Designer pass: warmth on the empty Generate page

The dark surface was reading as a flat black plane with one orange
button. Three small moves to add life without breaking the cleanup:

1. Body gets two soft brand-axis radial gradients — coral at top-right
(generative), mint at bottom-left (measured). 14% / 9% strength
color-mixed against transparent so the page stays Console-dark but
reads as a composed surface rather than #13141A everywhere.
2. Section labels (PROMPT / MODEL / DURATION / etc, rendered as
Gradio's span.has-info) flip from ink3 grey to coralb. Letter-
spacing bumped 0.08em → 0.10em for the caps. Gives the eye color
rhythm between cards.
3. The PROMPT textbox gets a 3px coral left-stripe + a faint
coral-tinted gradient on its surface — marks it as the primary
input of the page the way a DAW marks track identity.

Also bumps main.contain max-width 1200 → 1280px and adds 14px → 28px
top padding so the header has breathing room on desktop.

theme.py

@@ -323,15 +323,29 @@ html { zoom: 1 !important; -webkit-text-size-adjust: 100% !important; }
    margin:0 auto on main.contain won't center — assert it explicitly. */
 .wrap { display: block !important; }
 main.contain, .wrap > main {
-    background: var(--paper) !important;
+    background: transparent !important;
     color: var(--ink);
     width: 100% !important;
-    max-width: 1200px !important;
+    max-width: 1280px !important;
     margin: 0 auto !important;
-    padding: 14px 18px !important;
+    padding: 28px 24px !important;
     box-sizing: border-box !important;
 }
-body { background: var(--paper) !important; color: var(--ink); }
+body {
+    background: var(--paper) !important;
+    color: var(--ink);
+    position: relative;
+    /* Soft brand-axis gradients on the body bg — coral at top-right
+       (generative axis), mint at bottom-left (measured axis). Each
+       sits at ~5% opacity so the surface stays Console-dark but reads
+       as a composed page rather than a flat black plane. Designer
+       cleanup pass: gives the eye warmth without competing with the
+       Generate CTA. */
+    background-image:
+        radial-gradient(60% 50% at 95% 0%, color-mix(in srgb, var(--coral) 14%, transparent), transparent 60%),
+        radial-gradient(60% 60% at 5% 100%, color-mix(in srgb, var(--mint) 9%, transparent), transparent 65%) !important;
+    background-attachment: fixed !important;
+}
 
 /* ---- Gradio native surface overrides — needed so block/input/button
        backgrounds re-paint per palette (the gr.themes.Base values were
@@ -1309,16 +1323,20 @@ button.dc-section-chip:active {
     color: var(--ink2) !important;
 }
 
-/* ---- Field titles — Gradio v6 emits span.has-info inside the block */
+/* ---- Field titles — Gradio v6 emits span.has-info inside the block.
+       Pulled out of grey into a soft coral so the page reads as 'three
+       sections, primary action' rather than a uniform grey wash. The
+       coralb shade keeps the contrast on dark surfaces comfortable. */
 span.has-info {
-    color: var(--ink3) !important;
+    color: var(--coralb) !important;
     font-family: 'JetBrains Mono', monospace !important;
     font-size: 11px !important;
     font-weight: 600 !important;
-    letter-spacing: 0.08em !important;
+    letter-spacing: 0.10em !important;
     text-transform: uppercase !important;
     margin-bottom: 6px !important;
     display: block !important;
+    opacity: 0.85;
 }
 /* Info subtitle below field title — quieter.
    Targets both Gradio v6's `.info-text` (Slider/Number) and `.info` (other). */
@@ -1350,6 +1368,20 @@ span.has-info {
     color: var(--coralb) !important;
 }
 
+/* ---- Generate-tab prompt textbox — coral left-stripe marks it as the
+       primary input of the page (DAW-style track identity). All other
+       inputs (model dropdown, duration radio) stay neutral so the eye
+       lands on the prompt first. */
+#gen-prompt-box {
+    border-left: 3px solid var(--coral) !important;
+    background: linear-gradient(180deg,
+        color-mix(in srgb, var(--coral) 4%, var(--paper3)),
+        var(--paper3)) !important;
+}
+#gen-prompt-box textarea {
+    background: transparent !important;
+}
+
 /* ---- File-upload zones — Gradio v6 fills the drop area with a huge
        SVG arrow that swallows the entire viewport when the parent has
        no height cap. Constrain to a sensible 120px row + size the icon