:root {
  /* Color Palette */
  --primary-color: #FF4757;
  --dark-grey: #2F3542;
  --light-grey: #F1F2F6;
  --text-color: #2F3542;
  --text-light: #747d8c;
  --white: #ffffff;
  --footer-text: #A4B0BE;
  
  /* Typography */
  --font-heading: 'Source Han Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-body: 'PingFang SC', 'Microsoft YaHei', sans-serif;
  
  /* Layout */
  --max-width: 1200px;
  --grid-gap: 24px;
  --border-radius: 8px;
  
  /* Spacing */
  --section-padding: 80px 0;
}

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

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

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: bold;
  color: var(--dark-grey);
}

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

ul {
  list-style: none;
}

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

/* Layout Utilities */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--grid-gap);
}

.section-title {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  text-align: center;
}

.section-subtitle {
  text-align: center;
  color: var(--text-light);
  max-width: 600px;
  margin: 0 auto 3rem;
  font-size: 1.1rem;
}

/* Header */
header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  z-index: 1000;
  box-shadow: 0 2px 10px rgba(0,0,0,0.05);
  height: 70px;
  display: flex;
  align-items: center;
}

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

.logo img {
  height: 40px;
}

.nav-menu {
  display: flex;
  gap: 30px;
}

.nav-link {
  font-size: 1rem;
  font-weight: 500;
  position: relative;
}

.nav-link:hover, .nav-link.active {
  color: var(--primary-color);
}

/* Hero Section */
.hero {
  padding: 160px 0 100px;
  background: linear-gradient(135deg, var(--light-grey) 0%, #ffffff 100%);
  text-align: center;
}

.hero-content h1 {
  font-size: 3.5rem;
  margin-bottom: 1.5rem;
  color: var(--dark-grey);
}

.hero-content p {
  font-size: 1.25rem;
  color: var(--text-light);
  max-width: 800px;
  margin: 0 auto 2.5rem;
}

.btn {
  display: inline-block;
  padding: 12px 32px;
  background-color: var(--primary-color);
  color: var(--white);
  border-radius: var(--border-radius);
  font-weight: bold;
  font-size: 1.1rem;
  transition: transform 0.2s, background-color 0.2s;
}

.btn:hover {
  background-color: #ff2e40;
  transform: translateY(-2px);
}

/* Tool Categories */
.category-section {
  padding: var(--section-padding);
}

.category-section:nth-child(even) {
  background-color: var(--light-grey);
}

.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 30px;
}

.tool-card {
  background: var(--white);
  padding: 30px;
  border-radius: var(--border-radius);
  border: 1px solid #eee;
  transition: transform 0.3s, box-shadow 0.3s;
}

.tool-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 20px rgba(0,0,0,0.05);
  border-color: var(--primary-color);
}

.tool-icon {
  width: 48px;
  height: 48px;
  background: var(--light-grey);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  color: var(--primary-color);
}

.tool-name {
  font-size: 1.25rem;
  margin-bottom: 10px;
}

.tool-desc {
  color: var(--text-light);
  font-size: 0.95rem;
  margin-bottom: 15px;
  line-height: 1.5;
}

.tool-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  font-size: 0.8rem;
  padding: 4px 10px;
  background: #f8f9fa;
  border-radius: 4px;
  color: #666;
}

/* About Section */
.about-section {
  padding: var(--section-padding);
  background-color: var(--dark-grey);
  color: var(--white);
  text-align: center;
}

.about-content {
  max-width: 800px;
  margin: 0 auto;
}

.about-section h2 {
  color: var(--white);
  margin-bottom: 2rem;
}

.about-text {
  font-size: 1.1rem;
  opacity: 0.9;
  line-height: 1.8;
  margin-bottom: 2rem;
}

/* Footer */
footer {
  background-color: #1e222b;
  color: var(--footer-text);
  padding: 60px 0 30px;
  font-size: 0.9rem;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-col h4 {
  color: var(--white);
  margin-bottom: 20px;
  font-size: 1.1rem;
}

.footer-links li {
  margin-bottom: 10px;
}

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

.footer-bottom {
  border-top: 1px solid #333;
  padding-top: 30px;
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-items: center;
}

.beian-info {
  display: flex;
  align-items: center;
  gap: 10px;
  justify-content: center;
}

.police-icon {
  width: 16px;
  height: 16px;
  display: inline-block;
  background-image: url('data:image/png;base64,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'); /* Placeholder Icon */
  background-size: contain;
}

/* Responsive */
@media (max-width: 768px) {
  .hero-content h1 {
    font-size: 2.5rem;
  }
  
  .grid-12 {
    display: block;
  }
  
  header .container {
    padding: 0 15px;
  }
  
  .nav-menu {
    display: none; /* Simple mobile hide for now, or could implement hamburger */
  }
  
  .footer-content {
    flex-direction: column;
    gap: 30px;
  }
}