/* 
   Li Auto - High-Tech Minimalist Design System 
   Aesthetic: Apple/Tesla style. Titanium White, Electric Blue, Space Gray.
*/

:root {
  /* Color Palette */
  --color-titanium-white: #F5F5F7;
  --color-electric-blue: #2979FF;
  /* Vivid blue */
  --color-electric-blue-glow: rgba(41, 121, 255, 0.4);
  --color-space-gray: #1D1D1F;
  --color-dark-gray: #121212;
  --color-text-main: #1D1D1F;
  --color-text-secondary: #86868B;
  --color-text-inverse: #FFFFFF;

  /* Backgrounds */
  --bg-body: var(--color-titanium-white);
  --bg-glass: rgba(255, 255, 255, 0.7);
  --bg-glass-dark: rgba(29, 29, 31, 0.7);

  /* Typography */
  --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-body: 'Roboto', -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;

  /* Spacing & Layout */
  --spacing-unit: 8px;
  --container-width: 1200px;
  --header-height: 64px;

  /* Effects */
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --shadow-soft: 0 4px 20px rgba(0, 0, 0, 0.05);
  --shadow-hover: 0 10px 30px rgba(41, 121, 255, 0.2);
  --transition-fast: 0.2s ease;
  --transition-smooth: 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  --blur-amount: 20px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  background-color: var(--bg-body);
  color: var(--color-text-main);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--color-space-gray);
  margin-bottom: 1rem;
}

h1 {
  font-size: 3.5rem;
  line-height: 1.1;
}

h2 {
  font-size: 2.5rem;
  line-height: 1.2;
}

h3 {
  font-size: 1.75rem;
}

p {
  margin-bottom: 1.5rem;
  color: var(--color-text-secondary);
  font-size: 1.125rem;
}

a {
  text-decoration: none;
  color: inherit;
  transition: var(--transition-fast);
}

ul {
  list-style: none;
}

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

/* Utilities */
.container {
  width: 90%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 var(--spacing-unit);
}

.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}

.text-center {
  text-align: center;
}

.text-gradient {
  background: linear-gradient(135deg, var(--color-space-gray) 0%, var(--color-electric-blue) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* Components */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  border-radius: 100px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-smooth);
  border: 1px solid transparent;
}

.btn-primary {
  background-color: var(--color-electric-blue);
  color: var(--color-text-inverse);
  box-shadow: 0 4px 15px rgba(41, 121, 255, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(41, 121, 255, 0.4);
  background-color: #0066FF;
}

.btn-glass {
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.5);
  color: var(--color-space-gray);
}

.btn-glass:hover {
  background: rgba(255, 255, 255, 0.95);
  transform: translateY(-2px);
}

/* Navbar */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  background: rgba(245, 245, 247, 0.8);
  /* Titanium white transparent */
  backdrop-filter: blur(var(--blur-amount));
  z-index: 1000;
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

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

.logo {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.5rem;
  color: var(--color-space-gray);
  letter-spacing: -0.05em;
}

.logo span {
  color: var(--color-electric-blue);
}

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

.nav-link {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-text-secondary);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-electric-blue);
}

/* Sections */
section {
  padding: 100px 0;
}

/* Hero */
.hero {
  min-height: 100vh;
  padding-top: var(--header-height);
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 600px;
}

.hero-bg {
  position: absolute;
  top: 0;
  right: 0;
  width: 50%;
  height: 100%;
  object-fit: cover;
  z-index: 1;
  mask-image: linear-gradient(to right, transparent, black 20%);
  -webkit-mask-image: linear-gradient(to right, transparent, black 20%);
}

/* Feature Cards */
.pillar-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
  margin-top: 3rem;
}

.card {
  background: var(--color-text-inverse);
  /* White */
  padding: 2rem;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-soft);
  transition: var(--transition-smooth);
  border: 1px solid rgba(0, 0, 0, 0.03);
  position: relative;
  overflow: hidden;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-hover);
  border-color: var(--color-electric-blue-glow);
}

