diff --git a/assets/css/table.css b/assets/css/table.css
index 0c5a7b0..c498584 100644
--- a/assets/css/table.css
+++ b/assets/css/table.css
@@ -455,6 +455,43 @@
 }
 .profile-dropdown-close:hover { color: #1e1208; background: rgba(176, 152, 112, 0.16); }
 
+/* Tablet + desktop: the floating bottom button is mobile-only, so the panel
+   hangs off the bottom edge of the active-profile-row instead — dropping
+   down out of that row and shrinking back into it on close.
+   --profile-anchor-top is the row's live viewport bottom, set by
+   ConfigPanel.js. Phones (<=640px) keep the bottom sheet untouched. */
+@media (min-width: 641px) {
+  .profile-dropdown {
+    top: var(--profile-anchor-top, 0px);
+    bottom: auto;
+    max-height: calc(100vh - var(--profile-anchor-top, 0px) - 16px);
+    border: 1.5px solid #c9b08a;
+    border-radius: 12px;
+    overflow: hidden; /* keeps the scrolling body inside the rounded corners */
+    box-shadow: 0 12px 28px rgba(0, 0, 0, 0.18);
+    transform-origin: 50% 0;
+  }
+  .profile-dropdown-body {
+    max-height: calc(100vh - var(--profile-anchor-top, 0px) - 16px);
+  }
+
+  /* Too little room under the row for the content — revert to the mobile
+     bottom sheet (set by ConfigPanel.js) so the panel gets the full height. */
+  .profile-dropdown.is-bottom-sheet {
+    top: auto;
+    bottom: 0;
+    max-height: calc(100vh - 24px);
+    border: none;
+    border-top: 1.5px solid #c9b08a;
+    border-radius: 12px 12px 0 0;
+    box-shadow: 0 -10px 28px rgba(0, 0, 0, 0.18);
+    transform-origin: 50% 100%;
+  }
+  .profile-dropdown.is-bottom-sheet .profile-dropdown-body {
+    max-height: calc(100vh - 24px);
+  }
+}
+
 /* Read-only "what am I looking at" row above the day tabs — states the
    active profile and the thermal basis (SunSoak env / vehicle / building /
    fur colour) driving the numbers below. Clicking/Enter opens the same
@@ -465,15 +502,16 @@
   justify-content: center;
   flex-wrap: wrap;
   gap: 12px;
-  padding: 2px 16px;
-  margin-bottom: 6px;
+  padding: 8px 16px;
+  margin-bottom: 4px;
   /* --row-bg is set inline per the exact selected option (see ROW_GRADIENTS
      in DayTabs.js) — falls back to a flat parchment tone if unset. */
   background: var(--row-bg, #fdf8ee);
-  border: 1.5px solid #d4c0a0;
-  border-radius: 6px;
+  border: 2px solid #d4c0a0;
+  border-radius: 9px;
   cursor: pointer;
-  transition: filter 0.15s, border-color 0.15s;
+  box-shadow: inset 0 -1px 0 rgba(0,0,0,0.05), 0 1px 3px rgba(0,0,0,0.04);
+  transition: filter 0.2s, border-color 0.2s, box-shadow 0.2s;
 }
 /* Remove alpha from the default fallback color and any potential inherited 
    semi-transparent backgrounds while keeping the hue. */
@@ -494,13 +532,16 @@
 }
 .active-profile-row:hover,
 .active-profile-row:focus-visible {
-  filter: brightness(1.06);
+  filter: brightness(1.04);
   border-color: #c8922a;
+  box-shadow: inset 0 -1px 0 rgba(0,0,0,0.05), 0 3px 8px rgba(200,146,42,0.18);
   outline: none;
 }
+
+/* Breathing room between each "PROFILE" / "VIEWING" label and its value. */
 .active-profile-row-item {
   display: inline-flex;
-  align-items: center;
+  align-items: baseline;
   gap: 7px;
 }
 .active-profile-row-label {
@@ -521,12 +562,22 @@
 }
 .active-profile-row-sep { color: #c0a880; font-size: 16px; }
 .active-profile-row-edit {
+  display: inline-flex;
+  align-items: center;
+  gap: 5px;
   font-family: Manrope, sans-serif;
-  font-size: 13px;
+  font-size: 12.5px;
   font-weight: 700;
   letter-spacing: 0.04em;
   color: #9a6a1a;
-  margin-left: 4px;
+  margin-left: 8px;
+  opacity: 0.7;
+  transition: opacity 0.2s, transform 0.2s, color 0.2s;
+}
+.active-profile-row:hover .active-profile-row-edit,
+.active-profile-row:focus-visible .active-profile-row-edit {
+  opacity: 1;
+  color: #c8922a;
 }
 
