.mode-selection-container {
        min-height: calc(100vh - 100px);
        display: flex;
        align-items: center;
        background: var(--background-light);
}

.mode-card {
    background: var(--card-bg);
    border-radius: 1rem;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.05);
    border: 1px solid var(--border-color);
    max-width: 600px;
    width: 100%;
}

.mode-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    border-radius: 1rem 1rem 0 0;
    padding: 2rem;
    text-align: center;
}

.mode-option {
    padding: 1.5rem;
    margin: 1rem 0;
    border: 2px solid var(--border-color);
    border-radius: 0.75rem;
    cursor: pointer;
    transition: all 0.3s ease;
    background: var(--background-light);
}

.mode-option:hover {
    border-color: var(--primary-color);
    background: var(--card-bg);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.15);
}

.mode-option.selected {
    border-color: var(--primary-color);
    background: var(--primary-color);
    color: white;
}

.mode-option .form-check-input {
    display: none;
}

.mode-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.mode-option.selected .mode-icon {
    color: white;
}

.mode-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.mode-option.selected .mode-title {
    color: white;
}

.mode-description {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.mode-option.selected .mode-description {
    color: rgba(255, 255, 255, 0.9);
}

.mode-stats {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.mode-option.selected .mode-stats {
    color: rgba(255, 255, 255, 0.8);
}

.btn-start-chat {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    border: none;
    color: white;
    font-weight: 600;
    padding: 0.75rem 2rem;
    border-radius: 0.5rem;
    transition: var(--transition);
    width: 100%;
}

.btn-start-chat:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.4);
    color: white;
}

.selection-area {
    max-height: 200px;
    overflow-y: auto;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 0.5rem;
    background: white;
}

.document-item, .subject-item {
    padding: 0.75rem;
    border-radius: 0.375rem;
    cursor: pointer;
    transition: background-color 0.2s ease;
    border: 1px solid transparent;
    margin-bottom: 0.25rem;
}

.document-item:hover, .subject-item:hover {
    background: var(--background-light);
    border-color: var(--border-color);
}

.item-title {
    font-weight: 500;
    color: var(--text-primary);
}

.item-meta {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.empty-state {
    text-align: center;
    padding: 2rem;
    color: var(--text-secondary);
}

.empty-state i {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--text-muted);
}