diff --git a/.gitignore b/.gitignore
index 0ee218a..7b81a2c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,2 @@
-.min.js
+*.min.js
 node_modules/
diff --git a/README.md b/README.md
index a9219af..cb29652 100644
--- a/README.md
+++ b/README.md
@@ -149,8 +149,8 @@ Obs.js exposes the following classes under the following conditions:
 | Class                                   | Meaning                  | Computed/derived from                                           |
 | --------------------------------------- | ------------------------ | --------------------------------------------------------------- |
 | `.has-data-saver`                       | User enabled Data Saver  | `navigator.connection.saveData === true`                        |
-| `.has-battery-critical`                 | Battery ≤ 5%             | `battery.level ≤ 0.05`                                          |
-| `.has-battery-low`                      | 5% < battery ≤ 20%       | `0.05 < battery.level ≤ 0.2` (mutually exclusive with critical) |
+| `.has-battery-low`                      | Battery ≤ 20%            | `battery.level ≤ 0.2`                                           |
+| `.has-battery-critical`                 | Battery ≤ 5%             | `battery.level ≤ 0.05` (added **alongside** `.has-battery-low`) |
 | `.has-battery-charging`                 | On charge                | `battery.charging === true`                                     |
 | `.has-latency-low`                      | Low RTT                  | `rtt < 75ms`                                                    |
 | `.has-latency-medium`                   | Medium RTT               | `75–275ms`                                                      |
@@ -172,7 +172,7 @@ Obs.js also stores the following properties on the `window.obs` object:
 | `config.observeChanges`  | boolean                            | Whether Obs.js attaches change listeners      | **Default `false`**; set by you _before_ Obs.js runs           | Opt-in for SPAs or long-lived pages                                                        |
 | `dataSaver`              | boolean                            | User enabled Data Saver                       | `navigator.connection.saveData`                                | —                                                                                          |
 | `rttBucket`              | number (ms)                        | RTT bucketed to **ceil** 25 ms (e.g. 101→125) | `navigator.connection.rtt`                                     | Undefined if Connection API missing                                                        |
-| `rttCategory`            | `'low' \| 'medium' \| 'high'`      | CrUX tri-bin: `<75`, `75–275`, `>275`         | Derived from `rtt`                                             | Drives latency classes                                                                     |
+| `rttCategory`            | `'low' \| 'medium' \| 'high'`      | CrUX tri-bin: <75, 75–275, >275               | Derived from `rtt`                                             | Drives latency classes                                                                     |
 | `downlinkBucket`         | number (Mbps)                      | Downlink bucketed to **ceil** 1 Mbps          | `navigator.connection.downlink`                                | Low/High thresholds: `≤5` / `≥8`                                                           |
 | `downlinkMax`            | number (Mbps)                      | Max estimated downlink (if exposed)           | `navigator.connection.downlinkMax`                             | Not used for Stances; informational only                                                   |
 | `connectionCapability`   | `'strong' \| 'moderate' \| 'weak'` | Transport assessment                          | Derived from `rttCategory` and `downlinkBucket`                | Strong = low RTT **and** high BW; Weak = high RTT **or** low BW                            |
@@ -180,6 +180,6 @@ Obs.js also stores the following properties on the `window.obs` object:
 | `deliveryMode`           | `'rich' \| 'cautious' \| 'lite'`   | How “heavy” you should go                     | Derived from capability and conservation                       | Rich if **strong** and **not** conserving; Lite if **weak** or **conserve**; else Cautious |
 | `canShowRichMedia`       | boolean                            | Convenience: `deliveryMode === 'rich'`        | Derived from `deliveryMode`                                    | Shorthand for “go big”                                                                     |
 | `shouldAvoidRichMedia`   | boolean                            | Convenience: `deliveryMode === 'lite'`        | Derived from `deliveryMode`                                    | Shorthand for “be frugal”                                                                  |
-| `batteryCritical`        | boolean \| null                    | Battery `≤ 5%`                                | Battery API                                                    | Mutually exclusive with `batteryLow`; `null` if unknown                                    |
-| `batteryLow`             | boolean \| null                    | `5% < level ≤ 20%`                            | Battery API                                                    | `true` only when not `batteryCritical`                                                     |
+| `batteryLow`             | boolean \| null                    | Battery ≤20%                                  | Battery API                                                    | `true` when battery level is ≤20%; `null` if unknown                                       |
+| `batteryCritical`        | boolean \| null                    | Battery ≤5%                                   | Battery API                                                    | `true` when battery level is ≤5%; `true` in addition to `batteryLow`                       |
 | `batteryCharging`        | boolean \| null                    | On charge                                     | Battery API                                                    | `null` if unknown                                                                          |
diff --git a/obs.js b/obs.js
index 869612d..42804ff 100644
--- a/obs.js
+++ b/obs.js
@@ -228,14 +228,12 @@
     const low = Number.isFinite(level) ? level <= 0.2 : null;
     window.obs.batteryLow = low;
 
-    // Add most urgent battery class, removing any classes left over.
-    // E.g. `<html class="has-battery-critical">`
+    // Add battery classes (subset model): at ≤5% we want BOTH low and critical.
+    // First remove leftovers, then add any that apply.
+    // E.g. `<html class="has-battery-low has-battery-critical">`
     ['critical','low'].forEach(t => html.classList.remove(`has-battery-${t}`));
-    if (critical) {
-      html.classList.add('has-battery-critical');
-    } else if (low) {
-      html.classList.add('has-battery-low');
-    }
+    if (low)      html.classList.add('has-battery-low');
+    if (critical) html.classList.add('has-battery-critical');
 
     // Add a class to the `<html>` element if the device is currently charging.
     // E.g. `<html class="has-battery-charging">`
@@ -269,4 +267,3 @@
       .catch(() => { /* no‑op */ });
   }
 })();
-//# sourceURL=obs.js