/* Reset và Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

/* Header Styles */
.header {
    background: linear-gradient(135deg, #2c3e50 0%, #34495e 100%);
    color: white;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    position: relative;
    z-index: 1000;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: bold;
    color: #3498db;
}

.logo i {
    font-size: 2rem;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.1); }
    100% { transform: scale(1); }
}

.store-info h2 {
    font-size: 1.2rem;
    margin-bottom: 0.25rem;
    color: #ecf0f1;
}

.store-info p {
    font-size: 0.9rem;
    color: #bdc3c7;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.user-info, .clock {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: rgba(255,255,255,0.1);
    border-radius: 25px;
    backdrop-filter: blur(10px);
    transition: all 0.3s ease;
}

.user-info:hover, .clock:hover {
    background: rgba(255,255,255,0.2);
    transform: translateY(-2px);
}

.btn-logout {
    background: linear-gradient(135deg, #e74c3c 0%, #c0392b 100%);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 25px;
    cursor: pointer;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(231, 76, 60, 0.3);
}

.btn-logout:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(231, 76, 60, 0.4);
}

/* Main Content */
.main-content {
    display: flex;
    height: calc(100vh - 80px);
}

/* Sidebar Styles */
.sidebar {
    width: 320px;
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(20px);
    border-right: 1px solid rgba(255,255,255,0.2);
    overflow-y: auto;
    box-shadow: 4px 0 20px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
}

.sidebar::-webkit-scrollbar {
    width: 6px;
}

.sidebar::-webkit-scrollbar-track {
    background: rgba(0,0,0,0.1);
}

.sidebar::-webkit-scrollbar-thumb {
    background: rgba(52, 152, 219, 0.5);
    border-radius: 3px;
}

.nav-section {
    margin-bottom: 1rem;
}

.nav-section-title {
    padding: 1rem 1.5rem 0.5rem;
    font-size: 0.85rem;
    font-weight: 700;
    color: #2c3e50;
    text-transform: uppercase;
    letter-spacing: 1px;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    border-bottom: 2px solid #ecf0f1;
    margin-bottom: 0.5rem;
}

.nav-section-title i {
    color: #3498db;
    font-size: 1rem;
}

.nav-menu {
    list-style: none;
}

.nav-item {
    margin-bottom: 0.25rem;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1.5rem;
    color: #34495e;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    border-radius: 0 25px 25px 0;
    margin-right: 1rem;
    position: relative;
    overflow: hidden;
}

.nav-link::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 0;
    background: linear-gradient(135deg, #3498db 0%, #2980b9 100%);
    transition: width 0.3s ease;
    z-index: -1;
}

.nav-link:hover::before {
    width: 100%;
}

.nav-link:hover {
    color: white;
    transform: translateX(5px);
    box-shadow: 0 4px 15px rgba(52, 152, 219, 0.3);
}

.nav-link.active {
    background: linear-gradient(135deg, #3498db 0%, #2980b9 100%);
    color: white;
    box-shadow: 0 4px 15px rgba(52, 152, 219, 0.3);
}

.nav-link i {
    font-size: 1.1rem;
    width: 20px;
    text-align: center;
}

/* Content Area */
.content-area {
    flex: 1;
    padding: 2rem;
    overflow-y: auto;
    background: rgba(255,255,255,0.1);
    backdrop-filter: blur(10px);
}

.content-area::-webkit-scrollbar {
    width: 8px;
}

.content-area::-webkit-scrollbar-track {
    background: rgba(0,0,0,0.1);
}

.content-area::-webkit-scrollbar-thumb {
    background: rgba(52, 152, 219, 0.5);
    border-radius: 4px;
}

/* Screen Styles */
.screen {
    display: none;
    animation: fadeIn 0.5s ease;
}

.screen.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Login Screen */
.login-screen {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.login-container {
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(20px);
    padding: 3rem;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.1);
    width: 100%;
    max-width: 400px;
    text-align: center;
}

.login-container h1 {
    color: #2c3e50;
    margin-bottom: 2rem;
    font-size: 2rem;
}

.login-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.form-group {
    text-align: left;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: #34495e;
    font-weight: 600;
}

.form-group input {
    width: 100%;
    padding: 1rem;
    border: 2px solid #ecf0f1;
    border-radius: 10px;
    font-size: 1rem;
    transition: all 0.3s ease;
    background: rgba(255,255,255,0.8);
}

.form-group input:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.btn-login {
    background: linear-gradient(135deg, #3498db 0%, #2980b9 100%);
    color: white;
    border: none;
    padding: 1rem;
    border-radius: 10px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(52, 152, 219, 0.3);
}

.btn-login:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(52, 152, 219, 0.4);
}

/* POS Screen */
.pos-screen {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 2rem;
    height: 100%;
}

.products-grid {
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(20px);
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    overflow-y: auto;
}

.products-grid h2 {
    color: #2c3e50;
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.product-categories {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.category-btn {
    background: rgba(52, 152, 219, 0.1);
    color: #3498db;
    border: 2px solid #3498db;
    padding: 0.75rem 1.5rem;
    border-radius: 25px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
}

.category-btn:hover, .category-btn.active {
    background: #3498db;
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(52, 152, 219, 0.3);
}

.products-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
}

.product-card {
    background: white;
    border-radius: 10px;
    padding: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.product-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
    border-color: #3498db;
}

.product-card h3 {
    color: #2c3e50;
    margin-bottom: 0.5rem;
    font-size: 1rem;
}

.product-card .price {
    color: #e74c3c;
    font-weight: bold;
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
}

.product-card .stock {
    color: #7f8c8d;
    font-size: 0.9rem;
}

/* Cart Section */
.cart-section {
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(20px);
    border-radius: 15px;
    padding: 1.5rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    display: flex;
    flex-direction: column;
}

