/* ===== Variables ===== */
:root {
  --color-primary: #0d9488;
  --color-primary-dark: #0f766e;
  --color-primary-light: #14b8a6;
  --color-accent: #f59e0b;
  --color-bg: #f8fafc;
  --color-bg-alt: #f1f5f9;
  --color-surface: #ffffff;
  --color-text: #1e293b;
  --color-text-muted: #64748b;
  --color-border: #e2e8f0;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);
  --radius: 12px;
  --radius-lg: 16px;
  --font: "Noto Sans SC", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --max-width: 1140px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--color-primary-dark);
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.container.narrow {
  max-width: 800px;
}

/* ===== Header ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--color-text);
}

.logo:hover {
  color: var(--color-text);
}

.logo-icon {
  font-size: 1.5rem;
}

.nav {
  display: flex;
  gap: 0.25rem;
}

.nav-link {
  padding: 0.5rem 0.85rem;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text-muted);
  transition: all 0.2s;
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-primary);
  background: rgba(13, 148, 136, 0.08);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: 0.3s;
}

/* ===== Hero ===== */
.hero {
  padding: 4rem 0 5rem;
  background: linear-gradient(135deg, #ecfdf5 0%, #f0fdfa 40%, #f8fafc 100%);
  overflow: hidden;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

.hero-content h1 {
  font-size: 2.75rem;
  font-weight: 700;
  line-height: 1.2;
  margin: 1rem 0;
}

.gradient-text {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.badge {
  display: inline-block;
  padding: 0.35rem 0.85rem;
  background: rgba(13, 148, 136, 0.1);
  color: var(--color-primary-dark);
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 600;
}

.hero-lead {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  margin-bottom: 1.75rem;
  max-width: 520px;
}

.hero-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  padding: 0.7rem 1.5rem;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: all 0.2s;
  border: 2px solid transparent;
}

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

.btn-primary:hover {
  background: var(--color-primary-dark);
  color: white;
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

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

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

.btn-outline-light {
  border-color: rgba(255, 255, 255, 0.5);
  color: white;
  background: transparent;
}

.btn-outline-light:hover {
  background: rgba(255, 255, 255, 0.15);
  color: white;
}

.hero-stats {
  display: flex;
  gap: 2rem;
  margin-top: 2.5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--color-border);
}

.stat strong {
  display: block;
  font-size: 0.95rem;
  margin-bottom: 0.15rem;
}

.stat span {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

/* Phone mockup */
.phone-mockup {
  display: flex;
  justify-content: center;
}

.phone-screen {
  width: 280px;
  background: white;
  border-radius: 24px;
  padding: 1.25rem;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--color-border);
}

.mini-app-header {
  text-align: center;
  font-weight: 700;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 1rem;
}

.mini-app-card {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
  color: white;
  padding: 1.25rem;
  border-radius: var(--radius);
  margin-bottom: 0.75rem;
}

.mini-app-card.secondary {
  background: var(--color-bg-alt);
  color: var(--color-text);
}

.mini-app-card .tag {
  display: inline-block;
  background: rgba(255, 255, 255, 0.2);
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  font-size: 0.7rem;
  margin-bottom: 0.5rem;
}

.mini-app-card h3 {
  font-size: 1rem;
  margin-bottom: 0.25rem;
}

.mini-app-card p {
  font-size: 0.85rem;
  opacity: 0.9;
  margin-bottom: 0.75rem;
}

.mini-btn {
  background: white;
  color: var(--color-primary);
  border: none;
  padding: 0.5rem 1rem;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.85rem;
  cursor: default;
}

/* ===== Sections ===== */
.section {
  padding: 4rem 0;
}

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

.section-header {
  text-align: center;
  margin-bottom: 3rem;
}

.section-header h2 {
  font-size: 2rem;
  margin-bottom: 0.75rem;
}

.section-header p {
  color: var(--color-text-muted);
  max-width: 560px;
  margin: 0 auto;
}

/* ===== Cards ===== */
.card-grid {
  display: grid;
  gap: 1.5rem;
}

.card-grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
.card-grid.cols-3 { grid-template-columns: repeat(3, 1fr); }

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  transition: box-shadow 0.2s, transform 0.2s;
}