 /* Border + text accent per thermal-model group, reusing the same colour
diff --git a/assets/js/components/ConfigPanel.js b/assets/js/components/ConfigPanel.js
index 6e65d4e..2630282 100644
--- a/assets/js/components/ConfigPanel.js
+++ b/assets/js/components/ConfigPanel.js
@@ -55,6 +55,7 @@ export function ConfigPanel({
 }) {
   const profileScrollRef = useRef(null);
   const profileWrapRef   = useRef(null);
+  const dropdownRef      = useRef(null);
 
   const { mainConfigKey, mainLabel } = deriveProfileMain(activeProfile, outdoorsVariant);
 
@@ -77,6 +78,34 @@ export function ConfigPanel({
     return () => document.removeEventListener('keydown', onKey);
   }, [open, onClose]);
 
+  // From tablet up the panel drops *out of* the active-profile-row rather
+  // than sliding up from the floating button (which is mobile-only), so it
+  // has to be anchored to that row's live bottom edge — it's sticky on
+  // desktop and scrolls away on tablet, hence remeasuring on scroll/resize.
+  // Mobile (<=640px) ignores the var entirely and keeps the bottom sheet.
+  useEffect(() => {
+    const el = dropdownRef.current;
+    if (!el) return;
+    const measure = () => {
+      const row = document.querySelector('.active-profile-row');
+      const top = row ? Math.max(0, row.getBoundingClientRect().bottom) : 0;
+      el.style.setProperty('--profile-anchor-top', `${Math.round(top)}px`);
+      // Not enough room below the row for the panel's content? Fall back to
+      // the mobile bottom-sheet layout, which gets the full viewport height.
+      const body    = el.querySelector('.profile-dropdown-body');
+      const content = body ? body.scrollHeight : 0;
+      el.classList.toggle('is-bottom-sheet', content > window.innerHeight - top - 16);
+    };
+    measure();
+    if (!open) return;
+    window.addEventListener('scroll', measure, true);
+    window.addEventListener('resize', measure);
+    return () => {
+      window.removeEventListener('scroll', measure, true);
+      window.removeEventListener('resize', measure);
+    };
+  }, [open, activeTab, activeProfile, outdoorsVariant]);
+
   // Drag-to-scroll + fade edges for the horizontal profile card row.
   useEffect(() => {
     const el   = profileScrollRef.current;
@@ -226,7 +255,7 @@ export function ConfigPanel({
   return html`
     <${Fragment}>
       <div class=${`profile-dropdown-overlay${open ? ' is-open' : ''}`} onClick=${onClose}></div>
-      <div class=${`profile-dropdown${open ? ' is-open' : ''}`} role="dialog" aria-modal="true" aria-label="Profile and configuration" aria-hidden=${!open}>
+      <div ref=${dropdownRef} class=${`profile-dropdown${open ? ' is-open' : ''}`} role="dialog" aria-modal="true" aria-label="Profile and configuration" aria-hidden=${!open}>
         <button class="profile-dropdown-close" aria-label="Close" onClick=${onClose}>×</button>
         <div class="profile-dropdown-body">
 
diff --git a/assets/js/components/DayTabs.js b/assets/js/components/DayTabs.js
index 76fc8bc..0578b1d 100644
--- a/assets/js/components/DayTabs.js
+++ b/assets/js/components/DayTabs.js
@@ -35,7 +35,7 @@ import { h, Fragment } from '../../vendor/preact.js';
 import htm from '../../vendor/htm.js';
 import { confidenceBand, utciCategory, VEHICLE_SPEEDS, VEHICLE_TYPES, BUILDING_TYPES, FUR_COLORS } from '../utils.js';
 import { FREE_DAYS, UTCI_ENVIRONMENTS, deriveProfileMain, FILTER_PROFILES, variantIcons } from '../config.js';
-import { calcVehicleInteriorTemp } from '../physics.js';
+import { calcVehicleInteriorTempPass } from '../physics.js';
 import { CloudIcon, PrecipIcon, HouseIcon, CarIcon, FogIcon, IceIcon } from '../components.js';
 import { SubscribeModal } from './SubscribeModal.js';
 
@@ -222,9 +222,12 @@ export function DayTabs({
           let shadeHi = null, shadeLo = null;
           if (isVehicleProfile) {
             const speedMph = (VEHICLE_SPEEDS[vehicleSpeed] ?? VEHICLE_SPEEDS.static).mph;
-            const ventVals = d.rows
-              .map(r => calcVehicleInteriorTemp(r.Ta, r.glob, r.elev, vehicleType, true, speedMph))
-              .filter(v => isFinite(v));
+            // Run the lagged pass over the whole day, not per-hour equilibrium,
+            // so this hi/lo is directly comparable with the vehicleT column.
+            const ventVals = calcVehicleInteriorTempPass(
+              d.rows.map(r => r.Ta), d.rows.map(r => r.glob), d.rows.map(r => r.elev),
+              d.rows.map(r => r.va), vehicleType, true, speedMph
+            ).filter(v => v != null && isFinite(v));
             shadeHi = ventVals.length ? Math.round(Math.max(...ventVals)) : null;
             shadeLo = ventVals.length ? Math.round(Math.min(...ventVals)) : null;
           } else if (secondaryField) {
diff --git a/assets/js/components/SubscribeModal.js b/assets/js/components/SubscribeModal.js
index f15199d..a834113 100644
--- a/assets/js/components/SubscribeModal.js
+++ b/assets/js/components/SubscribeModal.js
@@ -23,13 +23,7 @@ import { Wordmark } from './Wordmark.js';
 const html = htm.bind(h);
 
