.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: rgba(18, 18, 42, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-around;
  padding: 0.5rem 0;
  padding-bottom: calc(0.5rem + env(safe-area-inset-bottom));
  z-index: 100;
}

.nav-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.2rem;
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 0.65rem;
  font-weight: 500;
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.2s ease;
  -webkit-tap-highlight-color: transparent;
}

.nav-btn .nav-icon { font-size: 1.3rem; transition: transform 0.2s ease; }

.nav-btn.active {
  color: var(--accent);
}

.nav-btn.active .nav-icon {
  transform: scale(1.1);
}

.nav-btn:active { transform: scale(0.92); }

.page {
  display: none;
  padding-bottom: 80px;
  padding-top: 1rem;
  min-height: 100dvh;
}
.page.active { display: block; }

.page-header {
  padding: 1rem 0;
  margin-bottom: 0.5rem;
}

.top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 0;
}

@media (min-width: 768px) {
  .container { max-width: 600px; }

  .bottom-nav {
    top: 0;
    bottom: auto;
    border-top: none;
    border-bottom: 1px solid var(--border);
    justify-content: center;
    gap: 0.25rem;
    padding: 0.4rem 1rem;
    background: rgba(18, 18, 42, 0.9);
  }

  .nav-btn {
    flex-direction: row;
    gap: 0.4rem;
    padding: 0.5rem 1rem;
    font-size: 0.75rem;
  }

  .page {
    padding-top: 70px;
    padding-bottom: 2rem;
  }

  .timer-page {
    min-height: calc(100dvh - 70px);
  }

  .home-stats {
    grid-template-columns: repeat(3, 1fr);
  }

  .stats-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .achievements-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .toast-container {
    top: 80px;
  }
}