SUN: white day — the brightest moment of the day is white (owner 2026-08-03)

- BG_STOPS: +10deg #e8ddcf (morning light), +30..90deg #ffffff; night half
  of the scale untouched (-4 #131a28, -12..-90 #070c14)
- drawn-plan paper vs white sky: all paper shapes now sit in one
  .hp-paperg group; in daynight mode the group gets a subtle
  drop-shadow so the sheet contour stays readable at high sun
  (static mode and night unaffected)
- pinned colors updated: test/sun.test.mjs, demo/smoke_sun.mjs;
  smoke_bg_color paperUnderneath follows the .hp-paperg wrapper
- docs/SUN.md: explicit BG_STOPS table
- demo/shot_daynight.mjs: noon/sunset/night stills of the scale

demo/shot_daynight.mjs

@@ -0,0 +1,36 @@
+// Three stills of the daynight scale (noon/sunset/night) for the white-day review.
+import { launch } from './serve.mjs';
+const outDir = process.argv[2] || '/tmp';
+const { page, browser } = await launch({ width: 700, height: 700 }, 1);
+await page.emulateMedia({ reducedMotion: 'reduce' });
+await page.evaluate(async () => {
+  const c = window.__card;
+  const sp = c._serverCfg.spaces.find((s) => s.id === 'f1');
+  sp.openings = [
+    { id: 'wN', type: 'window', x: 0.30, y: 0.14, angle: 0, length: 0.08 },
+    { id: 'wE', type: 'window', x: 0.96, y: 0.60, angle: 90, length: 0.08 },
+    { id: 'wW', type: 'window', x: 0.04, y: 0.30, angle: 90, length: 0.08 },
+  ];
+  sp.plan_url = ''; // hand-drawn plan: white paper — the risky case for a white day
+  sp.settings = { ...(sp.settings || {}), show_borders: true, fill_mode: 'glow' };
+  c._serverCfg.settings = { ...(c._serverCfg.settings || {}), north_deg: 0, sun_rays: true, bg_mode: 'daynight' };
+  c._cfgRev = (c._cfgRev || 0) + 1;
+});
+const shot = async (az, el, name) => {
+  await page.evaluate(async ([az, el]) => {
+    const c = window.__card;
+    c.hass = { ...c.hass, states: { ...c.hass.states, 'sun.sun': {
+      entity_id: 'sun.sun', state: el > 0 ? 'above_horizon' : 'below_horizon',
+      attributes: { azimuth: az, elevation: el },
+    } } };
+    c.requestUpdate(); await c.updateComplete;
+  }, [az, el]);
+  await page.waitForTimeout(300);
+  const stage = await page.evaluateHandle(() => window.__card.shadowRoot.querySelector('.stage'));
+  await stage.asElement().screenshot({ path: `${outDir}/${name}.png` });
+};
+await shot(180, 60, 'dn_noon');
+await shot(265, 3, 'dn_sunset');
+await shot(0, -20, 'dn_night');
+await browser.close();
+console.log('shots done');

demo/smoke_bg_color.mjs

@@ -231,9 +231,11 @@ const drawn = await page.evaluate(async () => {
     const cs = getComputedStyle(p);
     return cs.stroke === 'none' || cs.strokeOpacity === '0' || cs.strokeWidth === '0px';
   });
-  // paper first, everything else on top of it
+  // paper first, everything else on top of it (one .hp-paperg group wraps
+  // all paper shapes so the daynight drop shadow composites without seams)
   const first = sr().querySelector('.stage.noplan svg').firstElementChild;
-  out.paperUnderneath = !!first && first.classList.contains('hp-paper');
+  out.paperUnderneath = !!first && first.classList.contains('hp-paperg')
+    && !!first.firstElementChild && first.firstElementChild.classList.contains('hp-paper');
   // live resize preview: drag the L's right wall 0.625 -> 0.6875 — the paper
   // must move WITH the room, not lag behind until the drop
   const pv = JSON.parse(JSON.stringify(sp));

demo/smoke_sun.mjs

@@ -90,11 +90,11 @@ const res = await page.evaluate(async () => {
 
   // 8) day/night background: daynight breathes, static does not
   await setSun(180, 60);
-  out.staticBgAtNoon = !stageStyle().includes('background:#5a6673');
+  out.staticBgAtNoon = !stageStyle().includes('background:#ffffff');
   cfg().settings.bg_mode = 'daynight';
   touchCfg();
   await setSun(180, 60);
-  out.daynightNoonBg = stageStyle().includes('background:#5a6673');
+  out.daynightNoonBg = stageStyle().includes('background:#ffffff');
   out.daynightClass = !!sr().querySelector('.stage.daynight');
   await setSun(180, -20);
   out.daynightNightBg = stageStyle().includes('background:#070c14');

