/* ─── Общие стили rkvpo.ru ─── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: #0d0d10;
  color: #ededf2;
  min-height: 100vh;
  line-height: 1.6;
}

.page-bg {
  position: fixed;
  inset: 0;
  z-index: -2;
  background: url('images/bg.jpg') center/cover no-repeat;
}
.page-bg::after {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.83);
}

/* ─── Обёртка ─── */
.wrap {
  max-width: 860px;
  margin: 0 auto;
  padding: 40px 24px 80px;
}

/* ─── Навигация ─── */
nav.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 22px 0 28px;
  border-bottom: 1px solid rgba(255,255,255,0.06);
  margin-bottom: 40px;
}
nav.top .brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 16px;
  font-weight: 700;
  color: #fff;
  text-decoration: none;
}
nav.top .brand svg { flex-shrink: 0; }
nav.top .calc-link {
  font-size: 13px;
  color: #ff5c2e;
  text-decoration: none;
  font-weight: 600;
  border: 1px solid rgba(255,92,46,0.3);
  padding: 8px 16px;
  border-radius: 8px;
  transition: background 0.15s;
}
nav.top .calc-link:hover { background: rgba(255,92,46,0.1); }

/* ─── Хлебные крошки ─── */
.breadcrumb {
  font-size: 12px;
  color: #6a6a7e;
  margin-bottom: 28px;
}
.breadcrumb a { color: #6a6a7e; text-decoration: none; }
.breadcrumb a:hover { color: #ff5c2e; }
.breadcrumb span { margin: 0 6px; }

/* ─── Типографика ─── */
h1 {
  font-size: clamp(26px, 4vw, 40px);
  font-weight: 700;
  color: #fff;
  line-height: 1.2;
  margin-bottom: 16px;
}
h2 {
  font-size: 20px;
  font-weight: 700;
  color: #fff;
  margin: 40px 0 16px;
}
h3 {
  font-size: 14px;
  font-weight: 600;
  color: #fff;
  margin-bottom: 8px;
}
p {
  font-size: 14px;
  color: #8a8a97;
  line-height: 1.8;
  margin-bottom: 14px;
}
.lead {
  font-size: 16px;
  color: #8a8a97;
  line-height: 1.75;
  margin-bottom: 40px;
}

/* ─── Карточки ─── */
.card {
  background: #141418;
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: 14px;
  padding: 24px;
  margin-bottom: 12px;
}
.card p { margin: 0; }

.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 12px;
}
@media (max-width: 600px) { .grid-2 { grid-template-columns: 1fr; } }

/* ─── Бейдж категории ─── */
.cat-badge {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  border-radius: 12px;
  padding: 12px 20px;
  margin-bottom: 24px;
  border: 1px solid;
}
.cat-badge .letter {
  font-size: 36px;
  font-weight: 700;
  line-height: 1;
}
.cat-badge .label {
  font-size: 13px;
  color: #8a8a97;
  line-height: 1.4;
}

/* ─── Формульный блок ─── */
.formula-block {
  background: rgba(255,255,255,0.03);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: 12px;
  padding: 20px 24px;
  margin: 20px 0;
  font-family: 'Courier New', monospace;
  font-size: 13px;
  color: #ededf2;
  line-height: 2;
}

/* ─── CTA блок ─── */
.cta-block {
  background: rgba(255,92,46,0.07);
  border: 1px solid rgba(255,92,46,0.2);
  border-radius: 16px;
  padding: 32px;
  text-align: center;
  margin-top: 48px;
}
.cta-block h3 {
  font-size: 20px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 10px;
}
.cta-block p { margin-bottom: 22px; }

/* ─── Кнопки ─── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 30px;
  background: #ff5c2e;
  color: #fff;
  font-family: 'Inter', sans-serif;
  font-size: 15px;
  font-weight: 600;
  border-radius: 10px;
  text-decoration: none;
  transition: background 0.15s, transform 0.1s;
}
.btn:hover { background: #ff3d00; transform: translateY(-1px); }
.btn-ghost {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 30px;
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.12);
  color: #ededf2;
  font-family: 'Inter', sans-serif;
  font-size: 15px;
  font-weight: 500;
  border-radius: 10px;
  text-decoration: none;
  transition: background 0.15s;
}
.btn-ghost:hover { background: rgba(255,255,255,0.1); }

/* ─── Навигация по категориям ─── */
.nav-cats {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 40px;
  padding-top: 32px;
  border-top: 1px solid rgba(255,255,255,0.06);
}
.nav-cat {
  padding: 9px 18px;
  border-radius: 8px;
  border: 1px solid;
  text-decoration: none;
  font-size: 13px;
  font-weight: 600;
  transition: opacity 0.15s;
}
.nav-cat:hover { opacity: 0.75; }

/* ─── Подкатегории В1-В4 ─── */
.subcat-card {
  background: rgba(234,179,8,0.05);
  border: 1px solid rgba(234,179,8,0.18);
  border-radius: 12px;
  padding: 20px;
}
.subcat-card .sub-letter {
  font-size: 22px;
  font-weight: 700;
  color: #eab308;
  margin-bottom: 4px;
}
.subcat-card .sub-val {
  font-size: 13px;
  font-weight: 600;
  color: #fff;
  margin-bottom: 6px;
}
.subcat-card p { font-size: 12px; margin: 0; }

/* ─── Футер ─── */
.site-footer {
  border-top: 1px solid rgba(255,255,255,0.06);
  margin-top: 64px;
  padding: 32px 24px;
  max-width: 860px;
  margin-left: auto;
  margin-right: auto;
}
.footer-info { font-size: 12px; color: #4a4a58; line-height: 1.8; }
.footer-info a { color: #4a4a58; text-decoration: none; }
.footer-info a:hover { color: #ff5c2e; }
.footer-links { margin-top: 12px; display: flex; gap: 16px; }
.footer-links a { font-size: 12px; color: #6a6a7e; text-decoration: none; }
.footer-links a:hover { color: #ff5c2e; }