/* Reset & Base */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --primary: #1e40af;
  --primary-dark: #1e3a8a;
  --accent: #f59e0b;
  --accent-dark: #d97706;
  --text: #1f2937;
  --text-light: #6b7280;
  --bg: #ffffff;
  --bg-light: #f3f4f6;
  --border: #e5e7eb;
  --shadow: 0 1px 3px rgba(0,0,0,0.1);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
  --radius: 8px;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
}

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

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

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

/* Container */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 16px;
}

/* Header */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo img {
  width: 40px;
  height: 40px;
}

.logo-text {
  font-size: 20px;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Navigation */
.nav {
  display: none;
}

.nav.active {
  display: block;
  position: absolute;
  top: 64px;
  left: 0;
  right: 0;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  padding: 16px;
}

.nav-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  list-style: none;
}

.nav-link {
  display: block;
  padding: 8px 0;
  color: var(--text-light);
  font-size: 14px;
}

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

@media (min-width: 768px) {
  .nav {
    display: block;
    position: static;
    border: none;
    padding: 0;
  }
  
  .nav-list {
    flex-direction: row;
    gap: 32px;
  }
  
  .nav-link {
    padding: 0;
  }
}

/* Mobile Menu Toggle */
.menu-toggle {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text);
  transition: 0.3s;
}

@media (min-width: 768px) {
  .menu-toggle {
    display: none;
  }
}

/* Hero Section */
.hero {
  position: relative;
  background: linear-gradient(135deg, #1e3a8a 0%, #0f172a 100%);
  color: #fff;
  padding: 80px 0;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: url('../images/hero-banner.png') center/cover;
  opacity: 0.15;
}

.hero-content {
  position: relative;
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
}

.hero h1 {
  font-size: 32px;
  font-weight: 700;
  margin-bottom: 16px;
  line-height: 1.3;
}

@media (min-width: 768px) {
  .hero {
    padding: 120px 0;
  }
  
  .hero h1 {
    font-size: 48px;
  }
}

.hero p {
  font-size: 18px;
  color: rgba(255,255,255,0.8);
  margin-bottom: 32px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  font-size: 14px;
  font-weight: 600;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  transition: all 0.2s;
}

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

.btn-primary:hover {
  background: var(--accent-dark);
  color: var(--text);
}

.btn-outline {
  background: transparent;
  border: 1px solid #fff;
  color: #fff;
}

.btn-outline:hover {
  background: rgba(255,255,255,0.1);
  color: #fff;
}

/* Sections */
.section {
  padding: 64px 0;
}

.section-title {
  font-size: 24px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 12px;
}

.section-desc {
  text-align: center;
  color: var(--text-light);
  margin-bottom: 48px;
}

@media (min-width: 768px) {
  .section {
    padding: 80px 0;
  }
  
  .section-title {
    font-size: 32px;
  }
}

/* Features Grid */
.features-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

@media (min-width: 768px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.feature-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 24px;
  text-align: center;
  transition: box-shadow 0.2s;
}

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

.feature-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto 16px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
}

.feature-title {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
}

.feature-desc {
  font-size: 14px;
  color: var(--text-light);
}

/* Blog Grid */
.blog-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

@media (min-width: 768px) {
  .blog-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .blog-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.blog-card {
  display: block;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: all 0.2s;
}

.blog-card:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow-lg);
}

.blog-card-content {
  padding: 24px;
}

.blog-card-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 12px;
}

.blog-tag {
  display: inline-block;
  padding: 4px 8px;
  font-size: 12px;
  border-radius: 4px;
  background: #dbeafe;
  color: #1d4ed8;
}

.blog-tag.analysis { background: #fef3c7; color: #b45309; }
.blog-tag.tips { background: #d1fae5; color: #047857; }
.blog-tag.tutorial { background: #ede9fe; color: #6d28d9; }

.blog-card-title {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
  line-height: 1.4;
}

.blog-card:hover .blog-card-title {
  color: var(--primary);
}

.blog-card-excerpt {
  font-size: 14px;
  color: var(--text-light);
  margin-bottom: 12px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.blog-card-date {
  font-size: 12px;
  color: var(--text-light);
}

/* Warning Box */
.warning-box {
  background: #fef3c7;
  border: 1px solid #fcd34d;
  border-radius: var(--radius);
  padding: 24px;
}

.warning-title {
  font-size: 14px;
  font-weight: 600;
  color: #92400e;
  margin-bottom: 8px;
}

.warning-text {
  font-size: 13px;
  color: #a16207;
}

/* Stats Section */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

@media (min-width: 768px) {
  .stats-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.stat-item {
  text-align: center;
}

.stat-number {
  font-size: 32px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 4px;
}

