:root {
  --navy: #0f2a47;
  --blue: #2f78ba;
  --light-blue: #4da3e0;
  --slate: #6c8eaa;
  --granite: #8a8c91;
  --ink: #14202e;
  --muted: #55606d;
  --line: #d9e1ea;
  --bg: #ffffff;
  --bg-soft: #f2f7fc;
  --danger: #b42318;
  --radius: 12px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 108px; }
body {
  margin: 0; font-family: 'Poppins', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  color: var(--ink); background: var(--bg); line-height: 1.6; font-size: 17px;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--blue); }
.wrap { width: min(1040px, 100% - 32px); margin-inline: auto; }
h1, h2, h3 { color: var(--navy); line-height: 1.2; margin: 0 0 .5em; }
h1 { font-size: clamp(2rem, 5vw, 3.1rem); font-weight: 700; }
h2 { font-size: clamp(1.5rem, 3.4vw, 2.1rem); font-weight: 700; }
h3 { font-size: 1.1rem; font-weight: 600; }
p { margin: 0 0 1em; }
section { padding: 56px 0; }
section.soft { background: var(--bg-soft); }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 20; background: #fff; border-bottom: 1px solid var(--line);
}
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; height: 100px; gap: 12px; }
.site-header img { height: 80px; width: auto; }

/* Buttons */
.btn {
  display: inline-block; background: var(--blue); color: #fff; font: inherit; font-weight: 600;
  padding: 12px 26px; border-radius: 999px; border: 0; text-decoration: none; cursor: pointer;
}
.btn:hover { background: var(--navy); }
.btn:focus-visible, input:focus-visible, select:focus-visible { outline: 3px solid var(--light-blue); outline-offset: 2px; }
.btn[disabled] { opacity: .6; cursor: wait; }
.btn.big { padding: 15px 34px; font-size: 1.05rem; }
.cta { text-align: center; margin-top: 28px; }

/* Hero */
.hero { padding: 40px 0 56px; background: linear-gradient(180deg, var(--bg-soft), #fff); }
.hero .wrap { display: grid; grid-template-columns: 1.1fr .9fr; gap: 32px; align-items: center; }
.hero .lead { font-size: 1.15rem; color: var(--muted); }
.price-row { display: flex; align-items: baseline; gap: 10px; flex-wrap: wrap; margin: 18px 0 22px; }
.price { font-size: 2.6rem; font-weight: 700; color: var(--navy); }
.price-note { color: var(--muted); }
.hero-tanks { display: flex; justify-content: center; gap: 18px; align-items: flex-end; }
.hero-tanks img { height: min(430px, 60vw); width: auto; }
.tag { display: inline-block; background: #e3f0fb; color: var(--navy); font-weight: 600; font-size: .85rem; padding: 4px 12px; border-radius: 999px; margin-bottom: 14px; }

/* Specs and features */
.specs { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin: 24px 0 0; padding: 0; list-style: none; }
.specs li { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; text-align: center; }
.specs strong { display: block; font-size: 1.5rem; color: var(--navy); }
.specs span { color: var(--muted); font-size: .92rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; }
.card p { margin: 0; color: var(--muted); }
.colors { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; justify-items: center; }
.color-card { text-align: center; }
.color-card img { height: 380px; width: auto; margin: 0 auto 10px; }
.swatch { display: inline-block; width: 14px; height: 14px; border-radius: 50%; margin-right: 6px; vertical-align: -1px; }
.steps { counter-reset: s; display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; padding: 0; list-style: none; }
.steps li { counter-increment: s; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; }
.steps li::before { content: counter(s); display: inline-grid; place-items: center; width: 34px; height: 34px; border-radius: 50%; background: var(--navy); color: #fff; font-weight: 600; margin-bottom: 10px; }
.notice { background: #fff8e6; border: 1px solid #f0d58a; border-radius: var(--radius); padding: 14px 18px; }

/* FAQ */
details { border-bottom: 1px solid var(--line); padding: 14px 0; }
summary { cursor: pointer; font-weight: 600; color: var(--navy); }
details p { margin: 10px 0 0; color: var(--muted); }

/* Order form */
.order-grid { display: grid; grid-template-columns: 1.2fr .8fr; gap: 28px; align-items: start; }
form fieldset { border: 0; padding: 0; margin: 0 0 22px; }
form legend { font-weight: 600; color: var(--navy); padding: 0; margin-bottom: 8px; }
.field { margin-bottom: 14px; }
label { display: block; font-weight: 500; margin-bottom: 4px; font-size: .95rem; }
input[type=text], input[type=email], input[type=tel], select {
  width: 100%; font: inherit; padding: 11px 12px; border: 1px solid #b9c5d2; border-radius: 8px; background: #fff;
}
.row { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.choice { display: flex; gap: 10px; align-items: flex-start; border: 1px solid var(--line); border-radius: 10px; padding: 12px 14px; margin-bottom: 10px; cursor: pointer; background: #fff; }
.choice input { margin-top: 5px; }
.choice small { display: block; color: var(--muted); }
.choice:has(input:checked) { border-color: var(--blue); background: #eef6fd; }
.summary { position: sticky; top: 84px; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; }
.summary dl { margin: 0; }
.summary .line { display: flex; justify-content: space-between; gap: 12px; padding: 6px 0; border-bottom: 1px dashed var(--line); }
.summary .total { font-weight: 700; font-size: 1.2rem; color: var(--navy); border-bottom: 0; padding-top: 12px; }
.lead-time { background: #e3f0fb; border-radius: 10px; padding: 10px 14px; margin-top: 14px; font-weight: 600; color: var(--navy); }
.error { color: var(--danger); font-weight: 500; margin: 10px 0 0; min-height: 1.4em; }
.done { background: #eef6fd; border: 1px solid var(--blue); border-radius: var(--radius); padding: 24px; }
.order-no { font-size: 1.5rem; font-weight: 700; color: var(--navy); letter-spacing: .03em; }
[hidden] { display: none !important; }

/* Footer */
footer { background: var(--navy); color: #cfdcea; padding: 36px 0; font-size: .95rem; }
footer a { color: #fff; }
footer .wrap { display: flex; justify-content: space-between; gap: 18px; flex-wrap: wrap; }

/* Terms and thanks pages */
.prose { max-width: 760px; margin-inline: auto; padding: 40px 16px 64px; }
.prose h2 { margin-top: 1.6em; font-size: 1.35rem; }
.prose li { margin-bottom: .4em; }

@media (max-width: 820px) {
  .site-header .wrap { height: 76px; }
  .site-header img { height: 56px; }
  body { font-size: 16px; }
  section { padding: 40px 0; }
  .hero .wrap, .order-grid { grid-template-columns: 1fr; }
  .specs { grid-template-columns: repeat(2, 1fr); }
  .grid-3, .steps { grid-template-columns: 1fr; }
  .summary { position: static; }
  .color-card img { height: 300px; }
  .row { grid-template-columns: 1fr; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }