body {
  font-family: Arial, sans-serif;
  max-width: 800px;
  margin: 0 auto;
  padding: 20px;
  transition: background-color 0.3s, color 0.3s;
}

body.dark {
  background: #181c1f;
  color: #f0f0f0;
}

body.light-mode {
  background: #f0f0f0;
  color: #222;
}

.container {
  margin-top: 60px;
}

h1 {
  text-align: center;
  margin-bottom: 30px;
  color: #d32f2f;
  font-size: 2.5em;
}

body.dark h1 {
  color: #ef5350;
}

.countdown-section {
  background: linear-gradient(135deg, #c62828 0%, #d32f2f 100%);
  border-radius: 20px;
  padding: 40px 20px;
  margin-bottom: 30px;
  box-shadow: 0 8px 24px rgba(198, 40, 40, 0.3);
}

body.dark .countdown-section {
  background: linear-gradient(135deg, #b71c1c 0%, #c62828 100%);
}

.countdown-display {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 15px;
  flex-wrap: wrap;
}

.time-unit {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-width: 80px;
}

.time-value {
  font-size: 3.5em;
  font-weight: bold;
  color: white;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
  line-height: 1;
  margin-bottom: 8px;
}

.time-label {
  font-size: 0.9em;
  color: rgba(255, 255, 255, 0.9);
  text-transform: uppercase;
  letter-spacing: 1px;
  font-weight: 600;
}

.time-separator {
  font-size: 2.5em;
  color: white;
  font-weight: bold;
  margin: 0 5px;
  opacity: 0.8;
}

.section {
  background: #fff;
  border-radius: 12px;
  padding: 20px;
  margin-bottom: 20px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

body.dark .section {
  background: #23272a;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

h2 {
  margin-top: 0;
  margin-bottom: 15px;
  color: #1976d2;
  font-size: 1.3em;
}

body.dark h2 {
  color: #90caf9;
}

.setting-group {
  margin-bottom: 15px;
}

label {
  display: block;
  margin-bottom: 8px;
  color: #333;
  font-weight: 600;
}

body.dark label {
  color: #f0f0f0;
}

input[type="date"],
input[type="time"],
select {
  width: 100%;
  padding: 10px;
  border: 2px solid #ddd;
  border-radius: 8px;
  font-size: 1em;
  transition: border-color 0.2s;
  background: white;
  color: #222;
}

input[type="date"]:focus,
input[type="time"]:focus,
select:focus {
  outline: none;
  border-color: #1976d2;
}

body.dark input[type="date"],
body.dark input[type="time"],
body.dark select {
  background: #2c2f33;
  border-color: #444;
  color: #f0f0f0;
}

body.dark input[type="date"]:focus,
body.dark input[type="time"]:focus,
body.dark select:focus {
  border-color: #90caf9;
}

.update-btn {
  width: 100%;
  padding: 12px;
  background: #4caf50;
  color: white;
  font-size: 1.1em;
  font-weight: 600;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.2s, transform 0.1s;
  margin-top: 10px;
}

.update-btn:hover {
  background: #45a049;
  transform: translateY(-2px);
}

.update-btn:active {
  transform: translateY(0);
}

.presets {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.preset-btn {
  flex: 1;
  min-width: 150px;
  padding: 15px;
  background: #ff9800;
  color: white;
  font-size: 1em;
  font-weight: 600;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.2s, transform 0.1s;
}

.preset-btn:hover {
  background: #f57c00;
  transform: translateY(-2px);
}

.preset-btn:active {
  transform: translateY(0);
}

.message-section {
  background: #e8f5e9;
  border: 2px solid #4caf50;
  text-align: center;
}

body.dark .message-section {
  background: #1b5e20;
  border-color: #66bb6a;
}

.message-section h2 {
  color: #2e7d32;
  font-size: 2em;
  margin-bottom: 10px;
}

body.dark .message-section h2 {
  color: #66bb6a;
}

.message-section p {
  color: #1b5e20;
  font-size: 1.2em;
  margin: 0;
}

body.dark .message-section p {
  color: #a5d6a7;
}

.hidden {
  display: none;
}

@media (max-width: 600px) {
  .countdown-display {
    gap: 10px;
  }

  .time-value {
    font-size: 2.5em;
  }

  .time-separator {
    font-size: 1.8em;
  }

  .time-unit {
    min-width: 60px;
  }

  .presets {
    flex-direction: column;
  }

  .preset-btn {
    width: 100%;
  }
}