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

:root {
  --black: #000000;
  --white: #ffffff;
  --gray-50: #fafafa;
  --gray-100: #f5f5f5;
  --gray-200: #e5e5e5;
  --gray-300: #d4d4d4;
  --gray-400: #a3a3a3;
  --gray-500: #737373;
  --gray-600: #525252;
  --gray-700: #404040;
  --gray-800: #262626;
  --gray-900: #171717;
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: 3rem;
  --font-size-6xl: 3.75rem;
  --font-size-7xl: 4.5rem;
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;
  --container-max-width: 1200px;
  --section-padding: var(--space-20);
  --border-radius: 0.5rem;
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-base: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
}

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

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--gray-900);
  background-color: var(--white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--gray-200);
  transition: var(--transition-base);
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) var(--space-6);
  height: 80px;
}

.nav-brand a {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--black);
  text-decoration: none;
  letter-spacing: -0.025em;
  position: relative;
}

.nav-brand a::before {
  content: '';
  position: absolute;
  top: -2px;
  left: -2px;
  right: -2px;
  bottom: -2px;
  background: linear-gradient(45deg, var(--black), var(--gray-600));
  border-radius: 8px;
  opacity: 0;
  transition: var(--transition-fast);
  z-index: -1;
}

.nav-brand a:hover::before {
  opacity: 0.1;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-8);
}

.nav-link {
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--gray-600);
  text-decoration: none;
  letter-spacing: 0.025em;
  text-transform: uppercase;
  transition: var(--transition-fast);
  position: relative;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--border-radius);
}

.nav-link:hover {
  color: var(--black);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 50%;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--black), var(--gray-600));
  transition: var(--transition-fast);
  transform: translateX(-50%);
  border-radius: 1px;
}

.nav-link:hover::after {
  width: 80%;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
  border-radius: var(--border-radius);
  transition: var(--transition-fast);
}

.nav-toggle span {
  width: 24px;
  height: 2px;
  background: var(--black);
  transition: var(--transition-fast);
  border-radius: 1px;
}

.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: flex-start;
  padding: var(--space-20) var(--space-6);
  background: linear-gradient(rgba(0, 0, 0, 0.4), rgba(0, 0, 0, 0.3)), url('../assets/m4_showcase.jpg');
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, rgba(0, 0, 0, 0.6) 0%, rgba(0, 0, 0, 0.3) 100%);
  z-index: 1;
}

.hero-content {
  flex: 1;
  max-width: 700px;
  z-index: 2;
  position: relative;
  text-align: left;
}

.hero-subtitle {
  font-size: var(--font-size-lg);
  font-weight: 400;
  color: rgba(255, 255, 255, 0.9);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: var(--space-3);
  display: block;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
}

.hero-title {
  font-size: clamp(var(--font-size-4xl), 8vw, var(--font-size-7xl));
  font-weight: 700;
  line-height: 0.9;
  color: var(--white);
  margin-bottom: var(--space-6);
  letter-spacing: -0.05em;
  text-shadow: 0 4px 8px rgba(0, 0, 0, 0.7);
}

.hero-description {
  font-size: var(--font-size-xl);
  font-weight: 300;
  color: rgba(255, 255, 255, 0.95);
  margin-bottom: var(--space-10);
  line-height: 1.5;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
  max-width: 500px;
}

.hero-image {
  display: none;
}

.hero-image img {
  width: 100%;
  height: auto;
  object-fit: cover;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-lg);
}

.cta-button {
  display: inline-flex;
  align-items: center;
  padding: var(--space-4) var(--space-8);
  background: rgba(255, 255, 255, 0.95);
  color: var(--black);
  text-decoration: none;
  font-weight: 600;
  font-size: var(--font-size-base);
  letter-spacing: 0.025em;
  text-transform: uppercase;
  border-radius: var(--border-radius);
  transition: var(--transition-base);
  position: relative;
  overflow: hidden;
  border: 2px solid rgba(255, 255, 255, 0.3);
  backdrop-filter: blur(10px);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.cta-button::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
  transition: var(--transition-slow);
}

.cta-button:hover::before {
  left: 100%;
}

.cta-button:hover {
  transform: translateY(-2px);
  background: rgba(255, 255, 255, 1);
  border-color: rgba(255, 255, 255, 0.8);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
}

.section {
  padding: var(--section-padding) 0;
}

.section-dark {
  background: var(--gray-900);
  color: var(--white);
}

.section-light {
  background: var(--gray-50);
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-16);
}

.section-title {
  font-size: clamp(var(--font-size-3xl), 5vw, var(--font-size-5xl));
  font-weight: 700;
  margin-bottom: var(--space-4);
  letter-spacing: -0.025em;
}

