/* Electrified Home – one stylesheet for every page.

   Layout borrows from the Energy Saving Trust's site: a deep blue band at the
   top of each page, then blocks of solid colour that each lead somewhere.
   The colours still come from UK wiring: brown is live, blue is neutral,
   green and yellow is earth.

   Bands run the full width of the window while their content stays in
   main's column: a box-shadow paints the colour out to the edges and
   clip-path trims it top and bottom. Neither affects layout, so there is
   no sideways scroll. */

@font-face {
  font-family: "Atkinson Hyperlegible Next";
  src: url("fonts/atkinson-hyperlegible-next-latin-400-normal.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}
@font-face {
  font-family: "Atkinson Hyperlegible Next";
  src: url("fonts/atkinson-hyperlegible-next-latin-400-italic.woff2") format("woff2");
  font-weight: 400;
  font-style: italic;
  font-display: swap;
}
@font-face {
  font-family: "Atkinson Hyperlegible Next";
  src: url("fonts/atkinson-hyperlegible-next-latin-700-normal.woff2") format("woff2");
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

:root {
  --page: #ffffff;
  --sky: #eef3f9;       /* light bands */
  --ink: #16202b;
  --muted: #4b5866;
  --rule: #d3dbe4;
  --navy: #14365f;      /* top of every page, footer */
  --navy-ink: #dfe8f3;  /* text on navy */
  --blue: #2458a6;      /* neutral: links, buttons, the widgets' brand colour */
  --brown: #8a4b26;     /* live */
  --green: #2f7d3a;     /* earth */
  --yellow: #f0c63a;    /* earth */
  --slate: #43515c;
  --teal: #bfe3e6;
  --measure: 42rem;
  --wide: 72rem;
  --radius: 6px;
}

*,
*::before,
*::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--page);
  color: var(--ink);
  font-family: "Atkinson Hyperlegible Next", system-ui, -apple-system, "Segoe UI", sans-serif;
  font-size: 1.0625rem;
  line-height: 1.6;
}

a { color: var(--blue); text-underline-offset: 0.15em; }
a:hover { color: var(--ink); }

:focus-visible {
  outline: 3px solid var(--yellow);
  outline-offset: 2px;
  box-shadow: 0 0 0 6px var(--ink);
}

img, svg { max-width: 100%; }

/* ---------- Header ---------- */

.site-header {
  background: var(--page);
  border-bottom: 1px solid var(--rule);
}
.site-header .inner {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0.875rem 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem 2rem;
}
.site-name {
  font-weight: 700;
  font-size: 1.1875rem;
  color: var(--navy);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  white-space: nowrap;
}
.site-name svg { width: 1.75rem; height: 1.75rem; flex: none; }
.site-nav { margin-left: auto; }
.site-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  gap: 0.25rem 1.125rem;
}
.site-nav li { margin: 0; }
.site-nav a {
  display: block;
  color: var(--ink);
  text-decoration: none;
  font-size: 0.9375rem;
  padding: 0.375rem 0;
  border-bottom: 3px solid transparent;
  white-space: nowrap;
}
.site-nav a:hover { border-bottom-color: var(--rule); }
.site-nav a[aria-current="page"] { border-bottom-color: var(--brown); }
/* The last link, Tools, is a button. */
.site-nav li:last-child a {
  background: var(--blue);
  color: #fff;
  font-weight: 700;
  padding: 0.5rem 1rem;
  border-radius: 999px;
  border: 0;
}
.site-nav li:last-child a:hover { background: var(--navy); }
.site-nav li:last-child a[aria-current="page"] { background: var(--navy); }

/* Narrow screens: the nav becomes a strip under the name that scrolls
   sideways by itself, with a fade to show there's more. */
@media (max-width: 64rem) {
  .site-header .inner { flex-wrap: wrap; padding-bottom: 0; }
  .site-nav {
    margin: 0 -1rem;
    width: calc(100% + 2rem);
    overflow-x: auto;
    scrollbar-width: none;
    -webkit-mask-image: linear-gradient(to right, #000 85%, transparent);
    mask-image: linear-gradient(to right, #000 85%, transparent);
  }
  .site-nav::-webkit-scrollbar { display: none; }
  .site-nav ul { padding: 0.25rem 3rem 0.5rem 1rem; width: max-content; }
  /* Keep the Tools button in view, at the start of the strip. */
  .site-nav li:last-child { order: -1; }
}

