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

body {
  font-family: 'Segoe UI', sans-serif;
  background: linear-gradient(135deg, #1a1a2e, #16213e, #0f3460);
  min-height: 100vh;
  color: #fff;
}

.screen {
  display: none;
  min-height: 100vh;
  padding: 20px;
}

.screen.active {
  display: block;
}

.container {
  max-width: 700px;
  margin: 0 auto;
  padding: 30px 20px;
}

h1 {
  font-size: 2.2rem;
  text-align: center;
  margin-bottom: 8px;
  color: #e94560;
}

.subtitle {
  text-align: center;
  color: #a8b2d8;
  margin-bottom: 30px;
  font-size: 1rem;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  color: #a8b2d8;
  font-size: 0.95rem;
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 12px 16px;
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 10px;
  color: #fff;
  font-size: 1rem;
  outline: none;
  transition: border 0.3s;
}

.form-group input:focus,
.form-group select:focus {
  border-color: #e94560;
}

.form-group select option {
  background: #1a1a2e;
  color: #fff;
}

.btn-primary {
  width: 100%;
  padding: 14px;
  background: linear-gradient(135deg, #e94560, #c23152);
  border: none;
  border-radius: 10px;
  color: #fff;
  font-size: 1.1rem;
  font-weight: bold;
  cursor: pointer;
  margin-top: 10px;
  transition: transform 0.2s, opacity 0.2s;
}

.btn-primary:hover {
  transform: translateY(-2px);
  opacity: 0.9;
}

.btn-secondary {
  width: 100%;
  padding: 14px;
  background: transparent;
  border: 2px solid #e94560;
  border-radius: 10px;
  color: #e94560;
  font-size: 1.1rem;
  font-weight: bold;
  cursor: pointer;
  margin-top: 10px;
  transition: all 0.2s;
}

.btn-secondary:hover {
  background: #e94560;
  color: #fff;
}

/* Quiz Header */
.quiz-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 15px;
  flex-wrap: wrap;
  gap: 10px;
}

#quiz-info {
  display: flex;
  gap: 10px;
}

#quiz-info span {
  background: rgba(233,69,96,0.2);
  border: 1px solid #e94560;
  padding: 5px 12px;
  border-radius: 20px;
  font-size: 0.85rem;
  color: #e94560;
}

.score-box {
  background: rgba(255,255,255,0.1);
  padding: 8px 16px;
  border-radius: 20px;
  font-weight: bold;
  font-size: 1rem;
}

/* Progress Bar */
.progress-bar {
  width: 100%;
  height: 8px;
  background: rgba(255,255,255,0.1);
  border-radius: 10px;
  margin-bottom: 25px;
  overflow: hidden;
}

#progress-fill {
  height: 100%;
  background: linear-gradient(90deg, #e94560, #f5a623);
  border-radius: 10px;
  transition: width 0.5s ease;
  width: 0%;
}

/* Question Box */
#question-box {
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 16px;
  padding: 30px;
  min-height: 300px;
}

#question-number {
  color: #a8b2d8;
  font-size: 0.9rem;
  margin-bottom: 10px;
}

#question-text {
  font-size: 1.2rem;
  line-height: 1.6;
  margin-bottom: 25px;
  color: #fff;
}

/* Options */
#options-container {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.option-btn {
  padding: 14px 18px;
  background: rgba(255,255,255,0.07);
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 10px;
  color: #fff;
  font-size: 1rem;
  cursor: pointer;
  text-align: left;
  transition: all 0.2s;
}

.option-btn:hover:not(:disabled) {
  background: rgba(233,69,96,0.2);
  border-color: #e94560;
}

.option-btn.correct {
  background: rgba(46,213,115,0.2);
  border-color: #2ed573;
  color: #2ed573;
}

.option-btn.wrong {
  background: rgba(233,69,96,0.2);
  border-color: #e94560;
  color: #e94560;
}

/* Explanation */
#explanation-box {
  margin-top: 20px;
  padding: 15px;
  background: rgba(248,196,113,0.1);
  border-left: 4px solid #f8c471;
  border-radius: 8px;
}

