/* ==========================================================================
   Design DNA: Copper & Slate Editorial Aesthetic
   Project: Tankless Water Heater Installation Warminster PA
   ========================================================================== */

:root {
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --bg-card: #21262d;
  --border-subtle: #30363d;
  --text-main: #f0f6fc;
  --text-muted: #8b949e;
  --accent-copper: #d97706; /* Rich warm copper */
  --accent-copper-hover: #b45309;
  --accent-glow: rgba(217, 119, 6, 0.15);
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  --max-width: 1200px;
  --header-height: 80px;
}

[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-card: #f1f5f9;
  --border-subtle: #cbd5e1;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --accent-copper: #c2410c;
  --accent-copper-hover: #9a3412;
  --accent-glow: rgba(194, 65, 12, 0.1);
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-main);
  font-family: var(--font-sans);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a {
  color: inherit;
  text-decoration: none;
}

ul {
  list-style: none;
}

/* Layout container */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header & Navigation */
header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  background-color: rgba(13, 17, 23, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
  z-index: 1000;
  display: flex;
  align-items: center;
}

[data-theme="light"] header {
  background-color: rgba(248, 250, 252, 0.85);
}

.nav-wrapper {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

.logo {
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.02em;
  display: flex;
  flex-direction: column;
}

.logo span {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 400;
}

.nav-links {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.nav-links a {
  font-size: 0.9rem;
  color: var(--text-muted);
  transition: color 0.2s ease;
}

.nav-links a:hover, .nav-links a.active {
  color: var(--text-main);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.phone-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--accent-copper);
  color: #fff;
  padding: 0.6rem 1.2rem;
  border-radius: 4px;
  font-size: 0.9rem;
  font-weight: 600;
  transition: background 0.2s ease;
}

.phone-btn:hover {
  background: var(--accent-copper-hover);
}

.mobile-menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-main);
  cursor: pointer;
  font-size: 1.5rem;
}

/* Hero Section */
.hero {
  padding-top: calc(var(--header-height) + 4rem);
  padding-bottom: 6rem;
  border-bottom: 1px solid var(--border-subtle);
  position: relative;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 4rem;
  align-items: center;
}

.hero-content h1 {
  font-size.clamp: 2.5rem, 4vw, 3.8rem;
  font-size: 3.2rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 1.5rem;
}

.hero-content h1 span {
  color: var(--accent-copper);
}

.hero-lead {
  font-size: 1.15rem;
  color: var(--text-muted);
  margin-bottom: 2.5rem;
  max-width: 540px;
}

.hero-meta {
  display: flex;
  gap: 2rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-subtle);
  padding-top: 1.5rem;
}

.hero-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  padding: 2.5rem;
  box-shadow: 0 20px 40px rgba(0,0,0,0.2);
}

.hero-card h3 {
  font-size: 1.25rem;
  margin-bottom: 1rem;
}

.hero-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 1.5rem;
}

/* Sections & Typography */
section {
  padding: 5rem 0;
  border-bottom: 1px solid var(--border-subtle);
}

.section-header {
  max-width: 700px;
  margin-bottom: 3.5rem;
}

.section-tag {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent-copper);
  margin-bottom: 0.75rem;
  display: block;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

/* Grids & Cards */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2.5rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: 6px;
  padding: 2rem;
  transition: border-color 0.2s ease;
}

.card:hover {
  border-color: var(--accent-copper);
}

.card h3 {
  font-size: 1.2rem;
  margin-bottom: 0.75rem;
}

.card p {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* FAQ Accordion */
.accordion {
  border-top: 1px solid var(--border-subtle);
}

.accordion-item {
  border-bottom: 1px solid var(--border-subtle);
}

.accordion-header {
  width: 100%;
  background: none;
  border: none;
  padding: 1.5rem 0;
  text-align: left;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-main);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.accordion-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
  color: var(--text-muted);
  font-size: 0.95rem;
  padding-bottom: 0;
}

.accordion-item.active .accordion-content {
  max-height: 200px;
  padding-bottom: 1.5rem;
}

/* Footer */
footer {
  padding: 4rem 0;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-subtle);
  font-size: 0.9rem;
  color: var(--text-muted);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 3rem;
}

.footer-col h4 {
  color: var(--text-main);
  margin-bottom: 1rem;
  font-size: 1rem;
}

.footer-col ul li {
  margin-bottom: 0.5rem;
}

.footer-bottom {
  border-top: 1px solid var(--border-subtle);
  padding-top: 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Responsive */
@media (max-width: 968px) {
  .hero-grid, .grid-2, .grid-3, .footer-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  .nav-links, .header-actions .phone-btn {
    display: none;
  }
  .mobile-menu-toggle {
    display: block;
  }
}

/* Mobile Nav Modal */
.mobile-nav {
  position: fixed;
  top: var(--header-height);
  left: 0;
  width: 100%;
  height: calc(100vh - var(--header-height));
  background: var(--bg-primary);
  z-index: 999;
  display: flex;
  flex-direction: column;
  padding: 2rem;
  transform: translateX(100%);
  transition: transform 0.3s ease;
}

.mobile-nav.open {
  transform: translateX(0);
}

.mobile-nav a {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 1.5rem;
  color: var(--text-main);
}