/* ============================================
   Buttons
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  font-size: 1rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  transition: all var(--transition-base);
  min-height: 44px;
  min-width: 44px;
}

.btn:disabled {
  opacity: 0.7;
  cursor: not-allowed;
}

.btn-primary {
  background-color: var(--color-primary);
  color: #fff;
  box-shadow: 0 1px 2px rgba(26, 115, 232, 0.3);
}

.btn-primary:hover {
  background-color: var(--color-primary-hover);
  color: #fff;
  box-shadow: 0 2px 8px rgba(26, 115, 232, 0.4);
  transform: translateY(-1px);
}

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

.btn-secondary:hover {
  background-color: var(--color-bg-tertiary);
  border-color: var(--color-border);
  transform: translateY(-1px);
}

.btn-large {
  padding: var(--space-lg) var(--space-2xl);
  font-size: 1.125rem;
  border-radius: var(--radius-md);
}

.btn-block {
  width: 100%;
}

/* ============================================
   Cards
   ============================================ */
.card {
  background-color: var(--color-bg);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  padding: var(--space-xl);
  transition: all var(--transition-base);
  border: 1px solid var(--color-border-light);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.card-icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-primary-light);
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-md);
}

.card-icon svg {
  width: 24px;
  height: 24px;
  color: var(--color-primary);
}

.card-title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.card-text {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
}

/* ============================================
   Navigation
   ============================================ */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.nav.scrolled {
  border-bottom-color: var(--color-border-light);
  box-shadow: 0 1px 3px rgba(60, 64, 67, 0.08);
}

.nav-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-lg);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-text);
}

.nav-brand svg {
  width: 28px;
  height: 28px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
}

.nav-link {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  padding: var(--space-sm) 0;
  position: relative;
  transition: color var(--transition-fast);
}

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

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

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--color-primary);
  border-radius: 2px;
}

/* Mobile hamburger */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--space-sm);
  min-width: 44px;
  min-height: 44px;
  background: none;
  border: none;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--color-text);
  border-radius: 1px;
  transition: all 0.3s ease;
}

.nav-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

.nav-mobile {
  display: none;
  position: absolute;
  top: 64px;
  left: 0;
  right: 0;
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-border-light);
  box-shadow: var(--shadow-md);
  padding: var(--space-md) var(--space-lg);
}

.nav-mobile.open {
  display: block;
}

.nav-mobile .nav-link {
  display: block;
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border-light);
}

.nav-mobile .nav-link:last-child {
  border-bottom: none;
}

.nav-mobile .nav-link.active::after {
  display: none;
}

.nav-mobile .nav-link.active {
  background-color: var(--color-primary-light);
  margin: 0 calc(-1 * var(--space-lg));
  padding-left: var(--space-lg);
  padding-right: var(--space-lg);
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
  }
  
  .nav-toggle {
    display: flex;
  }
}

/* ============================================
   Accordion / FAQ
   ============================================ */
.accordion {
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.accordion-item {
  border-bottom: 1px solid var(--color-border-light);
}

.accordion-item:last-child {
  border-bottom: none;
}

.accordion-header {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-lg);
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-text);
  text-align: left;
  background: none;
  border: none;
  cursor: pointer;
  min-height: 44px;
}

.accordion-header:hover {
  background-color: var(--color-bg-secondary);
}

.accordion-header svg {
  width: 20px;
  height: 20px;
  color: var(--color-text-tertiary);
  transition: transform var(--transition-base);
  flex-shrink: 0;
  margin-left: var(--space-md);
}

.accordion-item.open .accordion-header svg {
  transform: rotate(180deg);
}

.accordion-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-slow), padding var(--transition-slow);
}

.accordion-item.open .accordion-body {
  max-height: 500px;
}

.accordion-content {
  padding: 0 var(--space-lg) var(--space-lg);
  color: var(--color-text-secondary);
  line-height: 1.7;
}

/* ============================================
   Tabs
   ============================================ */
.tabs {
  display: flex;
  gap: var(--space-sm);
  margin-bottom: var(--space-xl);
  flex-wrap: wrap;
}

.tab-btn {
  padding: var(--space-md) var(--space-xl);
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  min-height: 44px;
}

.tab-btn:hover {
  background-color: var(--color-bg-tertiary);
  color: var(--color-text);
}

.tab-btn.active {
  background-color: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
  box-shadow: 0 1px 3px rgba(26, 115, 232, 0.3);
}

.tab-panel {
  display: none;
}

.tab-panel.active {
  display: block;
  animation: fadeInUp 0.3s ease;
}

/* ============================================
   Platform Cards (download page)
   ============================================ */
.platform-card {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  box-shadow: var(--shadow-sm);
}

.platform-icon-large {
  width: 64px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-primary-light);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-lg);
}

.platform-icon-large svg {
  width: 32px;
  height: 32px;
  color: var(--color-primary);
}

.info-row {
  display: flex;
  justify-content: space-between;
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border-light);
  font-size: 0.9375rem;
}

.info-row:last-child {
  border-bottom: none;
}

.info-label {
  color: var(--color-text-secondary);
}

.info-value {
  font-weight: 500;
  color: var(--color-text);
}

/* ============================================
   Steps
   ============================================ */
.steps {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
}

.step {
  display: flex;
  gap: var(--space-lg);
  align-items: flex-start;
}

.step-number {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-primary);
  color: #fff;
  font-weight: 600;
  font-size: 1rem;
  border-radius: 50%;
  flex-shrink: 0;
}

.step-body {
  flex: 1;
  padding-top: var(--space-xs);
}

.step-title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.step-desc {
  color: var(--color-text-secondary);
  line-height: 1.7;
}

