/* 
   Hongqi Auto - Water Control Technology
   Design System & Main Stylesheet
*/

/* --- Variables & Design Integration --- */
:root {
  /* Colors */
  --primary-red: #B11217;
  --secondary-green: #1F5C3A;
  --bg-black: #0E0E0E;
  --tech-gray: #2A2F33;
  --text-white: #F5F5F5;
  --text-dim: #CCCCCC;

  /* Fonts */
  --font-title: 'Montserrat', sans-serif;
  --font-body: 'Open Sans', sans-serif;

  /* Spacing */
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 32px;
  --spacing-xl: 64px;

  /* Transitions */
  --transition-fast: 0.3s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg-black);
  color: var(--text-white);
  font-family: var(--font-body);
  line-height: 1.6;
  overflow-x: hidden;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-title);
  font-weight: 700;
  color: var(--text-white);
  margin-bottom: var(--spacing-md);
  text-transform: uppercase;
  letter-spacing: 1px;
}

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

ul {
  list-style: none;
}

img {
  max-width: 100%;
  display: block;
  border-radius: 4px;
}

/* --- Typography Utilities --- */
.text-primary {
  color: var(--primary-red);
}

.text-secondary {
  color: var(--secondary-green);
}

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

.section-title {
  font-size: 2.5rem;
  margin-bottom: var(--spacing-md);
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  display: block;
  width: 60px;
  height: 4px;
  background: var(--primary-red);
  margin: var(--spacing-sm) auto 0;
}

.subtitle {
  font-size: 1.2rem;
  color: var(--text-dim);
  max-width: 700px;
  margin: 0 auto var(--spacing-lg);
}

/* --- Components --- */

/* Buttons */
.btn {
  display: inline-block;
  padding: 12px 24px;
  font-family: var(--font-title);
  font-weight: 600;
  text-transform: uppercase;
  border: 2px solid transparent;
  border-radius: 4px;
  cursor: pointer;
  transition: all var(--transition-fast);
}

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

.btn-primary:hover {
  background-color: #8a0e12;
  /* Darker red */
  box-shadow: 0 0 15px rgba(177, 18, 23, 0.5);
  transform: translateY(-2px);
}

.btn-secondary {
  background-color: transparent;
  border-color: var(--primary-red);
  color: var(--text-white);
}

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

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

/* Section */
section {
  padding: var(--spacing-xl) 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

/* Cards */
.card {
  background-color: var(--tech-gray);
  padding: var(--spacing-lg);
  border-radius: 8px;
  border: 1px solid rgba(255, 255, 255, 0.05);
  transition: var(--transition-fast);
  height: 100%;
}

.card:hover {
  transform: translateY(-5px);
  border-color: var(--primary-red);
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.3);
}

/* Icons */
.icon-box {
  font-size: 3rem;
  margin-bottom: var(--spacing-md);
  display: inline-block;
}

/* --- Layout --- */

/* Header */
header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background-color: rgba(14, 14, 14, 0.95);
  backdrop-filter: blur(10px);
  z-index: 1000;
  padding: var(--spacing-md) 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-family: var(--font-title);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-white);
  display: flex;
  align-items: center;
  gap: 10px;
}

.logo span {
  color: var(--primary-red);
}

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

nav a {
  font-family: var(--font-title);
  font-size: 0.9rem;
  font-weight: 600;
  text-transform: uppercase;
}

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

.nav-cta {
  background-color: var(--primary-red);
  padding: 8px 16px;
  border-radius: 4px;
}

.nav-cta:hover {
  color: white !important;
}

/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 6px;
  cursor: pointer;
}

.menu-toggle span {
  width: 25px;
  height: 3px;
  background-color: white;
  transition: 0.3s;
}

/* Hero Section */
#home {
  height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  padding-top: 80px;
  /* Header offset */
  background: linear-gradient(rgba(14, 14, 14, 0.7), rgba(14, 14, 14, 0.7)), url('https://placehold.co/1920x1080/0e0e0e/2A2F33?text=Hero+Background:+Water+Droplets+on+Grass');
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
}

.hero-content {
  max-width: 800px;
  z-index: 1;
}

.hero-title {
  font-size: 3.5rem;
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
}

.hero-subtitle {
  font-size: 1.5rem;
  color: var(--text-dim);
  margin-bottom: var(--spacing-lg);
}

/* Challenge Section */
.challenge-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xl);
  align-items: center;
}

.challenge-img img {
  border-radius: 8px;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
  border: 1px solid var(--tech-gray);
}

