:root {
  --bg-color: #0b0c10;
  --bg-color-light: #1f2833;
  --text-color: #ffffff;
  --text-color-muted: #c5c6c7;
  --accent-color: #ffffff; /* Using white as accent in a black/white theme */
  --border-color: #333333;
  --transition: all 0.3s ease;
}

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

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

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

ul {
  list-style: none;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
}

h1 {
  font-size: 3.5rem;
  letter-spacing: -1px;
}

h2 {
  font-size: 2.5rem;
  text-align: center;
  margin-bottom: 3rem;
  position: relative;
}

h2::after {
  content: '';
  position: absolute;
  bottom: -15px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 4px;
  background-color: var(--accent-color);
  border-radius: 2px;
}

p {
  color: var(--text-color-muted);
  font-size: 1.1rem;
  margin-bottom: 1.5rem;
}

/* Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

section {
  padding: 100px 0;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 12px 30px;
  border-radius: 30px;
  font-weight: 600;
  font-size: 1.1rem;
  cursor: pointer;
  text-align: center;
  transition: var(--transition);
  border: 2px solid transparent;
}

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

.btn-primary:hover {
  background-color: transparent;
  color: var(--accent-color);
  border-color: var(--accent-color);
  box-shadow: 0 0 20px rgba(255, 255, 255, 0.3);
}

.btn-outline {
  background-color: transparent;
  color: var(--accent-color);
  border-color: var(--accent-color);
}

.btn-outline:hover {
  background-color: var(--accent-color);
  color: var(--bg-color);
  box-shadow: 0 0 20px rgba(255, 255, 255, 0.3);
}

/* Header & Navigation */
header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  padding: 20px 0;
  z-index: 1000;
  transition: var(--transition);
  background-color: rgba(11, 12, 16, 0.9);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--text-color);
  letter-spacing: 1px;
}

nav ul {
  display: flex;
  gap: 30px;
}

nav a {
  color: var(--text-color-muted);
  font-weight: 500;
  font-size: 1rem;
  position: relative;
}

nav a::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--accent-color);
  transition: var(--transition);
}

nav a:hover, nav a.active {
  color: var(--text-color);
}

nav a:hover::after, nav a.active::after {
  width: 100%;
}

.mobile-menu-btn {
  display: none;
  font-size: 1.5rem;
  color: var(--text-color);
  cursor: pointer;
}

/* Hero Section */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding-top: 80px;
  overflow: hidden;
}

#particles-js {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: -1;
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 800px;
}

.hero h1 {
  margin-bottom: 20px;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
}

.hero p {
  font-size: 1.3rem;
  margin-bottom: 40px;
}

.hero-btns {
  display: flex;
  gap: 20px;
  justify-content: center;
}

/* Advantages Section */
.advantages {
  background-color: rgba(31, 40, 51, 0.6);
}

.adv-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 30px;
  margin-top: 50px;
}

.adv-card {
  background-color: var(--bg-color);
  padding: 40px 30px;
  border-radius: 15px;
  text-align: center;
  transition: var(--transition);
  border: 1px solid var(--border-color);
}

.adv-card:hover {
  transform: translateY(-10px);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
  border-color: rgba(255, 255, 255, 0.2);
}

.adv-icon {
  font-size: 3rem;
  color: var(--accent-color);
  margin-bottom: 20px;
}

.adv-card h3 {
  font-size: 1.5rem;
  margin-bottom: 15px;
}

/* Pricing Section */
.pricing {
  background-color: rgba(11, 12, 16, 0.6);
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
  margin-top: 50px;
}

.pricing-card {
  background-color: var(--bg-color-light);
  border-radius: 20px;
  padding: 40px 30px;
  text-align: center;
  transition: var(--transition);
  border: 1px solid var(--border-color);
  position: relative;
  overflow: hidden;
}

.pricing-card:hover {
  transform: translateY(-10px);
  box-shadow: 0 15px 40px rgba(0, 0, 0, 0.6);
  border-color: rgba(255, 255, 255, 0.3);
}

.pricing-card.popular::before {
  content: '推荐';
  position: absolute;
  top: 20px;
  right: -35px;
  background-color: var(--accent-color);
  color: var(--bg-color);
  padding: 5px 40px;
  transform: rotate(45deg);
  font-weight: bold;
  font-size: 0.9rem;
}

.pricing-card h3 {
  font-size: 1.8rem;
  margin-bottom: 10px;
}

.price {
  font-size: 3rem;
  font-weight: 800;
  margin-bottom: 20px;
  color: var(--accent-color);
}

