:root {
  /* 蓝白色调配色方案 */
  --primary-color: #2563eb; /* 鲜亮的皇家蓝 */
  --primary-hover: #1d4ed8; /* 深蓝色用于悬停 */
  --secondary-color: #0ea5e9; /* 天蓝色 */
  --bg-color: #ffffff; /* 纯白背景 */
  --bg-secondary: #f0f9ff; /* 极浅的蓝色背景 */
  --text-primary: #0f172a; /* 深蓝灰色文字，接近黑色 */
  --text-secondary: #64748b; /* 灰色文字 */
  --glass-bg: rgba(255, 255, 255, 0.9);
  --glass-border: rgba(37, 99, 235, 0.1);
  --nav-height: 70px;
  --card-shadow: 0 10px 30px rgba(0, 0, 0, 0.05); /* 柔和的阴影 */
}

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

body {
  font-family: 'Inter', sans-serif;
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
}

a {
  text-decoration: none;
  color: inherit;
  transition: 0.3s;
}

ul {
  list-style: none;
}

/* Buttons */
.btn-primary {
  background-color: var(--primary-color);
  color: white;
  padding: 0.6rem 1.5rem;
  border-radius: 8px; /* 稍微方一点的圆角更显专业 */
  font-weight: 600;
  display: inline-block;
  border: none;
  cursor: pointer;
  transition: all 0.2s;
  box-shadow: 0 4px 6px rgba(37, 99, 235, 0.2);
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(37, 99, 235, 0.3);
}

.btn-secondary {
  background: white;
  border: 1px solid var(--primary-color);
  color: var(--primary-color);
  padding: 0.6rem 1.5rem;
  border-radius: 8px;
  font-weight: 600;
  display: inline-block;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-secondary:hover {
  background: var(--bg-secondary);
}

.btn-primary.large, .btn-secondary.large {
  padding: 0.8rem 2rem;
  font-size: 1.1rem;
}

/* Navbar */
.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  height: var(--nav-height);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 5%;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  z-index: 1000;
  border-bottom: 1px solid rgba(0,0,0,0.05);
  box-shadow: 0 2px 10px rgba(0,0,0,0.02);
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  color: var(--text-primary);
}

.logo .highlight {
  color: var(--primary-color);
}

.nav-links {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.nav-links a {
  font-weight: 500;
  color: var(--text-secondary);
}

.nav-links a:not(.btn-primary):hover {
  color: var(--primary-color);
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
}

.hamburger span {
  width: 25px;
  height: 3px;
  background-color: var(--text-primary);
}

/* Hero Section */
.hero-section {
  position: relative;
  height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: 0 20px;
  overflow: hidden;
  background: radial-gradient(circle at 50% 50%, #ffffff 0%, #f0f9ff 100%);
}

#hero-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  opacity: 0.6;
}

.hero-content {
  z-index: 1;
  max-width: 800px;
  opacity: 0;
  animation: fadeUp 1s ease forwards 0.5s;
}

.hero-title {
  font-size: 3.5rem;
  line-height: 1.1;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
  font-weight: 800;
}

.gradient-text {
  /* 改为纯蓝色强调 */
  color: var(--primary-color);
  background: none;
  -webkit-text-fill-color: initial;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: 2.5rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.hero-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
}

/* Scroll Indicator */
.scroll-indicator {
  position: absolute;
  bottom: 30px;
  left: 50%;
  transform: translateX(-50%);
  opacity: 0;
  animation: fadeIn 1s ease forwards 1.5s;
}

.mouse {
  width: 30px;
  height: 50px;
  border: 2px solid var(--primary-color);
  border-radius: 20px;
  position: relative;
}

.wheel {
  width: 4px;
  height: 8px;
  background: var(--primary-color);
  border-radius: 2px;
  position: absolute;
  top: 10px;
  left: 50%;
  transform: translateX(-50%);
  animation: scroll 1.5s infinite;
}

@keyframes scroll {
  0% { top: 10px; opacity: 1; }
  100% { top: 30px; opacity: 0; }
}

/* Features Section */
.features-section {
  padding: 100px 5%;
  background: var(--bg-color);
}

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

.section-title {
  text-align: center;
  font-size: 2.5rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
  font-weight: 700;
}

.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  margin-bottom: 4rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 2rem;
}

.feature-card {
  background: white;
  padding: 2.5rem;
  border-radius: 12px;
  border: 1px solid #e2e8f0;
  transition: 0.3s;
  position: relative;
  overflow: hidden;
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--card-shadow);
  border-color: var(--primary-color);
}

.feature-card .icon-box {
  font-size: 2rem;
  margin-bottom: 1.5rem;
  background: var(--bg-secondary);
  color: var(--primary-color);
  width: 64px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
}

