/* ============================================================
   LONGHUA TECHNOLOGY - Global Design System
   Industrial B2B Electrical Control Equipment
   ============================================================ */

:root {
  /* Primary Palette - Deep Blue Industrial */
  --color-primary: #0A2540;
  --color-primary-light: #1a3a5c;
  --color-primary-dark: #061a2d;
  --color-primary-50: #e8eef5;
  --color-primary-100: #c6d4e5;
  --color-primary-200: #9db4cf;
  --color-primary-700: #132d4a;

  /* Accent - Industrial Silver + Electric Blue */
  --color-accent: #2E86DE;
  --color-accent-dark: #1e6bc4;
  --color-silver: #C0C0C0;
  --color-silver-light: #E8E8E8;
  --color-silver-dark: #8A8A8A;

  /* Status & Semantic */
  --color-success: #16a34a;
  --color-warning: #d97706;
  --color-danger: #dc2626;

  /* Neutrals */
  --color-gray-50: #f8fafc;
  --color-gray-100: #f1f5f9;
  --color-gray-200: #e2e8f0;
  --color-gray-300: #cbd5e1;
  --color-gray-400: #94a3b8;
  --color-gray-500: #64748b;
  --color-gray-600: #475569;
  --color-gray-700: #334155;
  --color-gray-800: #1e293b;
  --color-gray-900: #0f172a;

  /* Typography */
  --font-sans: 'Inter', 'Helvetica Neue', Arial, sans-serif;
  --font-display: 'Inter', 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;

  /* Typography Scale */
  --text-xs: 0.75rem;   /* 12px */
  --text-sm: 0.875rem;  /* 14px */
  --text-base: 1rem;    /* 16px */
  --text-lg: 1.125rem;  /* 18px */
  --text-xl: 1.25rem;   /* 20px */
  --text-2xl: 1.5rem;   /* 24px */
  --text-3xl: 1.875rem; /* 30px */
  --text-4xl: 2.25rem;  /* 36px */
  --text-5xl: 3rem;     /* 48px */
  --text-6xl: 3.75rem;  /* 60px */

  /* Spacing */
  --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;

  /* Layout */
  --container-max: 1280px;
  --container-padding: clamp(1rem, 3vw, 2rem);
  --nav-height: 72px;
  --nav-height-mobile: 60px;

  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 10px;
  --radius-xl: 14px;

  /* Shadows - Soft, layered premium feel */
  --shadow-sm: 0 1px 3px rgba(10, 37, 64, 0.04), 0 1px 2px rgba(10, 37, 64, 0.03);
  --shadow-md: 0 4px 12px rgba(10, 37, 64, 0.06), 0 2px 4px rgba(10, 37, 64, 0.04);
  --shadow-lg: 0 12px 28px rgba(10, 37, 64, 0.08), 0 4px 10px rgba(10, 37, 64, 0.04);
  --shadow-xl: 0 20px 40px rgba(10, 37, 64, 0.10), 0 8px 16px rgba(10, 37, 64, 0.06);

  /* Transitions */
  --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);

  /* Z-index */
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-modal: 300;
  --z-floating: 400;
  --z-tooltip: 500;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--color-gray-800);
  background-color: #fff;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
  background: var(--color-gray-100);
}

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

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

ul, ol {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

input, textarea, select {
  font-family: inherit;
  font-size: inherit;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.25;
  color: var(--color-primary);
  letter-spacing: -0.01em;
}

h1 { font-size: clamp(2rem, 4.5vw, var(--text-5xl)); }
h2 { font-size: clamp(1.75rem, 3.5vw, var(--text-4xl)); }
h3 { font-size: clamp(1.375rem, 2.5vw, var(--text-2xl)); }
h4 { font-size: var(--text-xl); }
h5 { font-size: var(--text-lg); }
h6 { font-size: var(--text-base); }

p {
  color: var(--color-gray-600);
  line-height: 1.7;
}

/* Container */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.section {
  padding: clamp(3rem, 6vw, var(--space-20)) 0;
}

.section-sm {
  padding: clamp(2rem, 4vw, var(--space-12)) 0;
}

.section-header {
  text-align: center;
  max-width: 720px;
  margin: 0 auto clamp(2rem, 4vw, var(--space-12));
}

.section-label {
  display: inline-block;
  font-size: var(--text-sm);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--color-accent);
  margin-bottom: var(--space-3);
}

.section-title {
  font-size: clamp(1.75rem, 3.5vw, var(--text-4xl));
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: var(--space-4);
}

.section-subtitle {
  font-size: var(--text-lg);
  color: var(--color-gray-500);
  line-height: 1.7;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0.75rem 1.75rem;
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
  border: 1.5px solid transparent;
}

