:root {
    --bg-color: #181818;
    --container-bg: #222;
    --text-color: #fff;
    --text-muted: #aaa;
    --primary-bg: #00c853;
    --primary-hover: #009624;
    --secondary-bg: #555;
    --secondary-hover: #444;
    --danger-bg: #d32f2f;
    --danger-hover: #b71c1c;
    --border-color: #444;
    --dropzone-bg: #2a2a2a;
    --dropzone-border: #444;
    --dropzone-active: #333;
}

.light-mode {
    --bg-color: #f5f5f5;
    --container-bg: #ffffff;
    --text-color: #333;
    --text-muted: #666;
    --primary-bg: #007BFF;
    --primary-hover: #0056b3;
    --secondary-bg: #6c757d;
    --secondary-hover: #5a6268;
    --danger-bg: #dc3545;
    --danger-hover: #bd2130;
    --border-color: #ddd;
    --dropzone-bg: #f8f9fa;
    --dropzone-border: #ced4da;
    --dropzone-active: #e9ecef;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    padding: 20px;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background: var(--container-bg);
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

h1 {
    font-size: 28px;
    color: var(--text-color);
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.btn {
    padding: 10px 16px;
    border: none;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.btn.primary {
    background-color: var(--primary-bg);
    color: white;
}

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

.btn.secondary {
    background-color: var(--secondary-bg);
    color: white;
}

.btn.secondary:hover {
    background-color: var(--secondary-hover);
}

.btn.danger {
    background-color: var(--danger-bg);
    color: white;
}

.btn.danger:hover {
    background-color: var(--danger-hover);
}

.btn-group {
    display: flex;
    gap: 10px;
    margin-bottom: 15px;
    flex-wrap: wrap;
}

.upload-area {
    border: 2px dashed var(--dropzone-border);
    border-radius: 8px;
    padding: 30px;
    text-align: center;
    background-color: var(--dropzone-bg);
    transition: all 0.3s ease;
    margin-bottom: 20px;
}

.upload-area:hover {
    background-color: var(--dropzone-active);
}

.upload-area.drag-over {
    background-color: var(--dropzone-active);
    border-color: var(--primary-bg);
}

.upload-prompt {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.upload-prompt svg {
    margin-bottom: 10px;
}

.file-requirements {
    color: var(--text-muted);
    font-size: 12px;
    margin-top: 5px;
}

.status-message {
    padding: 10px;
    margin: 10px 0;
    border-radius: 4px;
    text-align: center;
    font-weight: 500;
}

.status-message.success {
    color: var(--primary-bg);
}

.status-message.error {
    color: var(--danger-bg);
}

.pdf-container {
    margin-top: 20px;
}

.pdf-controls {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 20px;
    margin-bottom: 15px;
}

.canvas-wrapper {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 15px;
    overflow: auto;
    max-height: 70vh;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background-color: var(--bg-color);
    padding: 10px;
}

/* A4 size: 210mm x 297mm ≈ 794 x 1123 pixels at 96 DPI */
canvas {
    display: block;
    width: 794px;   /* or use width: 210mm; */
    height: 1123px; /* or use height: 297mm; */
    background: white;
    box-shadow: 0 0 8px rgba(0, 0, 0, 0.1);
    border: 1px solid #ccc;
    margin: 0 auto;
}

.view-options {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-top: 15px;
}

.controls {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: 15px;
}

.controls label {
    font-size: 14px;
    color: var(--text-color);
}

.controls input[type="range"] {
    width: 100%;
    max-width: 300px;
}

.loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 15px;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.7);
    z-index: 1000;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 5px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: var(--primary-bg);
    animation: spin 1s ease-in-out infinite;
}

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

.hidden {
    display: none !important;
}

@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .btn-group {
        flex-direction: column;
    }
    
    .upload-area {
        padding: 20px;
    }
}