/* 
  Universal Electronics - Main Stylesheet 
  Clean, professional, mobile-friendly design.
*/

:root {
  /* Color Palette - Red & White Theme */
  --primary-color: #D32F2F;
  /* Universal Red */
  --primary-dark: #B71C1C;
  --accent-color: #FF5252;
  /* Bright Red/Orange for CTAs */
  --accent-dark: #D32F2F;
  --text-dark: #333333;
  --text-light: #666666;
  --bg-white: #ffffff;
  --bg-light: #f8f9fa;
  --bg-dark: #111111;
  --white: #ffffff;

  /* Spacing */
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --spacing-xl: 4rem;

  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 16px;

  /* Shadows */
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
}

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

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  line-height: 1.6;
  color: var(--text-dark);
  background-color: var(--bg-white);
}

a {
  text-decoration: none;
  color: inherit;
  transition: color 0.3s ease;
}

ul {
  list-style: none;
}

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

/* Utilities */
.container {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

.btn {
  display: inline-block;
  padding: 0.8rem 1.5rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s ease;
  border: none;
}

.btn-primary {
  background-color: var(--primary-color);
  color: var(--white);
}

.btn-primary:hover {
  background-color: var(--primary-dark);
  transform: translateY(-2px);
}

.btn-accent {
  background-color: var(--accent-color);
  color: var(--white);
}

.btn-accent:hover {
  background-color: var(--accent-dark);
  transform: translateY(-2px);
}

.btn-outline {
  border: 2px solid var(--primary-color);
  color: var(--primary-color);
  background: transparent;
}

.btn-outline:hover {
  background-color: var(--primary-color);
  color: var(--white);
}

.section-title {
  font-size: 2rem;
  margin-bottom: var(--spacing-md);
  color: var(--text-dark);
  text-align: center;
}

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

/* Header & Nav */
header {
  background-color: var(--white);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 1000;
  height: 70px;
  display: flex;
  align-items: center;
}

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

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-links {
  display: flex;
  gap: var(--spacing-lg);
}

.nav-links a {
  font-weight: 500;
  color: var(--text-dark);
}

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

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

/* Hero Section */
.hero {
  background: linear-gradient(rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.6)), url('https://images.unsplash.com/photo-1550009158-9ebf69173e03?ixlib=rb-4.0.3&auto=format&fit=crop&w=1920&q=80');
  background-size: cover;
  background-position: center;
  color: var(--white);
  padding: 6rem 0;
  text-align: center;
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: var(--spacing-sm);
}

.hero .tagline {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-lg);
  opacity: 0.9;
}

.hero-buttons {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* Features/Services Grid (Home Preview) */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
  margin-top: var(--spacing-lg);
}

.feature-card {
  background: var(--white);
  padding: var(--spacing-lg);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  text-align: center;
  transition: transform 0.3s ease;
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
}

.feature-icon {
  font-size: 2.5rem;
  color: var(--primary-color);
  margin-bottom: var(--spacing-md);
}

.feature-title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.feature-text {
  color: var(--text-light);
}

/* Footer */
footer {
  background-color: var(--bg-dark);
  color: #ddd;
  padding: var(--spacing-xl) 0 var(--spacing-lg);
}

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

.footer-col h3 {
  color: var(--white);
  margin-bottom: var(--spacing-md);
  font-size: 1.2rem;
}

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

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

.copyright {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: var(--spacing-md);
  text-align: center;
  font-size: 0.9rem;
  color: #888;
}

/* Mobile Responsiveness */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2rem;
  }

  .mobile-menu-btn {
    display: block;
  }

  .nav-links {
    position: fixed;
    top: 70px;
    left: 0;
    width: 100%;
    background-color: var(--white);
    flex-direction: column;
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-md);
    transform: translateY(-150%);
    transition: transform 0.3s ease-in-out;
  }

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