 const SUBSCRIBE_URL        = 'https://buy.stripe.com/9B63cw7vl8k15Ei9DQd7q00';
-// TODO: replace with the one-time Payment Link created in the Stripe
-// Dashboard (see plan Part 3) - a flat-rate product with a few selectable
-// price options (e.g. £3 / £5 / £10), since Stripe Payment Links don't
-// support true customer-chosen amounts. Configure its after-payment
-// redirect to https://sunscope.net/?session_id={CHECKOUT_SESSION_ID}
-// the same way the monthly link should be.
-const SUBSCRIBE_URL_ONEOFF = 'https://buy.stripe.com/REPLACE_WITH_ONEOFF_PAYMENT_LINK';
+const SUBSCRIBE_URL_ONEOFF = 'https://buy.stripe.com/14A14odTJ6bT0jY4jwd7q02';
 const MANAGE_URL           = 'https://billing.stripe.com/p/login/9B63cw7vl8k15Ei9DQd7q00';
 
 export function SubscribeModal({ title, detail, onClose, openRestore }) {
diff --git a/assets/js/compute.js b/assets/js/compute.js
index 4f801b1..adb623e 100644
--- a/assets/js/compute.js
+++ b/assets/js/compute.js
@@ -13,7 +13,7 @@
 
 import {
   vaporPressureHpa, solarElevationDeg, calcTmrt, utciApprox,
-  calcConcreteTempPass, calcVehicleInteriorTemp,
+  calcConcreteTempPass, calcVehicleInteriorTempPass,
   calcIndoorTempPass, calcManagedIndoorTempPass, calcShadeAirTemp,
   calcFurSurfaceTempPass,
 } from './physics.js';
@@ -88,7 +88,7 @@ export function buildHourlyRows({ forecast, airQuality, location, vehicleType, v
     // (building shadow, beach umbrella, canopy...). Shares SunSoak's TaEnv
     // baseline and env-reduced radiation, so the two columns stay consistent.
     const shadeT = calcShadeAirTemp(TaEnv, dirEnv + difEnv * 0.2, va, elev, env.shade);
-    const vehicleT = calcVehicleInteriorTemp(Ta, glob, elev, vehicleType, vehicleVent, vehicleSpeed);
+    // vehicleT is stamped in the two-pass section below (thermal lag).
     const eh       = vaporPressureHpa(Ta, RH);
     const Tmrt     = calcTmrt(TaEnv, dirEnv, difEnv, globEnv, elev);
     const utci     = utciApprox(TaEnv, Tmrt, va, eh);
@@ -153,7 +153,7 @@ export function buildHourlyRows({ forecast, airQuality, location, vehicleType, v
       cc, ccLow, ccMid, ccHigh, cloudCat,
       uv, uvA, uvB,
       precip, precipProb, lightning, cape, snow,
-      soilT0, soilT6, soilM, vehicleT, shadeT,
+      soilT0, soilT6, soilM, shadeT,
       effectiveRad,
       elev, Tmrt, utci, utciAdj, eh, compass,
       visKm, aqi,
@@ -161,8 +161,8 @@ export function buildHourlyRows({ forecast, airQuality, location, vehicleType, v
     };
   }) : [];
 
-  // Two-pass calculations: concrete thermal lag + indoor temperature.
-  // Both need the full hourly arrays so they can look back at previous
+  // Two-pass calculations: concrete thermal lag + indoor + vehicle cabin.
+  // All need the full hourly arrays so they can look back at previous
   // hours. Run after hourlyRows is built, then stamp each row.
   if (hourlyRows.length > 0) {
     const TaArr       = hourlyRows.map(r => r.Ta);
@@ -188,6 +188,15 @@ export function buildHourlyRows({ forecast, airQuality, location, vehicleType, v
     const managedTemps = calcManagedIndoorTempPass(TaArr, globArr, elevArr, buildingType);
     hourlyRows.forEach((r, i) => { r.indoorT = indoorTemps[i]; r.managedT = managedTemps[i]; });
 