/* Card Media Modifier (for cards with full-width images) */
.card.card-media {
  padding: 0;
  display: flex;
  flex-direction: column;
}

.card.card-media img {
  width: 100%;
  height: 220px;
  /* Slightly taller for better impact */
  object-fit: cover;
}

.card-content {
  padding: 2rem;
  flex: 1;
  /* Ensures content fills remaining space */
}

.card-icon {
  width: 48px;
  height: 48px;
  margin-bottom: 1.5rem;
  color: var(--color-electric-blue);
}

/* Footer */
footer {
  background-color: var(--color-space-gray);
  color: var(--color-text-inverse);
  padding: 4rem 0 2rem;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 3rem;
  margin-bottom: 3rem;
}

.footer-logo {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.footer-links h4 {
  color: var(--color-text-inverse);
  font-size: 1.1rem;
  margin-bottom: 1rem;
}

.footer-links a {
  display: block;
  margin-bottom: 0.5rem;
  color: #a1a1a6;
}

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

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 2rem;
  text-align: center;
  color: #a1a1a6;
  font-size: 0.9rem;
}

/* Page Headers */
.page-header {
  padding: 120px 0 60px;
  background: linear-gradient(to bottom, #fff, var(--color-titanium-white));
  text-align: center;
  background-image: radial-gradient(#e5e7eb 1px, transparent 1px);
  background-size: 24px 24px;
}

/* Forms */
.cyber-form {
  max-width: 600px;
  margin: 0 auto;
  padding: 2rem;
  background: white;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(0, 0, 0, 0.05);
}

.form-group {
  margin-bottom: 1.5rem;
  text-align: left;
}

.form-label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--color-space-gray);
}

.form-input,
.form-textarea {
  width: 100%;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid #e0e0e0;
  font-family: var(--font-body);
  font-size: 1rem;
  transition: all 0.2s;
}

.form-input:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--color-electric-blue);
  box-shadow: 0 0 0 3px var(--color-electric-blue-glow);
}

.checkbox-group {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  margin-top: 1rem;
  margin-bottom: 2rem;
}

.checkbox-group input {
  width: 18px;
  height: 18px;
  accent-color: var(--color-electric-blue);
}

.checkbox-group label {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  margin: 0;
}

/* Grid Utils */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
}

.glass-panel {
  background: rgba(255, 255, 255, 0.7);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.5);
  padding: 2rem;
  border-radius: var(--radius-md);
}


/* Contact Layout */
.contact-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}

@media (max-width: 768px) {
  .contact-layout {
    grid-template-columns: 1fr;
  }

  /* Highlight Section Mobile */
  .highlight-layout {
    flex-direction: column;
    text-align: center;
    gap: 2rem;
  }

  .highlight-text {
    padding-right: 0;
  }
}

/* Highlight Section Base */
.highlight-layout {
  display: flex;
  align-items: center;
  padding: 4rem 0;
  gap: 4rem;
}

.highlight-text {
  flex: 1;
}

.highlight-media {
  flex: 1;
}

/* Mobile Menu */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--color-space-gray);
  padding: 0.5rem;
}

@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: var(--header-height);
    left: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(20px);
    flex-direction: column;
    align-items: center;
    padding: 2rem;
    gap: 2rem;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    transform: translateY(-150%);
    transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    z-index: 999;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
  }

  .nav-links.active {
    transform: translateY(0);
  }

  .nav-links a {
    font-size: 1.25rem;
    font-weight: 600;
  }

  h1 {
    font-size: 2.5rem;
  }

  .grid-3 {
    grid-template-columns: 1fr;
  }

  .hero {
    flex-direction: column;
    padding-top: 100px;
    text-align: center;
  }

  .hero-bg {
    width: 100%;
    height: 400px;
    top: auto;
    bottom: 0;
    mask-image: linear-gradient(to top, transparent, black 20%);
    -webkit-mask-image: linear-gradient(to top, transparent, black 20%);
    opacity: 0.2;
  }

  .hero-content {
    max-width: 100%;
    padding-bottom: 4rem;
  }
}