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

:root {
  --primary: #7C3AED;
  --primary-dark: #6D28D9;
  --primary-light: #A78BFA;
  --primary-bg: #F5F3FF;
  --secondary: #111827;
  --text: #374151;
  --text-light: #6B7280;
  --background: #FFFFFF;
  --background-alt: #FAFAFA;
  --border: #E5E7EB;
  --success: #10B981;
  --gradient: linear-gradient(135deg, #7C3AED 0%, #4F46E5 50%, #2563EB 100%);
  --gradient-soft: linear-gradient(180deg, #F5F3FF 0%, #EEF2FF 50%, #FFFFFF 100%);
}

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  color: var(--text);
  line-height: 1.6;
  background: var(--background);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 32px;
}

h1, h2, h3 { color: var(--secondary); font-weight: 800; line-height: 1.15; }
h1 { font-size: clamp(3rem, 6vw, 4.5rem); letter-spacing: -0.04em; }
h2 { font-size: clamp(2rem, 4vw, 3rem); letter-spacing: -0.03em; }
h3 { font-size: 1.25rem; font-weight: 700; }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 32px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 1rem;
  text-decoration: none;
  transition: all 0.2s ease;
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: var(--gradient);
  color: white;
  box-shadow: 0 4px 20px rgba(124, 58, 237, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(124, 58, 237, 0.4);
}

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

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

.btn-large {
  padding: 18px 40px;
  font-size: 1.1rem;
  border-radius: 14px;
}

/* ==================== HEADER ==================== */
.header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(0,0,0,0.06);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}

.logo-img { width: 38px; height: 38px; }

.logo-text {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--secondary);
}

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

.nav-links a {
  color: var(--text-light);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.925rem;
  transition: color 0.2s;
}

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

.nav .btn-primary {
  padding: 10px 24px;
  font-size: 0.9rem;
  border-radius: 10px;
}

/* ==================== HERO — 超大居中 ==================== */
.hero {
  padding: 180px 0 100px;
  background: var(--gradient-soft);
  text-align: center;
}

.hero-inner {
  max-width: 860px;
  margin: 0 auto;
}

.hero h1 {
  margin-bottom: 28px;
}

.hero h1 .accent {
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-sub {
  font-size: 1.3rem;
  color: var(--text-light);
  line-height: 1.7;
  max-width: 640px;
  margin: 0 auto 44px;
}

.hero-buttons {
  display: flex;
  gap: 16px;
  justify-content: center;
  margin-bottom: 64px;
}

/* 社交证明条 */
.trust-bar {
  display: flex;
  justify-content: center;
  gap: 56px;
  padding-top: 48px;
  border-top: 1px solid rgba(124,58,237,0.1);
}

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

.trust-value {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--secondary);
  display: block;
  letter-spacing: -0.02em;
}

.trust-label {
  font-size: 0.85rem;
  color: var(--text-light);
  font-weight: 500;
  margin-top: 2px;
}

/* ==================== FEATURES — 左右交替大块 ==================== */
.features {
  padding: 120px 0;
}

.features .section-header {
  text-align: center;
  margin-bottom: 80px;
}

.section-header p {
  color: var(--text-light);
  font-size: 1.1rem;
  margin-top: 12px;
}

.feature-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: center;
  margin-bottom: 100px;
}

.feature-row:last-child {
  margin-bottom: 0;
}

.feature-row.reverse .feature-visual {
  order: -1;
}

.feature-text .feature-tag {
  display: inline-block;
  padding: 4px 14px;
  background: var(--primary-bg);
  color: var(--primary);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  border-radius: 6px;
  margin-bottom: 16px;
}

.feature-text h3 {
  font-size: 1.75rem;
  font-weight: 800;
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.feature-text p {
  color: var(--text-light);
  font-size: 1.05rem;
  line-height: 1.75;
}

.feature-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}

.feature-visual-box {
  width: 100%;
  aspect-ratio: 4/3;
  background: var(--gradient-soft);
  border: 1px solid rgba(124,58,237,0.08);
  border-radius: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 5rem;
}

/* ==================== HOW IT WORKS — 横排大卡 ==================== */
.how-it-works {
  padding: 120px 0;
  background: var(--secondary);
  color: white;
}

.how-it-works .section-header {
  text-align: center;
  margin-bottom: 64px;
}

.how-it-works .section-header h2 {
  color: white;
}

.how-it-works .section-header p {
  color: rgba(255,255,255,0.6);
}

.steps-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.step-card {
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: 20px;
  padding: 40px 32px;
  text-align: center;
  transition: background 0.3s;
}

.step-card:hover {
  background: rgba(255,255,255,0.1);
}

.step-num {
  width: 56px;
  height: 56px;
  margin: 0 auto 24px;
  background: var(--gradient);
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: 800;
  color: white;
}

.step-card h3 {
  color: white;
  margin-bottom: 12px;
  font-size: 1.2rem;
}

.step-card p {
  color: rgba(255,255,255,0.6);
  font-size: 0.95rem;
  line-height: 1.65;
}

/* ==================== LANGUAGES — 流式标签云 ==================== */
.languages {
  padding: 120px 0;
}

.languages .section-header {
  text-align: center;
  margin-bottom: 48px;
}

.lang-cloud {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  max-width: 900px;
  margin: 0 auto;
}

.lang-pill {
  padding: 10px 22px;
  background: var(--background-alt);
  border: 1px solid var(--border);
  border-radius: 100px;
  font-weight: 500;
  font-size: 0.925rem;
  color: var(--text);
  transition: all 0.2s;
}

