/* ============================================
   ThirdGenRegen — Main Stylesheet
   Clean, fast, mobile-first
   ============================================ */

:root {
  --color-bg: #ffffff;
  --color-text: #1a1a1a;
  --color-text-muted: #555555;
  --color-accent: #c0392b;
  --color-accent-hover: #a93226;
  --color-accent-light: #fdf2f0;
  --color-success: #27ae60;
  --color-surface: #f8f9fa;
  --color-border: #e0e0e0;
  --color-dark: #1a1a1a;
  --font-main: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --max-width: 1200px;
  --nav-height: 64px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

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

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

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--color-accent-hover);
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================================
   Navigation
   ============================================ */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  z-index: 1000;
  transition: box-shadow 0.3s;
}

.nav.scrolled {
  box-shadow: 0 1px 10px rgba(0, 0, 0, 0.1);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-size: 1.25rem;
  font-weight: 900;
  color: var(--color-dark);
  letter-spacing: 0.5px;
}

.nav-logo:hover {
  color: var(--color-accent);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-links a {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

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

.nav-cta {
  background: var(--color-accent) !important;
  color: white !important;
  padding: 8px 20px;
  border-radius: 6px;
  font-weight: 600 !important;
}

.nav-cta:hover {
  background: var(--color-accent-hover) !important;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-dark);
  transition: 0.3s;
}

/* ============================================
   Hero
   ============================================ */

.hero {
  padding-top: calc(var(--nav-height) + 60px);
  padding-bottom: 60px;
  display: flex;
  align-items: center;
  gap: 60px;
  max-width: var(--max-width);
  margin: 0 auto;
  padding-left: 24px;
  padding-right: 24px;
}

.hero-content {
  flex: 1;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--color-accent-light);
  color: var(--color-accent);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 6px 14px;
  border-radius: 100px;
  margin-bottom: 20px;
}

.flag-icon {
  width: 20px;
  height: 14px;
  border-radius: 2px;
  box-shadow: 0 1px 2px rgba(0,0,0,0.1);
}

.hero h1 {
  font-size: 2.75rem;
  font-weight: 900;
  line-height: 1.15;
  margin-bottom: 16px;
  color: var(--color-dark);
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--color-text-muted);
  line-height: 1.7;
  margin-bottom: 32px;
  max-width: 540px;
}

.hero-cta {
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: flex-start;
}

.hero-stock {
  color: var(--color-success);
  font-weight: 600;
  font-size: 0.95rem;
}

.hero-image {
  flex: 1;
  max-width: 500px;
}

.hero-image img {
  width: 100%;
  height: auto;
  border-radius: 12px;
  object-fit: cover;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 16px 36px;
  border-radius: 8px;
  font-size: 1.1rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.2s;
  border: none;
  text-align: center;
}

.btn-primary {
  background: var(--color-accent);
  color: white;
  box-shadow: 0 4px 14px rgba(192, 57, 43, 0.3);
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  color: white;
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(192, 57, 43, 0.4);
}

/* ============================================
   Problem / Solution
   ============================================ */

.problem-section {
  padding: 80px 0;
  background: var(--color-surface);
}

.problem-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
}

.problem-card, .solution-card {
  background: white;
  padding: 40px;
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
}

.problem-card h3 {
  color: var(--color-accent);
  font-size: 1.3rem;
  margin-bottom: 12px;
}

.solution-card h3 {
  color: var(--color-success);
  font-size: 1.3rem;
  margin-bottom: 12px;
}

.problem-card p, .solution-card p {
  color: var(--color-text-muted);
  margin-bottom: 20px;
}

.problem-image, .solution-image {
  width: 100%;
  height: auto;
  border-radius: 8px;
  object-fit: cover;
  max-height: 350px;
}

/* ============================================
   Product
   ============================================ */

.product-section {
  padding: 80px 0;
}

.product-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: start;
}

.product-main-image {
  width: 100%;
  height: auto;
  border-radius: 12px;
  object-fit: cover;
}

.product-thumbnails {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin-top: 12px;
}

.thumb {
  width: 100%;
  height: 80px;
  object-fit: cover;
  border-radius: 8px;
  cursor: pointer;
  border: 2px solid transparent;
  opacity: 0.7;
  transition: all 0.2s;
}

.thumb:hover,
.thumb.active {
  opacity: 1;
  border-color: var(--color-accent);
}

.product-details h2 {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 16px;
}

.product-price {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 8px;
}

.price {
  font-size: 2.25rem;
  font-weight: 900;
  color: var(--color-dark);
}

.price-note {
  font-size: 1rem;
  color: var(--color-success);
  font-weight: 600;
}

.product-stock {
  color: var(--color-success);
  font-weight: 600;
  font-size: 0.95rem;
  margin-bottom: 24px;
}

.product-description {
  color: var(--color-text-muted);
  margin-bottom: 24px;
  line-height: 1.7;
}

