/* ===== Site 2: Dark Tech Theme ===== */
/* Design: Dark background with cyan/teal neon accents, tech aesthetic */

:root {
  --bg: #0B0F19;
  --bg-alt: #111827;
  --bg-card: #1F2937;
  --border: #374151;
  --text: #F9FAFB;
  --text-secondary: #9CA3AF;
  --primary: #00D4AA;
  --primary-dark: #059669;
  --primary-glow: rgba(0,212,170,0.15);
  --accent: #60A5FA;
  --shadow: 0 0 20px rgba(0,212,170,0.1);
  --radius: 10px;
  --radius-sm: 6px;
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--text);
  line-height: 1.6;
  background: var(--bg);
}

.container {
  max-width: 1160px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== Header ===== */
.header {
  background: linear-gradient(180deg, rgba(11,15,25,0.95) 0%, rgba(11,15,25,0.8) 100%);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  letter-spacing: 0.5px;
}

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

.nav-links a {
  display: block;
  padding: 8px 18px;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  border-radius: var(--radius-sm);
  transition: all 0.25s;
  border: 1px solid transparent;
}

.nav-links a:hover {
  color: var(--primary);
  border-color: var(--border);
  background: var(--bg-card);
}

.nav-links a.active {
  color: var(--primary);
  background: var(--primary-glow);
  border-color: var(--primary);
}

/* ===== Hero ===== */
.hero {
  padding: 90px 0 100px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, var(--primary-glow) 0%, transparent 70%);
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 60px;
  align-items: center;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--primary);
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 500;
  margin-bottom: 24px;
  letter-spacing: 0.3px;
}

.hero h1 {
  font-size: 48px;
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 20px;
  letter-spacing: -1px;
}

.hero h1 span {
  color: var(--primary);
}

.hero-subtitle {
  font-size: 18px;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 36px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.hero-visual {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  height: 340px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.hero-visual::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: var(--radius);
  background: linear-gradient(135deg, var(--primary-glow) 0%, transparent 50%);
  pointer-events: none;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 30px;
  font-size: 15px;
  font-weight: 600;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.2s;
  font-family: inherit;
}

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

.btn-primary:hover {
  background: #00F0C0;
  box-shadow: 0 0 24px rgba(0,212,170,0.35);
  transform: translateY(-1px);
}

.btn-secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--bg-card);
}

.btn-lg {
  padding: 16px 36px;
  font-size: 16px;
}

/* ===== Sections ===== */
.section {
  padding: 80px 0;
}

.section-title {
  font-size: 34px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 16px;
}

.section-desc {
  text-align: center;
  color: var(--text-secondary);
  font-size: 17px;
  max-width: 560px;
  margin: 0 auto 56px;
}

.bg-alt { background: var(--bg-alt); }

/* ===== Feature Grid (tech style) ===== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 20px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  transition: all 0.25s;
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--primary) 0%, transparent 80%);
  opacity: 0;
  transition: opacity 0.25s;
}

.feature-card:hover {
  border-color: var(--primary);
  transform: translateY(-3px);
  box-shadow: var(--shadow);
}

.feature-card:hover::before {
  opacity: 1;
}

.feature-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--primary-glow);
  border-radius: var(--radius-sm);
  margin-bottom: 20px;
  color: var(--primary);
  border: 1px solid rgba(0,212,170,0.2);
}

.feature-card h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 10px;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.7;
}

/* ===== Platform Cards ===== */
.platforms-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.platform-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 24px;
  text-align: center;
  transition: all 0.25s;
}

.platform-card:hover {
  border-color: var(--accent);
  box-shadow: 0 0 20px rgba(96,165,250,0.1);
}

.platform-icon {
  width: 60px;
  height: 60px;
  margin: 0 auto 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-alt);
  border-radius: 14px;
  border: 1px solid var(--border);
}

