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

:root {
  --bg-dark: #000000;
  --bg-light: #f5f5f7;
  --bg-white: #ffffff;
  --text-primary: #1d1d1f;
  --text-secondary: #6e6e73;
  --text-light: #f5f5f7;
  --text-light-secondary: #a1a1a6;
  --accent: #0071e3;
  --accent-hover: #0077ed;
  --border: #d2d2d7;
  --radius: 18px;
  --radius-lg: 28px;
  --nav-height: 48px;
  --max-width: 980px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg-white);
  color: var(--text-primary);
  line-height: 1.5;
  overflow-x: hidden;
}

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

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

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

/* ===== Container ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 22px;
}

.center {
  text-align: center;
}

/* ===== Nav ===== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--nav-height);
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  z-index: 9999;
  transition: background var(--transition);
}

.nav-inner {
  max-width: 980px;
  margin: 0 auto;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 22px;
}

.nav-logo {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-light);
  letter-spacing: 0.5px;
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 0;
  margin: 0 auto;
}

.nav-link {
  color: var(--text-light);
  font-size: 12px;
  font-weight: 400;
  padding: 0 16px;
  opacity: 0.8;
  transition: opacity var(--transition);
}

.nav-link:hover, .nav-link.active {
  opacity: 1;
  color: var(--text-light);
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.lang-toggle {
  background: none;
  border: none;
  color: var(--text-light);
  font-size: 12px;
  cursor: pointer;
  opacity: 0.8;
  transition: opacity var(--transition);
  font-family: inherit;
}

.lang-toggle:hover {
  opacity: 1;
}

.nav-menu-btn {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  flex-direction: column;
  gap: 4px;
  padding: 4px;
}

.nav-menu-btn span {
  width: 18px;
  height: 1px;
  background: var(--text-light);
  transition: var(--transition);
}

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  padding: 12px 30px;
  border-radius: 980px;
  font-size: 15px;
  font-weight: 400;
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  font-family: inherit;
}

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

.btn-primary:hover {
  background: var(--accent-hover);
  color: white;
  transform: scale(1.02);
}

/* ===== Hero ===== */
.hero {
  height: 100vh;
  min-height: 600px;
  background: var(--bg-dark);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  width: 600px;
  height: 600px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(0, 113, 227, 0.15), transparent 70%);
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  animation: pulse 6s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { transform: translate(-50%, -50%) scale(1); opacity: 0.5; }
  50% { transform: translate(-50%, -50%) scale(1.3); opacity: 0.8; }
}

.hero-content {
  position: relative;
  z-index: 1;
  padding: 0 22px;
}

.hero-title {
  font-size: clamp(40px, 7vw, 80px);
  font-weight: 600;
  color: var(--text-light);
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
  animation: fadeUp 1s ease;
}

.hero-subtitle {
  font-size: clamp(16px, 2.5vw, 24px);
  color: var(--text-light-secondary);
  margin-bottom: 32px;
  animation: fadeUp 1s ease 0.2s both;
}

.hero .btn {
  animation: fadeUp 1s ease 0.4s both;
}

.hero-scroll {
  position: absolute;
  bottom: 30px;
  font-size: 12px;
  color: var(--text-light-secondary);
  animation: bounce 2s infinite;
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes bounce {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

/* ===== Sections ===== */
.section {
  padding: 100px 0;
}

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

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

.section-cta {
  background: var(--bg-light);
  padding: 120px 0;
}

.section-title {
  font-size: clamp(28px, 5vw, 48px);
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}

.section-dark .section-title {
  color: var(--text-light);
}

.section-desc {
  font-size: clamp(16px, 2vw, 20px);
  color: var(--text-secondary);
  margin-bottom: 50px;
}

.section-dark .section-desc {
  color: var(--text-light-secondary);
}

/* ===== Features ===== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 50px;
}

.feature-card {
  background: var(--bg-white);
  border-radius: var(--radius);
  padding: 40px 30px;
  text-align: center;
  transition: transform var(--transition), box-shadow var(--transition);
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.08);
}

.feature-icon {
  font-size: 40px;
  margin-bottom: 16px;
}

.feature-card h3 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ===== Product Preview (Home) ===== */
.product-preview-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 50px;
}

.product-preview-card {
  display: block;
  border-radius: var(--radius);
  overflow: hidden;
  transition: transform var(--transition);
}

.product-preview-card:hover {
  transform: scale(1.02);
  color: var(--text-light);
}

.product-preview-img {
  height: 240px;
  border-radius: var(--radius);
  margin-bottom: 16px;
}

.product-preview-card h3 {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-light);
  margin-bottom: 4px;
}

