:root {
    --fb-primary: #3b82f6; --fb-primary-hover: #2563eb; --fb-bg: #f9fafb; --fb-border: #e5e7eb;
    --fb-text: #1f2937; --fb-radius: 0.5rem;
}
.fb-wrapper * { box-sizing: border-box; }
.fb-wrapper { display: flex; gap: 2rem; align-items: flex-start; font-family: 'Inter', sans-serif; color: var(--fb-text); position: relative; }

/* Sidebar Positioning */
.fb-wrapper.fb-sidebar-right {
    flex-direction: row-reverse;
}

/* Canvas Area */
.fb-canvas-area { flex: 1; min-width: 0; display: flex; flex-direction: column; width: 100%; }

/* The Canvas itself */
.fb-canvas { 
    min-height: 500px; 
    background: white; 
    border: 2px dashed #d1d5db; 
    border-radius: 0.75rem; 
    padding: 2rem; 
    position: relative; /* Context for absolute centering */
    padding-bottom: 5rem; 
    transition: background 0.2s; 
}
.fb-canvas.drop-active { background-color: #eff6ff; border-color: var(--fb-primary); }

/* Empty State - Centered */
.fb-empty { 
    position: absolute; 
    top: 50%; 
    left: 50%; 
    transform: translate(-50%, -50%); /* True Center */
    display: flex; 
    flex-direction: column; 
    align-items: center; 
    justify-content: center; 
    text-align: center; 
    pointer-events: none; 
    opacity: 0.5; 
    width: 100%;
}
.fb-canvas:not(:empty) + .fb-empty { display: none; }

/* Sidebar (Toolbox) */
.fb-sidebar { 
    width: 18rem; 
    flex-shrink: 0; 
    position: sticky; 
    top: 1rem; 
    background: white; 
    border: 1px solid var(--fb-border); 
    border-radius: 0.75rem; 
    overflow: hidden; 
    box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1); 
    display: flex; 
    flex-direction: column; 
}
.fb-sidebar-header { padding: 1rem; background: #f9fafb; border-bottom: 1px solid var(--fb-border); font-weight: 700; font-size: 0.75rem; text-transform: uppercase; display: flex; align-items: center; gap: 0.5rem; }
.fb-toolbox { padding: 0.75rem; display: flex; flex-direction: column; gap: 0.5rem; overflow-y: auto; max-height: calc(100vh - 100px); }

/* Draggable Items */
.fb-item { display: flex; align-items: center; gap: 0.75rem; padding: 0.75rem; background: white; border: 1px solid var(--fb-border); border-radius: var(--fb-radius); cursor: pointer; user-select: none; transition: all 0.2s; }
.fb-item:hover { border-color: var(--fb-primary); box-shadow: 0 1px 2px rgba(0,0,0,0.05); background: #eff6ff; }
.fb-item span { font-size: 0.875rem; font-weight: 500; }
.fb-item.dragging { opacity: 0.5; }

/* Form Elements (Card) */
.fb-field { position: relative; padding: 1.25rem; background: white; border: 1px solid var(--fb-border); border-radius: 0.75rem; margin-bottom: 1rem; animation: fbSlideIn 0.2s ease-out; }
@keyframes fbSlideIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }
.fb-field:hover { border-color: #93c5fd; box-shadow: 0 4px 6px -1px rgba(0,0,0,0.05); }

/* Action Bar */
.fb-actions { position: absolute; right: 0.75rem; top: 0.75rem; display: flex; gap: 0.25rem; background: white; padding: 0.25rem; border: 1px solid var(--fb-border); border-radius: 0.5rem; opacity: 0; transition: opacity 0.2s; z-index: 10; }
.fb-field:hover .fb-actions { opacity: 1; }
.fb-btn { padding: 0.35rem; color: #9ca3af; background: transparent; border: none; cursor: pointer; border-radius: 0.25rem; display: flex; }
.fb-btn:hover { background: #f3f4f6; color: var(--fb-primary); }
.fb-btn.delete:hover { background: #fef2f2; color: #ef4444; }

/* Inputs */
.fb-label { display: block; font-size: 0.875rem; font-weight: 700; margin-bottom: 0.5rem; outline: none; border-bottom: 2px solid transparent; width: 100%; }
.fb-label:focus { border-color: var(--fb-primary); }
.fb-input-visual { width: 100%; background: #f9fafb; border: 1px solid #d1d5db; border-radius: var(--fb-radius); position: relative; }
.fb-input-visual.text { height: 2.5rem; } 
.fb-input-visual.textarea { height: 5rem; }

/* Footer & Helpers */
.fb-field-footer { margin-top: 1rem; padding-top: 0.75rem; border-top: 1px solid var(--fb-border); display: flex; justify-content: space-between; align-items: center; }
.fb-helper { font-size: 0.75rem; color: #9ca3af; font-style: italic; outline: none; flex: 1; transition: color 0.2s; border-bottom: 1px solid transparent; }
.fb-helper:hover { border-bottom: 1px dashed var(--fb-border); }
.fb-helper:focus { border-bottom: 1px solid var(--fb-border); }

/* Toggle Switch */
.fb-toggle-wrapper { display: flex; align-items: center; gap: 0.75rem; padding-left: 1rem; border-left: 1px solid var(--fb-border); }
.fb-toggle-label { font-size: 0.75rem; font-weight: 600; color: #6b7280; text-transform: uppercase; letter-spacing: 0.025em; }
.fb-switch { position: relative; display: inline-block; width: 2.25rem; height: 1.25rem; }
.fb-switch input { opacity: 0; width: 0; height: 0; }
.fb-slider { position: absolute; cursor: pointer; top: 0; left: 0; right: 0; bottom: 0; background-color: #e5e7eb; transition: .4s; border-radius: 34px; }
.fb-slider:before { position: absolute; content: ""; height: 1rem; width: 1rem; left: 0.125rem; bottom: 0.125rem; background-color: white; transition: .4s; border-radius: 50%; box-shadow: 0 1px 2px rgba(0,0,0,0.1); }
input:checked + .fb-slider { background-color: var(--fb-primary); }
input:focus + .fb-slider { box-shadow: 0 0 1px var(--fb-primary); }
input:checked + .fb-slider:before { transform: translateX(1rem); }

[contenteditable]:hover { background: #f3f4f6; border-radius: 4px; }

/* --- RESPONSIVE DESIGN --- */
@media (max-width: 768px) {
    /* Reset order for mobile: Sidebar first (top), Canvas second (bottom) */
    .fb-wrapper, 
    .fb-wrapper.fb-sidebar-right { 
        flex-direction: column; 
    } 
    
    .fb-sidebar { width: 100%; position: relative; top: 0; margin-bottom: 1.5rem; max-height: none; }
    
    /* Scrollable horizontal/grid toolbox */
    .fb-toolbox { 
        display: grid; 
        grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); 
        gap: 0.5rem; 
        padding: 1rem;
        max-height: 200px;
    }
    
    .fb-item { justify-content: center; flex-direction: column; text-align: center; gap: 0.25rem; }
    .fb-canvas { min-height: 300px; padding: 1rem; }
    .fb-actions { opacity: 1; border-color: #d1d5db; }
}