.card:hover {
  box-shadow: var(--shadow-md);
}

.feature-card .card-icon {
  font-size: 2rem;
  margin-bottom: 1rem;
}

.feature-card h3 {
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
}

.feature-card p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.detail-card h4 {
  font-size: 1rem;
  margin-bottom: 0.5rem;
}

.detail-card p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.detail-card.compact {
  padding: 1.25rem;
}

/* ===== Flow ===== */
.flow-steps {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.flow-step {
  text-align: center;
  max-width: 180px;
  padding: 1rem;
}

.step-num {
  width: 40px;
  height: 40px;
  background: var(--color-primary);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  margin: 0 auto 0.75rem;
}

.flow-step h4 {
  font-size: 0.95rem;
  margin-bottom: 0.35rem;
}

.flow-step p {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.flow-arrow {
  color: var(--color-text-muted);
  font-size: 1.25rem;
  padding-top: 1.5rem;
}

/* ===== CTA ===== */
.cta-section {
  padding: 3rem 0 5rem;
}

.cta-box {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
  color: white;
  text-align: center;
  padding: 3.5rem 2rem;
  border-radius: var(--radius-lg);
}

.cta-box h2 {
  font-size: 1.75rem;
  margin-bottom: 0.75rem;
}

.cta-box p {
  opacity: 0.9;
  margin-bottom: 1.5rem;
}

/* ===== Page Hero ===== */
.page-hero {
  padding: 3.5rem 0 2.5rem;
  background: linear-gradient(135deg, #ecfdf5 0%, #f8fafc 100%);
}

.page-hero h1 {
  font-size: 2.5rem;
  margin: 0.75rem 0;
}

.page-lead {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  max-width: 640px;
}

/* ===== Feature Modules ===== */
.feature-module {
  margin-bottom: 3.5rem;
}

.module-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 2px solid var(--color-border);
}

.module-icon {
  font-size: 2rem;
}

.module-header h2 {
  font-size: 1.5rem;
}

.status {
  display: inline-block;
  padding: 0.2rem 0.65rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
  margin-left: 0.5rem;
}

.status-done {
  background: #dcfce7;
  color: #166534;
}

.status-progress {
  background: #fef3c7;
  color: #92400e;
}

.status-planned {
  background: #e0e7ff;
  color: #3730a3;
}

/* ===== Solutions ===== */
.solution-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.solution-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: box-shadow 0.2s;
}

.solution-card:hover {
  box-shadow: var(--shadow-md);
}

.solution-icon {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.solution-card h3 {
  font-size: 1.15rem;
  margin-bottom: 1rem;
}

.solution-card ul {
  list-style: none;
}

.solution-card li {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  padding: 0.35rem 0;
  padding-left: 1.25rem;
  position: relative;
}

.solution-card li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--color-primary);
  font-weight: 700;
}

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

.persona-label {
  display: inline-block;
  background: rgba(13, 148, 136, 0.1);
  color: var(--color-primary-dark);
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
}

.wechat-features {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
}

.wechat-item {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  text-align: center;
}

.wechat-item strong {
  display: block;
  margin-bottom: 0.35rem;
}

.wechat-item span {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* ===== Tech ===== */
.arch-diagram {
  max-width: 700px;
  margin: 0 auto;
}

.arch-layer {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  text-align: center;
}

.arch-layer.highlight {
  border-color: var(--color-primary);
  background: linear-gradient(135deg, #ecfdf5 0%, white 100%);
}

.arch-layer h3 {
  font-size: 1rem;
  margin-bottom: 1rem;
  color: var(--color-text-muted);
}

.arch-items {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: center;
}

.arch-chip {
  display: inline-block;
  padding: 0.4rem 0.85rem;
  background: var(--color-bg-alt);
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 500;
}

.arch-chip.primary {
  background: rgba(13, 148, 136, 0.15);
  color: var(--color-primary-dark);
}

.arch-desc {
  margin-top: 0.75rem;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.arch-connector {
  text-align: center;
  padding: 0.75rem;
  color: var(--color-text-muted);
  font-size: 0.85rem;
}

.tech-list {
  list-style: none;
}

.tech-list li {
  padding: 0.5rem 0;
  font-size: 0.9rem;
  color: var(--color-text-muted);
  border-bottom: 1px solid var(--color-border);
}

