: message.clone(),
+                                severity: *severity,
+                            };
+                        }
+                    }
+                    // Handle update when already in Warning state (subsequent warnings)
+                    else if let SessionState::Warning {
+                        session_id: sid,
+                        entry_id,
+                        entry_name,
+                        ..
+                    } = state
+                    {
+                        if sid == session_id {
+                            *state = SessionState::Warning {
+                                session_id: session_id.clone(),
+                                entry_id: entry_id.clone(),
+                                entry_name: entry_name.clone(),
+                                warning_issued_at: std::time::Instant::now(),
+                                time_remaining_at_warning: time_remaining.as_secs(),
+                                message: message.clone(),
+                                severity: *severity,
                             };
                         }
                     }