:root {
  --primary: #07C160;
  --primary-dark: #06AD56;
  --primary-light: rgba(7, 193, 96, 0.1);
  --bg: #F7F8FA;
  --card-bg: #FFFFFF;
  --text: #1A1A2E;
  --text-secondary: #6B7280;
  --border: #E5E7EB;
  --shadow: 0 4px 24px rgba(0,0,0,0.06);
  --radius: 16px;
  --radius-sm: 10px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

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

/* ===== Logo ===== */
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, #07C160, #06AD56);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.logo-icon svg {
  width: 22px;
  height: 22px;
}

.logo-icon svg .chat-bubble {
  fill: none;
  stroke: #fff;
  stroke-width: 2.2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.logo-text {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.5px;
}

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

/* ===== Layout ===== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== Header ===== */
.header {
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  background: rgba(255,255,255,0.92);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
}

.nav {
  display: flex;
  gap: 8px;
}

.nav a {
  text-decoration: none;
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 500;
  padding: 8px 16px;
  border-radius: 8px;
  transition: var(--transition);
}

.nav a:hover {
  background: var(--primary-light);
  color: var(--primary);
}

.nav a.active {
  background: var(--primary);
  color: #fff;
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 24px;
  color: var(--text);
  cursor: pointer;
  padding: 4px;
}

/* ===== Hero ===== */
.hero {
  padding: 80px 0 60px;
  text-align: center;
  background: linear-gradient(180deg, var(--card-bg) 0%, var(--bg) 100%);
}

.hero h1 {
  font-size: clamp(36px, 5vw, 56px);
  font-weight: 800;
  letter-spacing: -1.5px;
  line-height: 1.15;
  margin-bottom: 16px;
}

.hero h1 span {
  background: linear-gradient(135deg, #07C160, #06AD56);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 18px;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 32px;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 40px;
  flex-wrap: wrap;
}

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

.hero-stat-number {
  font-size: 28px;
  font-weight: 800;
  color: var(--primary);
  display: block;
}

.hero-stat-label {
  font-size: 13px;
  color: var(--text-secondary);
  font-weight: 500;
}

/* ===== Section ===== */
.section {
  padding: 60px 0;
}

.section-title {
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 8px;
  letter-spacing: -0.5px;
}

.section-subtitle {
  color: var(--text-secondary);
  font-size: 15px;
  margin-bottom: 32px;
}

/* ===== Version Cards ===== */
.version-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}

.version-card {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.version-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0,0,0,0.08);
  border-color: var(--primary);
}

.version-card-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.version-platform-icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: var(--primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  flex-shrink: 0;
}

.version-platform-icon i {
  color: var(--primary);
}

.version-info {
  flex: 1;
}

.version-platform {
  font-weight: 600;
  font-size: 16px;
}

.version-number {
  font-size: 13px;
  color: var(--text-secondary);
}

.version-details {
  display: flex;
  gap: 16px;
  margin-bottom: 16px;
  font-size: 13px;
  color: var(--text-secondary);
}

.version-details span {
  display: flex;
  align-items: center;
  gap: 4px;
}

.version-badge {
  display: inline-block;
  background: var(--primary-light);
  color: var(--primary);
  font-size: 11px;
  font-weight: 600;
  padding: 2px 10px;
  border-radius: 20px;
  margin-bottom: 12px;
  align-self: flex-start;
}

.version-changelog {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 16px;
  flex: 1;
  line-height: 1.5;
}

.version-actions {
  display: flex;
  gap: 8px;
  margin-top: auto;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
  font-family: var(--font);
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  flex: 1;
}

.btn-primary:hover {
  background: var(--primary-dark);
  transform: scale(1.02);
}

.btn-outline {
  background: transparent;
  color: var(--text-secondary);
  border: 1.5px solid var(--border);
}

.btn-outline:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--primary-light);
}

.btn-sm {
  padding: 6px 14px;
  font-size: 12px;
}

/* ===== QR Section ===== */
.qr-section {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 40px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  text-align: center;
}

.qr-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
}

.qr-code {
  width: 180px;
  height: 180px;
  background: #fff;
  border-radius: 12px;
  padding: 12px;
  border: 2px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
}

.qr-code svg {
  width: 100%;
  height: 100%;
}

.qr-hint {
  font-size: 14px;
  color: var(--text-secondary);
}

.qr-platform-select {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: center;
}

.qr-platform-btn {
  padding: 8px 20px;
  border-radius: 20px;
  border: 1.5px solid var(--border);
  background: var(--card-bg);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  color: var(--text-secondary);
}

.qr-platform-btn.active {
  border-color: var(--primary);
  background: var(--primary-light);
  color: var(--primary);
}

.qr-platform-btn:hover {
  border-color: var(--primary);
}

/* ===== Guide ===== */
.guide-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px;
}

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

.guide-card h3 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.guide-card ol {
  list-style: none;
  counter-reset: step;
}

.guide-card ol li {
  counter-increment: step;
  padding: 6px 0;
  padding-left: 32px;
  position: relative;
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.5;
}

.guide-card ol li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 6px;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--primary-light);
  color: var(--primary);
  font-size: 12px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ===== FAQ ===== */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

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

.faq-item:hover {
  border-color: var(--primary);
}

.faq-question {
  padding: 18px 24px;
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  user-select: none;
  background: none;
  border: none;
  width: 100%;
  text-align: left;
  font-family: var(--font);
  color: var(--text);
}