+    // Vehicle cabin temperature with thermal lag. A parked vehicle climbs
+    // toward the hour's equilibrium rather than jumping to it, so a van that
+    // has been in the sun since morning reads hotter than the same van an
+    // hour after parking. vaArr feeds ambient wind into shell convection.
+    const vehicleTemps = calcVehicleInteriorTempPass(
+      TaArr, globArr, elevArr, vaArr, vehicleType, vehicleVent, vehicleSpeed
+    );
+    hourlyRows.forEach((r, i) => { r.vehicleT = vehicleTemps[i]; });
+
     // Fur surface temperature with thermal lag - Pets profile.
     const furAlbedo = (FUR_COLORS[furColor] || FUR_COLORS.brown).albedo;
     const furTemps = calcFurSurfaceTempPass(TaArr, radArr, vaArr, elevArr, furAlbedo);
diff --git a/assets/js/config.js b/assets/js/config.js
index 493c2ab..cf881f3 100644
--- a/assets/js/config.js
+++ b/assets/js/config.js
@@ -256,7 +256,7 @@ export const COL_DESCRIPTIONS = {
   soilT6:    { title: 'Soil Temp 6 cm',   desc: 'Temperature of the soil at 6 cm depth, the root zone for many crops and seedlings. Lags behind surface temperature by several hours.' },
   soilM:     { title: 'Soil Moisture',    desc: 'Water saturation of the top 1 cm of soil as a percentage. Above 40% suggests saturated ground; below 20% indicates dry conditions.' },
   concreteT: { title: 'Concrete Surface', desc: 'Estimated temperature of sun-exposed urban concrete or paving. Concrete absorbs more solar energy than grass and cannot cool itself through evaporation — surface temps can run 15–25 °C above air temperature on sunny days.' },
-  vehicleT:  { title: 'Vehicle Interior', desc: 'Estimated ambient cabin temperature inside a parked vehicle. Cars heat rapidly through thin body panels and glass; motorhomes and caravans are modelled as insulated occupied living spaces with retained warmth, lower glass gain, and slower heat response. Dangerous for children and pets above 35 °C; potentially fatal above 45 °C.' },
+  vehicleT:  { title: 'Vehicle Interior', desc: 'Estimated ambient cabin temperature inside a parked vehicle. Cars heat rapidly through thin body panels and glass; motorhomes and caravans are modelled as insulated occupied living spaces that warm more slowly but hold heat longer, with gain through the windscreen and rooflights and a little retained living-space warmth. Accounts for ambient wind over the bodywork, road speed, and whether the windows are open. Dangerous for children and pets above 35 °C; potentially fatal above 45 °C.' },
   indoorT:   { title: 'Indoors',          desc: 'Estimated ambient temperature inside a selected building type with windows closed and no air conditioning. Accounts for retained warmth, window solar gain, internal gains, and thermal lag without repeatedly accumulating solar heat hour after hour.' },
   managedT:  { title: 'Managed Indoors',  desc: 'Estimated indoor temperature with curtains closed and windows opened when outdoor air is cooler than inside — the standard UK heatwave advice. Curtains block most direct solar gain; smart ventilation pulls the temperature down during cooler periods.' },
   vis:       { title: 'Visibility',       desc: 'Horizontal visibility in kilometres, sourced from the CAMS air quality model. Values below 1 km indicate fog or very thick haze; below 10 km suggests mist, smoke, or significant pollution. Relevant for driving, flying, and photography.' },
diff --git a/assets/js/physics.js b/assets/js/physics.js
index edb907e..257ef24 100644
--- a/assets/js/physics.js
+++ b/assets/js/physics.js
@@ -11,7 +11,8 @@
 //    calcConcreteTempPass(arrays...)                        thermal-lag pass over full hourly arrays
 //    calcIndoorTempPass(TaArr, globArr, elevArr, buildingType)  passive indoor temp
 //    calcManagedIndoorTempPass(TaArr, globArr, elevArr, buildingType) managed indoor temp
-//    calcVehicleInteriorTemp(Ta, globalRad, solElev, vehicleType, ventilated, speedMph)
+//    calcVehicleInteriorTemp(Ta, globalRad, solElev, vehicleType, ventilated, speedMph, windMps)  equilibrium cabin temp
+//    calcVehicleInteriorTempPass(TaArr, globArr, elevArr, vaArr, vehicleType, ventilated, speedMph)  lagged cabin temp
 //    calcShadeAirTemp(TaEnv, effRadEnv, va, elev, shade)  per-env shade air temp
 //    vaporPressureHpa(Ta, RH)              Magnus formula - hPa
 //    solarElevationDeg(lat, lon, dateUTC)  NOAA simplified solar position (-)
@@ -375,92 +376,115 @@ export function calcManagedIndoorTempPass(TaArr, globArr, elevArr, buildingType
 //     fleet; dark paint ~0.10, silver/white ~0.40).
 //     Panel surface temp - conductive gain into cabin air.
 //
-//  2. SIDE-WINDOW GLAZING GAIN (sun-angle dependent)
+//  2. VERTICAL GLAZING GAIN (sun-angle dependent)
 //     When solar elevation is between ~10- and ~60-, the sun's rays
-//     cut through the side glass at an angle that allows significant
-//     transmission into the cabin (rather than hitting the roof or
-//     reflecting off at a shallow angle). This warms the cabin air
+//     cut through the side glass and windscreen at an angle that allows
+//     significant transmission into the cabin. This warms the cabin air
 //     but the occupant is modelled as NOT sitting in the beam -
 //     so it adds to ambient cabin temp, not direct radiant load.
-//     Above 60- the sun mostly hits the roof; below 10- it reflects.
+//     Outside that window a diffuse floor still applies: scattered sky
+//     light enters the glass at any sun angle, so the tent function is
+//     clamped rather than switched off (an unclamped tent produced a
+//     discontinuity where a LOWER sun gave MORE glazing gain).
 //
-//  Wind is ignored unless ventilation is enabled. No evaporative cooling.
+//  3. HORIZONTAL GLAZING GAIN (rooflights / panoramic roofs)
+//     Rooflights collect most strongly when the sun is high - the exact
+//     condition under which the vertical-glass term is tailing off. Scales
+//     with sin(elevation) and uses a lower transmission (0.40) because
+//     rooflights are typically smoked/tinted acrylic rather than clear glass.
+//
+//  Ambient wind scrubs the bodywork whether or not the windows are open, so
+//  it feeds the shell convection coefficient in every case; road speed does
+//  the same job and the larger of the two wins. No evaporative cooling.
 //  Cars warm quickly; motorhomes and caravans are treated as insulated living
-//  spaces with 25-35 mm sandwich panels, so panel heat gain is much smaller
-//  and the interior response is slower than a car cabin. Because they are
-//  occupied living spaces, they also retain warmth from previous hours, people,
-//  appliances, and background heating; without that, cool sunny days are
-//  under-estimated badly.
+//  spaces with 25-35 mm sandwich panels, so panel heat gain is much smaller.
+//  Their interiors are SLOWER, not COOLER - the insulation that keeps heat out
+//  also keeps it in, so a closed-up van ends up about as hot as a closed-up car
+//  once it has had a few hours to get there. Because they are occupied living
+//  spaces, they also retain a little warmth from previous hours, people,
+//  appliances, and background heating.
 //
 // Colour thresholds in the table:
 //   < 35 -C  - warm but tolerable for short periods
 //   35-45 -C - dangerous for children/pets (hyperthermia risk)
 //   > 45 -C  - potentially fatal within minutes
 // -------------------------------------------------------------------
-export function calcVehicleInteriorTemp(Ta, globalRad, solElev, vehicleType = 'car', ventilated = false, speedMph = 0) {
+export function calcVehicleInteriorTemp(Ta, globalRad, solElev, vehicleType = 'car', ventilated = false, speedMph = 0, windMps = 0) {
   if (globalRad == null || Ta == null) return null;
 
