:root {
  --blue: #1769ff;
  --blue-dark: #0b3b92;
  --blue-soft: #edf5ff;
  --cyan: #16b9d4;
  --ink: #122033;
  --muted: #61708a;
  --line: #dce7f5;
  --white: #ffffff;
  --shadow: 0 24px 70px rgba(24, 78, 148, 0.16);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  line-height: 1.6;
  background:
    radial-gradient(circle at top left, rgba(23, 105, 255, 0.14), transparent 34rem),
    linear-gradient(180deg, #f8fbff 0%, #ffffff 42%, #f6f9fd 100%);
}

a {
  color: inherit;
  text-decoration: none;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px clamp(20px, 5vw, 72px);
  border-bottom: 1px solid rgba(220, 231, 245, 0.78);
  background: rgba(255, 255, 255, 0.86);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 800;
  color: var(--blue-dark);
}

.brand-mark {
  display: grid;
  width: 38px;
  height: 38px;
  place-items: center;
  border-radius: 10px;
  color: var(--white);
  background: linear-gradient(135deg, var(--blue), var(--cyan));
  box-shadow: 0 12px 28px rgba(23, 105, 255, 0.25);
}

.nav {
  display: flex;
  gap: clamp(16px, 3vw, 34px);
  color: var(--muted);
  font-size: 15px;
}

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

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(340px, 520px);
  gap: clamp(34px, 6vw, 80px);
  align-items: center;
  max-width: 1180px;
  min-height: calc(100vh - 76px);
  margin: 0 auto;
  padding: 72px 24px 86px;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--blue);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 660px;
  margin-bottom: 24px;
  font-size: clamp(42px, 6vw, 72px);
  line-height: 1.06;
  letter-spacing: 0;
}

.hero-text {
  max-width: 620px;
  margin-bottom: 34px;
  color: var(--muted);
  font-size: 18px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0 22px;
  border-radius: 8px;
  font-weight: 700;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button.primary {
  color: var(--white);
  background: var(--blue);
  box-shadow: 0 16px 34px rgba(23, 105, 255, 0.24);
}

.button.secondary {
  color: var(--blue-dark);
  border: 1px solid var(--line);
  background: var(--white);
}

.chat-preview {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr);
  min-height: 440px;
  overflow: hidden;
  border: 1px solid rgba(220, 231, 245, 0.95);
  border-radius: 8px;
  background: var(--white);
  box-shadow: var(--shadow);
}

.preview-sidebar {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  padding-top: 28px;
  background: linear-gradient(180deg, var(--blue-dark), #0f58d6);
}

.preview-sidebar span {
  width: 34px;
  height: 34px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.22);
}

.preview-sidebar span:first-child {
  background: var(--white);
}

.preview-panel {
  display: flex;
  flex-direction: column;
  background: #f6f9fd;
}

.preview-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 22px;
  border-bottom: 1px solid var(--line);
  background: var(--white);
}

.preview-top strong,
.preview-top small {
  display: block;
}

.preview-top small {
  color: var(--muted);
}

.status {
  padding: 5px 10px;
  border-radius: 999px;
  color: var(--blue);
  font-size: 12px;
  font-weight: 800;
  background: var(--blue-soft);
}

.messages {
  display: flex;
  flex: 1;
  flex-direction: column;
  justify-content: center;
  gap: 16px;
  padding: 26px;
}

.message {
  display: flex;
}

.message span {
  max-width: 76%;
  padding: 13px 16px;
  border-radius: 8px;
  font-size: 15px;
  background: var(--white);
  box-shadow: 0 10px 24px rgba(27, 55, 96, 0.08);
}

.message.mine {
  justify-content: flex-end;
}

.message.mine span {
  color: var(--white);
  background: var(--blue);
}

.message.compact span {
  color: var(--blue-dark);
  background: #e9f7ff;
}

.composer {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 18px 22px;
  border-top: 1px solid var(--line);
  background: var(--white);
}

.composer span {
  flex: 1;
  height: 38px;
  border-radius: 8px;
  background: #edf2f8;
}

.composer b {
  color: var(--blue);
}

.section {
  max-width: 1180px;
  margin: 0 auto;
  padding: 86px 24px;
}

.section-heading {
  max-width: 690px;
  margin-bottom: 36px;
}

.section-heading h2,
.cta h2 {
  margin-bottom: 14px;
  font-size: clamp(30px, 4vw, 46px);
  line-height: 1.16;
}

.section-heading p,
.cta p {
  color: var(--muted);
  font-size: 17px;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 18px;
}

.feature-card {
  min-height: 228px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.82);
  box-shadow: 0 16px 42px rgba(20, 64, 122, 0.06);
}

.icon {
  display: grid;
  width: 44px;
  height: 44px;
  margin-bottom: 18px;
  place-items: center;
  border-radius: 8px;
  background: var(--blue-soft);
}

.feature-card h3,
.scene-item h3 {
  margin-bottom: 9px;
  font-size: 20px;
}

.feature-card p,
.scene-item p {
  margin-bottom: 0;
  color: var(--muted);
}

.scenes-section {
  max-width: none;
  background: linear-gradient(180deg, #f7fbff, #eef5ff);
}

.scenes-section .section-heading,
.scene-list {
  max-width: 1180px;
  margin-left: auto;
  margin-right: auto;
}

.scene-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.scene-item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 18px;
  align-items: start;
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--white);
}

.scene-number {
  color: var(--blue);
  font-size: 28px;
  font-weight: 900;
  line-height: 1;
}

.cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
  max-width: 1180px;
  margin: 86px auto;
  padding: 42px;
  border-radius: 8px;
  color: var(--white);
  background: linear-gradient(135deg, var(--blue-dark), var(--blue));
  box-shadow: var(--shadow);
}

.cta .eyebrow,
.cta p {
  color: rgba(255, 255, 255, 0.78);
}

.cta h2 {
  color: var(--white);
}

.cta .button.primary {
  color: var(--blue-dark);
  background: var(--white);
  box-shadow: none;
}

.footer {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding: 26px clamp(20px, 5vw, 72px);
  color: var(--muted);
  border-top: 1px solid var(--line);
  background: var(--white);
}

@media (max-width: 980px) {
  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .feature-grid,
  .scene-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 680px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
    gap: 14px;
  }

  .nav {
    width: 100%;
    justify-content: space-between;
    gap: 10px;
    font-size: 14px;
  }

  .hero {
    padding-top: 46px;
  }

  h1 {
    font-size: 42px;
  }

  .hero-text {
    font-size: 16px;
  }

  .chat-preview {
    grid-template-columns: 54px minmax(0, 1fr);
    min-height: 380px;
  }

  .preview-top,
  .messages,
  .composer {
    padding-left: 16px;
    padding-right: 16px;
  }

  .feature-grid,
  .scene-list {
    grid-template-columns: 1fr;
  }

  .feature-card {
    min-height: auto;
  }

  .scene-item {
    grid-template-columns: 1fr;
  }

  .cta {
    align-items: stretch;
    flex-direction: column;
    margin: 54px 20px;
    padding: 30px 24px;
  }

  .footer {
    flex-direction: column;
  }
}