/* ==========================================
   R&T Logistics - Main Stylesheet
   ========================================== */

/* CSS Variables - Design System */
:root {
  /* Colors */
  --color-primary: #1a365d;
  --color-primary-dark: #132744;
  --color-accent: #3182ce;
  --color-accent-light: #4299e1;
  --color-dark-bg: #0f172a;
  --color-light-bg: #f7fafc;
  --color-white: #ffffff;
  --color-text-dark: #1a202c;
  --color-text-muted: #718096;
  --color-success: #38a169;
  --color-border: #e2e8f0;

  /* Typography */
  --font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* Spacing */
  --section-padding: 100px 0;
  --container-max-width: 1200px;
  --nav-height: 72px;
  --border-radius: 8px;
  --border-radius-sm: 6px;

  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text-dark);
  background-color: var(--color-white);
}

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

ul, ol {
  list-style: none;
}

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

/* ==========================================
   Typography
   ========================================== */
h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-weight-bold);
  line-height: 1.2;
  color: var(--color-primary);
}

h1 {
  font-size: 3rem;
  margin-bottom: 1.5rem;
}

h2 {
  font-size: 2.5rem;
  margin-bottom: 1.25rem;
}

h3 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

h4 {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
}

p {
  margin-bottom: 1rem;
  color: var(--color-text-muted);
}

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

.text-white {
  color: var(--color-white);
}

.text-white p {
  color: rgba(255, 255, 255, 0.85);
}

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

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

.section-light {
  background-color: var(--color-light-bg);
}

.section-dark {
  background-color: var(--color-dark-bg);
}

.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-header p {
  max-width: 700px;
  margin: 0 auto;
  font-size: 1.125rem;
}

/* Grid System */
.grid {
  display: grid;
  gap: 30px;
}

.grid-2 {
  grid-template-columns: repeat(2, 1fr);
}

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

/* ==========================================
   Navigation
   ========================================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background-color: var(--color-white);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
  z-index: 1000;
  transition: background-color var(--transition-normal);
}

.navbar.transparent {
  background-color: transparent;
  box-shadow: none;
}

/* Transparent navbar - white text for dark hero background */
.navbar.transparent:not(.scrolled) .nav-logo {
  color: var(--color-white);
}

.navbar.transparent:not(.scrolled) .nav-logo span {
  color: rgba(255, 255, 255, 0.8);
}

.navbar.transparent:not(.scrolled) .nav-link {
  color: var(--color-white);
}

.navbar.transparent:not(.scrolled) .nav-link:hover {
  color: rgba(255, 255, 255, 0.8);
}

.navbar.transparent:not(.scrolled) .nav-link::after {
  background-color: var(--color-white);
}

.navbar.transparent:not(.scrolled) .lang-switcher {
  border-left-color: rgba(255, 255, 255, 0.3);
}

.navbar.transparent:not(.scrolled) .lang-btn {
  color: rgba(255, 255, 255, 0.8);
}

.navbar.transparent:not(.scrolled) .lang-btn:hover {
  color: var(--color-white);
}

.navbar.transparent:not(.scrolled) .lang-btn.active {
  background-color: var(--color-white);
  color: var(--color-primary);
}

.navbar.transparent:not(.scrolled) .nav-toggle span {
  background-color: var(--color-white);
}

.navbar.scrolled {
  background-color: var(--color-white);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

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

.nav-logo {
  font-size: 1.5rem;
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
}

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

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

.nav-link {
  font-size: 0.9375rem;
  font-weight: var(--font-weight-medium);
  color: var(--color-text-dark);
  padding: 8px 0;
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-accent);
  transition: width var(--transition-fast);
}

.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}

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

/* Language Switcher */
.lang-switcher {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-left: 16px;
  padding-left: 16px;
  border-left: 1px solid var(--color-border);
}

.lang-btn {
  padding: 6px 12px;
  font-size: 0.875rem;
  font-weight: var(--font-weight-medium);
  border: none;
  background: none;
  color: var(--color-text-muted);
  cursor: pointer;
  border-radius: var(--border-radius-sm);
  transition: all var(--transition-fast);
}

.lang-btn:hover {
  color: var(--color-accent);
}

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

/* Mobile Menu Toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  background: none;
  border: none;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-primary);
  transition: all var(--transition-fast);
}

/* ==========================================
   Buttons
   ========================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 28px;
  font-size: 1rem;
  font-weight: var(--font-weight-semibold);
  border-radius: var(--border-radius-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
  border: 2px solid transparent;
}

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

.btn-primary:hover {
  background-color: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
}

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

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

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

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

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

.btn-accent:hover {
  background-color: var(--color-accent-light);
  border-color: var(--color-accent-light);
}