.section-dark .section-title {
  color: var(--white);
}

.section-subtitle {
  font-size: var(--font-size-xl);
  font-weight: 300;
  color: var(--gray-600);
  max-width: 600px;
  margin: 0 auto;
}

.section-dark .section-subtitle {
  color: var(--gray-300);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-8);
  margin-top: var(--space-16);
}

.feature-card {
  text-align: center;
  padding: var(--space-8);
  background: var(--white);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-base);
  transition: var(--transition-base);
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.feature-number {
  font-size: var(--font-size-4xl);
  font-weight: 700;
  color: var(--black);
  margin-bottom: var(--space-4);
  line-height: 1;
}

.feature-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--space-3);
  color: var(--gray-900);
}

.feature-description {
  color: var(--gray-600);
  line-height: 1.6;
}

.design-hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: flex-start;
  padding: var(--space-20) var(--space-6);
  background: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.4)), url('../assets/m4_design.jpg');
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
  position: relative;
  overflow: hidden;
}

.design-hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(135deg, rgba(0, 0, 0, 0.7) 0%, rgba(0, 0, 0, 0.4) 100%);
  z-index: 1;
}

.design-content {
  flex: 1;
  max-width: 700px;
  z-index: 2;
  position: relative;
  text-align: left;
}

.design-title {
  font-size: clamp(var(--font-size-3xl), 5vw, var(--font-size-5xl));
  font-weight: 700;
  margin-bottom: var(--space-4);
  color: var(--white);
  letter-spacing: -0.025em;
  text-shadow: 0 4px 8px rgba(0, 0, 0, 0.7);
}

.design-subtitle {
  font-size: var(--font-size-xl);
  font-weight: 300;
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: var(--space-8);
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
}

.design-heading {
  font-size: var(--font-size-2xl);
  font-weight: 600;
  margin-bottom: var(--space-6);
  color: var(--white);
  letter-spacing: -0.025em;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
}

.design-description {
  font-size: var(--font-size-lg);
  line-height: 1.7;
  color: rgba(255, 255, 255, 0.95);
  margin-bottom: var(--space-8);
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
}

.design-features {
  list-style: none;
}

.design-features li {
  padding: var(--space-3) 0;
  color: rgba(255, 255, 255, 0.9);
  font-size: var(--font-size-base);
  position: relative;
  padding-left: var(--space-6);
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.5);
}

.design-features li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--white);
  font-weight: 600;
}

.models-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(380px, 1fr));
  gap: var(--space-8);
  margin-top: var(--space-16);
}

.model-card {
  background: var(--white);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-base);
  transition: var(--transition-base);
  border: 2px solid transparent;
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

.model-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: var(--gray-300);
}

.model-featured {
  border-color: var(--black);
  position: relative;
}

.model-featured::after {
  content: 'Popular';
  position: absolute;
  top: var(--space-4);
  right: var(--space-4);
  background: var(--black);
  color: var(--white);
  padding: var(--space-1) var(--space-3);
  font-size: var(--font-size-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-radius: var(--border-radius);
  z-index: 2;
}

.model-image {
  height: 200px;
  overflow: hidden;
  position: relative;
}

.model-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition-base);
}

.model-card:hover .model-image img {
  transform: scale(1.05);
}

.model-content {
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.model-name {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  margin-bottom: var(--space-2);
  color: var(--gray-900);
}

.model-power {
  font-size: var(--font-size-3xl);
  font-weight: 300;
  color: var(--gray-500);
  margin-bottom: var(--space-2);
}

.model-price {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--black);
  margin-bottom: var(--space-4);
}

.model-description {
  color: var(--gray-600);
  margin-bottom: var(--space-6);
  line-height: 1.6;
  flex-grow: 1;
}

.model-features {
  display: flex;
  gap: var(--space-3);
  margin-bottom: var(--space-6);
  flex-wrap: wrap;
}

.model-feature {
  background: var(--gray-100);
  color: var(--gray-700);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--border-radius);
  font-size: var(--font-size-sm);
  font-weight: 500;
  transition: var(--transition-fast);
}

.model-feature:hover {
  background: var(--gray-200);
}

.specs-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: var(--gray-50);
  border: 1px solid var(--gray-200);
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: var(--transition-fast);
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--gray-700);
  margin-bottom: var(--space-4);
}

.specs-toggle:hover {
  background: var(--gray-100);
  border-color: var(--gray-300);
}

.specs-toggle.active {
  background: var(--black);
  color: var(--white);
  border-color: var(--black);
}

.specs-toggle .chevron {
  transition: var(--transition-fast);
}

.specs-toggle.active .chevron {
  transform: rotate(180deg);
}

.specs-dropdown {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease-out;
  margin-bottom: var(--space-4);
}