#explanation-text {
  color: #f8c471;
  font-size: 0.95rem;
  line-height: 1.5;
}

/* Loading */
.loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 200px;
  gap: 15px;
  color: #a8b2d8;
}

.spinner {
  width: 45px;
  height: 45px;
  border: 4px solid rgba(255,255,255,0.1);
  border-top: 4px solid #e94560;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Result */
.result-card {
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 16px;
  padding: 30px;
  text-align: center;
  margin: 20px 0;
}

.result-card p {
  color: #a8b2d8;
  margin-bottom: 8px;
  font-size: 1rem;
}

.result-score {
  font-size: 4rem;
  font-weight: bold;
  color: #e94560;
  margin: 15px 0;
}

#result-percent {
  font-size: 1.3rem;
  color: #f8c471 !important;
  font-weight: bold;
}

#result-message {
  font-size: 1.1rem;
  color: #2ed573 !important;
  margin-top: 10px;
}

/* Leaderboard */
#leaderboard-list {
  margin: 20px 0;
}

.leaderboard-item {
  display: flex;
  align-items: center;
  gap: 15px;
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 12px;
  padding: 15px 20px;
  margin-bottom: 12px;
}

.rank {
  font-size: 1.5rem;
  font-weight: bold;
  min-width: 40px;
}

.rank-1 { color: #ffd700; }
.rank-2 { color: #c0c0c0; }
.rank-3 { color: #cd7f32; }

.lb-info {
  flex: 1;
}

.lb-name {
  font-weight: bold;
  font-size: 1rem;
}

.lb-exam {
  color: #a8b2d8;
  font-size: 0.85rem;
}

.lb-score {
  font-size: 1.3rem;
  font-weight: bold;
  color: #e94560;
}

.empty-leaderboard {
  text-align: center;
  color: #a8b2d8;
  padding: 40px;
  font-size: 1rem;
}

@media (max-width: 500px) {
  h1 { font-size: 1.6rem; }
  #question-text { font-size: 1rem; }
  .result-score { font-size: 3rem; }
}

/* Timer */
.timer-box {
  text-align: center;
  margin-bottom: 15px;
}

.timer-circle {
  width: 70px;
  height: 70px;
  border-radius: 50%;
  background: conic-gradient(#e94560 0%, rgba(255,255,255,0.1) 0%);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto;
  position: relative;
  transition: background 1s linear;
}

.timer-number {
  font-size: 1.4rem;
  font-weight: bold;
  color: #fff;
  z-index: 1;
}

.timer-warning {
  background: conic-gradient(#f8c471 0%, rgba(255,255,255,0.1) 0%);
}

.timer-danger {
  background: conic-gradient(#e94560 0%, rgba(255,255,255,0.1) 0%);
  animation: pulse 0.5s infinite alternate;
}

@keyframes pulse {
  from { transform: scale(1); }
  to { transform: scale(1.1); }
}

/* Exam dropdown optgroup styling */
#exam-select optgroup {
  background: #0f3460;
  color: #e94560;
  font-weight: bold;
  font-size: 0.85rem;
  padding: 5px;
}

#exam-select option {
  background: #16213e;
  color: #fff;
  padding: 8px;
  font-size: 1rem;
}

/* Login Screen */
.login-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  text-align: center;
}

.login-card {
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 16px;
  padding: 40px;
  margin-top: 20px;
  width: 100%;
  max-width: 400px;
}

.login-card p {
  color: #a8b2d8;
  margin-bottom: 25px;
  font-size: 1rem;
}

.google-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  background: #fff;
  color: #333;
  padding: 14px 24px;
  border-radius: 10px;
  text-decoration: none;
  font-weight: bold;
  font-size: 1rem;
  transition: transform 0.2s, box-shadow 0.2s;
}

.google-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 5px 20px rgba(255,255,255,0.2);
}

.google-btn img {
  width: 24px;
  height: 24px;
}

/* Navbar */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 30px;
  flex-wrap: wrap;
  gap: 10px;
}