.platform-card h4 {
  font-size: 17px;
  margin-bottom: 8px;
}

.platform-card p {
  color: var(--text-secondary);
  font-size: 13px;
  margin-bottom: 16px;
  line-height: 1.6;
}

.platform-card .btn {
  width: 100%;
  padding: 11px;
  font-size: 14px;
}

/* ===== Detail Blocks ===== */
.detail-block {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
  margin-bottom: 72px;
  padding: 40px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.detail-block:last-child {
  margin-bottom: 0;
}

.detail-block:nth-child(even) {
  direction: rtl;
}

.detail-block:nth-child(even) > * {
  direction: ltr;
}

.detail-block h3 {
  font-size: 26px;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--primary);
}

.detail-block p {
  color: var(--text-secondary);
  font-size: 15px;
  line-height: 1.8;
  margin-bottom: 12px;
}

.detail-visual {
  background: var(--bg-alt);
  border-radius: var(--radius);
  height: 260px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
}

/* ===== Reviews ===== */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 20px;
}

.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
}

.review-stars {
  color: #FBBF24;
  margin-bottom: 12px;
}

.review-card p {
  color: var(--text);
  font-size: 14px;
  line-height: 1.7;
  margin-bottom: 16px;
}

.review-author {
  display: flex;
  align-items: center;
  gap: 10px;
}

.review-avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--primary-glow);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  color: var(--primary);
  font-size: 13px;
  border: 1px solid rgba(0,212,170,0.3);
}

.review-author span {
  font-weight: 500;
  font-size: 13px;
  color: var(--text-secondary);
}

/* ===== Stats ===== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.stat-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 20px;
  text-align: center;
}

.stat-item h4 {
  font-size: 36px;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 8px;
}

.stat-item p {
  color: var(--text-secondary);
  font-size: 14px;
}

/* ===== Comparison Table ===== */
.comparison-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}

.comparison-table th {
  background: var(--bg-card);
  padding: 14px 18px;
  text-align: left;
  font-weight: 600;
  border-bottom: 2px solid var(--border);
  color: var(--primary);
}

.comparison-table td {
  padding: 14px 18px;
  border-bottom: 1px solid var(--border);
  color: var(--text-secondary);
}

.comparison-table tr:hover td {
  background: rgba(255,255,255,0.02);
}

.check-yes { color: var(--primary); font-weight: 600; }
.check-no { color: #EF4444; }

/* ===== FAQ ===== */
.faq-list { max-width: 780px; margin: 0 auto; }

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

.faq-question {
  width: 100%;
  padding: 18px 22px;
  background: transparent;
  border: none;
  font-size: 15px;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: inherit;
  color: var(--text);
}

.faq-question:hover { background: rgba(255,255,255,0.02); }

.faq-icon {
  color: var(--text-secondary);
  transition: transform 0.25s;
  flex-shrink: 0;
}

.faq-item.active .faq-icon {
  transform: rotate(180deg);
  color: var(--primary);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}

.faq-item.active .faq-answer {
  max-height: 500px;
}

.faq-answer-inner {
  padding: 0 22px 18px;
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.7;
}

/* ===== Download Page ===== */
.download-hero {
  padding: 70px 0;
  text-align: center;
  position: relative;
}

.download-hero::before {
  content: '';
  position: absolute;
  top: -30%;
  left: 50%;
  transform: translateX(-50%);
  width: 500px;
  height: 400px;
  background: radial-gradient(ellipse, var(--primary-glow) 0%, transparent 70%);
  pointer-events: none;
}

.download-hero h1 {
  font-size: 40px;
  font-weight: 800;
  margin-bottom: 12px;
}

.download-hero p {
  color: var(--text-secondary);
  font-size: 17px;
  margin-bottom: 36px;
}

.download-main {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 48px;
  max-width: 560px;
  margin: 0 auto;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.download-main::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--primary), transparent);
}

.version-meta {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin: 18px 0;
  font-size: 13px;
  color: var(--text-secondary);
}

