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

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #64748b;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-light: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --border-color: #334155;
    --success: #10b981;
    --error: #ef4444;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    color: var(--text-primary);
    min-height: 100vh;
    padding: 20px;
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

header {
    text-align: center;
    margin-bottom: 40px;
    padding: 30px 0;
}

header h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 10px;
    background: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

header p {
    font-size: 1.2rem;
    color: var(--text-secondary);
}

.upload-section {
    margin-bottom: 30px;
}

.upload-area {
    border: 3px dashed var(--border-color);
    border-radius: 16px;
    padding: 60px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: var(--surface);
    position: relative;
    overflow: hidden;
}

.upload-area::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(99, 102, 241, 0.1), transparent);
    transition: left 0.5s;
}

.upload-area:hover::before {
    left: 100%;
}

.upload-area:hover {
    border-color: var(--primary-color);
    background: var(--surface-light);
    transform: translateY(-2px);
}

.upload-area.dragover {
    border-color: var(--primary-color);
    background: var(--surface-light);
    transform: scale(1.02);
}

.upload-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 20px;
    color: var(--primary-color);
    stroke-width: 1.5;
}

.upload-area h2 {
    font-size: 1.5rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.upload-area p {
    color: var(--text-secondary);
    font-size: 1rem;
}

.file-info {
    margin-top: 20px;
    padding: 20px;
    background: var(--surface);
    border-radius: 12px;
    text-align: center;
}

.file-info p {
    margin-bottom: 15px;
    color: var(--text-secondary);
}

.file-info strong {
    color: var(--text-primary);
}

#fileName {
    color: var(--primary-color);
    font-weight: 600;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
}

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

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
}

.btn-secondary {
    background: var(--surface-light);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

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

.btn-icon {
    padding: 10px;
    background: var(--surface-light);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
}

.btn-icon svg {
    width: 20px;
    height: 20px;
}

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

.viewer-section {
    background: var(--surface);
    border-radius: 16px;
    padding: 24px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
}

.viewer-header {
    margin-bottom: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}

.viewer-header h2 {
    font-size: 1.5rem;
    color: var(--text-primary);
}

.viewer-controls {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}

.page-info {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

#pageInput {
    width: 60px;
    padding: 6px 10px;
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-primary);
    font-size: 0.9rem;
    text-align: center;
}

#pageInput:focus {
    outline: none;
    border-color: var(--primary-color);
}

.zoom-level {
    padding: 0 10px;
    color: var(--text-secondary);
    font-size: 0.9rem;
    min-width: 50px;
    text-align: center;
}

.pdf-viewer {
    background: #2d3748;
    border-radius: 12px;
    padding: 20px;
    overflow: auto;
    max-height: calc(100vh - 300px);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    box-shadow: inset 0 2px 10px rgba(0, 0, 0, 0.3);
}

#pdfCanvas {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
    background: white;
}

@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    .upload-area {
        padding: 40px 15px;
    }

    .viewer-header {
        flex-direction: column;
        align-items: stretch;
    }

    .viewer-controls {
        justify-content: center;
    }

    .pdf-viewer {
        max-height: calc(100vh - 400px);
        padding: 10px;
    }
}