.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-2);
  font-family: var(--font-primary);
  font-size: 14px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  padding: var(--spacing-2) var(--spacing-4);
  border: var(--border-inner);
  border-radius: var(--radius-small);
  background: var(--panel);
  color: var(--border);
  cursor: pointer;
  transition:
    background var(--transition-fast),
    box-shadow var(--transition-fast),
    transform var(--transition-fast);
  box-shadow:
    inset 0 1px var(--border-highlight),
    inset 0 -1px rgba(0,0,0,.18);
  min-height: 40px;
  user-select: none;
  -webkit-user-select: none;
}

.btn:hover {
  filter: brightness(1.03);
}

.btn:active {
  transform: translateY(1px);
  box-shadow:
    inset 0 1px rgba(0,0,0,.18),
    inset 0 -1px var(--border-highlight);
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.btn--primary {
  background: var(--border);
  color: var(--bg);
  box-shadow:
    inset 0 1px rgba(255,255,255,.25),
    inset 0 -1px rgba(0,0,0,.25);
}

.btn--primary:hover {
  filter: brightness(1.1);
}

.btn--primary:active {
  box-shadow:
    inset 0 1px rgba(0,0,0,.25),
    inset 0 -1px rgba(255,255,255,.1);
}

.btn--icon {
  padding: var(--spacing-2);
  min-width: 40px;
}

.btn--sm {
  font-size: 11px;
  padding: var(--spacing-1) var(--spacing-2);
  min-height: 32px;
}

.btn--lg {
  font-size: 16px;
  padding: var(--spacing-3) var(--spacing-5);
  min-height: 48px;
}

.btn--ghost {
  background: transparent;
  border-color: transparent;
  box-shadow: none;
}

.btn--ghost:hover {
  background: var(--panel);
}