/* Solution Section */
.solution-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-lg);
  margin-top: var(--spacing-lg);
}

/* For Whom Section */
.audience-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
}

.audience-card {
  position: relative;
  overflow: hidden;
  border-radius: 8px;
  height: 400px;
  /* Fixed height for consistency */
}

.audience-card img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.audience-card:hover img {
  transform: scale(1.1);
}

.audience-overlay {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  background: linear-gradient(to top, rgba(0, 0, 0, 0.9), transparent);
  padding: var(--spacing-lg);
}

/* Differential Section */
.differential-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--spacing-lg);
}

.diff-item {
  flex: 1 1 200px;
  text-align: center;
  max-width: 250px;
}

.diff-icon {
  width: 80px;
  height: 80px;
  background: var(--tech-gray);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--spacing-md);
  font-size: 2rem;
  color: var(--primary-red);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

/* Benefits Section */
.benefits-list {
  max-width: 800px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-md);
}

.benefit-item {
  background: rgba(42, 47, 51, 0.5);
  padding: var(--spacing-md);
  border-left: 4px solid var(--secondary-green);
  display: flex;
  align-items: center;
  font-size: 1.1rem;
}

.benefit-item i {
  color: var(--secondary-green);
  margin-right: var(--spacing-md);
}

/* Contact Section */
#contact {
  background: linear-gradient(rgba(14, 14, 14, 0.9), rgba(14, 14, 14, 0.9)), url('https://placehold.co/1920x1080/0e0e0e/2A2F33?text=Contact+Background');
  background-size: cover;
}

.contact-form {
  max-width: 600px;
  margin: 0 auto;
  background: var(--tech-gray);
  padding: var(--spacing-xl);
  border-radius: 8px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
  border-top: 4px solid var(--primary-red);
}

.form-group {
  margin-bottom: var(--spacing-md);
}

label {
  display: block;
  margin-bottom: 5px;
  font-weight: 600;
  font-size: 0.9rem;
}

input,
select,
textarea {
  width: 100%;
  padding: 12px;
  background: rgba(14, 14, 14, 0.5);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 4px;
  color: white;
  font-family: var(--font-body);
}

input:focus,
select:focus,
textarea:focus {
  outline: none;
  border-color: var(--primary-red);
}

.checkbox-group {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
}

.checkbox-group input {
  width: auto;
}

/* Footer */
footer {
  background: #050505;
  padding: var(--spacing-xl) 0 var(--spacing-lg);
  border-top: 1px solid var(--tech-gray);
  text-align: center;
}

.footer-links {
  margin: var(--spacing-md) 0;
  display: flex;
  justify-content: center;
  gap: 20px;
}

.footer-links a {
  color: var(--text-dim);
  font-size: 0.9rem;
}

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

.copyright {
  color: #666;
  font-size: 0.85rem;
  margin-top: var(--spacing-lg);
}

.motto {
  color: var(--primary-red);
  font-family: var(--font-title);
  letter-spacing: 2px;
  text-transform: uppercase;
  font-size: 0.9rem;
  margin-bottom: var(--spacing-md);
}

/* Responsiveness */
@media (max-width: 768px) {
  :root {
    --spacing-xl: 40px;
    /* Reduce section spacing on mobile */
    --spacing-lg: 24px;
  }

  .menu-toggle {
    display: flex;
  }

  nav ul {
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: var(--bg-black);
    flex-direction: column;
    padding: var(--spacing-md);
    display: none;
    border-bottom: 1px solid var(--primary-red);
  }

  nav ul.active {
    display: flex;
  }

  .hero-title {
    font-size: 2.5rem;
  }

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

  .section-title {
    font-size: 2rem;
  }

  /* Page Header Mobile Adjustments */
  .page-header {
    padding: 100px 0 40px !important;
    /* Override desktop padding */
  }

  .page-header .hero-title {
    font-size: 2rem !important;
  }
}

/* Page Header Styles (Moved from inline) */
.page-header {
  padding: 180px 0 80px;
  text-align: center;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  position: relative;
}

/* Specific Header Backgrounds */
.page-header-about {
  background: linear-gradient(rgba(14, 14, 14, 0.8), rgba(14, 14, 14, 0.8)), url('../assets/images/about_header.png');
  background-size: cover;
  background-position: center;
}

.page-header-services {
  background: linear-gradient(rgba(14, 14, 14, 0.8), rgba(14, 14, 14, 0.8)), url('../assets/images/services_header.png');
  background-size: cover;
  background-position: center;
}