   // Look up vehicle preset; fall back to a standard car if key unknown.
   const preset = VEHICLE_TYPES[vehicleType] || VEHICLE_TYPES.car;
 
-  // Road speed in m/s. speedMph = 0 is "Static" (parked) and reproduces the
-  // original stationary model exactly; higher speeds scrub the shell with
-  // forced airflow and (windows down) flush the cabin toward ambient.
+  // Road speed in m/s. speedMph = 0 is "Static" (parked); higher speeds scrub
+  // the shell with forced airflow and (windows down) flush the cabin toward
+  // ambient.
   const vMs = Math.max(0, speedMph) * 0.447; // mph -> m/s
 
   // -- 1. Panel conduction ------------------------------------------
   const panelAbsorbed = globalRad * (1 - preset.albedo); // W/m- absorbed by bodywork
   // Panel surface temp: absorbed solar / convective loss to outside air.
-  // Parked, a light breeze over the panels gives hOut ~10 W/m-K. Once moving,
-  // forced convection rises with road speed (same sqrt form as the surface
-  // model), so the bodywork runs progressively closer to ambient.
-  const hOut = 10 + 5.5 * Math.sqrt(vMs);
+  // Convection over the shell is driven by whichever airflow is stronger -
+  // the ambient wind or the car's own road speed. A parked vehicle in a
+  // 15 mph wind has bodywork far closer to ambient than one in still air,
+  // so ambient wind must not be ignored just because the windows are shut.
+  // The 1.5 m/s floor is not fudge: hOut is steep near calm, and a reported
+  // wind of 0 m/s does not mean still air at the bodywork - thermal plumes off
+  // hot panels and ordinary gustiness keep it moving. Without the floor a dead
+  // calm hour sent a sealed car to ~67 -C. It only bites below ~3 mph, so it
+  // leaves the calibration anchors untouched.
+  const vShell = Math.max(1.5, vMs, Math.max(0, windMps || 0));
+  const hOut = 10 + 5.5 * Math.sqrt(vShell);
   const panelSurfaceTemp = Ta + panelAbsorbed / hOut;
   // Conductive gain into cabin. Cars are thin metal + trim; motorhomes and
   // caravans use insulated sandwich panels, so their bodyU is much lower.
   const hCabin = preset.bodyU ?? 4;
   const conductionGain = hCabin * (panelSurfaceTemp - Ta); // W/m-
 
