/* Buttons */
.nav-buttons {
  display: flex;
  gap: var(--space-3);
  margin-top: var(--space-6);
  flex-wrap: wrap;
  align-items: stretch;
}

.nav-buttons .btn {
  flex: 1 1 140px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.7rem 1.25rem;
  border-radius: var(--radius-lg);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  line-height: 1.2;
  cursor: pointer;
  border: none;
  transition: background 0.2s, opacity 0.2s, transform 0.1s;
  flex: 1;
  text-decoration: none;
  white-space: nowrap;
  text-align: center;
  min-height: 2.6rem;
  font-family: inherit;
}

.btn:active:not(:disabled) { transform: scale(0.98); }

.btn-primary { background: var(--fg-0); color: var(--bg-0); }
.btn-primary:hover { background: var(--fg-2); }
.btn-secondary {
  background: transparent;
  color: var(--fg-2);
  border: 1px solid var(--rule-strong);
}
.btn-secondary:hover { background: var(--bg-2); }
.btn-success { background: var(--success); color: white; }
.btn-success:hover { background: var(--success-hover); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* Modern keyboard-focus ring (does not affect mouse/touch). */
.btn:focus-visible,
a:focus-visible,
button:focus-visible,
.mode-tab:focus-visible,
.filter-chip:focus-visible {
  outline: 2px solid var(--fg-0);
  outline-offset: 2px;
}

.btn-icon {
  flex: 0 0 auto;
  width: 2.5rem;
  height: 2.5rem;
  min-height: 0;
  padding: 0;
}