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

:root {
    --primary-color: #667eea;
    --primary-dark: #5568d3;
    --secondary-color: #764ba2;
    --success-color: #27ae60;
    --danger-color: #e74c3c;
    --text-color: #333;
    --text-light: #666;
    --border-color: #e0e0e0;
    --bg-light: #f5f5f5;
    --white: #ffffff;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    color: var(--text-color);
    background: var(--bg-light);
    min-height: 100vh;
}

.screen {
    display: none;
}

.screen.active {
    display: block;
}

/* Login Screen */
.login-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    padding: 20px;
}

.login-box {
    background: var(--white);
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    padding: 40px;
    width: 100%;
    max-width: 400px;
}

.login-header {
    text-align: center;
    margin-bottom: 30px;
}

.login-header h1 {
    font-size: 2.5em;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.login-header p {
    color: var(--text-light);
    font-size: 1.1em;
}

.login-form {
    margin-top: 30px;
}

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

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-color);
    font-weight: 600;
}

.form-group input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    text-decoration: none;
    display: inline-block;
}

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

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

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

.btn-secondary:hover {
    background: #555;
}

.btn-block {
    width: 100%;
}

.error-message {
    background: #f8d7da;
    color: #721c24;
    padding: 12px;
    border-radius: 8px;
    margin-bottom: 20px;
    border-left: 4px solid var(--danger-color);
}

/* Main Screen */
.header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: var(--white);
    padding: 20px 0;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header h1 {
    font-size: 1.8em;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 15px;
}

.user-info {
    font-size: 14px;
    opacity: 0.9;
}

.main-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 30px 20px;
}

.content-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
    gap: 15px;
}

.content-header h2 {
    font-size: 1.8em;
    color: var(--text-color);
}

.search-box-container {
    flex: 1;
    min-width: 250px;
    max-width: 400px;
}

.search-box {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s;
}

.search-box:focus {
    outline: none;
    border-color: var(--primary-color);
}

.loading {
    text-align: center;
    padding: 60px 20px;
    color: var(--primary-color);
}

.spinner {
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

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

.users-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.user-card {
    background: var(--white);
    border-radius: 12px;
    padding: 20px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.user-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 20px rgba(0,0,0,0.15);
}

.user-card-header {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
}

.user-avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    font-size: 1.5em;
    font-weight: bold;
}

.user-info-card h3 {
    font-size: 1.2em;
    margin-bottom: 5px;
    color: var(--text-color);
}

.user-info-card p {
    color: var(--text-light);
    font-size: 0.9em;
}

.user-details {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid var(--border-color);
}

.user-detail-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
    font-size: 0.9em;
}

.user-detail-label {
    color: var(--text-light);
    font-weight: 600;
}

.user-detail-value {
    color: var(--text-color);
}

.badge {
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    display: inline-block;
}

.badge-success {
    background: #d4edda;
    color: #155724;
}

.badge-danger {
    background: #f8d7da;
    color: #721c24;
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-light);
}

.empty-state svg {
    width: 100px;
    height: 100px;
    margin-bottom: 20px;
    opacity: 0.3;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--white);
    padding: 30px;
    border-radius: 12px;
    max-width: 600px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--border-color);
}

.modal-header h2 {
    color: var(--primary-color);
    font-size: 1.8em;
}

.close-btn {
    background: none;
    border: none;
    font-size: 28px;
    cursor: pointer;
    color: var(--text-light);
    transition: color 0.3s;
    padding: 0;
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.close-btn:hover {
    color: var(--text-color);
}

.form-actions {
    display: flex;
    gap: 10px;
    justify-content: flex-end;
    margin-top: 30px;
}

.success-message {
    background: #d4edda;
    color: #155724;
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 20px;
    border-left: 4px solid var(--success-color);
}

.user-card-actions {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid var(--border-color);
    display: flex;
    gap: 10px;
}

@media (max-width: 768px) {
    .content-header {
        flex-direction: column;
        align-items: stretch;
    }

    .search-box-container {
        max-width: 100%;
    }

    .users-container {
        grid-template-columns: 1fr;
    }

    .header-content {
        flex-direction: column;
        gap: 15px;
    }
}