/*
 * SparkCore LLC - Enterprise Official Website
 * Design System: Neo-corporate, Apple-inspired, Minimalist & Trustworthy
 * Fonts: Inter, system-ui
 */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

:root {
  /* Colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #f1f3f5;
  --text-primary: #111827;
  --text-secondary: #4b5563;
  --text-tertiary: #9ca3af;

  --brand-primary: #0f172a;
  /* Deep slate for corporate trust */
  --brand-accent: #2563eb;
  /* Technology blue */
  --brand-accent-hover: #1d4ed8;
  --brand-success: #10b981;
  /* Emerald for success states */

  /* Surfaces */
  --surface: #ffffff;
  --surface-border: #e5e7eb;
  --surface-glass: rgba(255, 255, 255, 0.85);

  /* Radii */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-glow: 0 0 20px rgba(37, 99, 235, 0.15);

  /* Transitions */
  --t-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --t-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* === Layout & Containers === */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 96px 0;
}

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

.section-header {
  text-align: center;
  margin-bottom: 56px;
  max-width: 680px;
  margin-left: auto;
  margin-right: auto;
}

.section-label {
  display: inline-block;
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--brand-accent);
  margin-bottom: 16px;
}

.section-title {
  font-size: 36px;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--brand-primary);
  margin-bottom: 16px;
}

.section-subtitle {
  font-size: 18px;
  color: var(--text-secondary);
}

/* === Navbar === */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 72px;
  background: var(--surface-glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--surface-border);
  z-index: 1000;
  display: flex;
  align-items: center;
}

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

.nav-brand {
  font-size: 20px;
  font-weight: 700;
  color: var(--brand-primary);
  text-decoration: none;
  letter-spacing: -0.5px;
}

.nav-links {
  display: flex;
  gap: 32px;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 500;
  transition: color var(--t-fast);
}

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

/* === Hero Section === */
.hero {
  padding: 160px 0 100px;
  text-align: center;
  background: radial-gradient(circle at 50% -20%, var(--bg-secondary) 0%, var(--bg-primary) 80%);
  position: relative;
}

.hero::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 300px;
  background: linear-gradient(180deg, rgba(37, 99, 235, 0.05) 0%, rgba(255, 255, 255, 0) 100%);
  z-index: -1;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  padding: 6px 16px;
  background: var(--surface);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-full);
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  box-shadow: var(--shadow-sm);
  margin-bottom: 24px;
}

.hero h1 {
  font-size: 56px;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  color: var(--brand-primary);
  margin-bottom: 24px;
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

.hero p {
  font-size: 20px;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 40px;
  line-height: 1.6;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 16px;
}

/* === Buttons === */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  border-radius: var(--radius-full);
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  transition: all var(--t-smooth);
  cursor: pointer;
  border: none;
}

.btn-primary {
  background-color: var(--brand-primary);
  color: #ffffff;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  background-color: #000000;
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-outline {
  background-color: transparent;
  color: var(--brand-primary);
  border: 1px solid var(--surface-border);
}

.btn-outline:hover {
  background-color: var(--bg-secondary);
  border-color: #cbd5e1;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none !important;
  box-shadow: none !important;
}

/* === Company Intro === */
.intro-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.intro-content h3 {
  font-size: 28px;
  font-weight: 700;
  color: var(--brand-primary);
  margin-bottom: 16px;
}

.intro-content p {
  color: var(--text-secondary);
  font-size: 16px;
  margin-bottom: 24px;
}

.intro-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-top: 32px;
  padding-top: 32px;
  border-top: 1px solid var(--surface-border);
}

.stat-num {
  font-size: 32px;
  font-weight: 700;
  color: var(--brand-accent);
  margin-bottom: 4px;
}

.stat-label {
  font-size: 14px;
  color: var(--text-secondary);
  font-weight: 500;
}

/* === Products Matrix === */
.products-wrapper {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 32px;
}

.product-card {
  background: var(--surface);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-lg);
  padding: 32px;
  transition: all var(--t-smooth);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
}

.product-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  border-color: rgba(37, 99, 235, 0.2);
}

.product-icon {
  width: 48px;
  height: 48px;
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
  color: var(--brand-primary);
}

.product-card h3 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--brand-primary);
}

.product-card p {
  color: var(--text-secondary);
  font-size: 15px;
  flex-grow: 1;
  margin-bottom: 32px;
}

/* === Pricing Plans === */
.plans-wrapper {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 32px;
  max-width: 800px;
  margin: 0 auto;
}