@media (min-width: 768px) {
  .stat-number {
    font-size: 40px;
  }
}

.stat-label {
  font-size: 14px;
  color: var(--text-light);
}

/* Footer */
.footer {
  background: var(--bg-light);
  border-top: 1px solid var(--border);
  padding: 48px 0 24px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  margin-bottom: 32px;
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: 2fr 1fr 1fr;
  }
}

.footer-brand {
  font-size: 20px;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 16px;
}

.footer-desc {
  font-size: 14px;
  color: var(--text-light);
  max-width: 400px;
}

.footer-title {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 16px;
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: 8px;
}

.footer-links a {
  font-size: 14px;
  color: var(--text-light);
}

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

.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 24px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

@media (min-width: 768px) {
  .footer-bottom {
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
  }
}

.footer-copyright {
  font-size: 14px;
  color: var(--text-light);
}

.footer-disclaimer {
  font-size: 12px;
  color: var(--text-light);
}

/* Page Header */
.page-header {
  background: linear-gradient(135deg, #1e3a8a 0%, #0f172a 100%);
  color: #fff;
  padding: 48px 0;
}

.breadcrumb {
  font-size: 14px;
  color: rgba(255,255,255,0.7);
  margin-bottom: 16px;
}

.breadcrumb a {
  color: rgba(255,255,255,0.7);
}

.breadcrumb a:hover {
  color: #fff;
}

.page-title {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 12px;
}

@media (min-width: 768px) {
  .page-header {
    padding: 64px 0;
  }
  
  .page-title {
    font-size: 36px;
  }
}

.page-desc {
  font-size: 16px;
  color: rgba(255,255,255,0.8);
}

/* Article */
.article-header {
  padding: 48px 0;
  background: linear-gradient(135deg, #1e3a8a 0%, #0f172a 100%);
  color: #fff;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.article-title {
  font-size: 24px;
  font-weight: 700;
  margin-bottom: 16px;
}

@media (min-width: 768px) {
  .article-title {
    font-size: 32px;
  }
}

.article-excerpt {
  font-size: 16px;
  color: rgba(255,255,255,0.8);
}

.article-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 48px 16px;
}

.article-content h2 {
  font-size: 20px;
  font-weight: 600;
  margin: 32px 0 16px;
}

.article-content h3 {
  font-size: 18px;
  font-weight: 600;
  margin: 24px 0 12px;
}

.article-content p {
  margin-bottom: 16px;
  color: var(--text-light);
  line-height: 1.8;
}

.article-content ul,
.article-content ol {
  margin-bottom: 16px;
  padding-left: 24px;
}

.article-content li {
  margin-bottom: 8px;
  color: var(--text-light);
  line-height: 1.8;
}

.article-content strong {
  color: var(--text);
}

/* Sidebar */
.sidebar {
  margin-top: 48px;
}

@media (min-width: 1024px) {
  .article-layout {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 48px;
  }
  
  .sidebar {
    margin-top: 0;
  }
}

.sidebar-box {
  background: var(--bg-light);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 24px;
}

.sidebar-title {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 16px;
}

.related-post {
  display: block;
  padding: 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 12px;
  background: var(--bg);
}

.related-post:hover {
  border-color: var(--primary);
}

.related-post-meta {
  font-size: 12px;
  color: var(--text-light);
  margin-bottom: 4px;
}

.related-post-title {
  font-size: 14px;
  font-weight: 500;
}

/* Tips Cards */
.tips-category {
  margin-bottom: 48px;
}

.tips-category-title {
  display: inline-block;
  padding: 8px 16px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
  font-size: 14px;
  font-weight: 600;
  border-radius: 4px;
  margin-bottom: 24px;
}

.tip-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 16px;
}

.tip-title {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
}

.tip-content {
  font-size: 14px;
  color: var(--text-light);
}

/* Analysis Tools */
.tools-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

@media (min-width: 768px) {
  .tools-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.tool-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}

.tool-title {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 12px;
}

.tool-number {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 14px;
  font-weight: 600;
}

.tool-desc {
  font-size: 14px;
  color: var(--text-light);
  margin-bottom: 16px;
}

.tool-features {
  list-style: none;
}

.tool-features li {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--text-light);
  margin-bottom: 8px;
}

.tool-features li::before {
  content: '✓';
  color: #10b981;
}

/* Data Table */
.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.data-table th,
.data-table td {
  padding: 12px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

.data-table th {
  font-weight: 600;
  background: var(--bg-light);
}

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

/* Utility Classes */
.bg-light {
  background: var(--bg-light);
}

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

.mt-8 {
  margin-top: 32px;
}

.mb-4 {
  margin-bottom: 16px;
}