.oxygen-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

.oxygen-header {
    background: linear-gradient(135deg, #3B82F6, #1D4ED8);
    color: white;
    padding: 20px;
    border-radius: 12px;
    margin-bottom: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.oxygen-header h2 {
    margin: 0;
    font-size: 24px;
}

.stats-summary {
    display: flex;
    gap: 15px;
}

.stats-summary span {
    background: rgba(255,255,255,0.2);
    padding: 8px 12px;
    border-radius: 6px;
    font-size: 14px;
}

.oxygen-tabs {
    display: flex;
    background: white;
    border-radius: 8px;
    padding: 4px;
    margin-bottom: 20px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.tab-btn {
    flex: 1;
    padding: 12px 16px;
    border: none;
    background: transparent;
    cursor: pointer;
    border-radius: 6px;
    transition: all 0.3s ease;
    font-weight: 500;
}

.tab-btn.active {
    background: #3B82F6;
    color: white;
}

.tab-btn:hover:not(.active) {
    background: #F3F4F6;
}

.tab-content {
    display: none;
    background: white;
    border-radius: 12px;
    padding: 24px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.tab-content.active {
    display: block;
}

/* Dashboard Styles */
.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    padding: 24px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    gap: 16px;
    color: white;
}

.stat-card.blue { background: linear-gradient(135deg, #3B82F6, #1D4ED8); }
.stat-card.green { background: linear-gradient(135deg, #10B981, #059669); }
.stat-card.orange { background: linear-gradient(135deg, #F59E0B, #D97706); }
.stat-card.red { background: linear-gradient(135deg, #EF4444, #DC2626); }

.stat-icon {
    font-size: 32px;
}

.stat-info h3 {
    margin: 0;
    font-size: 28px;
    font-weight: bold;
}

.stat-info p {
    margin: 4px 0 0 0;
    opacity: 0.9;
}

/* Scanner Styles */
.scanner-container {
    text-align: center;
}

.camera-wrapper {
    position: relative;
    display: inline-block;
    margin-bottom: 20px;
}

#qr-video {
    width: 100%;
    max-width: 400px;
    border-radius: 12px;
    background: #000;
}

.scan-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    align-items: center;
    justify-content: center;
}

.scan-frame {
    width: 200px;
    height: 200px;
    border: 3px solid #10B981;
    border-radius: 12px;
    position: relative;
}

.scan-frame::before,
.scan-frame::after {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    border: 3px solid #10B981;
}

.scan-frame::before {
    top: -3px;
    left: -3px;
    border-right: none;
    border-bottom: none;
}

.scan-frame::after {
    bottom: -3px;
    right: -3px;
    border-left: none;
    border-top: none;
}

.camera-controls {
    display: flex;
    gap: 12px;
    justify-content: center;
    margin-bottom: 20px;
}

/* Generator Styles */
.generator-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
}

.generator-form h3 {
    margin-top: 0;
    color: #1F2937;
}

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

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #374151;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 12px;
    border: 2px solid #E5E7EB;
    border-radius: 8px;
    font-size: 14px;
    transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: #3B82F6;
}

.form-group textarea {
    resize: vertical;
    min-height: 80px;
}

.quick-actions {
    display: flex;
    gap: 8px;
    margin-bottom: 20px;
}

.qr-output {
    text-align: center;
    padding: 20px;
    border: 2px dashed #E5E7EB;
    border-radius: 12px;
    min-height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* List Styles */
.list-controls {
    display: flex;
    gap: 16px;
    margin-bottom: 20px;
}

.list-controls input,
.list-controls select {
    padding: 10px 12px;
    border: 2px solid #E5E7EB;
    border-radius: 8px;
    font-size: 14px;
}

.list-controls input {
    flex: 1;
}

.tank-list {
    display: grid;
    gap: 16px;
}

.tank-item {
    background: #F9FAFB;
    border: 2px solid #E5E7EB;
    border-radius: 12px;
    padding: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.tank-item:hover {
    border-color: #3B82F6;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.15);
}

.tank-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.tank-serial {
    font-size: 18px;
    font-weight: bold;
    color: #1F2937;
}

.status-badge {
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
}

.status-full { background: #D1FAE5; color: #065F46; }
.status-empty { background: #F3F4F6; color: #374151; }
.status-in-use { background: #DBEAFE; color: #1E40AF; }
.status-maintenance { background: #FED7AA; color: #9A3412; }

.tank-details {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 12px;
    font-size: 14px;
    color: #6B7280;
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
}

.modal-content {
    background-color: white;
    margin: 5% auto;
    padding: 0;
    border-radius: 12px;
    width: 90%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 24px;
    border-bottom: 2px solid #E5E7EB;
}

.modal-header h3 {
    margin: 0;
    color: #1F2937;
}

.close {
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
    color: #9CA3AF;
}

.close:hover {
    color: #374151;
}

#tank-form {
    padding: 24px;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.form-actions {
    display: flex;
    justify-content: space-between;
    margin-top: 24px;
    padding-top: 20px;
    border-top: 2px solid #E5E7EB;
}

/* Button Styles */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.btn-primary {
    background: #3B82F6;
    color: white;
}

.btn-primary:hover {
    background: #2563EB;
}

.btn-secondary {
    background: #6B7280;
    color: white;
}

.btn-secondary:hover {
    background: #4B5563;
}

.btn-success {
    background: #10B981;
    color: white;
}

.btn-success:hover {
    background: #059669;
}

.btn-danger {
    background: #EF4444;
    color: white;
}

.btn-danger:hover {
    background: #DC2626;
}

.btn-outline {
    background: transparent;
    border: 2px solid #E5E7EB;
    color: #374151;
}

.btn-outline:hover {
    border-color: #3B82F6;
    color: #3B82F6;
}

/* Loading Styles */
.loading {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255,255,255,0.9);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 2000;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #E5E7EB;
    border-top: 4px solid #3B82F6;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Responsive Design */
@media (max-width: 768px) {
    .oxygen-container {
        padding: 10px;
    }
    
    .oxygen-header {
        flex-direction: column;
        gap: 12px;
        text-align: center;
    }
    
    .stats-summary {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .dashboard-grid {
        grid-template-columns: 1fr;
    }
    
    .generator-container {
        grid-template-columns: 1fr;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .list-controls {
        flex-direction: column;
    }
    
    .tank-details {
        grid-template-columns: 1fr;
    }
    
    .form-actions {
        flex-direction: column;
        gap: 12px;
    }
}