.faq-question::after {
  content: '+';
  font-size: 20px;
  font-weight: 300;
  color: var(--text-secondary);
  transition: var(--transition);
  flex-shrink: 0;
}

.faq-item.active .faq-question::after {
  transform: rotate(45deg);
  color: var(--primary);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.4s ease;
  padding: 0 24px;
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

.faq-item.active .faq-answer {
  max-height: 300px;
  padding: 0 24px 18px;
}

/* ===== Changelog ===== */
.changelog-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.changelog-item {
  background: var(--card-bg);
  border-radius: var(--radius-sm);
  padding: 20px 24px;
  border: 1px solid var(--border);
  transition: var(--transition);
}

.changelog-item:hover {
  border-color: var(--primary);
}

.changelog-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
  flex-wrap: wrap;
}

.changelog-version {
  font-weight: 700;
  font-size: 16px;
}

.changelog-platform {
  font-size: 12px;
  color: var(--text-secondary);
  background: var(--bg);
  padding: 2px 10px;
  border-radius: 12px;
}

.changelog-date {
  font-size: 13px;
  color: var(--text-secondary);
  margin-left: auto;
}

.changelog-body {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ===== Footer ===== */
.footer {
  background: var(--card-bg);
  border-top: 1px solid var(--border);
  padding: 40px 0 24px;
  margin-top: 40px;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-links {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 13px;
  transition: var(--transition);
}

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

.footer-copy {
  font-size: 13px;
  color: var(--text-secondary);
}

/* ===== Admin ===== */
.admin-wrap {
  max-width: 800px;
  margin: 40px auto;
  padding: 0 24px;
}

.admin-card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  padding: 32px;
}

.admin-card h2 {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 24px;
}

.admin-form label {
  display: block;
  font-weight: 500;
  font-size: 14px;
  margin-bottom: 6px;
  color: var(--text);
}

.admin-form input,
.admin-form select,
.admin-form textarea {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid var(--border);
  border-radius: 10px;
  font-size: 14px;
  font-family: var(--font);
  transition: var(--transition);
  background: var(--bg);
  color: var(--text);
  margin-bottom: 16px;
}

.admin-form input:focus,
.admin-form select:focus,
.admin-form textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-light);
}

.admin-form textarea {
  min-height: 80px;
  resize: vertical;
}

.admin-login-error {
  background: #FEE2E2;
  color: #DC2626;
  padding: 10px 16px;
  border-radius: 10px;
  font-size: 14px;
  margin-bottom: 16px;
}

.admin-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 16px;
}

.admin-table th {
  text-align: left;
  padding: 12px 8px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-secondary);
  border-bottom: 2px solid var(--border);
}

.admin-table td {
  padding: 12px 8px;
  font-size: 14px;
  border-bottom: 1px solid var(--border);
}

.admin-table .actions {
  display: flex;
  gap: 6px;
}

.admin-table .actions button {
  padding: 4px 12px;
  border-radius: 6px;
  border: none;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}

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

.btn-delete {
  background: #FEE2E2;
  color: #DC2626;
}

.btn-edit:hover { background: var(--primary); color: #fff; }
.btn-delete:hover { background: #DC2626; color: #fff; }

.admin-actions {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .header-inner {
    flex-wrap: wrap;
  }
  
  .nav {
    display: none;
    flex-direction: column;
    width: 100%;
    padding: 12px 0 0;
    gap: 4px;
  }
  
  .nav.open {
    display: flex;
  }
  
  .mobile-menu-btn {
    display: block;
  }
  
  .hero {
    padding: 48px 0 36px;
  }
  
  .hero-stats {
    gap: 24px;
  }
  
  .version-grid {
    grid-template-columns: 1fr;
  }
  
  .guide-grid {
    grid-template-columns: 1fr;
  }
  
  .qr-section {
    padding: 24px;
  }
  
  .footer-inner {
    flex-direction: column;
    text-align: center;
  }
  
  .admin-table {
    display: block;
    overflow-x: auto;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }
  
  .section {
    padding: 36px 0;
  }
  
  .section-title {
    font-size: 22px;
  }
  
  .version-actions {
    flex-direction: column;
  }
  
  .changelog-header {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .changelog-date {
    margin-left: 0;
  }
}

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

.animate-in {
  animation: fadeInUp 0.6s ease forwards;
}

.animate-in-delay-1 { animation-delay: 0.1s; }
.animate-in-delay-2 { animation-delay: 0.2s; }
.animate-in-delay-3 { animation-delay: 0.3s; }
.animate-in-delay-4 { animation-delay: 0.4s; }

/* ===== Verification ===== */
.verify-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  background: #ECFDF5;
  color: #059669;
  font-size: 12px;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 20px;
}

.verify-badge svg {
  width: 14px;
  height: 14px;
}

/* ===== Toast ===== */
.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--text);
  color: #fff;
  padding: 12px 24px;
  border-radius: 12px;
  font-size: 14px;
  font-weight: 500;
  opacity: 0;
  transition: all 0.4s ease;
  z-index: 999;
  pointer-events: none;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ===== Inline SVG icons used in cards ===== */
.platform-icon {
  width: 24px;
  height: 24px;
  fill: none;
  stroke: var(--primary);
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}