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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: #f8f9fa;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

.header {
    background: #2c3e50;
    color: white;
    padding: 15px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.header h1 {
    font-size: 1.5rem;
    margin: 0;
}

.header .user-info {
    display: flex;
    align-items: center;
    gap: 10px;
}

.login-container {
    max-width: 400px;
    margin: 50px auto;
    padding: 30px;
    background: white;
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
}

.login-container h2 {
    text-align: center;
    margin-bottom: 20px;
    color: #2c3e50;
}

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

.login-container label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
}

.login-container input {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 1rem;
}

.login-container button {
    width: 100%;
    padding: 12px;
    background: #2c3e50;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.3s;
}

.login-container button:hover {
    background: #1a252f;
}

.alert {
    padding: 15px;
    margin: 20px 0;
    border-radius: 5px;
    font-weight: bold;
}

.alert-danger {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.dashboard {
    background: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
    margin-top: 20px;
}

.dashboard h2 {
    color: #2c3e50;
    margin-bottom: 20px;
    border-bottom: 2px solid #2c3e50;
    padding-bottom: 10px;
}

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

.action-card {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 10px;
    text-align: center;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    transition: transform 0.3s;
    cursor: pointer;
}

.action-card:hover {
    transform: translateY(-5px);
    background: #e9ecef;
}

.action-card i {
    font-size: 2rem;
    margin-bottom: 10px;
    color: #2c3e50;
}

.action-card a {
    display: block;
    text-decoration: none;
    color: #2c3e50;
    font-weight: bold;
    margin-top: 10px;
}

.upload-section {
    background: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
    margin-top: 20px;
}

.drop-zone {
    border: 2px dashed #2c3e50;
    border-radius: 10px;
    padding: 30px;
    text-align: center;
    cursor: pointer;
    transition: background 0.3s;
    margin-bottom: 20px;
}

.drop-zone:hover {
    background: #e9ecef;
}

.drop-zone i {
    font-size: 3rem;
    color: #2c3e50;
    margin-bottom: 10px;
}

.drop-zone p {
    margin: 10px 0;
    font-weight: bold;
}

.validate-section {
    background: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
    margin-top: 20px;
}

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

.summary-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 15px;
    border-radius: 10px;
    text-align: center;
}

.error { background: #ffebee; border-left: 5px solid #f44336; }
.warning { background: #fff8e1; border-left: 5px solid #ff9800; }
.success { background: #e8f5e9; border-left: 5px solid #4caf50; }

.btn {
    padding: 8px 16px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-weight: bold;
    transition: background 0.3s;
    text-decoration: none;
    display: inline-block;
    text-align: center;
}

.btn-primary { background: #2c3e50; color: white; }
.btn-primary:hover { background: #1a252f; }
.btn-secondary { background: #6c757d; color: white; }
.btn-secondary:hover { background: #545b62; }

.footer {
    text-align: center;
    padding: 10px;
    background: #333;
    color: white;
    font-size: 0.9rem;
    margin-top: 30px;
}

.preview-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
    background: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.preview-table th {
    background: #2c3e50;
    color: white;
    padding: 12px;
    text-align: left;
}

.preview-table td {
    padding: 10px;
    border-bottom: 1px solid #eee;
}

@media (max-width: 768px) {
    .header { flex-direction: column; text-align: center; }
    .actions { grid-template-columns: 1fr; }
    .summary { grid-template-columns: 1fr; }
}