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

.btn-primary:hover {
  background-color: var(--color-accent);
  border-color: var(--color-accent);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(10, 37, 64, 0.15);
}

.btn-outline {
  background-color: transparent;
  color: #fff;
  border-color: rgba(255, 255, 255, 0.6);
}

.btn-outline:hover {
  background-color: #fff;
  color: var(--color-primary);
  border-color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.1);
}

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

.btn-outline-dark:hover {
  background-color: var(--color-primary);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(10, 37, 64, 0.15);
}

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

.btn-accent:hover {
  background-color: var(--color-accent-dark);
  border-color: var(--color-accent-dark);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(217, 119, 87, 0.25);
}

.btn-sm {
  padding: 0.5rem 1.25rem;
  font-size: var(--text-xs);
}

.btn-lg {
  padding: 1rem 2.25rem;
  font-size: var(--text-base);
}

/* Cards */
.card {
  background: #fff;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
  border: 1px solid var(--color-gray-100);
}

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

.card-image {
  width: 100%;
  aspect-ratio: 4/3;
  object-fit: cover;
  background: var(--color-gray-100);
}

.card-body {
  padding: var(--space-6);
}

.card-title {
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--color-primary);
  margin-bottom: var(--space-2);
}

.card-desc {
  font-size: var(--text-sm);
  color: var(--color-gray-500);
  line-height: 1.6;
}

/* Form Elements */
.form-group {
  margin-bottom: var(--space-4);
}

.form-label {
  display: block;
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-gray-700);
  margin-bottom: var(--space-2);
}

.form-control {
  width: 100%;
  padding: 0.75rem 1rem;
  font-size: var(--text-base);
  color: var(--color-gray-800);
  background: #fff;
  border: 1px solid var(--color-gray-300);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.form-control:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(46, 134, 222, 0.1);
}

.form-control::placeholder {
  color: var(--color-gray-400);
}

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

select.form-control {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  padding-right: 2.5rem;
}

/* Grid */
.grid {
  display: grid;
  gap: var(--space-6);
}

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

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

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

.grid-5 {
  grid-template-columns: repeat(5, 1fr);
}

/* Utilities */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.text-primary { color: var(--color-primary); }
.text-accent { color: var(--color-accent); }
.text-gray-500 { color: var(--color-gray-500); }
.text-white { color: #fff; }

.bg-primary { background-color: var(--color-primary); }
.bg-primary-dark { background-color: var(--color-primary-dark); }
.bg-gray-50 { background-color: var(--color-gray-50); }
.bg-gray-100 { background-color: var(--color-gray-100); }

.mb-2 { margin-bottom: var(--space-2); }
.mb-3 { margin-bottom: var(--space-3); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }
.mt-4 { margin-top: var(--space-4); }
.mt-8 { margin-top: var(--space-8); }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.justify-center { justify-content: center; }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.flex-wrap { flex-wrap: wrap; }

/* Divider */
.divider {
  width: 60px;
  height: 3px;
  background: var(--color-accent);
  margin: var(--space-4) 0;
}

.divider-center {
  margin: var(--space-4) auto;
}

/* Page Header (inner pages) */
.page-header {
  position: relative;
  padding: clamp(4rem, 8vw, 7rem) 0 clamp(2.5rem, 5vw, 4rem);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
  color: #fff;
  overflow: hidden;
}

.page-header::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='0.04'%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;
}

.page-header .container {
  position: relative;
  z-index: 1;
}

.page-header h1 {
  color: #fff;
  margin-bottom: var(--space-3);
  font-weight: 700;
}

.page-header p {
  color: rgba(255, 255, 255, 0.8);
  font-size: var(--text-lg);
  max-width: 600px;
}

/* Breadcrumb */
.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-2);
  font-size: var(--text-sm);
  color: rgba(255, 255, 255, 0.7);
  margin-bottom: var(--space-5);
}

.breadcrumb a {
  color: rgba(255, 255, 255, 0.8);
}

.breadcrumb a:hover {
  color: #fff;
}

.breadcrumb-separator {
  color: rgba(255, 255, 255, 0.4);
}

.breadcrumb-current {
  color: rgba(255, 255, 255, 0.95);
}

/* Responsive */
@media (max-width: 1024px) {
  .grid-4 { grid-template-columns: repeat(3, 1fr); }
  .grid-5 { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 768px) {
  .grid-2, .grid-3, .grid-4, .grid-5 {
    grid-template-columns: 1fr;
  }
}

/* Scroll animations */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* Selection */
::selection {
  background: var(--color-accent);
  color: #fff;
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

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

::-webkit-scrollbar-thumb {
  background: var(--color-gray-400);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-gray-500);
}