:root {
  --nav-height: 64px;
  --nav-bg: rgba(15, 23, 42, 0.8);
  --nav-border: rgba(148, 163, 184, 0.25);
  --nav-text: #e2e8f0;
  --nav-muted: #94a3b8;
  --nav-active-bg: rgba(56, 189, 248, 0.16);
  --nav-active-border: rgba(56, 189, 248, 0.65);
  --nav-hover-bg: rgba(148, 163, 184, 0.18);
  --nav-blur: 14px;
}

body.with-nav {
  padding-top: var(--nav-height);
}

.top-nav {
  position: fixed;
  inset: 0 0 auto 0;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
  background: linear-gradient(135deg, rgba(15, 23, 42, 0.9), rgba(15, 23, 42, 0.6));
  border-bottom: 1px solid var(--nav-border);
  backdrop-filter: blur(var(--nav-blur));
  z-index: 10;
  box-shadow: 0 12px 30px rgba(2, 6, 23, 0.35);
}

.tab-list {
  display: flex;
  gap: 0.75rem;
  align-items: center;
}

.tab {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.55rem 1.25rem;
  border-radius: 999px;
  border: 1px solid transparent;
  color: var(--nav-muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  transition: all 140ms ease;
  background: transparent;
}

.tab:hover,
.tab:focus-visible {
  color: var(--nav-text);
  border-color: rgba(148, 163, 184, 0.35);
  background: var(--nav-hover-bg);
  outline: none;
}

.tab--active {
  color: #f8fafc;
  background: var(--nav-active-bg);
  border-color: var(--nav-active-border);
  box-shadow: 0 6px 18px rgba(56, 189, 248, 0.35);
}

.nav-controls {
  display: flex;
  align-items: center;
  gap: 1rem;
  color: var(--nav-muted);
  font-size: 0.9rem;
}

.nav-controls label {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--nav-text);
}

.nav-controls select {
  appearance: none;
  border: 1px solid rgba(148, 163, 184, 0.35);
  background: rgba(15, 23, 42, 0.65);
  color: #f8fafc;
  padding: 0.45rem 2.2rem 0.45rem 0.85rem;
  border-radius: 999px;
  font-size: 0.9rem;
  letter-spacing: 0.01em;
  transition: border-color 120ms ease, background-color 120ms ease;
  cursor: pointer;
}

.nav-controls select:hover,
.nav-controls select:focus-visible {
  border-color: rgba(56, 189, 248, 0.55);
  background: rgba(15, 23, 42, 0.85);
  outline: none;
}

.nav-controls select:focus-visible {
  box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.25);
}

.nav-controls option {
  color: #0f172a;
}