.btn {
  font-family: 'Klee One', serif;
  font-size: 17px;
  padding: 14px 28px;
  border: none;
  border-radius: 18px;
  cursor: pointer;
  transition: all 0.15s;
  box-shadow: 0 4px 0 rgba(0,0,0,0.15);
  color: white;
  letter-spacing: 0.05em;
  user-select: none;
}
.btn:active {
  transform: translateY(3px);
  box-shadow: 0 1px 0 rgba(0,0,0,0.15);
}
.btn:disabled { opacity: 0.4; cursor: not-allowed; }

.btn-start { background: var(--leaf); }
.btn-stop { background: var(--rose); }
.btn-save { background: var(--gold-deep); }
.btn-reset { background: var(--ink-soft); }
.btn-small {
  font-size: 14px;
  padding: 9px 18px;
  border-radius: 12px;
}