.product-preview-card p {
  font-size: 14px;
  color: var(--text-light-secondary);
}

/* ===== Page Header ===== */
.page-header {
  padding: 140px 0 60px;
  background: var(--bg-dark);
  text-align: center;
}

.page-header h1 {
  font-size: clamp(32px, 6vw, 56px);
  font-weight: 600;
  color: var(--text-light);
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.page-header p {
  font-size: clamp(16px, 2vw, 20px);
  color: var(--text-light-secondary);
}

/* ===== Products Page ===== */
.filter-bar {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 40px;
}

.filter-btn {
  padding: 8px 20px;
  border-radius: 980px;
  border: 1px solid var(--border);
  background: var(--bg-white);
  font-size: 14px;
  cursor: pointer;
  transition: all var(--transition);
  font-family: inherit;
  color: var(--text-primary);
}

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

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

.product-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.product-card {
  background: var(--bg-white);
  border-radius: var(--radius);
  overflow: hidden;
  transition: transform var(--transition), box-shadow var(--transition);
}

.product-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.08);
}

.product-img {
  height: 200px;
  position: relative;
}

.product-tag {
  position: absolute;
  top: 12px;
  right: 12px;
  background: var(--accent);
  color: white;
  font-size: 11px;
  padding: 4px 10px;
  border-radius: 980px;
}

.product-info {
  padding: 18px 16px;
}

.product-info h3 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 4px;
}

.product-info p {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 10px;
  min-height: 39px;
}

.product-price {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-primary);
  display: block;
  margin-bottom: 4px;
}

.product-status {
  font-size: 12px;
  color: var(--text-secondary);
}

.product-note {
  text-align: center;
  margin-top: 50px;
  color: var(--text-secondary);
  font-size: 14px;
}

/* ===== About Page ===== */
.about-story {
  max-width: 680px;
  margin: 0 auto 60px;
  text-align: center;
}

.about-story h2 {
  font-size: 32px;
  font-weight: 600;
  margin-bottom: 20px;
}

.about-story p {
  font-size: 17px;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 16px;
}

.value-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-top: 50px;
}

.value-card {
  background: var(--bg-white);
  border-radius: var(--radius);
  padding: 36px 20px;
  text-align: center;
  transition: transform var(--transition);
}

.value-card:hover {
  transform: translateY(-4px);
}

.value-icon {
  font-size: 32px;
  margin-bottom: 12px;
}

.value-card h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 6px;
}

.value-card p {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ===== Contact Page ===== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.5fr;
  gap: 50px;
  margin-top: 30px;
}

.contact-info h2,
.contact-form-wrap h2 {
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 24px;
}

.contact-item {
  margin-bottom: 20px;
}

.contact-label {
  display: block;
  font-size: 12px;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 4px;
}

.contact-value {
  font-size: 16px;
  color: var(--text-primary);
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.form-group {
  display: flex;
  flex-direction: column;
}

.form-group label {
  font-size: 13px;
  font-weight: 500;
  margin-bottom: 6px;
}

.form-group input,
.form-group textarea {
  padding: 12px 16px;
  border: 1px solid var(--border);
  border-radius: 12px;
  font-size: 15px;
  font-family: inherit;
  background: var(--bg-white);
  transition: border-color var(--transition);
  color: var(--text-primary);
}

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

.form-group textarea {
  resize: vertical;
}

.form-note {
  color: var(--accent);
  font-size: 14px;
  margin-top: 8px;
}

/* ===== Footer ===== */
.footer {
  background: #000;
  color: var(--text-light-secondary);
  padding: 40px 0 30px;
  font-size: 12px;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.footer-logo {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-light);
}

.footer-links {
  display: flex;
  gap: 20px;
}

.footer-links a {
  color: var(--text-light-secondary);
  font-size: 12px;
}

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

.footer-copy {
  font-size: 11px;
  opacity: 0.6;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: fixed;
    top: var(--nav-height);
    left: 0;
    width: 100%;
    flex-direction: column;
    background: rgba(0, 0, 0, 0.95);
    backdrop-filter: blur(20px);
    padding: 20px 0;
    gap: 0;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links li {
    text-align: center;
    padding: 12px 0;
  }

  .nav-link {
    font-size: 16px;
  }

  .nav-menu-btn {
    display: flex;
  }

  .feature-grid,
  .product-preview-grid {
    grid-template-columns: 1fr;
  }

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

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

  .contact-grid {
    grid-template-columns: 1fr;
    gap: 30px;
  }

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

  .section {
    padding: 60px 0;
  }

  .section-cta {
    padding: 80px 0;
  }
}

@media (max-width: 480px) {
  .product-grid {
    grid-template-columns: 1fr;
  }

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