.feature-card h3 {
  margin-bottom: 0.8rem;
  font-size: 1.25rem;
  color: var(--text-primary);
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* Demo Section */
.demo-section {
  padding: 100px 5%;
  background: var(--bg-secondary);
}

.split-layout {
  display: flex;
  align-items: center;
  gap: 5rem;
}

.demo-text {
  flex: 1;
}

.demo-text h2 {
  font-size: 2.5rem;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
  line-height: 1.2;
}

.demo-points {
  margin-top: 2rem;
}

.demo-points li {
  margin-bottom: 1.2rem;
  font-size: 1.1rem;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 10px;
}

.demo-interface {
  flex: 1;
}

.chat-window {
  background: white;
  border-radius: 16px;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.1);
  border: 1px solid #e2e8f0;
  overflow: hidden;
  height: 550px;
  display: flex;
  flex-direction: column;
}

.chat-header {
  padding: 1rem 1.5rem;
  background: white;
  border-bottom: 1px solid #f1f5f9;
  display: flex;
  align-items: center;
  gap: 12px;
}

.bot-avatar {
  width: 40px;
  height: 40px;
  background: var(--primary-color);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  font-size: 0.9rem;
}

.status {
  font-size: 0.9rem;
  color: #10b981;
  font-weight: 500;
}

.chat-messages {
  flex: 1;
  padding: 1.5rem;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  background-color: #fafafa;
}

.message {
  max-width: 85%;
  padding: 1rem 1.2rem;
  border-radius: 12px;
  font-size: 0.95rem;
  line-height: 1.5;
  box-shadow: 0 1px 2px rgba(0,0,0,0.05);
}

.message.bot {
  background: white;
  color: var(--text-primary);
  align-self: flex-start;
  border-bottom-left-radius: 2px;
  border: 1px solid #e5e7eb;
}

.message.user {
  background: var(--primary-color);
  color: white;
  align-self: flex-end;
  border-bottom-right-radius: 2px;
}

.chat-input-area {
  padding: 1rem 1.5rem;
  background: white;
  border-top: 1px solid #f1f5f9;
}

.suggestion-chips {
  display: flex;
  gap: 0.8rem;
  margin-bottom: 1rem;
  overflow-x: auto;
  padding-bottom: 5px;
}

.chip {
  background: #f1f5f9;
  border: 1px solid transparent;
  color: var(--primary-color);
  padding: 0.5rem 1rem;
  border-radius: 20px;
  font-size: 0.85rem;
  white-space: nowrap;
  cursor: pointer;
  transition: 0.2s;
  font-weight: 500;
}

.chip:hover {
  background: #e0f2fe;
  border-color: #bae6fd;
}

.input-box {
  display: flex;
  gap: 12px;
}

.input-box input {
  flex: 1;
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  padding: 0.8rem 1rem;
  border-radius: 8px;
  color: var(--text-primary);
  outline: none;
  transition: border 0.2s;
}

.input-box input:focus {
  border-color: var(--primary-color);
  background: white;
}

.send-btn {
  background: var(--primary-color);
  border: none;
  width: 44px;
  border-radius: 8px;
  color: white;
  cursor: pointer;
  font-size: 1.2rem;
  transition: background 0.2s;
}

.send-btn:hover {
  background: var(--primary-hover);
}

/* CTA Section */
.cta-section {
  padding: 100px 5%;
  text-align: center;
  background: var(--primary-color);
  color: white;
}

.cta-content h2 {
  font-size: 2.5rem;
  margin-bottom: 1.5rem;
  font-weight: 700;
}

.cta-content p {
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: 2.5rem;
  font-size: 1.1rem;
}

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

.cta-section .btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 20px rgba(0,0,0,0.2);
  background: #f8fafc;
}

/* Footer */
footer {
  background: #0f172a; /* 保持深色作为页脚，增加稳重感 */
  padding: 80px 5% 30px;
  color: #f8fafc;
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 4rem;
  margin-bottom: 4rem;
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
}

.footer-col h4 {
  margin-bottom: 1.5rem;
  color: white;
  font-size: 1.1rem;
}

.footer-col a {
  display: block;
  color: #94a3b8;
  margin-bottom: 0.8rem;
  font-size: 0.95rem;
}

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

.logo-col p {
  color: #94a3b8;
  margin-top: 1rem;
  font-size: 0.9rem;
}

.copyright {
  text-align: center;
  color: #64748b;
  font-size: 0.85rem;
  padding-top: 30px;
  border-top: 1px solid #1e293b;
}

/* Animations */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* Responsive */
@media (max-width: 768px) {
  .hero-title { font-size: 2.5rem; }
  .split-layout { flex-direction: column; text-align: center; gap: 3rem; }
  .nav-links { display: none; } /* 简化处理 */
  .hamburger { display: flex; }
  .demo-points { text-align: left; display: inline-block; }
  .chat-window { height: 450px; }
}