:root {
  --pomodoro: #d95550;
  --shortBreak: #4c9195;
  --longBreak: #457ca3;
  --light-text: #ffffff;
  --dark-text: #1e2128;
  --bg-color: var(--pomodoro);
  --btn-color: var(--pomodoro);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Poppins', sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background-color: var(--bg-color);
  color: var(--light-text);
  transition: background-color 0.5s ease-in-out;
}

body[data-mode='pomodoro'] {
  --bg-color: var(--pomodoro);
  --btn-color: var(--pomodoro);
}
body[data-mode='shortBreak'] {
  --bg-color: var(--shortBreak);
  --btn-color: var(--shortBreak);
}
body[data-mode='longBreak'] {
  --bg-color: var(--longBreak);
  --btn-color: var(--longBreak);
}

.container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 100%;
  max-width: 480px;
  padding: 20px;
}

.timer {
  background-color: rgba(255, 255, 255, 0.1);
  padding: 2rem 3rem;
  border-radius: 10px;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.15);
}

.mode-buttons {
  display: flex;
  gap: 10px;
  margin-bottom: 2rem;
  background-color: rgba(0, 0, 0, 0.2);
  padding: 0.5rem;
  border-radius: 25px;
}

.mode-btn {
  background: transparent;
  border: none;
  color: var(--light-text);
  padding: 0.5rem 1rem;
  border-radius: 20px;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 500;
  transition: all 0.2s ease-in-out;
}

.mode-btn.active {
  background-color: var(--light-text);
  color: var(--btn-color);
  font-weight: bold;
}

.time-display {
  font-size: 6rem;
  font-weight: bold;
  margin-bottom: 2rem;
}

.controls {
  display: flex;
  align-items: center;
  gap: 1rem;
}

#start-stop-btn {
  background-color: var(--light-text);
  color: var(--btn-color);
  border: none;
  padding: 1rem 3rem;
  border-radius: 5px;
  font-size: 1.5rem;
  font-weight: bold;
  cursor: pointer;
  text-transform: uppercase;
  letter-spacing: 2px;
  box-shadow: 0 6px rgba(0, 0, 0, 0.2);
  transition: all 0.1s ease-in-out;
}

#start-stop-btn:active {
  transform: translateY(4px);
  box-shadow: 0 2px rgba(0, 0, 0, 0.2);
}

#reset-btn {
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  opacity: 0.8;
  transition: opacity 0.2s ease-in-out;
}

#reset-btn:hover {
  opacity: 1;
}

#reset-btn svg {
  width: 32px;
  height: 32px;
  fill: var(--light-text);
}

@media (max-width: 480px) {
  .timer {
    padding: 1.5rem;
  }
  .mode-btn {
    padding: 0.5rem;
    font-size: 0.9rem;
  }
  .time-display {
    font-size: 4.5rem;
  }
  #start-stop-btn {
    padding: 0.8rem 2rem;
    font-size: 1.2rem;
  }
  #reset-btn svg {
    width: 28px;
    height: 28px;
  }
}