.skip {
  position: absolute;
  left: -999px;
}
.skip:focus { left: 1rem; top: 0.5rem; background: var(--page); padding: 0.5rem; z-index: 10; }

/* ---------- Page body ---------- */

main {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0 1rem;
}
main > * { max-width: var(--measure); }
main > :is(.wide, .page-head, .hero, .band, .cards, .split, .steps) { max-width: none; }

h1, h2, h3 { line-height: 1.2; font-weight: 700; color: var(--navy); }
h1 { font-size: clamp(2.125rem, 5vw, 3.25rem); margin: 0 0 1rem; letter-spacing: -0.015em; }
h2 { font-size: clamp(1.5rem, 3vw, 1.875rem); margin: 3rem 0 0.75rem; letter-spacing: -0.01em; }
h3 { font-size: 1.1875rem; margin: 2rem 0 0.5rem; }
p, ul, ol { margin: 0 0 1rem; }
li { margin-bottom: 0.375rem; }

.lede { font-size: 1.25rem; line-height: 1.5; }

.eyebrow {
  font-size: 0.9375rem;
  font-weight: 700;
  margin: 0 0 0.5rem;
  color: var(--yellow);
}
.page-head .eyebrow a { color: inherit; }

.note {
  border-left: 4px solid var(--brown);
  padding: 0.25rem 0 0.25rem 1rem;
  color: var(--muted);
}

.sources { font-size: 0.9375rem; color: var(--muted); margin-top: 3rem; }
.sources h2 { font-size: 1.0625rem; color: var(--muted); }

/* ---------- Bands ---------- */

.page-head,
.hero,
.band {
  position: relative;
  box-shadow: 0 0 0 100vmax var(--band);
  clip-path: inset(0 -100vmax);
  background: var(--band);
}

/* Top of every page but the home page: h1 and lede on navy. */
.page-head {
  --band: var(--navy);
  color: #fff;
  padding: 2.75rem 0 2.5rem;
  margin-bottom: 2.5rem;
}
.page-head h1 { color: #fff; max-width: 20em; }
.page-head .lede { color: var(--navy-ink); max-width: var(--measure); margin-bottom: 0; }
.page-head a { color: #fff; }

.band {
  --band: var(--sky);
  padding: 1rem 0 2.5rem;
  margin: 3rem 0;
}
.band > * { max-width: var(--measure); }
.band > :is(.cards, .split, .wide) { max-width: none; }

/* ---------- Home page ---------- */

.hero {
  --band: var(--navy);
  color: #fff;
  padding: 3rem 0 3.5rem;
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  align-items: center;
  gap: 2rem 3rem;
}
.hero h1 { color: #fff; font-size: clamp(2.375rem, 6vw, 4rem); }
.hero .lede { color: var(--navy-ink); }
.hero-art { width: 100%; height: auto; display: block; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 0.75rem; margin: 1.75rem 0 0; }

.button {
  display: inline-block;
  font-weight: 700;
  text-decoration: none;
  padding: 0.75rem 1.375rem;
  border-radius: 999px;
  background: var(--yellow);
  color: var(--ink);
  border: 2px solid var(--yellow);
}
.button:hover { background: #fff; border-color: #fff; color: var(--ink); }
.button.ghost { background: transparent; color: #fff; border-color: rgba(255, 255, 255, 0.7); }
.button.ghost:hover { background: #fff; color: var(--ink); }

@media (max-width: 48rem) {
  .hero { grid-template-columns: 1fr; padding: 2rem 0 2.5rem; }
  .hero-art { max-width: 26rem; margin: 0 auto; }
}

/* ---------- Cards ----------
   A list of links, each a block: <ul class="cards"><li class="i-NAME">
   <a href>Title</a><p>Summary</p></li></ul>. The whole block is clickable
   (the link's ::after covers it). The i- class picks an icon from
   /assets/icons/; without one, the card gets a plain one. */