.install-guide { margin-top: 48px; }

.guide-steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  margin-top: 32px;
}

.guide-step {
  text-align: center;
  padding: 24px 16px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.step-num {
  width: 36px;
  height: 36px;
  background: var(--primary);
  color: var(--bg);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 14px;
  margin: 0 auto 14px;
}

.guide-step h4 {
  font-size: 15px;
  margin-bottom: 8px;
  color: var(--text);
}

.guide-step p {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.6;
}

.sys-req-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
  margin-top: 32px;
}

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

.sys-req-card h4 {
  font-size: 16px;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--primary);
}

.sys-req-card ul {
  list-style: none;
  font-size: 13px;
  color: var(--text-secondary);
}

.sys-req-card ul li {
  padding: 5px 0;
  border-bottom: 1px solid rgba(55,65,81,0.5);
}

.sys-req-card ul li:last-child { border: none; }

.changelog-list { max-width: 780px; margin: 32px auto 0; }

.changelog-item {
  border-left: 2px solid var(--primary);
  padding-left: 24px;
  padding-bottom: 28px;
  position: relative;
}

.changelog-item::before {
  content: '';
  position: absolute;
  left: -6px;
  top: 2px;
  width: 10px;
  height: 10px;
  background: var(--primary);
  border-radius: 50%;
  box-shadow: 0 0 8px var(--primary);
}

.changelog-item:last-child { border-left-color: transparent; }

.changelog-item h4 { font-size: 17px; margin-bottom: 4px; color: var(--text); }

.changelog-date { font-size: 12px; color: var(--text-secondary); margin-bottom: 8px; }

.changelog-item ul { font-size: 13px; color: var(--text-secondary); padding-left: 18px; }

.changelog-item ul li { margin-bottom: 4px; line-height: 1.6; }

/* ===== zh-cn Article ===== */
.article-content { max-width: 860px; margin: 0 auto; }

.article-content h2 {
  font-size: 26px;
  font-weight: 700;
  margin: 48px 0 18px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
  color: var(--primary);
}

.article-content h3 {
  font-size: 20px;
  font-weight: 600;
  margin: 28px 0 12px;
  color: var(--text);
}

.article-content p {
  font-size: 15px;
  line-height: 1.9;
  color: var(--text-secondary);
  margin-bottom: 14px;
}

.article-content ul, .article-content ol {
  padding-left: 22px;
  margin-bottom: 18px;
}

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

.tips-box {
  background: rgba(0,212,170,0.08);
  border-left: 3px solid var(--primary);
  padding: 18px 22px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 24px 0;
  font-size: 14px;
  color: var(--text-secondary);
}

.tips-box strong { color: var(--primary); }

/* ===== Footer ===== */
.footer {
  background: #000;
  border-top: 1px solid var(--border);
  color: #6B7280;
  padding: 40px 0;
  text-align: center;
  font-size: 13px;
}

.footer p { margin-bottom: 8px; }

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .hero-grid { grid-template-columns: 1fr; }
  .hero h1 { font-size: 32px; }
  .hero-visual { height: 240px; }
  .section-title { font-size: 26px; }
  .nav-links { display: none; }
  .features-grid { grid-template-columns: 1fr; }
  .detail-block { grid-template-columns: 1fr; gap: 32px; padding: 24px; }
  .detail-block:nth-child(even) { direction: ltr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .comparison-table { font-size: 12px; }
  .comparison-table th, .comparison-table td { padding: 10px 12px; }
  .platforms-grid { grid-template-columns: 1fr; }
  .download-main { padding: 32px 20px; }
  .guide-steps { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
  .hero { padding: 60px 0 70px; }
  .hero h1 { font-size: 26px; }
  .section { padding: 60px 0; }
  .stats-grid { grid-template-columns: 1fr 1fr; }
  .stat-item h4 { font-size: 28px; }
}