.navbar h2 {
  color: #e94560;
  font-size: 1.4rem;
}

.user-info {
  display: flex;
  align-items: center;
  gap: 10px;
}

#user-avatar {
  width: 35px;
  height: 35px;
  border-radius: 50%;
  border: 2px solid #e94560;
}

#user-name {
  font-size: 0.95rem;
  color: #fff;
}

.daily-badge {
  background: rgba(233,69,96,0.2);
  border: 1px solid #e94560;
  color: #e94560;
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 0.8rem;
}

.logout-btn {
  background: transparent;
  border: 1px solid rgba(255,255,255,0.2);
  color: #a8b2d8;
  padding: 6px 14px;
  border-radius: 8px;
  text-decoration: none;
  font-size: 0.85rem;
  transition: all 0.2s;
}

.logout-btn:hover {
  border-color: #e94560;
  color: #e94560;
}

/* Mobile Responsive */
@media (max-width: 768px) {
  .container {
    padding: 15px 10px;
  }

  h1 {
    font-size: 1.6rem;
  }

  .navbar {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }

  .user-info {
    flex-wrap: wrap;
    gap: 8px;
  }

  #user-name {
    font-size: 0.85rem;
  }

  .daily-badge {
    font-size: 0.75rem;
  }

  .logout-btn {
    font-size: 0.75rem;
    padding: 4px 10px;
  }

  #quiz-info {
    flex-wrap: wrap;
    gap: 6px;
  }

  #quiz-info span {
    font-size: 0.75rem;
    padding: 4px 8px;
  }

  .score-box {
    font-size: 0.85rem;
    padding: 6px 12px;
  }

  #question-box {
    padding: 15px;
  }

  #question-text {
    font-size: 1rem;
  }

  .option-btn {
    padding: 12px 14px;
    font-size: 0.9rem;
  }

  .timer-circle {
    width: 55px;
    height: 55px;
  }

  .timer-number {
    font-size: 1.1rem;
  }

  .result-score {
    font-size: 3rem;
  }

  .btn-primary, .btn-secondary {
    font-size: 1rem;
    padding: 12px;
  }

  .leaderboard-item {
    padding: 12px 15px;
    gap: 10px;
  }

  .lb-score {
    font-size: 1rem;
  }

  .google-btn {
    padding: 12px 20px;
    font-size: 0.95rem;
  }
}

/* Tablet */
@media (max-width: 480px) {
  h1 {
    font-size: 1.4rem;
  }

  .result-score {
    font-size: 2.5rem;
  }

  #question-text {
    font-size: 0.95rem;
  }
}

/* Footer */
.footer {
  background: rgba(0,0,0,0.3);
  border-top: 1px solid rgba(255,255,255,0.1);
  padding: 20px;
  text-align: center;
  color: #a8b2d8;
  font-size: 0.85rem;
  margin-top: 30px;
}

.footer strong {
  color: #f8c471;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin: 12px 0;
  flex-wrap: wrap;
}

.footer-links a {
  color: #e94560;
  text-decoration: none;
  font-weight: bold;
  transition: opacity 0.2s;
}

.footer-links a:hover {
  opacity: 0.7;
}

.footer-copy {
  font-size: 0.8rem;
  color: #666;
  margin-top: 8px;
}

.lang-toggle-btn {
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.3);
  color: #fff;
  padding: 6px 14px;
  border-radius: 20px;
  cursor: pointer;
  font-size: 0.85rem;
  margin-bottom: 15px;
  transition: all 0.2s;
}

.lang-toggle-btn:hover {
  background: rgba(255,255,255,0.2);
}

.back-to-home a {
  display: inline-block;
  color: #a8b2d8;
  text-decoration: none;
  font-size: 0.95rem;
  padding: 8px 16px;
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 8px;
  transition: all 0.3s ease;
}

.back-to-home a:hover {
  color: #e94560;
  border-color: #e94560;
  background: rgba(233,69,96,0.1);
}

.exam-badge {
  background: rgba(233, 69, 96, 0.2);
  color: #e94560;
  border: 1px solid #e94560;
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: bold;
}