docs/SUN.md

@@ -50,8 +50,19 @@ only — no entities are created, no services are called.
 - `'static'` — the existing `bg_color` behaviour, color picker and
   all. Nothing changes for existing installs.
 - `'daynight'` — the stage background follows the sun's elevation:
-  neutral by day, a warm shift in the golden hour (elevation below
-  ~10°), cooling through dusk, deep darkening at night. The PLAN
+  WHITE at full day (the brightest moment of the day is white — owner,
+  2026-08-03), a warm bright shift in the golden hour (elevation below
+  ~10°), cooling through dusk, deep darkening at night. The scale
+  (piecewise-linear between stops, `BG_STOPS` in `src/sun.ts`):
+
+  | elevation | color | phase |
+  | --- | --- | --- |
+  | −90°…−12° | `#070c14` | deep night |
+  | −4° | `#131a28` | dusk cools down |
+  | 0° | `#4a3527` | warm band right at the horizon |
+  | +10° | `#e8ddcf` | morning light — warm and bright |
+  | +30°…+90° | `#ffffff` | plain day, white |
+ The PLAN
   itself dims only ~10% at night (`filter: brightness(.9)`), so the
   daytime room fills stay readable. Transitions are a CSS
   background/filter transition tens of seconds long;

src/houseplan-card.ts

@@ -5071,15 +5071,18 @@ class HouseplanCard extends LitElement {
               // L-shaped house — the scene bg reaches the exterior walls).
               // `space` comes from _renderCfg, so a live resize preview
               // (_rszPreview) moves the paper together with the rooms.
+              // One <g> around ALL paper shapes: the daynight drop shadow
+              // (styles.ts) is composited once for the whole sheet, so
+              // adjacent rooms never cast seams onto each other's paper.
               if (space.bg) {
                 const pp = this._paperRect(space)!;
-                return svg`<rect class="hp-paper" x="${pp.x}" y="${pp.y}" width="${pp.w}" height="${pp.h}" pointer-events="none"></rect>`;
+                return svg`<g class="hp-paperg"><rect class="hp-paper" x="${pp.x}" y="${pp.y}" width="${pp.w}" height="${pp.h}" pointer-events="none"></rect></g>`;
               }
-              return paperRoomShapes(space.rooms).map((sh) =>
+              return svg`<g class="hp-paperg">${paperRoomShapes(space.rooms).map((sh) =>
                 'poly' in sh
                   ? svg`<polygon class="hp-paper" points="${sh.poly}" pointer-events="none"></polygon>`
                   : svg`<rect class="hp-paper" x="${sh.rect.x}" y="${sh.rect.y}" width="${sh.rect.w}" height="${sh.rect.h}" rx="${sh.rect.rx}" pointer-events="none"></rect>`,
-              );
+              )}</g>`;
             })()}
             ${this._editing ? this._renderMarkupDefs(vb) : nothing}
             ${this._editing && !this._markup

src/styles.ts

@@ -328,6 +328,14 @@ export const cardStyles = css`
     .stage.noplan .hp-paper {
       fill: #ffffff;
     }
+    /* White day (owner 2026-08-03): at high sun the daynight sky is #ffffff —
+       the same white as a drawn plan's paper. A whisper of a drop shadow on
+       the paper GROUP keeps the sheet's contour readable on the white sky
+       (user units on the 1000-unit canvas ≈ a few screen px). Invisible at
+       night against the dark sky; 'static' mode never gets it. */
+    .stage.daynight .hp-paperg {
+      filter: drop-shadow(0 2px 8px rgba(10, 16, 26, 0.28));
+    }
     .room {
       transition: 0.12s;
       cursor: default; /* v1.40.1: rooms are not clickable — the label's link icon is */

src/sun.ts

@@ -49,9 +49,9 @@ const BG_STOPS: [number, string][] = [
   [-12, '#070c14'],
   [-4, '#131a28'],  // dusk cools down
   [0, '#4a3527'],   // warm band right at the horizon
-  [10, '#46505f'],  // golden hour fades into neutral
-  [30, '#5a6673'],  // plain day
-  [90, '#5a6673'],
+  [10, '#e8ddcf'],  // morning light — warm and bright on the way to white
+  [30, '#ffffff'],  // plain day: the brightest moment is white (owner 2026-08-03)
+  [90, '#ffffff'],
 ];
 
 const clamp01 = (t: number) => Math.min(1, Math.max(0, t));

test/sun.test.mjs

@@ -50,12 +50,12 @@ test('sunDirOnPlan: compass points map to canvas vectors (y grows down)', () =>
   assert.ok(near(d[0], 0, 1e-12) && near(d[1], -1, 1e-12));
 });
 
-test('dayPhase: night is dark and dim, noon is neutral, sunrise is warm', () => {
+test('dayPhase: night is dark and dim, noon is white, sunrise is warm', () => {
   const night = dayPhase(-20);
   const dawn = dayPhase(2);
   const noon = dayPhase(60);
   assert.equal(night.bg, '#070c14');
-  assert.equal(noon.bg, '#5a6673');
+  assert.equal(noon.bg, '#ffffff');
   assert.notEqual(dawn.bg, night.bg);
   assert.notEqual(dawn.bg, noon.bg);
   assert.ok(near(night.planDim, 0.1));