.lang-pill:hover {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
  transform: translateY(-2px);
}

.lang-pill.highlight {
  background: var(--gradient);
  color: white;
  border-color: transparent;
  font-weight: 600;
}

/* ==================== OUTPUT OPTIONS — 2x2大卡 ==================== */
.output-options {
  padding: 120px 0;
  background: var(--background-alt);
}

.output-options .section-header {
  text-align: center;
  margin-bottom: 64px;
}

.output-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  max-width: 880px;
  margin: 0 auto;
}

.output-card {
  background: var(--background);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 40px 36px;
  display: flex;
  gap: 24px;
  align-items: flex-start;
  transition: all 0.25s;
}

.output-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 16px 48px rgba(0,0,0,0.08);
}

.output-card-icon {
  width: 56px;
  height: 56px;
  min-width: 56px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
}

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

.icon-purple { background: #EDE9FE; }
.icon-green { background: #D1FAE5; }
.icon-blue { background: #DBEAFE; }
.icon-red { background: #FEE2E2; }

.output-card h3 {
  margin-bottom: 6px;
  font-size: 1.1rem;
}

.output-card p {
  color: var(--text-light);
  font-size: 0.925rem;
  line-height: 1.6;
}

/* ==================== PRICING ==================== */
.pricing {
  padding: 120px 0;
}

.pricing .section-header {
  text-align: center;
  margin-bottom: 64px;
}

.pricing-row {
  display: flex;
  justify-content: center;
  gap: 28px;
  max-width: 820px;
  margin: 0 auto;
}

.pricing-card {
  background: var(--background);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 48px 40px;
  flex: 1;
  position: relative;
}

.pricing-card.featured {
  border: 2px solid var(--primary);
  box-shadow: 0 8px 40px rgba(124,58,237,0.12);
}

.pricing-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--gradient);
  color: white;
  padding: 6px 22px;
  border-radius: 100px;
  font-size: 0.8rem;
  font-weight: 600;
}

.pricing-card h3 {
  text-align: center;
  font-size: 1.4rem;
  margin-bottom: 8px;
}

.price-row {
  text-align: center;
  margin-bottom: 32px;
}

.price-big {
  font-size: 3.5rem;
  font-weight: 800;
  color: var(--secondary);
  letter-spacing: -0.03em;
}

.price-period {
  color: var(--text-light);
  font-size: 0.95rem;
}

.pricing-list {
  list-style: none;
  margin-bottom: 36px;
}

.pricing-list li {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.95rem;
}

.pricing-list li:last-child { border-bottom: none; }

.check { color: var(--success); font-weight: 700; font-size: 1.1rem; }

.pricing-card .btn {
  width: 100%;
  justify-content: center;
}

/* ==================== CTA ==================== */
.cta {
  padding: 120px 0;
  background: var(--gradient);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta::before {
  content: '';
  position: absolute;
  width: 600px; height: 600px;
  top: -200px; right: -200px;
  background: rgba(255,255,255,0.05);
  border-radius: 50%;
}

.cta::after {
  content: '';
  position: absolute;
  width: 400px; height: 400px;
  bottom: -150px; left: -100px;
  background: rgba(255,255,255,0.03);
  border-radius: 50%;
}

.cta-inner { position: relative; z-index: 1; }

.cta h2 {
  color: white;
  font-size: clamp(2rem, 4vw, 2.75rem);
  margin-bottom: 16px;
}

.cta p {
  color: rgba(255,255,255,0.8);
  font-size: 1.15rem;
  margin-bottom: 36px;
}

.cta .btn {
  background: white;
  color: var(--primary);
  box-shadow: 0 4px 20px rgba(0,0,0,0.15);
  font-size: 1.1rem;
  padding: 18px 44px;
}

.cta .btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(0,0,0,0.2);
}

/* ==================== FOOTER ==================== */
.footer {
  padding: 48px 0;
  background: var(--secondary);
  color: white;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 600;
}

.footer-logo { width: 32px; height: 32px; }

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

.footer-links a {
  color: rgba(255,255,255,0.5);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.2s;
}

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

.footer-copy {
  color: rgba(255,255,255,0.3);
  font-size: 0.8rem;
}

/* ==================== RESPONSIVE ==================== */
@media (max-width: 1024px) {
  .feature-row {
    gap: 48px;
  }

  .output-grid {
    max-width: 100%;
  }
}

@media (max-width: 768px) {
  .nav-links { display: none; }

  .hero { padding: 140px 0 80px; }
  .hero h1 { font-size: clamp(2.25rem, 8vw, 3rem); }

  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }

  .trust-bar {
    flex-wrap: wrap;
    gap: 32px;
  }

  .feature-row,
  .feature-row.reverse {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .feature-row.reverse .feature-visual { order: 0; }

  .feature-visual-box {
    max-height: 240px;
    aspect-ratio: auto;
  }

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

  .lang-cloud { gap: 8px; }
  .lang-pill { padding: 8px 16px; font-size: 0.85rem; }

  .output-grid { grid-template-columns: 1fr; }
  .output-card { padding: 28px 24px; }

  .pricing-row { flex-direction: column; align-items: center; }
  .pricing-card { max-width: 420px; width: 100%; }

  .footer-inner {
    flex-direction: column;
    gap: 24px;
    text-align: center;
  }

  .footer-links { flex-wrap: wrap; justify-content: center; }
}

@media (max-width: 480px) {
  .trust-bar { flex-direction: column; gap: 24px; }

  .btn-large { width: 100%; justify-content: center; }
}