/* ============================================
   Tables
   ============================================ */
.table-wrap {
  overflow-x: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border-light);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9375rem;
}

.data-table th,
.data-table td {
  padding: var(--space-md) var(--space-lg);
  text-align: left;
  border-bottom: 1px solid var(--color-border-light);
}

.data-table th {
  background-color: var(--color-bg-secondary);
  font-weight: 600;
  color: var(--color-text);
  white-space: nowrap;
}

.data-table td {
  color: var(--color-text-secondary);
}

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

.data-table tr:hover td {
  background-color: var(--color-bg-secondary);
}

/* ============================================
   Footer
   ============================================ */
.footer {
  background-color: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border-light);
  padding: var(--space-3xl) 0 var(--space-xl);
}

.footer-links {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: var(--space-md) var(--space-xl);
  margin-bottom: var(--space-xl);
}

.footer-links a {
  color: var(--color-text-secondary);
  font-size: 0.9375rem;
}

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

.footer-bottom {
  text-align: center;
  padding-top: var(--space-xl);
  border-top: 1px solid var(--color-border-light);
}

.footer-bottom p {
  font-size: 0.875rem;
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-sm);
}

/* ============================================
   Code / Hash blocks
   ============================================ */
.code-block {
  background-color: var(--color-bg-tertiary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: var(--space-md);
  font-family: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, monospace;
  font-size: 0.8125rem;
  color: var(--color-text);
  word-break: break-all;
  line-height: 1.5;
}

/* ============================================
   Hero Illustration (CSS-drawn browser)
   ============================================ */
.browser-mockup {
  width: 100%;
  max-width: 520px;
  margin: 0 auto;
  background-color: var(--color-bg);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--color-border-light);
  overflow: hidden;
}

.browser-header {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-lg);
  background-color: var(--color-bg-secondary);
  border-bottom: 1px solid var(--color-border-light);
}

.browser-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.browser-dot-red { background-color: #ea4335; }
.browser-dot-yellow { background-color: #fbbc04; }
.browser-dot-green { background-color: #34a853; }

.browser-address {
  flex: 1;
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 100px;
  padding: var(--space-xs) var(--space-md);
  font-size: 0.75rem;
  color: var(--color-text-tertiary);
  margin-left: var(--space-sm);
}

.browser-content {
  padding: var(--space-xl);
  min-height: 200px;
}

.browser-content-line {
  height: 12px;
  background-color: var(--color-bg-tertiary);
  border-radius: 6px;
  margin-bottom: var(--space-md);
}

.browser-content-line.short {
  width: 60%;
}

.browser-content-line.medium {
  width: 80%;
}

/* ============================================
   Platform Grid
   ============================================ */
.platform-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-xl);
}

.platform-item {
  text-align: center;
  padding: var(--space-xl);
  border-radius: var(--radius-md);
  background-color: var(--color-bg);
  border: 1px solid var(--color-border-light);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
  cursor: pointer;
}

.platform-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
}

.platform-item svg {
  width: 40px;
  height: 40px;
  color: var(--color-primary);
  margin-bottom: var(--space-md);
}

.platform-item h3 {
  font-size: 1rem;
  margin-bottom: var(--space-sm);
}

.platform-item p {
  font-size: 0.875rem;
}

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

/* ============================================
   Card Grid
   ============================================ */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

@media (max-width: 992px) {
  .card-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 576px) {
  .card-grid {
    grid-template-columns: 1fr;
  }
}

/* ============================================
   Article list
   ============================================ */
.article-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

.article-card {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  padding: var(--space-xl);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

.article-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.article-card h3 {
  font-size: 1.125rem;
  margin-bottom: var(--space-md);
  color: var(--color-text);
}

.article-card p {
  font-size: 0.9375rem;
  line-height: 1.7;
  color: var(--color-text-secondary);
}

@media (max-width: 992px) {
  .article-list {
    grid-template-columns: 1fr;
  }
}

/* ============================================
   CTA Section
   ============================================ */
.cta-section {
  background-color: var(--color-primary);
  color: #fff;
  padding: var(--space-3xl) var(--space-lg);
  border-radius: var(--radius-lg);
  text-align: center;
}

.cta-section h2 {
  color: #fff;
  font-size: 1.75rem;
  margin-bottom: var(--space-md);
}

.cta-section p {
  color: rgba(255, 255, 255, 0.85);
  font-size: 1.0625rem;
  max-width: 560px;
  margin: 0 auto var(--space-xl);
}

.cta-section .btn-secondary {
  background-color: #fff;
  color: var(--color-primary);
  border-color: #fff;
}

.cta-section .btn-secondary:hover {
  background-color: rgba(255, 255, 255, 0.9);
}

/* ============================================
   Version comparison
   ============================================ */
.version-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

.version-card {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  padding: var(--space-xl);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

.version-card:hover {
  box-shadow: var(--shadow-md);
}

.version-card.featured {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 1px var(--color-primary), var(--shadow-sm);
}

.version-badge {
  display: inline-block;
  padding: var(--space-xs) var(--space-md);
  border-radius: 100px;
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: var(--space-md);
}

.version-badge.stable {
  background-color: var(--color-primary-light);
  color: var(--color-primary);
}

.version-badge.beta {
  background-color: #fef3c7;
  color: #92400e;
}

.version-badge.dev {
  background-color: #fee2e2;
  color: #991b1b;
}

.version-card h3 {
  font-size: 1.25rem;
  margin-bottom: var(--space-sm);
}

.version-card p {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-md);
}

.version-meta {
  font-size: 0.875rem;
  color: var(--color-text-tertiary);
}

@media (max-width: 992px) {
  .version-grid {
    grid-template-columns: 1fr;
  }
}