-  // -- 2. Side-window glazing gain (angle-dependent) -----------------
+  // -- 2. Vertical glazing gain (angle-dependent) --------------------
   // Glazing transmission for auto glass ~0.70; scaled by vehicle glazing area.
+  // Tent function peaks at 35- elevation, where the sun cuts squarely through
+  // side glass and windscreen, and tapers either side. It is clamped at 0.30
+  // (= the 0.15 diffuse floor once the 0.5 not-in-beam factor is applied) so
+  // scattered sky light always gets in. Without that clamp the gain fell to
+  // zero at 10- and 60- and then jumped back up outside the range.
   const tau = 0.70 * preset.glazingArea;
-  let glazingGain = 0;
-  if (solElev != null && solElev > 10 && solElev < 60) {
-    // Scale factor: peaks around 30-40- elevation (sun cuts squarely
-    // through side glass), tapers off toward 10- (shallow/reflected)
-    // and 60- (sun increasingly hitting roof not side glass).
-    // Use a simple tent function peaking at 35-.
-    const peak = 35;
-    const halfWidth = 25; // degrees either side
-    const factor = Math.max(0, 1 - Math.abs(solElev - peak) / halfWidth);
-    // Diffuse radiation also enters through glass regardless of angle
-    glazingGain = tau * globalRad * factor * 0.5; // occupant not in beam - 50% ambient
-  } else {
-    // Outside the side-window zone: diffuse only (scattered sky light)
-    glazingGain = tau * (globalRad * 0.15); // ~15% diffuse fraction
-  }
+  const tent = (solElev != null && solElev > 0)
+    ? Math.max(0, 1 - Math.abs(solElev - 35) / 25)
+    : 0;
+  const glazingGain = tau * globalRad * Math.max(0.30, tent) * 0.5; // occupant not in beam
+
+  // -- 3. Horizontal glazing gain (rooflights, panoramic roof) -------
+  // Rooflights collect in proportion to sin(elevation), so they peak at midday
+  // just as the vertical-glass term is falling away. Smoked acrylic transmits
+  // roughly 0.40 rather than the 0.70 of clear auto glass.
+  const roofGain = (solElev != null && solElev > 0)
+    ? 0.40 * (preset.roofGlazing ?? 0) * globalRad * Math.sin(solElev * Math.PI / 180)
+    : 0;
 
   // -- Combine into cabin air temperature ---------------------------
   // Total heat input per m- of cabin surface
-  const totalGain = conductionGain + glazingGain;
+  const totalGain = conductionGain + glazingGain + roofGain;
   // Cabin heat rejection: an effective blend of leakage, internal air volume,
-  // and surfaces exchanging heat with the outside. With windows open it is
-  // roughly 5x higher when parked - air moves freely through the cabin,
-  // flushing heat out and capping interior temperature much closer to ambient.
+  // and surfaces exchanging heat with the outside. Opening the windows when
+  // parked multiplies it by the preset's ventMult - a car with every window
+  // down flushes far harder per unit volume than a van with two windows and a
+  // rooflight open, so that multiplier is per-vehicle, not a shared constant.
   // On the move the through-draught multiplies this further (a 70 mph open
   // window flushes the cabin almost to ambient). Sealed but moving rejects a
   // little faster too, because the cooler shell pulls cabin heat out.
   const speedFactor = 1 + vMs / 12; // grows with road speed (windows-open draught)
-  const lossMult = ventilated ? 5 * speedFactor : 1 + vMs / 40;
+  const lossMult = ventilated ? (preset.ventMult ?? 4) * speedFactor : 1 + vMs / 40;
   const effectiveHLoss = preset.hCabinLoss * lossMult;
-  const thermalMass = preset.thermalMass ?? 1;
-  const solarRise = (totalGain / effectiveHLoss) * thermalMass;
+  const solarRise = totalGain / effectiveHLoss;
 
   // Motorhomes/caravans behave more like small insulated rooms than parked
   // cars. This term captures retained living-space warmth: strongest on cool
   // days, tapering away as outdoor air warms, and reduced when ventilated.
+  // It used to be much larger (8 - 0.25*Ta) because it was silently standing
+  // in for solar gain the model was throwing away; now that the glazing terms
+  // are right it only has to cover occupancy and residual warmth.
   const retainedWarmth = preset.retainedWarmth
-    ? Math.max(0, 8 - 0.25 * Ta) * (ventilated ? 0.35 : 1)
+    ? Math.max(0, 5 - 0.20 * Ta) * (ventilated ? 0.35 : 1)
     : 0;
   const internalGain = (preset.internalGain ?? 0) * (ventilated ? 0.35 : 1);
 
@@ -470,6 +494,57 @@ export function calcVehicleInteriorTemp(Ta, globalRad, solElev, vehicleType = 'c
   return Math.max(Ta, Math.min(Ti, 90));
 }
 
