.header {
     background: linear-gradient(135deg, #E31E24 0%, #764ba2 100%);
     color: white;
     padding: 10px 20px;
     display: flex;
     justify-content: space-between;
     align-items: center;
     box-shadow: 0 2px 10px rgba(0,0,0,0.1);
     z-index: 1000;
     position: relative;
}
 .logo {
     font-size: 18px;
     font-weight: bold;
}
 .session-info {
     font-size: 14px;
     background: rgba(255,255,255,0.2);
     padding: 8px 16px;
     border-radius: 20px;
     backdrop-filter: blur(10px);
}
 .toolbar {
     background: white;
     padding: 15px 20px;
     display: flex;
     gap: 15px;
     align-items: center;
     box-shadow: 0 2px 10px rgba(0,0,0,0.1);
     flex-wrap: wrap;
     border-bottom: 1px solid #eee;
}
 .tool-group {
     display: flex;
     gap: 8px;
     align-items: center;
     padding: 8px;
     border-radius: 8px;
     background: #f8f9ff;
}
 .tool-btn {
     padding: 10px 15px;
     border: 2px solid #ddd;
     background: white;
     border-radius: 8px;
     cursor: pointer;
     transition: all 0.3s ease;
     font-size: 14px;
     display: flex;
     align-items: center;
     gap: 5px;
     color: #000000;
}
 .tool-btn:hover {
     border-color: #E31E24;
     background: #f0f4ff;
}
 .tool-btn.active {
     background: #E31E24;
     color: white !important;
     border-color: #E31E24;
}
 .color-picker {
     width: 40px;
     height: 40px;
     border: 2px solid #ddd;
     border-radius: 50%;
     cursor: pointer;
     appearance: none;
     -webkit-appearance: none;
}
 .color-picker::-webkit-color-swatch {
     border: none;
     border-radius: 50%;
}
 .size-slider {
     width: 100px;
     margin: 0 10px;
}
 .canvas-container {
     position: relative;
     flex: 1;
     overflow: hidden;
     background: white;
     margin: 0;
}
 #whiteboard {
     display: block;
     cursor: crosshair;
     background: white;
}
 .chemistry-panel {
     position: fixed;
     right: 20px;
     top: 120px;
     background: white;
     padding: 20px;
     border-radius: 12px;
     box-shadow: 0 10px 30px rgba(0,0,0,0.1);
     width: 200px;
     max-height: 70vh;
     overflow-y: auto;
     z-index: 100;
}
 .chemistry-panel h3 {
     color: #E31E24;
     margin-bottom: 15px;
     font-size: 16px;
}
 .chem-symbol {
     display: inline-block;
     padding: 8px 12px;
     margin: 3px;
     background: #f0f4ff;
     border: 1px solid #ddd;
     border-radius: 6px;
     cursor: pointer;
     font-size: 14px;
     transition: all 0.3s ease;
}
 .chem-symbol:hover {
     background: #E31E24;
     color: white;
}
 .equation-template {
     background: #f8f9ff;
     padding: 10px;
     margin: 5px 0;
     border-radius: 6px;
     cursor: pointer;
     font-size: 12px;
     border: 1px solid #eee;
}
 .equation-template:hover {
     border-color: #E31E24;
}
 .floating-menu {
     position: fixed;
     background: white;
     border-radius: 8px;
     padding: 10px;
     box-shadow: 0 5px 20px rgba(0,0,0,0.2);
     display: none;
     z-index: 1000;
}
 .zoom-controls {
     position: fixed;
     bottom: 20px;
     right: 20px;
     display: flex;
     gap: 5px;
     z-index: 100;
}
 .zoom-btn {
     width: 40px;
     height: 40px;
     border: none;
     background: #667eea;
     color: white;
     border-radius: 50%;
     cursor: pointer;
     font-size: 16px;
     display: flex;
     align-items: center;
     justify-content: center;
     transition: all 0.3s ease;
}
 .zoom-btn:hover {
     background: #5a6fd8;
     transform: scale(1.1);
}
 .participants {
     position: fixed;
     top: 120px;
     left: 20px;
     background: white;
     padding: 15px;
     border-radius: 12px;
     box-shadow: 0 10px 30px rgba(0,0,0,0.1);
     z-index: 100;
}
 .participant {
     display: flex;
     align-items: center;
     gap: 8px;
     margin: 5px 0;
     font-size: 14px;
}
 .status-dot {
     width: 8px;
     height: 8px;
     border-radius: 50%;
     background: #4CAF50;
}
 @media (max-width: 768px) {
     .toolbar {
         padding: 10px;
         gap: 8px;
    }
     .chemistry-panel {
         position: fixed;
         bottom: 0;
         right: 0;
         left: 0;
         top: auto;
         width: 100%;
         max-height: 30vh;
         border-radius: 12px 12px 0 0;
    }
     .participants {
         top: 80px;
         left: 10px;
         padding: 10px;
    }
}