.cards {
  list-style: none;
  padding: 0;
  margin: 1.5rem 0 2rem;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(15.5rem, 1fr));
  gap: 1rem;
}
.cards li {
  --icon: url("icons/tool.svg");
  position: relative;
  margin: 0;
  padding: 1.25rem 1.25rem 3.25rem;
  border-radius: var(--radius);
  background: var(--page);
  border: 1px solid var(--rule);
  display: flex;
  flex-direction: column;
  gap: 0.375rem;
  transition: transform 120ms ease-out, box-shadow 120ms ease-out;
}
.cards li::before {
  content: "";
  width: 2.5rem;
  height: 2.5rem;
  margin-bottom: 0.5rem;
  background: currentColor;
  -webkit-mask: var(--icon) center / contain no-repeat;
  mask: var(--icon) center / contain no-repeat;
  color: var(--blue);
}
/* An arrow in the bottom corner, as on the Energy Saving Trust's cards. */
.cards li::after {
  content: "\2192";
  position: absolute;
  left: 1.25rem;
  bottom: 0.875rem;
  font-size: 1.375rem;
  line-height: 1;
  font-weight: 700;
  transition: transform 120ms ease-out;
}
.cards li:hover { transform: translateY(-2px); box-shadow: 0 6px 18px rgba(20, 54, 95, 0.14); }
.cards li:hover::after { transform: translateX(4px); }
.cards a {
  font-weight: 700;
  font-size: 1.1875rem;
  line-height: 1.25;
  color: inherit;
  text-decoration: none;
}
.cards a::after { content: ""; position: absolute; inset: 0; border-radius: var(--radius); }
.cards a:hover { text-decoration: underline; }
.cards a:focus-visible { outline: none; box-shadow: none; }
.cards li:focus-within { outline: 3px solid var(--yellow); outline-offset: 2px; }
.cards p { margin: 0; font-size: 0.9375rem; line-height: 1.5; }
.cards .needs { margin-top: auto; padding-top: 0.625rem; font-size: 0.875rem; font-weight: 700; }

.cards.compact { grid-template-columns: repeat(auto-fill, minmax(13rem, 1fr)); }
.cards.compact li { padding: 1rem 1rem 2.75rem; }
.cards.compact li::before { width: 2rem; height: 2rem; margin-bottom: 0.25rem; }
.cards.compact li::after { left: 1rem; bottom: 0.75rem; }
.cards.compact a { font-size: 1.0625rem; }

/* On a phone, cards are rows: icon on the left, text beside it. */
@media (max-width: 40rem) {
  .cards, .cards.compact { grid-template-columns: 1fr; gap: 0.625rem; }
  .cards li, .cards.compact li {
    display: grid;
    grid-template-columns: 2rem 1fr;
    column-gap: 0.875rem;
    row-gap: 0.25rem;
    align-content: start;
    padding: 1rem;
  }
  .cards li::before, .cards.compact li::before {
    grid-row: span 2;
    width: 2rem;
    height: 2rem;
    margin: 0;
  }
  .cards li::after { display: none; }
  .cards li > * { grid-column: 2; }
  .cards a, .cards.compact a { font-size: 1.0625rem; }
  .cards .needs { padding-top: 0.25rem; }
}

/* Tool cards are solid colour, taking the next colour in turn, so a new
   tool gets one without anyone choosing it. */
.tool-cards li { border: 0; color: #fff; }
.tool-cards li::before { color: currentColor; }
.tool-cards li:nth-child(7n+1) { background: var(--blue); }
.tool-cards li:nth-child(7n+2) { background: var(--green); }
.tool-cards li:nth-child(7n+3) { background: var(--brown); }
.tool-cards li:nth-child(7n+4) { background: var(--yellow); color: var(--ink); }
.tool-cards li:nth-child(7n+5) { background: var(--navy); }
.tool-cards li:nth-child(7n+6) { background: var(--teal); color: var(--ink); }
.tool-cards li:nth-child(7n+7) { background: var(--slate); }