+// -------------------------------------------------------------------
+// VEHICLE INTERIOR TEMPERATURE - TWO-PASS (thermal lag)
+// -------------------------------------------------------------------
+// calcVehicleInteriorTemp above returns the EQUILIBRIUM cabin temperature
+// for one hour's conditions - where the interior would settle if those
+// conditions held. Real cabins take time to get there, so this pass relaxes
+// toward that target with a per-vehicle time constant, exactly as
+// calcConcreteTempPass and calcIndoorTempPass do.
+//
+// This replaces an earlier 'thermalMass' multiplier that scaled the
+// equilibrium rise down (motorhomes ran at 0.35x). That conflated two
+// different things: thermal mass delays how fast you reach equilibrium, it
+// does not lower the equilibrium itself. A van parked in the sun since
+// breakfast is close to equilibrium by mid-afternoon, so the multiplier
+// under-predicted every long parked spell - badly enough that a ventilated
+// motorhome came out barely a degree above ambient at peak sun.
+//
+// Cars use a short constant (~0.5 h - a car is hot within the half hour);
+// motorhomes and caravans a longer one (~1.5-1.7 h) reflecting their larger
+// air volume and heavier interior fit-out.
+//
+// vaArr is ambient wind in m/s (Open-Meteo wind_speed_10m with
+// wind_speed_unit=ms) and may be null/omitted, in which case still air is
+// assumed. speedMph is the selected road-speed class, not per-hour data.
+// -------------------------------------------------------------------
+export function calcVehicleInteriorTempPass(TaArr, globArr, elevArr, vaArr, vehicleType = 'car', ventilated = false, speedMph = 0) {
+  const preset = VEHICLE_TYPES[vehicleType] || VEHICLE_TYPES.car;
+  const n = TaArr.length;
+  const result = new Array(n);
+  const alpha = 1 - Math.exp(-1 / (preset.lagHours ?? 0.5));
+
+  // Seed at the first hour's air temp - a vehicle left overnight has
+  // equalised with the outside air.
+  let Ti = TaArr[0] ?? 15;
+
+  for (let i = 0; i < n; i++) {
+    const Ta = TaArr[i];
+    if (Ta == null) { result[i] = null; continue; }
+    const target = calcVehicleInteriorTemp(
+      Ta, globArr[i] ?? 0, elevArr[i], vehicleType, ventilated, speedMph,
+      vaArr ? (vaArr[i] ?? 0) : 0
+    );
+    if (target == null) { result[i] = null; continue; }
+    Ti = Ti + alpha * (target - Ti);
+    // Can't be cooler than outside air; physical cap at 90 -C.
+    result[i] = Math.max(Ta, Math.min(Ti, 90));
+  }
+
+  return result;
+}
+
 // -------------------------------------------------------------------
 // SHADE AIR TEMPERATURE (per-environment microclimate)
 // -------------------------------------------------------------------
@@ -576,7 +651,8 @@ export function calcFurSurfaceTempPass(TaArr, radArr, vaArr, elevArr, furAlbedo
 // calcVehicleInteriorTemp now takes a speedMph argument (Static / 20 / 50 / 70
 // mph in the UI). Forced convection over the shell scales with road speed, and
 // windows-open through-flow scales further with speed, so a moving cabin runs
-// cooler than the same parked car. speedMph = 0 reproduces the static model.
+// cooler than the same parked car. speedMph = 0 is the parked case - which is
+// no longer "no airflow", since ambient wind now drives shell convection too.
 //
 // -- CYCLIST AT SPEED (FUTURE) ------------------------------------------------
 // A cyclist generates their own headwind, so the felt temperature (UTCI) is
diff --git a/assets/js/utils.js b/assets/js/utils.js
index cb462da..3d2b4c7 100644
--- a/assets/js/utils.js
+++ b/assets/js/utils.js
@@ -209,23 +209,37 @@ export function burnLabel(mins) {
 // -------------------------------------------------------------------
 // Each entry tweaks the physical levers in calcVehicleInteriorTemp:
 //   albedo       - how much solar the bodywork reflects (0 = black, 1 = mirror)
-//   glazingArea  - relative sun-exposed glass area (1.0 = typical car)
+//   glazingArea  - relative VERTICAL glass area (1.0 = typical car). A coachbuilt
+//                  motorhome has a huge near-vertical windscreen plus cab side
+//                  windows, so it is far from the 0.25 once assumed here.
+//   roofGlazing  - relative HORIZONTAL glass area (rooflights / Heki hatches /
+//                  panoramic glass roof). Gains from these peak at high sun,
+//                  which is exactly when the vertical-glass term is tailing off.
 //   bodyU        - effective body/panel conductance into the cabin. Cars are
 //                  thin metal/glass boxes; motorhomes/caravans have insulated
 //                  sandwich panels, commonly around 25-35 mm thick.
 //   hCabinLoss   - effective heat rejection/infiltration from the cabin air.
-//   thermalMass  - lower values mean the interior warms more slowly in the hour.
+//                  Motorhomes/caravans reject heat more SLOWLY than cars (better
+//                  sealed, smaller aperture per unit volume), which is why a
+//                  closed-up van gets as hot as a car despite its insulation.
+//   ventMult     - how much opening the windows multiplies hCabinLoss when
+//                  parked. A car with all windows down flushes far more
+//                  effectively per unit volume than a van with two windows and
+//                  a rooflight open, so this is not a shared constant.
+//   lagHours     - interior thermal time constant. This is a DELAY on reaching
+//                  the hour's equilibrium, not a reduction of it - see the note
+//                  in calcVehicleInteriorTempPass.
 //   retainedWarmth - occupied insulated living spaces hold heat from previous
 //                  hours, people, appliances, and background heating.
 //   internalGain   - small living-space warmth boost when closed up.
 // -------------------------------------------------------------------
 export const VEHICLE_TYPES = {
-  car:       { name: 'Car / Hatchback',       albedo: 0.25, glazingArea: 1.0,  bodyU: 4.0, hCabinLoss: 20, thermalMass: 1.00, retainedWarmth: false, internalGain: 0.0 },
-  mpv:       { name: 'MPV / People Carrier',  albedo: 0.25, glazingArea: 1.3,  bodyU: 4.0, hCabinLoss: 20, thermalMass: 1.00, retainedWarmth: false, internalGain: 0.0 },
-  suv:       { name: 'SUV / 4x4',             albedo: 0.22, glazingArea: 1.1,  bodyU: 3.8, hCabinLoss: 19, thermalMass: 0.95, retainedWarmth: false, internalGain: 0.0 },
-  truck:     { name: 'Truck / HGV Cab',       albedo: 0.30, glazingArea: 1.2,  bodyU: 3.5, hCabinLoss: 18, thermalMass: 0.90, retainedWarmth: false, internalGain: 0.0 },
-  motorhome: { name: 'Motorhome / Campervan', albedo: 0.55, glazingArea: 0.25, bodyU: 0.9, hCabinLoss: 12, thermalMass: 0.35, retainedWarmth: true,  internalGain: 1.2 },
-  caravan:   { name: 'Caravan (towed)',       albedo: 0.60, glazingArea: 0.22, bodyU: 0.8, hCabinLoss: 11, thermalMass: 0.35, retainedWarmth: true,  internalGain: 1.2 },
+  car:       { name: 'Car / Hatchback',       albedo: 0.25, glazingArea: 1.00, roofGlazing: 0.00, bodyU: 4.0, hCabinLoss: 11.0, ventMult: 4.0, lagHours: 0.5, retainedWarmth: false, internalGain: 0.0 },
+  mpv:       { name: 'MPV / People Carrier',  albedo: 0.25, glazingArea: 1.30, roofGlazing: 0.02, bodyU: 4.0, hCabinLoss: 11.5, ventMult: 4.0, lagHours: 0.6, retainedWarmth: false, internalGain: 0.0 },
+  suv:       { name: 'SUV / 4x4',             albedo: 0.22, glazingArea: 1.10, roofGlazing: 0.02, bodyU: 3.8, hCabinLoss: 11.0, ventMult: 4.0, lagHours: 0.6, retainedWarmth: false, internalGain: 0.0 },
+  truck:     { name: 'Truck / HGV Cab',       albedo: 0.30, glazingArea: 1.20, roofGlazing: 0.00, bodyU: 3.5, hCabinLoss: 10.5, ventMult: 4.0, lagHours: 0.7, retainedWarmth: false, internalGain: 0.0 },
+  motorhome: { name: 'Motorhome / Campervan', albedo: 0.55, glazingArea: 0.85, roofGlazing: 0.06, bodyU: 0.9, hCabinLoss:  6.5, ventMult: 2.5, lagHours: 1.5, retainedWarmth: true,  internalGain: 1.2 },
+  caravan:   { name: 'Caravan (towed)',       albedo: 0.60, glazingArea: 0.55, roofGlazing: 0.07, bodyU: 0.8, hCabinLoss:  6.2, ventMult: 2.4, lagHours: 1.7, retainedWarmth: true,  internalGain: 1.2 },
 };
 