.plan-card {
  background: var(--surface);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-lg);
  padding: 40px;
  box-shadow: var(--shadow-md);
  position: relative;
  overflow: hidden;
  transition: transform var(--t-smooth);
}

.plan-card:hover {
  transform: translateY(-4px);
  border-color: var(--brand-accent);
}

.plan-card.popular::before {
  content: "RECOMMENDED";
  position: absolute;
  top: 16px;
  right: -32px;
  background: var(--brand-primary);
  color: white;
  font-size: 11px;
  font-weight: 700;
  padding: 4px 40px;
  transform: rotate(45deg);
  letter-spacing: 1px;
}

.plan-header {
  border-bottom: 1px solid var(--surface-border);
  padding-bottom: 24px;
  margin-bottom: 24px;
}

.plan-name {
  font-size: 20px;
  font-weight: 600;
  color: var(--brand-primary);
  margin-bottom: 12px;
}

.plan-price {
  font-size: 40px;
  font-weight: 700;
  color: var(--brand-primary);
  letter-spacing: -1px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.plan-interval {
  font-size: 14px;
  color: var(--text-tertiary);
  font-weight: 400;
  letter-spacing: 0;
}

.plan-features {
  list-style: none;
  margin-bottom: 32px;
}

.plan-features li {
  position: relative;
  padding-left: 28px;
  margin-bottom: 16px;
  color: var(--text-secondary);
  font-size: 15px;
}

.plan-features li::before {
  content: '✓';
  position: absolute;
  left: 0;
  top: 0;
  color: var(--brand-success);
  font-weight: 700;
}

.plan-card .btn {
  width: 100%;
}

/* === Compliance & Legal Section === */
.compliance-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  background: var(--surface);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-lg);
  padding: 48px;
  box-shadow: var(--shadow-sm);
}

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

.detail-label {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-tertiary);
  font-weight: 600;
  margin-bottom: 4px;
}

.detail-value {
  font-size: 15px;
  color: var(--text-primary);
  font-weight: 500;
}

.detail-value a {
  color: var(--brand-accent);
  text-decoration: none;
}

.detail-value a:hover {
  text-decoration: underline;
}

/* === Common Form & Order Blocks === */
.order-info {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.order-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  color: var(--text-secondary);
  font-size: 14px;
}

.order-row strong {
  color: var(--brand-primary);
  font-weight: 600;
}

.input {
  width: 100%;
  border: 1px solid var(--surface-border);
  background: var(--surface);
  color: var(--text-primary);
  border-radius: var(--radius-md);
  padding: 10px 14px;
  font-size: 14px;
  outline: none;
  transition: border-color var(--t-fast), box-shadow var(--t-fast);
}

.input:focus {
  border-color: var(--brand-accent);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

/* === Footer === */
.footer {
  background-color: #0f172a;
  /* Deep corporate color */
  color: #94a3b8;
  padding: 80px 0 40px;
}

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 64px;
  margin-bottom: 64px;
}

.footer-brand {
  font-size: 20px;
  font-weight: 700;
  color: white;
  margin-bottom: 16px;
}

.footer-desc {
  font-size: 14px;
  line-height: 1.6;
  max-width: 300px;
}

.footer-title {
  color: white;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 24px;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.footer-links {
  list-style: none;
}

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

.footer-links a {
  color: #94a3b8;
  text-decoration: none;
  font-size: 14px;
  transition: color var(--t-fast);
}

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

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 32px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
}

.trust-badges {
  display: flex;
  gap: 16px;
  align-items: center;
  color: #cbd5e1;
}

/* === Responsive === */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 40px;
  }

  .intro-grid,
  .compliance-grid,
  .footer-top {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .compliance-grid {
    padding: 32px;
  }

  .footer-top {
    gap: 40px;
  }
}

/* === i18n System === */
html.lang-en .sh-zh {
  display: none !important;
}

html.lang-zh .sh-en {
  display: none !important;
}

.lang-toggle-btn {
  background: var(--surface-glass);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-full);
  padding: 6px 14px;
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  color: var(--text-secondary);
  transition: all var(--t-fast);
  margin-left: 16px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.lang-toggle-btn:hover {
  background: var(--bg-tertiary);
  color: var(--brand-primary);
}

@media (max-width: 768px) {
  .nav-links {
    display: flex !important;
    flex-wrap: wrap;
    justify-content: center;
  }

  /* Show in mobile to keep toggle btn */
}