:root {
  --bg-primary: #0b132b;
  --bg-secondary: #1c2541;
  --bg-card: #141c36;
  --bg-sidebar: #0e1733;
  --border-color: #2a3861;
  --text-primary: #f0f4f8;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-blue: #00b4d8;
  --accent-cyan: #90e0ef;
  --accent-green: #10b981;
  --accent-amber: #f59e0b;
  --accent-red: #ef4444;
  --code-bg: #070d1e;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.3);
  --shadow-lg: 0 10px 25px rgba(0,0,0,0.5);
  --radius: 12px;
  --sidebar-width: 280px;
}

[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-card: #ffffff;
  --bg-sidebar: #f1f5f9;
  --border-color: #e2e8f0;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --accent-blue: #0284c7;
  --accent-cyan: #0369a1;
  --accent-green: #059669;
  --accent-amber: #d97706;
  --accent-red: #dc2626;
  --code-bg: #1e293b;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.05);
  --shadow-lg: 0 10px 25px rgba(0,0,0,0.1);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  display: flex;
  min-height: 100vh;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Sidebar Navigation */
.sidebar {
  width: var(--sidebar-width);
  background-color: var(--bg-sidebar);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  z-index: 100;
  overflow-y: auto;
}

.sidebar-header {
  padding: 24px 20px;
  display: flex;
  align-items: center;
  gap: 12px;
  border-bottom: 1px solid var(--border-color);
}

.brand-icon {
  width: 38px;
  height: 38px;
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-cyan));
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  color: #0b132b;
  font-size: 20px;
}

.brand-title {
  font-size: 20px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.5px;
}

.sidebar-search {
  padding: 16px 20px 8px;
}

.search-input {
  width: 100%;
  padding: 10px 14px;
  border-radius: 8px;
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-size: 14px;
  outline: none;
  transition: border-color 0.2s ease;
}

.search-input:focus {
  border-color: var(--accent-blue);
}

.nav-list {
  list-style: none;
  padding: 12px 12px;
}

.nav-section-title {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--text-muted);
  font-weight: 700;
  padding: 16px 12px 8px;
}

.nav-item a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s ease;
}

.nav-item a:hover {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
}

.nav-item.active a {
  background: linear-gradient(90deg, rgba(0, 180, 216, 0.15), transparent);
  color: var(--accent-blue);
  border-left: 3px solid var(--accent-blue);
  font-weight: 600;
}

/* Main Content Layout */
.main-wrapper {
  margin-left: var(--sidebar-width);
  flex: 1;
  display: flex;
  flex-direction: column;
}

.top-bar {
  height: 64px;
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 32px;
  position: sticky;
  top: 0;
  z-index: 90;
}

.breadcrumbs {
  font-size: 14px;
  color: var(--text-muted);
  display: flex;
  gap: 8px;
  align-items: center;
}

.breadcrumbs a {
  color: var(--text-secondary);
  text-decoration: none;
}

.breadcrumbs span.current {
  color: var(--text-primary);
  font-weight: 600;
}

.header-controls {
  display: flex;
  align-items: center;
  gap: 16px;
}

.theme-toggle-btn {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 8px 14px;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
  font-size: 13px;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: background-color 0.2s ease;
}

.theme-toggle-btn:hover {
  border-color: var(--accent-blue);
}

.content-container {
  max-width: 1080px;
  padding: 40px 48px;
  margin: 0 auto;
  width: 100%;
}

.page-header {
  margin-bottom: 36px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 24px;
}

.page-title {
  font-size: 32px;
  font-weight: 800;
  letter-spacing: -0.5px;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.page-subtitle {
  font-size: 18px;
  color: var(--text-secondary);
}

.doc-section {
  margin-bottom: 48px;
}

.doc-section h2 {
  font-size: 24px;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 10px;
  border-bottom: 1px dashed var(--border-color);
  padding-bottom: 8px;
}

.doc-section h3 {
  font-size: 18px;
  font-weight: 600;
  margin: 24px 0 12px;
  color: var(--accent-blue);
}

.doc-section p {
  margin-bottom: 16px;
  color: var(--text-secondary);
  font-size: 15px;
}

.doc-section ul, .doc-section ol {
  margin-bottom: 20px;
  padding-left: 24px;
  color: var(--text-secondary);
}

.doc-section li {
  margin-bottom: 8px;
}

/* Feature Cards & Grid */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  margin: 24px 0;
}

.feature-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.feature-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent-blue);
}

.feature-card-icon {
  font-size: 28px;
  margin-bottom: 12px;
  color: var(--accent-blue);
}

.feature-card h4 {
  font-size: 17px;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.feature-card p {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 0;
}

/* Visual Media Frame */
.image-frame {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 12px;
  margin: 24px 0;
  box-shadow: var(--shadow-lg);
  text-align: center;
}

.image-frame img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  display: block;
  margin: 0 auto;
}

.image-caption {
  font-size: 13px;
  color: var(--text-muted);
  margin-top: 10px;
  font-style: italic;
}

/* Alert Callout Boxes */
.alert-box {
  padding: 16px 20px;
  border-radius: 10px;
  margin: 20px 0;
  border-left: 4px solid;
  background-color: var(--bg-card);
  font-size: 14px;
}

.alert-box.info {
  border-color: var(--accent-blue);
  background-color: rgba(0, 180, 216, 0.08);
}

.alert-box.warning {
  border-color: var(--accent-amber);
  background-color: rgba(245, 158, 11, 0.08);
}

.alert-box.success {
  border-color: var(--accent-green);
  background-color: rgba(16, 185, 129, 0.08);
}

.alert-title {
  font-weight: 700;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 8px;
}

/* Code Snippet Box */
.code-block {
  background-color: var(--code-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 16px 20px;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 13px;
  color: #e2e8f0;
  overflow-x: auto;
  margin: 20px 0;
  position: relative;
}

.copy-btn {
  position: absolute;
  top: 10px;
  right: 10px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 12px;
  padding: 4px 8px;
  border-radius: 4px;
  cursor: pointer;
}

.copy-btn:hover {
  color: var(--text-primary);
  border-color: var(--accent-blue);
}

/* Step-by-Step Tutorial Container */
.step-container {
  margin: 24px 0;
}

.step-item {
  display: flex;
  gap: 16px;
  margin-bottom: 24px;
}

.step-number {
  width: 32px;
  height: 32px;
  background-color: var(--accent-blue);
  color: #0b132b;
  font-weight: 700;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.step-content h4 {
  font-size: 16px;
  margin-bottom: 6px;
  color: var(--text-primary);
}

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

/* Tabs */
.tab-header {
  display: flex;
  gap: 8px;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 20px;
}

.tab-btn {
  padding: 10px 16px;
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--text-secondary);
  font-weight: 600;
  cursor: pointer;
  font-size: 14px;
}

.tab-btn.active {
  border-color: var(--accent-blue);
  color: var(--accent-blue);
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
}

/* Footer */
.site-footer {
  margin-top: 60px;
  padding: 24px 0;
  border-top: 1px solid var(--border-color);
  text-align: center;
  color: var(--text-muted);
  font-size: 14px;
}

/* Responsive */
@media (max-width: 868px) {
  .sidebar {
    transform: translateX(-100%);
    transition: transform 0.3s ease;
  }
  .sidebar.open {
    transform: translateX(0);
  }
  .main-wrapper {
    margin-left: 0;
  }
  .content-container {
    padding: 24px 20px;
  }
}