.btn-group {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

/* ==========================================
   Hero Section
   ========================================== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-dark-bg) 100%);
  padding-top: var(--nav-height);
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.03'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
  opacity: 0.5;
}

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

.hero-badge {
  display: inline-block;
  padding: 8px 16px;
  background-color: rgba(255, 255, 255, 0.1);
  border-radius: 50px;
  font-size: 0.875rem;
  font-weight: var(--font-weight-medium);
  color: var(--color-white);
  margin-bottom: 24px;
  backdrop-filter: blur(4px);
}

.hero h1 {
  color: var(--color-white);
  font-size: 3.5rem;
  margin-bottom: 24px;
}

.hero p {
  font-size: 1.25rem;
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 40px;
  max-width: 600px;
}

.hero-stats {
  display: flex;
  gap: 48px;
  margin-top: 60px;
  padding-top: 40px;
  border-top: 1px solid rgba(255, 255, 255, 0.2);
}

.hero-stat {
  text-align: left;
}

.hero-stat-number {
  font-size: 2.5rem;
  font-weight: var(--font-weight-bold);
  color: var(--color-white);
  line-height: 1;
}

.hero-stat-label {
  font-size: 0.9375rem;
  color: rgba(255, 255, 255, 0.7);
  margin-top: 8px;
}

/* ==========================================
   Cards
   ========================================== */
.card {
  background-color: var(--color-white);
  border-radius: var(--border-radius);
  padding: 32px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
  transition: all var(--transition-normal);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.1);
}

.card-icon {
  width: 56px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-light-bg);
  border-radius: var(--border-radius);
  margin-bottom: 20px;
  color: var(--color-accent);
}

.card-icon svg {
  width: 28px;
  height: 28px;
}

.card h3 {
  margin-bottom: 12px;
}

.card p {
  margin-bottom: 0;
}

/* Service Card */
.service-card {
  text-align: left;
}

.service-card .card-icon {
  background-color: rgba(49, 130, 206, 0.1);
}

/* Location Card */
.location-card {
  position: relative;
  padding: 40px 32px;
  text-align: center;
  border: 1px solid var(--color-border);
}

.location-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background-color: var(--color-accent);
  border-radius: var(--border-radius) var(--border-radius) 0 0;
}

.location-card h3 {
  color: var(--color-primary);
  margin-bottom: 8px;
}

.location-card .location-area {
  font-size: 0.9375rem;
  color: var(--color-accent);
  font-weight: var(--font-weight-medium);
  margin-bottom: 16px;
}

.location-card address {
  font-style: normal;
  color: var(--color-text-muted);
  font-size: 0.9375rem;
  line-height: 1.7;
}

/* Feature Card */
.feature-card {
  display: flex;
  gap: 20px;
  padding: 0;
  box-shadow: none;
  background: transparent;
}

.feature-card:hover {
  transform: none;
  box-shadow: none;
}

.feature-card .card-icon {
  flex-shrink: 0;
}

/* ==========================================
   About Section
   ========================================== */
.about-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.about-text h2 {
  margin-bottom: 24px;
}

.about-text p {
  font-size: 1.0625rem;
}

.about-features {
  display: grid;
  gap: 24px;
  margin-top: 32px;
}

.about-feature {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.about-feature-icon {
  width: 24px;
  height: 24px;
  color: var(--color-success);
  flex-shrink: 0;
  margin-top: 2px;
}

.about-image {
  position: relative;
  border-radius: var(--border-radius);
  overflow: hidden;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
  aspect-ratio: 4/3;
  display: flex;
  align-items: center;
  justify-content: center;
}

.about-image-placeholder {
  color: var(--color-white);
  font-size: 4rem;
  opacity: 0.3;
}

/* ==========================================
   Technology Section
   ========================================== */
.tech-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 30px;
}

.tech-card {
  background-color: var(--color-white);
  border-radius: var(--border-radius);
  padding: 32px;
  border: 1px solid var(--color-border);
}

.tech-card h4 {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.tech-card h4 svg {
  width: 24px;
  height: 24px;
  color: var(--color-accent);
}

.tech-list {
  margin-top: 16px;
}

.tech-list li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 8px 0;
  color: var(--color-text-muted);
  font-size: 0.9375rem;
}

.tech-list li svg {
  width: 18px;
  height: 18px;
  color: var(--color-success);
  flex-shrink: 0;
  margin-top: 2px;
}

/* ==========================================
   CTA Section
   ========================================== */
.cta-section {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-dark-bg) 100%);
  text-align: center;
  padding: 80px 0;
}

