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

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  padding: 20px;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  background: white;
  border-radius: 20px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
  overflow: hidden;
}

.header {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 30px;
  text-align: center;
}

.header h1 {
  font-size: 2.5em;
  margin-bottom: 10px;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.header p {
  font-size: 1.2em;
  opacity: 0.95;
}

.content {
  padding: 30px;
}

.student-info {
  background: #f8f9fa;
  padding: 20px;
  border-radius: 10px;
  margin-bottom: 30px;
  border-left: 4px solid #667eea;
}

.info-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 15px;
  margin-top: 15px;
}

.info-field {
  display: flex;
  flex-direction: column;
}

.info-field label {
  font-weight: 600;
  color: #667eea;
  margin-bottom: 5px;
  font-size: 0.9em;
}

.info-field input {
  padding: 10px;
  border: 2px solid #e0e0e0;
  border-radius: 5px;
  font-size: 1em;
  transition: border-color 0.3s;
}

.info-field input:focus {
  outline: none;
  border-color: #667eea;
}

.section {
  margin-bottom: 30px;
}

.section h2 {
  color: #667eea;
  font-size: 1.8em;
  margin-bottom: 15px;
  border-bottom: 3px solid #667eea;
  padding-bottom: 10px;
}

.section h3 {
  color: #764ba2;
  font-size: 1.3em;
  margin: 20px 0 10px 0;
}

.objectives-list {
  background: #f0f4ff;
  padding: 20px;
  border-radius: 10px;
  border-left: 4px solid #764ba2;
}

.objectives-list li {
  margin-left: 20px;
  margin-bottom: 10px;
  line-height: 1.6;
}

.equipment-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 15px;
  margin-top: 15px;
}

.equipment-item {
  background: white;
  padding: 15px;
  border-radius: 10px;
  text-align: center;
  border: 2px solid #e0e0e0;
  transition: all 0.3s;
}

.equipment-item:hover {
  transform: translateY(-5px);
  box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
  border-color: #667eea;
}

.equipment-item .icon {
  font-size: 2em;
  margin-bottom: 10px;
}

.simulation-container {
  background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  padding: 30px;
  border-radius: 15px;
  margin: 20px 0;
  position: relative;
  min-height: 500px;
}

.lab-setup {
  display: flex;
  justify-content: center;
  align-items: flex-end;
  gap: 30px;
  margin: 30px 0;
  position: relative;
  height: 400px;
}

.apparatus {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.flask {
  width: 120px;
  height: 150px;
  background: linear-gradient(to bottom, transparent 0%, transparent 30%, #87CEEB 30%, #4682B4 100%);
  border: 3px solid #333;
  border-radius: 10px 10px 50px 50px;
  position: relative;
  transition: all 0.5s;
}

.flask.reacting {
  animation: bubble 2s infinite;
  background: linear-gradient(to bottom, transparent 0%, transparent 30%, #E6F3FF 30%, #87CEEB 100%);
}

@keyframes bubble {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-5px); }
}

.flask-neck {
  width: 40px;
  height: 60px;
  background: transparent;
  border: 3px solid #333;
  border-bottom: none;
  border-radius: 5px 5px 0 0;
  position: absolute;
  top: -60px;
  left: 50%;
  transform: translateX(-50%);
}

.bubbles {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translateX(-50%);
  width: 80%;
}

.bubble {
  width: 10px;
  height: 10px;
  background: rgba(255, 255, 255, 0.6);
  border-radius: 50%;
  position: absolute;
  animation: rise 1.5s infinite;
}

.bubble:nth-child(1) { left: 20%; animation-delay: 0s; }
.bubble:nth-child(2) { left: 40%; animation-delay: 0.3s; }
.bubble:nth-child(3) { left: 60%; animation-delay: 0.6s; }
.bubble:nth-child(4) { left: 80%; animation-delay: 0.9s; }

@keyframes rise {
  0% { 
    transform: translateY(0) scale(0);
    opacity: 0;
  }
  50% {
    opacity: 1;
  }
  100% { 
    transform: translateY(-80px) scale(1);
    opacity: 0;
  }
}

.test-tube {
  width: 60px;
  height: 200px;
  background: linear-gradient(to bottom, rgba(255, 255, 255, 0.3) 0%, rgba(173, 216, 230, 0.3) 100%);
  border: 3px solid #333;
  border-radius: 0 0 30px 30px;
  position: relative;
  transition: all 0.5s;
}

.test-tube.collecting {
  background: linear-gradient(to bottom, rgba(255, 255, 255, 0.3) 0%, rgba(135, 206, 235, 0.6) 100%);
}

.test-tube.full {
  background: linear-gradient(to bottom, rgba(135, 206, 235, 0.8) 0%, rgba(70, 130, 180, 0.8) 100%);
}

