/* ============================================
   公共组件 - 导航 + 页脚 + 工具栏
   ============================================ */

/* ===== 导航栏 ===== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 1rem 0;
  transition: all 0.3s var(--ease-out);
}

.nav.scrolled {
  background: rgba(6, 8, 24, 0.85);
  backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--border-subtle);
  padding: 0.625rem 0;
}

[data-theme="light"] .nav.scrolled {
  background: rgba(248, 250, 252, 0.85);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-lg);
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  font-weight: 700;
  font-size: var(--fs-lg);
  letter-spacing: -0.02em;
}

.nav-logo {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--gradient-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  font-weight: 800;
  color: #fff;
  position: relative;
  overflow: hidden;
}

.nav-logo::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, transparent 40%, rgba(255,255,255,0.3) 50%, transparent 60%);
  animation: shimmer 3s infinite;
}

@keyframes shimmer {
  0%, 100% { transform: translateX(-100%); }
  50% { transform: translateX(100%); }
}

.nav-brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.nav-brand-text small {
  font-size: 0.625rem;
  font-weight: 400;
  color: var(--text-tertiary);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  list-style: none;
}

.nav-link {
  padding: 0.5rem 0.875rem;
  font-size: var(--fs-sm);
  font-weight: 500;
  color: var(--text-secondary);
  border-radius: var(--r-sm);
  transition: all 0.2s var(--ease-out);
  position: relative;
}

.nav-link:hover, .nav-link.active {
  color: var(--text-primary);
  background: var(--bg-glass);
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 2px;
  background: var(--gradient-primary);
  border-radius: 2px;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.theme-toggle {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--bg-glass);
  border: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s var(--ease-out);
}

.theme-toggle:hover {
  border-color: var(--brand-primary);
  transform: rotate(20deg);
}

.theme-toggle svg { width: 16px; height: 16px; }

.nav-toggle {
  display: none;
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--bg-glass);
  border: 1px solid var(--border-subtle);
  align-items: center;
  justify-content: center;
}

.nav-toggle span {
  display: block;
  width: 16px;
  height: 1.5px;
  background: var(--text-primary);
  position: relative;
  transition: all 0.3s var(--ease-out);
}

.nav-toggle span::before,
.nav-toggle span::after {
  content: '';
  position: absolute;
  width: 16px;
  height: 1.5px;
  background: var(--text-primary);
  left: 0;
  transition: all 0.3s var(--ease-out);
}

.nav-toggle span::before { top: -5px; }
.nav-toggle span::after { top: 5px; }

.nav-toggle.active span { background: transparent; }
.nav-toggle.active span::before { transform: rotate(45deg); top: 0; }
.nav-toggle.active span::after { transform: rotate(-45deg); top: 0; }

@media (max-width: 1024px) {
  .nav-menu {
    position: fixed;
    inset: 70px 1rem auto 1rem;
    flex-direction: column;
    align-items: stretch;
    padding: 1rem;
    background: var(--bg-elevated);
    border: 1px solid var(--border-subtle);
    border-radius: var(--r-lg);
    box-shadow: var(--shadow-lg);
    backdrop-filter: blur(20px);
    opacity: 0;
    pointer-events: none;
    transform: translateY(-10px);
    transition: all 0.3s var(--ease-out);
  }
  .nav-menu.open {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
  }
  .nav-menu .nav-link { padding: 0.75rem 1rem; }
  .nav-toggle { display: flex; }
  .nav-cta { display: none; }
}

/* ===== 页脚 ===== */
.footer {
  border-top: 1px solid var(--border-subtle);
  padding-block: var(--space-2xl) var(--space-lg);
  margin-top: var(--space-3xl);
  position: relative;
  z-index: 1;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-2xl);
  margin-bottom: var(--space-2xl);
}

.footer-brand p {
  margin-top: var(--space-md);
  font-size: var(--fs-sm);
  max-width: 320px;
}

.footer-col h5 {
  font-size: var(--fs-sm);
  font-weight: 600;
  margin-bottom: var(--space-md);
  color: var(--text-primary);
}

.footer-col ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
}

.footer-col a {
  font-size: var(--fs-sm);
  color: var(--text-tertiary);
  transition: color 0.2s var(--ease-out);
}

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

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--space-lg);
  border-top: 1px solid var(--border-subtle);
  font-size: var(--fs-xs);
  color: var(--text-muted);
  flex-wrap: wrap;
  gap: var(--space-md);
}

.footer-bottom a { color: var(--text-tertiary); }
.footer-bottom a:hover { color: var(--brand-primary); }

.footer-links { display: flex; gap: var(--space-md); }

@media (max-width: 768px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xl);
  }
  .footer-brand { grid-column: 1 / -1; }
}

/* ===== 回到顶部 ===== */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--gradient-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  box-shadow: var(--shadow-glow);
  opacity: 0;
  pointer-events: none;
  transform: translateY(20px);
  transition: all 0.3s var(--ease-out);
  z-index: 50;
}

.back-to-top.show {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.back-to-top:hover {
  transform: translateY(-4px);
}