:root {
  --graphite: #1b1e21;
  --graphite-2: #25292d;
  --textile: #3b4046;
  --gray: #eceeef;
  --gray-2: #d7dadd;
  --ink: #16181a;
  --muted: #5d646b;
  --orange: #ff6a13;
  --orange-d: #e2560a;
  --radius: 14px;
  --wrap: 1120px;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: #fff;
  color: var(--ink);
  font: 17px/1.55 system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  overflow-x: hidden;
}
img { display: block; max-width: 100%; height: auto; }
figure { margin: 0; }
h1, h2, h3 { line-height: 1.15; margin: 0 0 .6em; letter-spacing: -.01em; }
h1 { font-size: clamp(2rem, 6.5vw, 3.4rem); font-weight: 800; }
h2 { font-size: clamp(1.55rem, 4.6vw, 2.3rem); font-weight: 800; }
h3 { font-size: 1.2rem; font-weight: 700; }
p { margin: 0 0 1em; }
a { color: var(--orange-d); }

.wrap { width: 100%; max-width: var(--wrap); margin: 0 auto; padding: 0 16px; }
.narrow { max-width: 760px; }
.center { text-align: center; }

/* Верхняя панель */
.topbar { position: sticky; top: 0; z-index: 10; background: rgba(27, 30, 33, .96); color: #fff; }
.topbar__in { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 60px; }
.logo { color: #fff; text-decoration: none; font-weight: 700; font-size: .98rem; line-height: 1.2; }
.logo::before { content: ""; display: inline-block; width: 10px; height: 10px; margin-right: 8px; border-radius: 2px; background: var(--orange); vertical-align: 1px; }

/* Кнопки */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  min-height: 52px; padding: 0 24px; border: 2px solid var(--orange); border-radius: 12px;
  background: var(--orange); color: #fff; font: inherit; font-weight: 700; text-decoration: none;
  cursor: pointer; transition: background .15s, border-color .15s;
}
.btn:hover { background: var(--orange-d); border-color: var(--orange-d); }
.btn:focus-visible, summary:focus-visible, input:focus-visible { outline: 3px solid #ffb07f; outline-offset: 2px; }
.btn--ghost { background: transparent; color: #fff; border-color: rgba(255, 255, 255, .55); }
.btn--ghost:hover { background: rgba(255, 255, 255, .1); border-color: #fff; }
.btn--sm { min-height: 42px; padding: 0 14px; font-size: .9rem; white-space: nowrap; }
.btn--lg { min-height: 58px; padding: 0 32px; font-size: 1.1rem; }

/* Первый экран */
.hero { background: var(--graphite); color: #fff; padding: 22px 0 40px; }
.hero__grid { display: grid; gap: 20px; grid-template-areas: "head" "img" "text"; }
.hero__head { grid-area: head; }
.hero__head h1 { margin-bottom: 0; }
.hero__img { grid-area: img; }
.hero__text { grid-area: text; }
.hero__img img { border-radius: var(--radius); }
.eyebrow { color: var(--orange); font-weight: 700; font-size: .9rem; text-transform: uppercase; letter-spacing: .06em; margin-bottom: .8em; }
.lead { font-size: 1.1rem; color: #d9dcdf; }
.price { font-size: 1.25rem; margin: 1em 0; }
.price strong { color: var(--orange); font-size: 1.5em; white-space: nowrap; }
.actions { display: flex; flex-wrap: wrap; gap: 12px; }
.actions .btn { flex: 1 1 220px; }
.note { margin-top: 1.2em; font-size: .88rem; color: #9ea4aa; }

/* Секции */
.section { padding: 56px 0; }
.section--dark { background: var(--graphite-2); color: #eef0f1; }
.section--gray { background: var(--gray); }
.split { display: grid; gap: 28px; align-items: center; }
.split__img img { border-radius: var(--radius); }
.split__img--card { max-width: 440px; width: 100%; justify-self: center; }
.muted { color: var(--muted); }
.section--dark .muted { color: #a8aeb4; }

.ticks { list-style: none; padding: 0; margin: 0 0 1em; }
.ticks li { position: relative; padding-left: 28px; margin-bottom: .7em; }
.ticks li::before { content: ""; position: absolute; left: 0; top: .55em; width: 14px; height: 4px; border-radius: 2px; background: var(--orange); }

.steps { padding-left: 1.4em; margin: 0; }
.steps li { margin-bottom: .6em; padding-left: .2em; }
.steps li::marker { color: var(--orange-d); font-weight: 800; }

/* Конструкция */
.parts { display: grid; gap: 28px; }
.part img { border-radius: var(--radius); margin-bottom: 14px; }
.part p { color: var(--muted); }

/* Размеры */
.sizes { width: 100%; max-width: 420px; border-collapse: collapse; margin-bottom: 20px; }
.sizes th, .sizes td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--gray-2); }
.sizes th { font-size: .85rem; color: var(--muted); font-weight: 600; }
.sizes td:first-child { font-weight: 800; width: 90px; }

.calc { background: var(--gray); border-radius: var(--radius); padding: 18px; }
.calc__hint { font-size: .93rem; color: var(--muted); }
.calc__row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-bottom: 14px; }
.calc label { display: grid; gap: 6px; font-size: .9rem; font-weight: 600; }
.calc input { width: 100%; min-height: 50px; padding: 0 12px; border: 2px solid var(--gray-2); border-radius: 10px; font: inherit; background: #fff; }
.calc input:focus { border-color: var(--orange); }
.calc .btn { width: 100%; }
.calc__result:not(:empty) { margin-top: 16px; padding: 14px; border-radius: 10px; background: #fff; border-left: 4px solid var(--orange); }
.calc__result p { margin: 0 0 .5em; }
.calc__result p:last-child { margin: 0; }
.calc__result .btn { margin-top: 8px; }
.calc__result--err { border-left-color: #b3261e !important; }

/* Вопросы */
details { border-bottom: 1px solid var(--gray-2); }
summary { list-style: none; cursor: pointer; padding: 18px 36px 18px 0; font-weight: 700; position: relative; }
summary::-webkit-details-marker { display: none; }
summary::after { content: "+"; position: absolute; right: 4px; top: 12px; font-size: 1.6rem; color: var(--orange-d); font-weight: 400; }
details[open] summary::after { content: "–"; }
details p { margin: 0 0 18px; color: var(--muted); }

.final { background: var(--graphite); color: #fff; }
.final p { color: #d9dcdf; margin-bottom: 1.4em; }

.footer { background: #121416; color: #8d949a; font-size: .85rem; padding: 22px 0; }
.footer p { margin: 0; }

@media (min-width: 720px) {
  .parts { grid-template-columns: repeat(3, 1fr); }
  .actions .btn { flex: 0 0 auto; }
}
@media (min-width: 960px) {
  body { font-size: 18px; }
  .hero { padding: 56px 0 72px; }
  .hero__grid { grid-template-columns: 1fr 1.05fr; grid-template-areas: "head img" "text img"; column-gap: 48px; row-gap: 20px; align-items: end; }
  .hero__text { align-self: start; }
  .hero__img { align-self: center; }
  .section { padding: 88px 0; }
  .split { grid-template-columns: 1fr 1fr; gap: 56px; }
  .split--rev > :first-child { order: 2; }
  .logo { font-size: 1.05rem; }
}
@media (max-width: 380px) {
  .logo { font-size: .86rem; }
  .btn--sm { padding: 0 10px; font-size: .84rem; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }