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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
  color: #fff;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden;
  user-select: none;
  -webkit-user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.container {
  width: 100%;
  max-width: 600px;
  padding: 20px;
  text-align: center;
}

h1 {
  font-size: 2rem;
  margin-bottom: 10px;
  font-weight: 700;
}

h2 {
  font-size: 1.3rem;
  margin-bottom: 20px;
  font-weight: 400;
  opacity: 0.8;
}

.subtitle {
  font-size: 1.2rem;
  opacity: 0.7;
  margin-bottom: 30px;
}

.hidden {
  display: none !important;
}

.zone-select h1 {
  margin-bottom: 30px;
}

.zone-buttons {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.zone-btn {
  background: rgba(255, 255, 255, 0.1);
  border: 2px solid rgba(255, 255, 255, 0.2);
  color: #fff;
  padding: 18px 24px;
  font-size: 1.1rem;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.2s;
}

.zone-btn:hover,
.zone-btn:active {
  background: rgba(255, 255, 255, 0.2);
  border-color: rgba(255, 255, 255, 0.4);
  transform: scale(1.02);
}

.lecture-buttons {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 20px;
}

.lecture-btn {
  background: rgba(255, 255, 255, 0.1);
  border: 2px solid rgba(255, 255, 255, 0.2);
  color: #fff;
  padding: 16px 20px;
  font-size: 1rem;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.2s;
  text-align: left;
}

.lecture-btn:hover,
.lecture-btn:active {
  background: rgba(255, 255, 255, 0.2);
  border-color: rgba(255, 255, 255, 0.4);
}

.stars {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-bottom: 15px;
}

.star {
  background: none;
  border: none;
  font-size: 3rem;
  color: rgba(255, 255, 255, 0.25);
  cursor: pointer;
  transition: all 0.15s;
  padding: 5px;
  line-height: 1;
}

.star:hover {
  transform: scale(1.15);
}

.star.active {
  color: #ffd700;
  text-shadow: 0 0 20px rgba(255, 215, 0, 0.5);
}

.star.hover {
  color: rgba(255, 215, 0, 0.6);
}

.star-label {
  font-size: 1.1rem;
  min-height: 30px;
  margin-bottom: 25px;
  opacity: 0.8;
}

.submit-btn {
  background: linear-gradient(135deg, #ffd700, #ffaa00);
  color: #1a1a2e;
  border: none;
  padding: 18px 40px;
  font-size: 1.2rem;
  font-weight: 700;
  border-radius: 50px;
  cursor: pointer;
  transition: all 0.2s;
  width: 100%;
  max-width: 400px;
}

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

.submit-btn:not(:disabled):hover,
.submit-btn:not(:disabled):active {
  transform: scale(1.03);
  box-shadow: 0 5px 25px rgba(255, 215, 0, 0.4);
}

.back-btn {
  background: none;
  border: none;
  color: rgba(255, 255, 255, 0.5);
  font-size: 1rem;
  cursor: pointer;
  margin-top: 15px;
  padding: 10px;
}

.back-btn:hover {
  color: rgba(255, 255, 255, 0.8);
}

.thank-you {
  animation: fadeIn 0.3s ease;
}

.checkmark {
  font-size: 5rem;
  color: #4caf50;
  margin-bottom: 20px;
  animation: scaleIn 0.4s ease;
}

.thank-you h1 {
  margin-bottom: 10px;
}

.thank-you p {
  opacity: 0.7;
  font-size: 1.1rem;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes scaleIn {
  from { transform: scale(0); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}

@media (max-width: 480px) {
  h1 { font-size: 1.5rem; }
  .star { font-size: 2.2rem; }
  .stars { gap: 4px; }
  .zone-btn, .lecture-btn { padding: 14px 16px; font-size: 0.95rem; }
}