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

.tech-table-wrap {
  overflow-x: auto;
}

.tech-table {
  width: 100%;
  border-collapse: collapse;
  background: white;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--color-border);
}

.tech-table th,
.tech-table td {
  padding: 0.85rem 1.25rem;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

.tech-table th {
  background: var(--color-bg-alt);
  font-weight: 600;
  font-size: 0.85rem;
}

.tech-table td {
  font-size: 0.9rem;
}

.tech-table tr:last-child td {
  border-bottom: none;
}

/* ===== Timeline ===== */
.timeline {
  max-width: 720px;
  margin: 0 auto;
}

.timeline-item {
  display: flex;
  gap: 1.5rem;
  margin-bottom: 2rem;
  position: relative;
}

.timeline-item:not(:last-child)::after {
  content: "";
  position: absolute;
  left: 27px;
  top: 56px;
  bottom: -2rem;
  width: 2px;
  background: var(--color-border);
}

.timeline-marker {
  flex-shrink: 0;
  width: 56px;
  height: 56px;
  background: var(--color-bg-alt);
  border: 2px solid var(--color-border);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--color-text-muted);
}

.timeline-item.current .timeline-marker {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
}

.timeline-content {
  flex: 1;
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
}

.timeline-item.current .timeline-content {
  border-color: var(--color-primary);
}

.timeline-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.5rem;
}

.timeline-header h3 {
  font-size: 1.15rem;
}

.phase-status {
  font-size: 0.75rem;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  background: #dcfce7;
  color: #166534;
  font-weight: 600;
}

.phase-status.planned {
  background: var(--color-bg-alt);
  color: var(--color-text-muted);
}

.timeline-content > p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-bottom: 1rem;
}

.phase-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  list-style: none;
}

.phase-tags li {
  background: var(--color-bg-alt);
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.priority-list {
  max-width: 560px;
  margin: 0 auto;
}

.priority-item {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  padding: 1rem 0;
  border-bottom: 1px solid var(--color-border);
}

.priority-num {
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  background: var(--color-primary);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
}

.priority-item strong {
  display: block;
  margin-bottom: 0.15rem;
}

.priority-item p {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* ===== About ===== */
.about-block {
  margin-bottom: 3rem;
}

.about-block h2 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

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

.about-values {
  list-style: none;
}

.about-values li {
  padding: 1rem 0;
  border-bottom: 1px solid var(--color-border);
}

.about-values strong {
  display: block;
  margin-bottom: 0.25rem;
}

.about-values span {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.contact-cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin-top: 1.5rem;
}

.contact-card {
  background: white;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem;
}

.contact-label {
  display: block;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin-bottom: 0.35rem;
}

/* ===== Footer ===== */
.site-footer {
  background: #0f172a;
  color: #94a3b8;
  padding: 3rem 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2rem;
  padding-bottom: 2rem;
}

.footer-brand .logo {
  color: white;
  margin-bottom: 0.75rem;
}

.footer-desc {
  font-size: 0.9rem;
  line-height: 1.6;
}

.footer-links h4 {
  color: white;
  font-size: 0.9rem;
  margin-bottom: 0.75rem;
}

.footer-links a {
  display: block;
  color: #94a3b8;
  font-size: 0.85rem;
  padding: 0.25rem 0;
}

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

.footer-bottom {
  border-top: 1px solid #1e293b;
  padding: 1.25rem 0;
  text-align: center;
  font-size: 0.8rem;
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .hero-inner {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-lead {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-actions {
    justify-content: center;
  }

  .hero-stats {
    justify-content: center;
  }

  .hero-visual {
    order: -1;
  }

  .card-grid.cols-3,
  .solution-grid,
  .wechat-features {
    grid-template-columns: repeat(2, 1fr);
  }

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

@media (max-width: 640px) {
  .nav {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: white;
    flex-direction: column;
    padding: 1rem;
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
  }

  .nav.open {
    display: flex;
  }

  .nav-toggle {
    display: flex;
  }

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

  .card-grid.cols-2,
  .card-grid.cols-3,
  .solution-grid,
  .wechat-features,
  .contact-cards {
    grid-template-columns: 1fr;
  }

  .flow-arrow {
    display: none;
  }

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