.cta-section h2 {
  color: var(--color-white);
  margin-bottom: 16px;
}

.cta-section p {
  color: rgba(255, 255, 255, 0.85);
  font-size: 1.125rem;
  margin-bottom: 32px;
}

/* ==========================================
   Contact Section
   ========================================== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
}

.contact-info h3 {
  margin-bottom: 24px;
}

.contact-item {
  display: flex;
  gap: 16px;
  margin-bottom: 24px;
}

.contact-item-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-light-bg);
  border-radius: var(--border-radius);
  color: var(--color-accent);
  flex-shrink: 0;
}

.contact-item-icon svg {
  width: 24px;
  height: 24px;
}

.contact-item-content h4 {
  margin-bottom: 4px;
}

.contact-item-content p {
  margin-bottom: 0;
  font-size: 0.9375rem;
}

/* Contact Form */
.contact-form {
  background-color: var(--color-white);
  border-radius: var(--border-radius);
  padding: 40px;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
}

.form-group {
  margin-bottom: 24px;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: var(--font-weight-medium);
  color: var(--color-text-dark);
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 14px 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius-sm);
  font-size: 1rem;
  font-family: inherit;
  transition: border-color var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--color-accent);
}

.form-group textarea {
  min-height: 120px;
  resize: vertical;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

/* ==========================================
   Footer
   ========================================== */
.footer {
  background-color: var(--color-dark-bg);
  color: var(--color-white);
  padding: 60px 0 24px;
}

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

.footer-brand p {
  color: rgba(255, 255, 255, 0.7);
  margin-top: 16px;
  font-size: 0.9375rem;
}

.footer-title {
  font-size: 1rem;
  font-weight: var(--font-weight-semibold);
  margin-bottom: 20px;
  color: var(--color-white);
}

.footer-links li {
  margin-bottom: 12px;
}

.footer-links a {
  color: rgba(255, 255, 255, 0.7);
  font-size: 0.9375rem;
  transition: color var(--transition-fast);
}

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

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.6);
}

/* ==========================================
   Page Header (for subpages)
   ========================================== */
.page-header {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-dark-bg) 100%);
  padding: 140px 0 80px;
  text-align: center;
}

.page-header h1 {
  color: var(--color-white);
  margin-bottom: 16px;
}

.page-header p {
  color: rgba(255, 255, 255, 0.85);
  font-size: 1.125rem;
  max-width: 600px;
  margin: 0 auto;
}

/* ==========================================
   Responsive Design
   ========================================== */
@media (max-width: 1024px) {
  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }

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

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

@media (max-width: 768px) {
  :root {
    --section-padding: 60px 0;
  }

  h1 {
    font-size: 2.25rem;
  }

  h2 {
    font-size: 1.875rem;
  }

  /* Navigation */
  .nav-menu {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    bottom: 0;
    flex-direction: column;
    background-color: var(--color-white);
    padding: 32px 24px;
    gap: 0;
    transform: translateX(100%);
    transition: transform var(--transition-normal);
  }

  .nav-menu.active {
    transform: translateX(0);
  }

  .nav-link {
    padding: 16px 0;
    border-bottom: 1px solid var(--color-border);
    width: 100%;
  }

  .lang-switcher {
    margin-left: 0;
    padding-left: 0;
    border-left: none;
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid var(--color-border);
    width: 100%;
    justify-content: center;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }

  .nav-toggle.active span:nth-child(2) {
    opacity: 0;
  }

  .nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
  }

  /* Hero */
  .hero {
    min-height: auto;
    padding: 120px 0 80px;
  }

  .hero h1 {
    font-size: 2.5rem;
  }

  .hero-stats {
    flex-direction: column;
    gap: 24px;
  }

  /* Grids */
  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .about-content {
    grid-template-columns: 1fr;
  }

  .about-image {
    order: -1;
  }

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

  .form-row {
    grid-template-columns: 1fr;
  }

  /* Footer */
  .footer-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 16px;
    text-align: center;
  }

  /* Buttons */
  .btn-group {
    flex-direction: column;
  }

  .btn-group .btn {
    width: 100%;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

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

  .card {
    padding: 24px;
  }

  .contact-form {
    padding: 24px;
  }
}

/* ==========================================
   Animations
   ========================================== */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in-up {
  animation: fadeInUp 0.6s ease forwards;
}

.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.2s; }
.delay-3 { animation-delay: 0.3s; }
.delay-4 { animation-delay: 0.4s; }

/* ==========================================
   Utilities
   ========================================== */
.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }
.mt-4 { margin-top: 1rem; }
.mb-4 { margin-bottom: 1rem; }
.mt-8 { margin-top: 2rem; }
.mb-8 { margin-bottom: 2rem; }

.hidden {
  display: none !important;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}