/*
  Основные стили для сайта "Забор под ключ".
  Используются CSS‑переменные, семантические классы и адаптивная сетка.
*/

:root {
  --color-bg: #f8f9fa;
  --color-text: #333;
  --color-primary: #4a5964; /* графитово‑стальной оттенок */
  --color-secondary: #8c6d4a; /* оттенок дерева */
  --color-accent: #2c353d; /* темный акцент */
  --color-border: #e0e5e9;
  --radius: 16px;
  --radius-lg: 24px;
  --shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
  --transition: 0.2s ease-in-out;
  --max-width: 1200px;
  --font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-family);
  line-height: 1.6;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition);
}
a:hover,
a:focus {
  color: var(--color-accent);
  text-decoration: underline;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* Container */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: 1rem;
  padding-right: 1rem;
}

/* Header */
.site-header {
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 1000;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.5rem 0;
}
.logo {
  display: flex;
  align-items: center;
  font-weight: 600;
  font-size: 1.25rem;
  color: var(--color-accent);
}
.logo svg {
  margin-right: 0.5rem;
  fill: var(--color-primary);
}

/* Navigation */
.main-nav {
  position: relative;
}
.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--color-primary);
  cursor: pointer;
}
.nav-toggle:focus {
  outline: 2px dashed var(--color-primary);
  outline-offset: 4px;
}
.nav-list {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: 1rem;
}
.nav-list li a {
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius);
  color: var(--color-accent);
  font-weight: 500;
}
.nav-list li a:hover,
.nav-list li a:focus,
.nav-list li a.active {
  background-color: var(--color-primary);
  color: #fff;
}

/* Mobile Navigation */
@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }
  .nav-list {
    position: absolute;
    top: 100%;
    right: 0;
    background-color: var(--color-bg);
    flex-direction: column;
    gap: 0;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 0.5rem;
    display: none;
    min-width: 200px;
  }
  .nav-list.open {
    display: flex;
  }
  .nav-list li a {
    width: 100%;
    display: block;
    padding: 0.5rem 1rem;
  }
}

/* Hero Section */
.hero {
  position: relative;
  overflow: hidden;
  background-color: #f0f4f7;
  border-bottom: 1px solid var(--color-border);
}
.hero-background {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0.2;
  z-index: -1;
}
.hero-content {
  padding: 4rem 0 3rem;
  text-align: center;
}
.hero h1 {
  margin-top: 0;
  margin-bottom: 1rem;
  font-size: 2rem;
  color: var(--color-accent);
}
.hero p {
  font-size: 1.125rem;
  margin-bottom: 2rem;
  max-width: 680px;
  margin-left: auto;
  margin-right: auto;
}
.button {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius);
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: background-color var(--transition), color var(--transition);
  text-align: center;
}
.button.primary {
  background-color: var(--color-primary);
  color: #fff;
}
.button.primary:hover,
.button.primary:focus {
  background-color: var(--color-accent);
}
.button.secondary {
  background-color: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}
.button.secondary:hover,
.button.secondary:focus {
  background-color: var(--color-primary);
  color: #fff;
}

/* Sections */
.section {
  padding: 3rem 0;
}
.section h2 {
  margin-top: 0;
  margin-bottom: 1.5rem;
  font-size: 1.75rem;
  color: var(--color-accent);
  text-align: center;
}

/* Cards grid */
.cards-grid {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
}
.card {
  background-color: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem;
  text-align: center;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  transition: transform var(--transition), box-shadow var(--transition);
}
.card:hover,
.card:focus-within {
  transform: translateY(-4px);
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}
.icon-wrapper {
  margin-bottom: 1rem;
}
.icon-wrapper svg {
  width: 48px;
  height: 48px;
  fill: var(--color-primary);
}
.card h3 {
  margin-top: 0;
  margin-bottom: 0.5rem;
  font-size: 1.25rem;
  color: var(--color-accent);
}
.card p {
  margin: 0;
  font-size: 0.95rem;
  color: var(--color-text);
}

/* Steps list */
.steps-list {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: step;
}
.steps-list li {
  position: relative;
  padding-left: 3rem;
  margin-bottom: 2rem;
}
.steps-list li::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  background-color: var(--color-primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
}
.steps-list h3 {
  margin: 0 0 0.25rem;
  font-size: 1.15rem;
  color: var(--color-accent);
}
.steps-list p {
  margin: 0;
  font-size: 0.95rem;
  color: var(--color-text);
}

/* Materials grid */
.materials-grid {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
}
.material-item {
  background-color: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem;
}
.material-item h3 {
  margin-top: 0;
  margin-bottom: 0.5rem;
  font-size: 1.2rem;
  color: var(--color-accent);
}
.material-item p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--color-text);
}

/* Cost factors */
.factor-list {
  list-style: disc inside;
  margin: 0;
  padding-left: 1rem;
  max-width: 720px;
  margin-left: auto;
  margin-right: auto;
}
.factor-list li {
  margin-bottom: 0.75rem;
}

/* Solutions preview */
.solutions-preview .solution-card {
  display: block;
  background-color: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  transition: transform var(--transition), box-shadow var(--transition);
  box-shadow: var(--shadow);
}
.solutions-preview .solution-card:hover,
.solutions-preview .solution-card:focus {
  transform: translateY(-4px);
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.08);
}
.solutions-preview .solution-card h3 {
  margin-top: 0;
  margin-bottom: 0.5rem;
  font-size: 1.2rem;
  color: var(--color-accent);
}
.solutions-preview .solution-card p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--color-text);
}

/* FAQ */
.faq-list {
  max-width: 720px;
  margin: 0 auto;
}
.faq-list dt {
  font-weight: 600;
  margin-top: 1rem;
  color: var(--color-accent);
}
.faq-list dd {
  margin-left: 0;
  margin-bottom: 0.75rem;
  font-size: 0.95rem;
  color: var(--color-text);
}

/* Geography */
.cities-list {
  columns: 2;
  column-gap: 2rem;
  list-style: none;
  padding: 0;
  margin: 0;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}
.cities-list li {
  margin-bottom: 0.5rem;
  font-size: 0.95rem;
}

/* Contact form */
.lead-form {
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}
.form-row {
  margin-bottom: 1rem;
  display: flex;
  flex-direction: column;
}
.form-row label {
  margin-bottom: 0.25rem;
  font-weight: 500;
  color: var(--color-accent);
}
.form-row input,
.form-row select,
.form-row textarea {
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background-color: #fff;
  font-size: 1rem;
  color: var(--color-accent);
}
.form-row input:focus,
.form-row select:focus,
.form-row textarea:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 0;
}
.checkbox-row {
  flex-direction: row;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
}
.checkbox-row input[type="checkbox"] {
  width: 1rem;
  height: 1rem;
  margin: 0;
}
.form-result {
  margin-top: 1rem;
  font-size: 0.95rem;
  color: var(--color-accent);
}

/* Footer */
.site-footer {
  background-color: var(--color-accent);
  color: #fff;
  padding: 2rem 0;
  margin-top: 3rem;
}
.footer-inner {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  text-align: center;
}
.footer-nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem;
}
.footer-nav a {
  color: #fff;
  padding: 0.25rem 0.5rem;
  font-size: 0.9rem;
  transition: background-color var(--transition);
}
.footer-nav a:hover,
.footer-nav a:focus {
  background-color: rgba(255, 255, 255, 0.2);
  border-radius: var(--radius);
}
.contacts-block a {
  color: #fff;
  text-decoration: underline;
}

/* Responsive adjustments */
@media (max-width: 640px) {
  .cities-list {
    columns: 1;
  }
}