.cards .i-heating { --icon: url("icons/heat-pump.svg"); }
.cards .i-hot-water { --icon: url("icons/hot-water.svg"); }
.cards .i-cooking { --icon: url("icons/hob.svg"); }
.cards .i-car { --icon: url("icons/car.svg"); }
.cards .i-solar { --icon: url("icons/sun.svg"); }
.cards .i-tariffs { --icon: url("icons/meter.svg"); }
.cards .i-insulation { --icon: url("icons/house.svg"); }
.cards .i-paying { --icon: url("icons/pound.svg"); }
.cards .i-installers { --icon: url("icons/badge.svg"); }
.cards .i-savings-calculator { --icon: url("icons/calculator.svg"); }
.cards .i-grant-finder { --icon: url("icons/form.svg"); }
.cards .i-boiler-escape-plan { --icon: url("icons/calendar.svg"); }
.cards .i-installer-finder { --icon: url("icons/pin.svg"); }
.cards .i-heat-pump-visualiser { --icon: url("icons/phone-ar.svg"); }
.cards .i-sound-simulator { --icon: url("icons/speaker.svg"); }
.cards .i-house-tour { --icon: url("icons/cube.svg"); }

/* ---------- Home page: steps and the two big links ---------- */

.steps {
  list-style: none;
  counter-reset: step;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(19rem, 1fr));
  gap: 1.5rem 2rem;
  margin: 1.5rem 0 2rem;
}
.steps li {
  counter-increment: step;
  position: relative;
  padding-left: 3.25rem;
  margin: 0;
}
.steps li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 50%;
  background: var(--yellow);
  color: var(--ink);
  font-weight: 700;
  display: grid;
  place-items: center;
}
.steps h3 { margin: 0.25rem 0 0.375rem; font-size: 1.125rem; }
.steps p { margin: 0; }

.split {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(18rem, 1fr));
  gap: 1rem;
  margin: 3rem 0;
}
.split a {
  display: block;
  padding: 2rem 1.75rem 3.5rem;
  border-radius: var(--radius);
  color: #fff;
  text-decoration: none;
  position: relative;
  min-height: 12rem;
}
.split a:nth-child(1) { background: var(--green); }
.split a:nth-child(2) { background: var(--brown); }
.split a::after {
  content: "\2192";
  position: absolute;
  left: 1.75rem;
  bottom: 1.25rem;
  font-size: 1.5rem;
  font-weight: 700;
  transition: transform 120ms ease-out;
}
.split a:hover::after { transform: translateX(4px); }
.split h2 { color: #fff; margin: 0 0 0.5rem; font-size: 1.5rem; }
.split a:hover h2 { text-decoration: underline; }
.split p { margin: 0; max-width: 30rem; }

/* ---------- Embedded tools ---------- */

.tool {
  max-width: var(--wide);
  margin: 2rem 0 2.5rem;
}
.tool-frame {
  background: var(--page);
  border: 1px solid var(--rule);
  border-top: 5px solid var(--blue);
  border-radius: var(--radius);
  padding: 0.5rem;
  min-height: 12rem;
  box-shadow: 0 8px 24px rgba(20, 54, 95, 0.08);
}
.tool figcaption {
  margin-top: 0.5rem;
  font-size: 0.875rem;
  color: var(--muted);
  max-width: var(--measure);
}
.band .tool { margin-bottom: 0.5rem; }

@media (prefers-reduced-motion: reduce) {
  .cards li, .cards li::after, .split a::after { transition: none; }
  .cards li:hover { transform: none; }
}

/* ---------- Footer ---------- */

.site-footer {
  margin-top: 4rem;
  background: var(--navy);
  color: var(--navy-ink);
  font-size: 0.9375rem;
}
.site-footer .inner {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 2.5rem 1rem 2rem;
}
.footer-cols {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(12rem, 1fr));
  gap: 1.5rem 2rem;
  margin-bottom: 2rem;
}
.site-footer h2 { font-size: 1rem; color: #fff; margin: 0 0 0.75rem; }
.site-footer ul { list-style: none; padding: 0; margin: 0; }
.site-footer li { margin-bottom: 0.375rem; }
.site-footer p { margin: 0 0 0.5rem; max-width: var(--measure); }
.site-footer a { color: #fff; }
.site-footer .small {
  border-top: 1px solid rgba(255, 255, 255, 0.2);
  padding-top: 1.25rem;
}

@media (max-width: 30rem) {
  body { font-size: 1rem; }
  .lede { font-size: 1.125rem; }
  .page-head { padding: 2rem 0 1.75rem; }
  /* On a phone the widget needs every pixel: run the frame almost to the
     screen edge instead of inside main's 1rem gutter. */
  .tool { margin-left: -0.75rem; margin-right: -0.75rem; }
  .tool-frame { padding: 0; }
  .tool figcaption { padding: 0 0.75rem; }
}