.kit-contents {
  margin-bottom: 28px;
}

.kit-contents h4 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.kit-contents ul {
  list-style: none;
  padding: 0;
}

.kit-contents li {
  padding: 6px 0;
  padding-left: 24px;
  position: relative;
  color: var(--color-text-muted);
}

.kit-contents li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--color-success);
  font-weight: 700;
}

.buy-button-wrapper {
  margin: 28px 0;
  padding: 24px;
  background: var(--color-surface);
  border-radius: 12px;
  text-align: center;
}

.paypal-placeholder {
  padding: 20px;
  border: 2px dashed var(--color-border);
  border-radius: 8px;
  color: var(--color-text-muted);
}

.paypal-placeholder .small {
  font-size: 0.8rem;
  margin-top: 4px;
}

.trust-badges {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.badge {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text-muted);
  background: var(--color-surface);
  padding: 8px 14px;
  border-radius: 6px;
}

.install-link {
  display: inline-block;
  font-weight: 600;
  font-size: 0.95rem;
}

/* ============================================
   Compatibility
   ============================================ */

.compatibility-section {
  padding: 80px 0;
  background: var(--color-surface);
}

.compatibility-section h2 {
  text-align: center;
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 8px;
}

.section-subtitle {
  text-align: center;
  color: var(--color-text-muted);
  margin-bottom: 48px;
  font-size: 1.1rem;
}

.compat-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.compat-card {
  background: white;
  padding: 32px 24px;
  border-radius: 12px;
  text-align: center;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
}

.compat-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.compat-years {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--color-accent);
  margin-bottom: 8px;
}

.compat-card p:last-child {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* ============================================
   About
   ============================================ */

.about-section {
  padding: 80px 0;
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.about-image img {
  width: 100%;
  height: auto;
  border-radius: 12px;
  object-fit: cover;
}

.about-content h2 {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 16px;
}

.about-content p {
  color: var(--color-text-muted);
  margin-bottom: 16px;
  line-height: 1.7;
}

/* ============================================
   FAQ
   ============================================ */

.faq-section {
  padding: 80px 0;
  background: var(--color-surface);
}

.faq-section h2 {
  text-align: center;
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 40px;
}

.faq-list {
  max-width: 720px;
  margin: 0 auto;
}

.faq-item {
  background: white;
  border-radius: 10px;
  margin-bottom: 12px;
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
  overflow: hidden;
}

.faq-item summary {
  padding: 20px 24px;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  font-size: 1.4rem;
  font-weight: 300;
  color: var(--color-text-muted);
  transition: transform 0.2s;
}

.faq-item[open] summary::after {
  content: "−";
}

.faq-item p {
  padding: 0 24px 20px;
  color: var(--color-text-muted);
  line-height: 1.7;
}

/* ============================================
   Footer
   ============================================ */

.footer {
  background: var(--color-dark);
  color: #ccc;
  padding: 60px 0 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 40px;
}

.footer-brand h3 {
  color: white;
  font-size: 1.25rem;
  font-weight: 900;
  letter-spacing: 0.5px;
  margin-bottom: 12px;
}

.footer-brand p {
  line-height: 1.6;
}

.footer h4 {
  color: white;
  font-size: 0.9rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 16px;
}

.footer-links a,
.footer-contact a {
  display: block;
  color: #aaa;
  padding: 4px 0;
  font-size: 0.9rem;
}

.footer-links a:hover,
.footer-contact a:hover {
  color: white;
}

.footer-bottom {
  border-top: 1px solid #333;
  padding-top: 20px;
  text-align: center;
  font-size: 0.8rem;
  color: #666;
}

/* ============================================
   Image Placeholders (remove when real images added)
   ============================================ */

.image-placeholder {
  background: #e9ecef;
  border: 2px dashed #ced4da;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 300px;
  color: #868e96;
  font-weight: 500;
  font-size: 0.9rem;
}

/* ============================================
   Mobile Responsive
   ============================================ */

@media (max-width: 968px) {
  .hero {
    flex-direction: column;
    padding-top: calc(var(--nav-height) + 40px);
    padding-bottom: 40px;
    gap: 40px;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero-image {
    max-width: 100%;
  }

  .problem-grid,
  .product-grid,
  .about-grid {
    grid-template-columns: 1fr;
  }

  .compat-grid {
    grid-template-columns: 1fr 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }
}

@media (max-width: 640px) {
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: white;
    flex-direction: column;
    padding: 24px;
    gap: 16px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
  }

  .nav-links.active {
    display: flex;
  }

  .hero h1 {
    font-size: 1.75rem;
  }

  .hero-subtitle {
    font-size: 1rem;
  }

  .compat-grid {
    grid-template-columns: 1fr;
  }

  .trust-badges {
    flex-direction: column;
  }

  .product-details h2 {
    font-size: 1.5rem;
  }

  .price {
    font-size: 1.75rem;
  }
}