.price span {
  font-size: 1.2rem;
  color: var(--text-color-muted);
  font-weight: normal;
}

.pricing-features {
  margin-bottom: 30px;
  text-align: left;
}

.pricing-features li {
  padding: 10px 0;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-color-muted);
  display: flex;
  align-items: center;
}

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

.pricing-features i {
  color: var(--accent-color);
  margin-right: 10px;
}

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

/* Node Status Section */
.nodes {
  background-color: rgba(31, 40, 51, 0.6);
}

.node-container {
  max-width: 800px;
  margin: 0 auto;
  background-color: var(--bg-color);
  border-radius: 15px;
  padding: 30px;
  border: 1px solid var(--border-color);
}

.node-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 15px 0;
  border-bottom: 1px solid var(--border-color);
}

.node-item:last-child {
  border-bottom: none;
}

.node-info {
  display: flex;
  align-items: center;
  gap: 15px;
}

.flag {
  font-size: 1.5rem;
}

.node-name {
  font-weight: 600;
  font-size: 1.1rem;
}

.node-latency {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: monospace;
  font-size: 1.1rem;
}

.status-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: #4CAF50; /* Green for online */
  box-shadow: 0 0 8px #4CAF50;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% { box-shadow: 0 0 0 0 rgba(76, 175, 80, 0.7); }
  70% { box-shadow: 0 0 0 10px rgba(76, 175, 80, 0); }
  100% { box-shadow: 0 0 0 0 rgba(76, 175, 80, 0); }
}

/* Reviews Section */
.reviews {
  background-color: rgba(11, 12, 16, 0.6);
}

.review-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
}

.review-card {
  background-color: var(--bg-color-light);
  padding: 30px;
  border-radius: 15px;
  border: 1px solid var(--border-color);
}

.review-header {
  display: flex;
  align-items: center;
  gap: 15px;
  margin-bottom: 20px;
}

.review-avatar {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background-color: #333;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  font-size: 1.2rem;
}

.review-user h4 {
  margin-bottom: 5px;
  font-size: 1.1rem;
}

.stars {
  color: #FFD700;
  font-size: 0.9rem;
}

/* FAQ Section */
.faq {
  background-color: rgba(31, 40, 51, 0.6);
}

.faq-container {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  margin-bottom: 15px;
  background-color: var(--bg-color);
  border-radius: 10px;
  border: 1px solid var(--border-color);
  overflow: hidden;
}

.faq-question {
  padding: 20px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
  font-size: 1.1rem;
  transition: var(--transition);
}

.faq-question:hover {
  background-color: rgba(255, 255, 255, 0.05);
}

.faq-answer {
  padding: 0 20px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  color: var(--text-color-muted);
}

.faq-item.active .faq-answer {
  padding: 20px;
  max-height: 1000px;
  border-top: 1px solid var(--border-color);
}

.faq-item.active .faq-question i {
  transform: rotate(180deg);
}

/* Knowledge Base Section */
.knowledge {
  background-color: rgba(11, 12, 16, 0.6);
}

.kb-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 25px;
}

.kb-card {
  background-color: var(--bg-color-light);
  border-radius: 10px;
  padding: 25px;
  border: 1px solid var(--border-color);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.kb-card:hover {
  transform: translateY(-5px);
  border-color: var(--accent-color);
}

.kb-card h3 {
  font-size: 1.2rem;
  margin-bottom: 15px;
}

.kb-card p {
  font-size: 0.95rem;
  flex-grow: 1;
}

.read-more {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-weight: 600;
  margin-top: 15px;
}

.read-more:hover {
  gap: 10px;
}

/* Footer */
footer {
  background-color: var(--bg-color-light);
  padding: 50px 0 20px;
  border-top: 1px solid var(--border-color);
  text-align: center;
}

.footer-content {
  margin-bottom: 30px;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.footer-bottom {
  color: #888;
  font-size: 0.9rem;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
}

/* Responsive */
@media (max-width: 768px) {
  h1 { font-size: 2.5rem; }
  h2 { font-size: 2rem; }
  
  .mobile-menu-btn { display: block; }
  
  nav {
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background-color: var(--bg-color);
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    display: none;
  }
  
  nav.active { display: block; }
  
  nav ul {
    flex-direction: column;
    gap: 15px;
    text-align: center;
  }
  
  .hero-btns {
    flex-direction: column;
  }
}