* {
  box-sizing: border-box;
}
html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  font-family: Inter, system-ui, Arial, sans-serif;
  background: linear-gradient(135deg, #ffe9b3, #ec8a11);
  display: flex;
  align-items: center;
  justify-content: center;
}

#clock {
  background: white;
  width: 360px;
  padding: 24px;
  border-radius: 14px;
  box-shadow: 0 8px 25px rgba(0,0,0,0.08);
  color: #5a3b00;
  text-align: center;
  user-select: none;
}

h1 {
  margin-bottom: 20px;
  font-weight: 700;
}

.length-control {
  display: flex;
  justify-content: space-between;
  margin: 12px 0;
  align-items: center;
}

.length-control button {
  background: linear-gradient(180deg, #fff, #f8f8f8);
  border: none;
  border-radius: 8px;
  font-weight: 700;
  font-size: 18px;
  width: 36px;
  height: 36px;
  cursor: pointer;
  box-shadow: 0 4px 8px rgba(0,0,0,0.05);
  transition: all 0.08s ease-in-out;
}

.length-control button:active {
  transform: translateY(2px);
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.length-control span {
  font-size: 18px;
  font-weight: 700;
  flex: 1;
  text-align: center;
}

#timer {
  margin-top: 24px;
  background: linear-gradient(180deg, #fff7f0, #fffdfa);
  border-radius: 14px;
  padding: 20px;
  font-size: 64px;
  font-weight: 900;
  border: 1px solid rgba(0,0,0,0.05);
  color: #8b4513;
  user-select: none;
}

#timer-label {
  font-size: 24px;
  font-weight: 700;
  margin-bottom: 8px;
}

#controls {
  margin-top: 20px;
  display: flex;
  justify-content: center;
  gap: 24px;
}

#start_stop, #reset {
  background: #fcd34d;
  border: none;
  border-radius: 12px;
  font-weight: 700;
  font-size: 20px;
  padding: 12px 32px;
  cursor: pointer;
  box-shadow: 0 4px 10px rgba(0,0,0,0.1);
  transition: all 0.1s ease-in-out;
}

#start_stop:active, #reset:active {
  transform: translateY(2px);
  box-shadow: 0 2px 5px rgba(0,0,0,0.15);
}