frontend/src/components/layout/AppShell.css

/* ── Top Nav + main layout ────────────────────────────── */
.app-shell {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  background: var(--bg);
}

/* ── Top Navigation ───────────────────────────────────── */
.top-nav {
  height: 60px;
  background: rgba(var(--surface-rgb), 0.85);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  color: var(--text-main);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 32px;
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.nav-brand {
  display: flex;
  align-items: baseline;
  gap: 8px;
  white-space: nowrap;
}

.brand-text {
  font-weight: 800;
  font-size: 18px;
  letter-spacing: -0.5px;
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: var(--primary); /* Fallback for browsers that don't support clip-text */
  -webkit-text-fill-color: transparent;
}

.brand-version {
  font-size: 9px;
  color: var(--text-muted);
  font-weight: 600;
  padding: 1px 6px;
  background: var(--surface-hover);
  border-radius: 4px;
  border: 1px solid var(--border);
}

/* ── Navigation items ─────────────────────────────────── */
.nav-links {
  display: flex;
  align-items: center;
  gap: 12px;
  height: 100%;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 13px;
  font-weight: 600;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  border-radius: 20px;
  white-space: nowrap;
}

.nav-item:hover {
  color: var(--text-main);
  background: var(--surface-hover);
}

.nav-item.active {
  color: var(--primary);
  background: var(--primary-light);
}

.nav-icon {
  font-size: 14px;
}

/* ── Theme Toggle ─────────────────────────────────────── */
.nav-actions {
  display: flex;
  align-items: center;
}

.theme-toggle {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-main);
  font-size: 14px;
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  transition: all 0.2s;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
}

.theme-toggle:hover {
  border-color: var(--primary);
  color: var(--primary);
  transform: translateY(-1px);
  box-shadow: var(--shadow);
}

/* ── Main content area ────────────────────────────────── */
.main-content {
  flex: 1;
  padding: 16px 24px;
}