:root {
    --primary-color: #0078d4;
    --primary-hover: #106ebe;
    --success-color: #107c10;
    --error-color: #d13438;
    --text-color: #323130;
    --border-color: #d1d1d1;
    --bg-gray: #f3f2f1;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: white;
    border-radius: 12px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px 30px;
    text-align: center;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 5px;
}

header .subtitle {
    font-size: 1.1rem;
    opacity: 0.95;
}

main {
    padding: 40px 30px;
    min-height: 400px;
}

.drop-zone {
    border: 3px dashed var(--border-color);
    border-radius: 12px;
    padding: 60px 30px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: var(--bg-gray);
}

.drop-zone:hover {
    border-color: var(--primary-color);
    background: #e8f4fd;
}

.drop-zone.drag-over {
    border-color: var(--primary-color);
    background: #e8f4fd;
    transform: scale(1.02);
}

.upload-icon {
    width: 64px;
    height: 64px;
    color: var(--primary-color);
    margin-bottom: 20px;
}

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

.drop-zone p {
    color: #605e5c;
    margin-bottom: 5px;
}

.file-hint {
    font-size: 0.9rem;
    color: #8a8886;
    margin-top: 10px;
}

.file-info {
    background: var(--bg-gray);
    padding: 30px;
    border-radius: 12px;
    text-align: center;
}

.file-info p {
    margin-bottom: 15px;
    font-size: 1.05rem;
}

.btn {
    padding: 12px 32px;
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    margin: 5px;
}

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

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 120, 212, 0.3);
}

.btn-secondary {
    background: #f3f2f1;
    color: var(--text-color);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: #e1dfdd;
}

.btn-success {
    background: var(--success-color);
    color: white;
    font-size: 1.1rem;
}

.btn-success:hover {
    background: #0e6b0e;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(16, 124, 16, 0.3);
}

.processing-section,
.success-section,
.error-section {
    text-align: center;
    padding: 40px 20px;
}

.spinner {
    border: 4px solid var(--bg-gray);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 60px;
    height: 60px;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.success-icon,
.error-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 20px;
}

.success-icon {
    color: var(--success-color);
}

.error-icon {
    color: var(--error-color);
}

.success-section h3 {
    color: var(--success-color);
    margin-bottom: 15px;
}

.error-section h3 {
    color: var(--error-color);
    margin-bottom: 15px;
}

footer {
    background: var(--bg-gray);
    padding: 30px;
    border-top: 1px solid var(--border-color);
}

.info-box {
    background: white;
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 20px;
    border: 1px solid var(--border-color);
}

.info-box h4 {
    color: var(--primary-color);
    margin-bottom: 15px;
}

.info-box ul {
    list-style: none;
    padding-left: 0;
}

.info-box li {
    padding: 8px 0;
    border-bottom: 1px solid var(--bg-gray);
}

.info-box li:last-child {
    border-bottom: none;
}

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

.version {
    text-align: center;
    color: #8a8886;
    font-size: 0.9rem;
}

@media (max-width: 600px) {
    header h1 {
        font-size: 1.8rem;
    }
    
    .drop-zone {
        padding: 40px 20px;
    }
    
    main {
        padding: 30px 20px;
    }
}