diff --git a/README.md b/README.md
index 7639b56..0a4a904 100644
--- a/README.md
+++ b/README.md
@@ -129,7 +129,8 @@ list; the two with real content:
 
 - `theme set <name>` — switch theme. Modes: `light`, `dark`, `auto`, plus any
   colour theme file under `assets/css/themes/*.css` (ships with `paper`,
-  `dracula`, `valentine`). Persisted to `localStorage`, no flash on reload.
+  `dracula`, `valentine`, `ocean`). Persisted to `localStorage`, no flash on
+  reload.
 - `music play` / `music stop` / `music volume <0-10>` — an 8-bit soundtrack
   synthesised live with WebAudio (no audio files), one tune per theme,
   keeps playing across page navigation.
diff --git a/assets/css/themes/ocean.css b/assets/css/themes/ocean.css
new file mode 100644
index 0000000..546c322
--- /dev/null
+++ b/assets/css/themes/ocean.css
@@ -0,0 +1,14 @@
+/* Ocean — deep navy water, foam-pale ink, teal + coral pops.
+   Concatenated after main.css (see baseof.html). */
+:root[data-theme="ocean"] {
+  --bg: #0b1e2d; --fg: #dceef5; --muted: #5c8aa3; --border: #1c3a4f;
+  --accent: #22b8cf; --accent-fg: #06232e; --selection: #1e4a5f; --code: #ffa94d;
+  --c-red: #ff6b6b; --c-orange: #ffa94d; --c-yellow: #ffd93d; --c-green: #38d9a9;
+  --c-cyan: #22d3ee; --c-blue: #4dabf7; --c-purple: #9775fa; --c-pink: #f783ac;
+  /* sets: cool water surfaces, coral console for contrast */
+  --link: var(--c-cyan);
+  --pill: var(--c-green); --pill-fg: var(--bg);
+  --row:  var(--c-blue);  --row-fg:  var(--bg);
+  --term: var(--c-pink);  --term-fg: var(--bg);
+  --focus: var(--c-orange);
+}
diff --git a/assets/js/console.js b/assets/js/console.js
index 5cb147e..715f5e2 100644
--- a/assets/js/console.js
+++ b/assets/js/console.js
@@ -70,7 +70,7 @@
       case "theme": {
         var sub = (cmd.args[0] || "").toLowerCase();
         // base modes first, then colour palettes (see main.css)
-        var modes = ["light", "dark", "auto", "paper", "dracula", "valentine"];
+        var modes = ["light", "dark", "auto", "paper", "dracula", "valentine", "ocean"];
         if (sub === "list") {
           return { lines: modes.map(function (m) { return { text: "   " + m }; }) };
         }
@@ -341,6 +341,7 @@
     assert.strictEqual(run("theme set dark", {}).theme, "dark");
     assert.strictEqual(run("theme set dracula", {}).theme, "dracula");
     assert.strictEqual(run("theme set valentine", {}).theme, "valentine");
+    assert.strictEqual(run("theme set ocean", {}).theme, "ocean");
     assert.ok(/usage: theme set/.test(run("theme set purple", {}).lines[0].text));
     assert.ok(/dark/.test(run("theme list", {}).lines[1].text));
     assert.ok(/Subcommands/.test(run("theme", {}).lines[4].text));
diff --git a/assets/js/tunes.js b/assets/js/tunes.js
index de1c15b..988ba6c 100644
--- a/assets/js/tunes.js
+++ b/assets/js/tunes.js
@@ -52,6 +52,28 @@
              47, 0, 0, 0, 0, 0, 0, 0, 43, 0, 0, 0, 0, 0, 0, 0,
              38, 0, 0, 0, 0, 0, 0, 0, 45, 0, 0, 0, 0, 0, 0, 0,
              47, 0, 0, 0, 0, 0, 0, 0, 43, 0, 0, 0, 0, 0, 0, 0]
+    },
+    // D whole-tone, sine lead — no eighth-note rests, a continuous rippling
+    // current instead of a beat-driven melody. Whole-tone (no semitones) is
+    // the classic "underwater" scale (Debussy, water-level video game themes)
+    // since it has no leading tone pulling anywhere — it just drifts. One
+    // swelling 8-bar wave: rises to a crest in bar 5, recedes back to the
+    // tonic to loop. Bass pedal follows the same swell (D, up to the tritone
+    // G#, back to D) rather than outlining a chord progression.
+    ocean: {
+      bpm: 78, wave: "sine",
+      lead: [62, 64, 66, 64, 62, 60, 58, 60,
+             64, 66, 68, 66, 64, 62, 60, 62,
+             66, 68, 70, 68, 66, 64, 62, 64,
+             68, 70, 72, 70, 68, 66, 64, 66,
+             70, 72, 74, 76, 74, 72, 70, 68,
+             68, 66, 64, 62, 64, 66, 68, 70,
+             64, 62, 60, 58, 60, 62, 64, 66,
+             62, 60, 58, 56, 54, 52, 50, 50],
+      bass: [38, 0, 0, 0, 0, 0, 0, 0, 38, 0, 0, 0, 0, 0, 0, 0,
+             42, 0, 0, 0, 0, 0, 0, 0, 44, 0, 0, 0, 0, 0, 0, 0,
+             44, 0, 0, 0, 0, 0, 0, 0, 42, 0, 0, 0, 0, 0, 0, 0,
+             38, 0, 0, 0, 0, 0, 0, 0, 38, 0, 0, 0, 0, 0, 0, 0]
     }
   };
   if (typeof module !== "undefined" && module.exports) module.exports = TUNES;