diff --git a/style/main.css b/style/main.css
index 710a03d..6a410cd 100644
--- a/style/main.css
+++ b/style/main.css
@@ -1,8 +1,10 @@
 /* ── cnats · message-bus console ─────────────────────────────────────────
-   dark phosphor terminal: deep green-black ground, mint signal, amber id.
+   phosphor terminal in two prints: dark (green-black ground, mint signal)
+   and light (green-tinted paper, forest signal), following the OS scheme.
    type: Archivo (UI voice) + IBM Plex Mono (wire voice). */
 
 :root {
+  color-scheme: light dark;
   --ink-0: #060a09;
   --ink-1: #0b1210;
   --ink-2: #101a17;
@@ -16,10 +18,34 @@
   --signal-dim: #2a8f6c;
   --amber: #ffb454;
   --alarm: #ff6b6b;
+  --scanline: rgba(255, 255, 255, 0.015);
+  --vignette: rgba(0, 0, 0, 0.45);
+  --card-shadow: rgba(0, 0, 0, 0.55);
   --mono: "IBM Plex Mono", ui-monospace, monospace;
   --sans: "Archivo", system-ui, sans-serif;
 }
 
+@media (prefers-color-scheme: light) {
+  :root {
+    --ink-0: #f3f6f4;
+    --ink-1: #eaf0ec;
+    --ink-2: #dfe8e2;
+    --ink-3: #d2ded6;
+    --line: #c3d2c9;
+    --line-hot: #a3bcae;
+    --text: #14211c;
+    --text-dim: #46584f;
+    --text-faint: #74887e;
+    --signal: #0b7a52;
+    --signal-dim: #2f8a66;
+    --amber: #a85f00;
+    --alarm: #c73f3f;
+    --scanline: rgba(6, 10, 9, 0.02);
+    --vignette: rgba(6, 10, 9, 0.06);
+    --card-shadow: rgba(20, 33, 28, 0.18);
+  }
+}
+
 * { margin: 0; padding: 0; box-sizing: border-box; }
 
 html, body { height: 100%; }
@@ -39,8 +65,8 @@ body::before {
   pointer-events: none;
   z-index: 999;
   background:
-    repeating-linear-gradient(0deg, rgba(255, 255, 255, 0.015) 0 1px, transparent 1px 3px),
-    radial-gradient(ellipse 120% 90% at 50% 40%, transparent 55%, rgba(0, 0, 0, 0.45));
+    repeating-linear-gradient(0deg, var(--scanline) 0 1px, transparent 1px 3px),
+    radial-gradient(ellipse 120% 90% at 50% 40%, transparent 55%, var(--vignette));
 }
 
 ::selection { background: var(--signal); color: var(--ink-0); }
@@ -53,7 +79,7 @@ body::before {
   place-items: center;
   padding: 2rem;
   background:
-    radial-gradient(ellipse 60% 45% at 50% 0%, rgba(78, 240, 177, 0.07), transparent 70%),
+    radial-gradient(ellipse 60% 45% at 50% 0%, color-mix(in srgb, var(--signal) 7%, transparent), transparent 70%),
     linear-gradient(var(--ink-0), var(--ink-1));
 }
 
@@ -69,7 +95,7 @@ body::before {
   background: linear-gradient(160deg, var(--ink-2), var(--ink-1) 60%);
   padding: 3rem 2.75rem 2.5rem;
   position: relative;
-  box-shadow: 0 40px 80px rgba(0, 0, 0, 0.55);
+  box-shadow: 0 40px 80px var(--card-shadow);
   animation: rise 0.5s cubic-bezier(0.2, 0.9, 0.3, 1) both;
 }
 
@@ -129,7 +155,8 @@ body::before {
 .gate-btn:hover {
   background: transparent;
   color: var(--signal);
-  box-shadow: 0 0 24px rgba(78, 240, 177, 0.25), inset 0 0 12px rgba(78, 240, 177, 0.08);
+  box-shadow: 0 0 24px color-mix(in srgb, var(--signal) 25%, transparent),
+    inset 0 0 12px color-mix(in srgb, var(--signal) 8%, transparent);
 }
 
 .gate-btn-glyph { font-size: 1.05rem; }
@@ -458,7 +485,7 @@ body::before {
 
 .composer:focus-within {
   border-color: var(--signal-dim);
-  box-shadow: 0 0 0 1px var(--signal-dim), 0 0 30px rgba(78, 240, 177, 0.08);
+  box-shadow: 0 0 0 1px var(--signal-dim), 0 0 30px color-mix(in srgb, var(--signal) 8%, transparent);
 }
 
 .composer-prompt {
@@ -551,7 +578,7 @@ body::before {
   transition: background 120ms;
 }
 
-.call-leave:hover { background: rgba(255, 90, 90, 0.12); }
+.call-leave:hover { background: color-mix(in srgb, var(--alarm) 12%, transparent); }
 
 /* motion */