.oxygen-label {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: rgba(255, 255, 255, 0.9);
  padding: 5px 10px;
  border-radius: 5px;
  font-weight: bold;
  font-size: 0.9em;
  color: #667eea;
}

.tube-connecting {
  position: absolute;
  top: 80px;
  right: -100px;
  width: 100px;
  height: 3px;
  background: #333;
  transform-origin: left center;
}

.control-panel {
  display: flex;
  justify-content: center;
  gap: 15px;
  margin-top: 30px;
  flex-wrap: wrap;
}

.btn {
  padding: 12px 24px;
  border: none;
  border-radius: 8px;
  font-size: 1em;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(0, 0, 0, 0.2);
}

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

.btn-primary {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
}

.btn-success {
  background: linear-gradient(135deg, #11998e 0%, #38ef7d 100%);
  color: white;
}

.btn-warning {
  background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  color: white;
}

.btn-info {
  background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
  color: white;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

.experiments {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
  margin-top: 20px;
}

.experiment-card {
  background: white;
  padding: 20px;
  border-radius: 10px;
  border: 2px solid #e0e0e0;
  transition: all 0.3s;
}

.experiment-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
  border-color: #667eea;
}

.experiment-card h4 {
  color: #764ba2;
  margin-bottom: 10px;
  font-size: 1.2em;
}

.experiment-visual {
  height: 150px;
  background: #f5f7fa;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 15px 0;
  position: relative;
  overflow: hidden;
}

.experiment-visual.burning {
  background: linear-gradient(to top, #ff6b6b, #ffd93d);
  animation: flicker 0.5s infinite;
}

@keyframes flicker {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.8; }
}

.flame {
  width: 40px;
  height: 60px;
  background: linear-gradient(to top, #ff6b6b, #ffd93d, transparent);
  border-radius: 50% 50% 50% 50% / 60% 60% 40% 40%;
  position: relative;
  animation: flame-dance 1s infinite;
}

@keyframes flame-dance {
  0%, 100% { transform: scaleY(1) translateY(0); }
  50% { transform: scaleY(1.1) translateY(-5px); }
}

.observation-notes {
  background: #fff9e6;
  padding: 15px;
  border-radius: 8px;
  border-left: 4px solid #ffd93d;
  margin-top: 15px;
}

.observation-notes textarea {
  width: 100%;
  padding: 10px;
  border: 2px solid #e0e0e0;
  border-radius: 5px;
  font-family: inherit;
  font-size: 1em;
  min-height: 100px;
  resize: vertical;
}

.conclusion-box {
  background: #e6f7ff;
  padding: 20px;
  border-radius: 10px;
  border-left: 4px solid #4facfe;
  margin-top: 20px;
}

.conclusion-box textarea {
  width: 100%;
  padding: 15px;
  border: 2px solid #e0e0e0;
  border-radius: 5px;
  font-family: inherit;
  font-size: 1em;
  min-height: 120px;
  resize: vertical;
}

.export-section {
  background: #f8f9fa;
  padding: 25px;
  border-radius: 10px;
  margin-top: 30px;
  text-align: center;
}

.export-buttons {
  display: flex;
  justify-content: center;
  gap: 15px;
  margin-top: 20px;
  flex-wrap: wrap;
}

.progress-indicator {
  background: #667eea;
  color: white;
  padding: 15px;
  border-radius: 8px;
  margin-top: 20px;
  text-align: center;
  font-weight: 600;
}

.safety-warning {
  background: #fff3cd;
  border: 2px solid #ffc107;
  border-radius: 8px;
  padding: 15px;
  margin: 20px 0;
  display: flex;
  align-items: center;
  gap: 15px;
}

.safety-warning .icon {
  font-size: 2em;
  color: #ff6b6b;
}

.chemical-equation {
  background: white;
  padding: 20px;
  border-radius: 10px;
  font-size: 1.3em;
  text-align: center;
  border: 2px solid #667eea;
  margin: 20px 0;
  font-family: 'Courier New', monospace;
}

.info-box {
  background: #e8f5e9;
  padding: 15px;
  border-radius: 8px;
  border-left: 4px solid #4caf50;
  margin: 15px 0;
}

.info-box h4 {
  color: #2e7d32;
  margin-bottom: 10px;
}

.hidden {
  display: none;
}

@media print {
  body {
    background: white;
    padding: 0;
  }
  
  .control-panel,
  .export-section,
  .btn {
    display: none !important;
  }
  
  .container {
    box-shadow: none;
  }
}

@media (max-width: 768px) {
  .header h1 {
    font-size: 1.8em;
  }
  
  .lab-setup {
    flex-direction: column;
    height: auto;
    gap: 50px;
  }
  
  .info-grid {
    grid-template-columns: 1fr;
  }
  
  .experiments {
    grid-template-columns: 1fr;
  }
}