.specs-dropdown.active {
  max-height: 300px;
}

.specs-content {
  padding: var(--space-4);
  background: var(--gray-50);
  border: 1px solid var(--gray-200);
  border-top: none;
  border-radius: 0 0 var(--border-radius) var(--border-radius);
}

.spec-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-2) 0;
  border-bottom: 1px solid var(--gray-200);
}

.spec-row:last-child {
  border-bottom: none;
}

.spec-label {
  font-weight: 500;
  color: var(--gray-600);
  font-size: var(--font-size-sm);
}

.spec-value {
  font-weight: 600;
  color: var(--gray-900);
  font-size: var(--font-size-sm);
  text-align: right;
}

.specs-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: var(--space-12);
  margin-top: var(--space-16);
}

.spec-category {
  background: var(--white);
  border-radius: var(--border-radius);
  padding: var(--space-8);
  box-shadow: var(--shadow-base);
  transition: var(--transition-base);
  border-left: 4px solid var(--black);
}

.spec-category:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.spec-category-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--gray-900);
  margin-bottom: var(--space-6);
  text-align: left;
}

.spec-items {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.spec-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--gray-200);
  text-align: left;
}

.spec-item:last-child {
  border-bottom: none;
}

.spec-label {
  font-weight: 500;
  color: var(--gray-600);
  flex: 1;
}

.spec-value {
  font-weight: 600;
  color: var(--gray-900);
  text-align: right;
}

.footer {
  background: var(--gray-900);
  color: var(--white);
  padding: var(--space-16) 0 var(--space-8);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-8);
}

.footer-brand span {
  font-size: var(--font-size-xl);
  font-weight: 700;
}

.footer-links {
  display: flex;
  gap: var(--space-8);
}

.footer-link {
  color: var(--gray-400);
  text-decoration: none;
  font-size: var(--font-size-sm);
  transition: var(--transition-fast);
}

.footer-link:hover {
  color: var(--white);
}

.footer-social {
  display: flex;
  gap: var(--space-4);
}

.social-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--gray-800);
  color: var(--gray-400);
  border-radius: 50%;
  transition: var(--transition-fast);
}

.social-link:hover {
  background: var(--white);
  color: var(--black);
}

.footer-bottom {
  text-align: center;
  padding-top: var(--space-8);
  border-top: 1px solid var(--gray-800);
}

.footer-bottom p {
  color: var(--gray-500);
  font-size: var(--font-size-sm);
}

@media (max-width: 1024px) {
  .hero {
    flex-direction: column;
    text-align: center;
    gap: var(--space-12);
  }
  
  .design-hero {
    text-align: center;
  }
  
  .models-grid {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  }
}

@media (max-width: 768px) {
  :root {
    --section-padding: var(--space-12);
  }
  
  .nav-links {
    display: none;
  }
  
  .nav-toggle {
    display: flex;
  }
  
  .hero {
    padding: var(--space-16) var(--space-4);
    min-height: 90vh;
  }
  
  .container {
    padding: 0 var(--space-4);
  }
  
  .features-grid {
    grid-template-columns: 1fr;
    gap: var(--space-6);
  }
  
  .models-grid {
    grid-template-columns: 1fr;
  }
  
  .footer-content {
    flex-direction: column;
    gap: var(--space-6);
    text-align: center;
  }
  
  .footer-links {
    order: 2;
  }
  
  .footer-social {
    order: 1;
  }
}

@media (max-width: 480px) {
  .nav {
    padding: var(--space-3) var(--space-4);
    height: 60px;
  }
  
  .hero {
    padding: var(--space-12) var(--space-4);
  }
  
  .section-header {
    margin-bottom: var(--space-12);
  }
  
  .feature-card,
  .model-card {
    padding: var(--space-6);
  }
}

@media (prefers-reduced-motion: no-preference) {
  .hero-content > * {
    animation: fadeInUp 0.8s ease-out forwards;
    opacity: 0;
    transform: translateY(30px);
  }
  
  .hero-subtitle {
    animation-delay: 0.1s;
  }
  
  .hero-title {
    animation-delay: 0.2s;
  }
  
  .hero-description {
    animation-delay: 0.3s;
  }
  
  .cta-button {
    animation-delay: 0.4s;
  }
  
  .hero-image {
    animation: fadeInRight 1s ease-out 0.5s forwards;
    opacity: 0;
    transform: translateX(50px);
  }
}

@keyframes fadeInUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInRight {
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

::-webkit-scrollbar {
  width: 6px;
}

::-webkit-scrollbar-track {
  background: var(--gray-100);
}

::-webkit-scrollbar-thumb {
  background: var(--gray-400);
  border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--gray-600);
}