 // -------------------------------------------------------------------
diff --git a/build.js b/build.js
index f55de72..e3b9ea2 100644
--- a/build.js
+++ b/build.js
@@ -232,7 +232,8 @@ async function build() {
 
   // 8. Copy static files
   console.log('  Copying static files...');
-  for (const f of ['robots.txt', 'sitemap.xml', 'og-image.png', 'favicon.svg', 'restore.php', 'track.php', 'stats.php']) {
+  for (const f of ['robots.txt', 'sitemap.xml', 'og-image.png', 'favicon.svg', 'restore.php', 'track.php', 'stats.php',
+       'verify-session.php', 'check-subscription.php', 'dev-unlock.php', 'secrets.local.php']) {
     const src = path.join(ROOT, f);
     if (fs.existsSync(src)) {
       copyFile(src, path.join(DIST, f));
diff --git a/data/tracking.json b/data/tracking.json
index b90dfb0..7fdb78a 100644
--- a/data/tracking.json
+++ b/data/tracking.json
@@ -158,5 +158,18 @@
             "alltemps": 2,
             "showall": 2
         }
+    },
+    "2026-07-25": {
+        "visits": 7,
+        "profiles": {
+            "home": 10,
+            "vehicle": 7,
+            "pets": 5,
+            "basic": 5,
+            "alltemps": 3,
+            "showall": 1,
+            "custom": 1,
+            "farming": 1
+        }
     }
 }
\ No newline at end of file