body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: rgba(255, 255, 255, 0.95);
    border-radius: 15px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(10px);
}

h1, h2 {
    text-align: center;
    color: #4a5568;
    margin-bottom: 30px;
}

h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
}

.subtitle {
    text-align: center;
    color: #718096;
    font-size: 1.1em;
    margin-bottom: 40px;
}

.form-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #4a5568;
}

input, select, textarea {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s ease;
    box-sizing: border-box;
}

input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

button, .btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 12px 25px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 16px;
    font-weight: 600;
    text-decoration: none;
    display: inline-block;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    margin: 5px;
}

button:hover, .btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
    background: linear-gradient(135deg, #718096 0%, #4a5568 100%);
}

.btn-danger {
    background: linear-gradient(135deg, #e53e3e 0%, #c53030 100%);
}

.alert {
    padding: 15px;
    margin: 20px 0;
    border-radius: 8px;
    font-weight: 500;
}

.alert-success {
    background-color: #c6f6d5;
    color: #22543d;
    border: 1px solid #9ae6b4;
}

.alert-error {
    background-color: #fed7d7;
    color: #742a2a;
    border: 1px solid #fc8181;
}

.alert-info {
    background-color: #bee3f8;
    color: #2a4365;
    border: 1px solid #90cdf4;
}

.upload-zone {
    border: 3px dashed #cbd5e0;
    border-radius: 12px;
    padding: 40px;
    text-align: center;
    margin: 20px 0;
    transition: all 0.3s ease;
    background: #f7fafc;
}

.upload-zone.dragover {
    border-color: #667eea;
    background: #edf2f7;
}

.upload-zone:hover {
    border-color: #a0aec0;
}

.file-info {
    background: #f7fafc;
    padding: 15px;
    border-radius: 8px;
    margin: 10px 0;
    border-left: 4px solid #667eea;
}

.download-link {
    background: #e6fffa;
    padding: 20px;
    border-radius: 8px;
    margin: 20px 0;
    border: 1px solid #81e6d9;
    word-break: break-all;
}

.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin: 30px 0;
}

.stat-card {
    background: #f7fafc;
    padding: 20px;
    border-radius: 8px;
    text-align: center;
    border-left: 4px solid #667eea;
}

.stat-number {
    font-size: 2em;
    font-weight: bold;
    color: #4a5568;
}

.stat-label {
    color: #718096;
    margin-top: 5px;
}

.table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}

.table th,
.table td {
    padding: 12px;
    text-align: left;
    border-bottom: 1px solid #e2e8f0;
}

.table th {
    background: #f7fafc;
    font-weight: 600;
    color: #4a5568;
}

.table tr:hover {
    background: #f7fafc;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: #e2e8f0;
    border-radius: 4px;
    overflow: hidden;
    margin: 10px 0;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea 0%, #764ba2 100%);
    transition: width 0.3s ease;
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 2px solid #e2e8f0;
}

.nav-links {
    display: flex;
    gap: 15px;
}

@media (max-width: 768px) {
    .container {
        margin: 10px;
        padding: 20px;
    }
    
    .stats {
        grid-template-columns: 1fr;
    }
    
    .nav {
        flex-direction: column;
        gap: 15px;
    }
}

.code-display {
    background: #2d3748;
    color: #e2e8f0;
    padding: 20px;
    border-radius: 8px;
    font-family: 'Courier New', monospace;
    font-size: 18px;
    font-weight: bold;
    text-align: center;
    margin: 20px 0;
    letter-spacing: 2px;
}

.copy-btn {
    background: #4299e1;
    font-size: 14px;
    padding: 8px 15px;
}

.login-form {
    max-width: 400px;
    margin: 50px auto;
}