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

:root {
    --bg: #f5f5f5;
    --surface: #ffffff;
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --danger: #dc2626;
    --text: #1e293b;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --radius: 8px;
    --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header & Toolbar */
header {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 12px 24px;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

header h1 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 8px;
}

#toolbar {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    align-items: center;
}

.toolbar-group {
    display: flex;
    align-items: center;
    gap: 8px;
}

.toolbar-group label {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 500;
}

/* Tool toggle buttons */
.tool-toggle {
    background: var(--bg);
    border-radius: var(--radius);
    padding: 2px;
}

.tool-btn {
    padding: 4px 12px;
    border: 1px solid transparent;
    background: transparent;
    font-size: 0.8rem;
    font-weight: 600;
    border-radius: 6px;
}

.tool-btn.active {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

.tool-btn:not(.active):hover {
    background: var(--surface);
}

#toolbar input[type="number"] {
    width: 56px;
    padding: 4px 6px;
    border: 1px solid var(--border);
    border-radius: 4px;
    font-size: 0.85rem;
    text-align: center;
}

#toolbar input[type="color"] {
    width: 32px;
    height: 28px;
    padding: 0;
    border: 1px solid var(--border);
    border-radius: 4px;
    cursor: pointer;
    background: none;
}

#toolbar input[type="range"] {
    width: 60px;
    height: 4px;
    cursor: pointer;
    accent-color: var(--primary);
    vertical-align: middle;
}

.opacity-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    min-width: 30px;
    text-align: right;
}

#toolbar select {
    padding: 4px 8px;
    border: 1px solid var(--border);
    border-radius: 4px;
    font-size: 0.85rem;
    background: var(--surface);
}

button {
    padding: 6px 14px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--surface);
    font-size: 0.85rem;
    cursor: pointer;
    transition: background 0.15s, border-color 0.15s;
    white-space: nowrap;
}

button:hover {
    background: var(--bg);
    border-color: #cbd5e1;
}

button.danger {
    color: var(--danger);
    border-color: var(--danger);
}

button.danger:hover:not(:disabled) {
    background: var(--danger);
    color: white;
}

button.primary {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
}

button.primary:hover {
    background: var(--primary-hover);
    border-color: var(--primary-hover);
}

#pageInfo {
    font-size: 0.85rem;
    color: var(--text-muted);
    min-width: 80px;
    text-align: center;
}

.toolbar-separator {
    color: var(--text-muted);
    font-size: 0.85rem;
}

/* Main Content */
main {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 24px;
}

/* Upload Area */
#uploadArea {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    min-height: 60vh;
}

#dropZone {
    border: 2px dashed var(--border);
    border-radius: 16px;
    padding: 48px 64px;
    text-align: center;
    background: var(--surface);
    transition: border-color 0.2s, background 0.2s;
    cursor: pointer;
    max-width: 480px;
    width: 100%;
}

#dropZone:hover,
#dropZone.dragover {
    border-color: var(--primary);
    background: #eff6ff;
}

#dropZone svg {
    color: var(--text-muted);
    margin-bottom: 16px;
}

#dropZone p {
    font-size: 1rem;
    margin-bottom: 8px;
}

#dropZone .subtle {
    font-size: 0.85rem;
    color: var(--text-muted);
}

#filePickerBtn {
    margin-top: 8px;
    background: var(--primary);
    color: white;
    border-color: var(--primary);
    padding: 10px 24px;
    font-size: 0.95rem;
    border-radius: var(--radius);
}

#filePickerBtn:hover {
    background: var(--primary-hover);
}

/* Editor Area */
#editorArea {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
}

#canvasContainer {
    position: relative;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    background: white;
    display: inline-block;
}

#pdfCanvas {
    display: block;
}

#textLayer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

#hint {
    margin-top: 12px;
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* Text Overlay Boxes */
.text-overlay {
    position: absolute;
    background: transparent;
    border: 1px dashed transparent;
    padding: 2px 4px;
    min-width: 40px;
    min-height: 1.2em;
    outline: none;
    cursor: text;
    word-break: break-word;
    white-space: pre-wrap;
    line-height: 1.2;
}

.text-overlay:focus,
.text-overlay:hover {
    border-color: var(--primary);
    background: rgba(37, 99, 235, 0.04);
}

.text-overlay.selected {
    border-color: var(--primary);
}

.text-overlay-handle {
    position: absolute;
    top: -18px;
    right: -2px;
    width: 16px;
    height: 16px;
    background: var(--danger);
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 10px;
    line-height: 16px;
    text-align: center;
    cursor: pointer;
    display: none;
    padding: 0;
}

.text-overlay:focus .text-overlay-handle,
.text-overlay:hover .text-overlay-handle {
    display: block;
}

/* Rectangle Overlay */
.rect-overlay {
    position: absolute;
    cursor: move;
    box-sizing: border-box;
}

.rect-overlay:hover,
.rect-overlay.selected {
    outline: 2px dashed var(--primary);
    outline-offset: 2px;
}

.rect-overlay .text-overlay-handle {
    display: none;
}

.rect-overlay:hover .text-overlay-handle {
    display: block;
}

.rect-overlay.dragging {
    cursor: grabbing;
    opacity: 0.8;
    outline: 2px dashed var(--primary);
    outline-offset: 2px;
}

/* Drawing cursor */
#textLayer.drawing-rect {
    cursor: crosshair;
}

/* Preview rectangle while dragging */
.rect-preview {
    position: absolute;
    border: 2px dashed var(--primary);
    background: rgba(37, 99, 235, 0.1);
    pointer-events: none;
}

/* Loading */
#loadingOverlay {
    position: fixed;
    inset: 0;
    background: rgba(255,255,255,0.85);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--border);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin-bottom: 12px;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Utility */
.hidden {
    display: none !important;
}

/* Responsive */
@media (max-width: 768px) {
    header {
        padding: 10px 12px;
    }

    #toolbar {
        gap: 8px;
    }

    .toolbar-group {
        gap: 4px;
    }

    #dropZone {
        padding: 32px 24px;
    }

    main {
        padding: 12px;
    }
}