.cart-section h2 {
    color: #2c3e50;
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.cart-items {
    flex: 1;
    overflow-y: auto;
    margin-bottom: 1rem;
}

.cart-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    background: rgba(52, 152, 219, 0.1);
    border-radius: 10px;
    margin-bottom: 0.5rem;
    transition: all 0.3s ease;
}

.cart-item:hover {
    background: rgba(52, 152, 219, 0.2);
}

.cart-item-info h4 {
    color: #2c3e50;
    margin-bottom: 0.25rem;
}

.cart-item-info .price {
    color: #e74c3c;
    font-weight: bold;
}

.cart-item-controls {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.quantity-btn {
    background: #3498db;
    color: white;
    border: none;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    cursor: pointer;
    font-weight: bold;
    transition: all 0.3s ease;
}

.quantity-btn:hover {
    background: #2980b9;
    transform: scale(1.1);
}

.quantity-display {
    font-weight: bold;
    color: #2c3e50;
    min-width: 30px;
    text-align: center;
}

.cart-total {
    border-top: 2px solid #ecf0f1;
    padding-top: 1rem;
    margin-top: auto;
}

.total-row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.total-row.final {
    font-size: 1.2rem;
    color: #e74c3c;
    border-top: 1px solid #ecf0f1;
    padding-top: 0.5rem;
}

.payment-methods {
    margin: 1rem 0;
}

.payment-method {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 5px;
    transition: all 0.3s ease;
}

.payment-method:hover {
    background: rgba(52, 152, 219, 0.1);
}

.payment-method input[type="radio"] {
    margin: 0;
}

.cart-actions {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.btn-clear, .btn-checkout {
    flex: 1;
    padding: 1rem;
    border: none;
    border-radius: 10px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn-clear {
    background: #e74c3c;
    color: white;
}

.btn-clear:hover {
    background: #c0392b;
    transform: translateY(-2px);
}

.btn-checkout {
    background: linear-gradient(135deg, #27ae60 0%, #2ecc71 100%);
    color: white;
}

.btn-checkout:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(39, 174, 96, 0.4);
}

/* Responsive Design */
@media (max-width: 1200px) {
    .sidebar {
        width: 280px;
    }
    
    .pos-screen {
        grid-template-columns: 1.5fr 1fr;
    }
}

@media (max-width: 768px) {
    .main-content {
        flex-direction: column;
    }
    
    .sidebar {
        width: 100%;
        height: auto;
        max-height: 300px;
    }
    
    .pos-screen {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .header {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .header-left, .header-right {
        flex-direction: column;
        gap: 1rem;
    }
}

/* Loading Animation */
.loading {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 200px;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #ecf0f1;
    border-top: 4px solid #3498db;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Notification Styles */
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 1rem 1.5rem;
    border-radius: 10px;
    color: white;
    font-weight: 600;
    z-index: 10000;
    animation: slideIn 0.3s ease;
    max-width: 300px;
}

.notification.success {
    background: linear-gradient(135deg, #27ae60 0%, #2ecc71 100%);
}

.notification.error {
    background: linear-gradient(135deg, #e74c3c 0%, #c0392b 100%);
}

.notification.warning {
    background: linear-gradient(135deg, #f39c12 0%, #e67e22 100%);
}

@keyframes slideIn {
    from { transform: translateX(100%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    z-index: 10000;
    backdrop-filter: blur(5px);
}

.modal.active {
    display: flex;
    justify-content: center;
    align-items: center;
}

.modal-content {
    background: white;
    border-radius: 15px;
    padding: 2rem;
    max-width: 500px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: 0 20px 40px rgba(0,0,0,0.2);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from { transform: scale(0.8); opacity: 0; }
    to { transform: scale(1); opacity: 1; }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid #ecf0f1;
}

.modal-title {
    font-size: 1.5rem;
    color: #2c3e50;
    font-weight: 600;
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: #7f8c8d;
    transition: color 0.3s ease;
}

.modal-close:hover {
    color: #e74c3c;
}

/* Button Styles */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, #3498db 0%, #2980b9 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(52, 152, 219, 0.4);
}

.btn-success {
    background: linear-gradient(135deg, #27ae60 0%, #2ecc71 100%);
    color: white;
}

.btn-success:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(39, 174, 96, 0.4);
}

.btn-danger {
    background: linear-gradient(135deg, #e74c3c 0%, #c0392b 100%);
    color: white;
}

.btn-danger:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(231, 76, 60, 0.4);
}

.btn-warning {
    background: linear-gradient(135deg, #f39c12 0%, #e67e22 100%);
    color: white;
}

.btn-warning:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(243, 156, 18, 0.4);
}

/* Table Styles */
.table-container {
    background: white;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.table {
    width: 100%;
    border-collapse: collapse;
}

.table th {
    background: linear-gradient(135deg, #3498db 0%, #2980b9 100%);
    color: white;
    padding: 1rem;
    text-align: left;
    font-weight: 600;
}

.table td {
    padding: 1rem;
    border-bottom: 1px solid #ecf0f1;
}

.table tr:hover {
    background: rgba(52, 152, 219, 0.05);
}

/* Form Styles */
.form-container {
    background: white;
    border-radius: 10px;
    padding: 2rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
    margin-bottom: 1rem;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #2c3e50;
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 0.75rem;
    border: 2px solid #ecf0f1;
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

/* Card Styles */
.card {
    background: white;
    border-radius: 10px;
    padding: 1.5rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid #ecf0f1;
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: #2c3e50;
}

/* Status Badges */
.badge {
    padding: 0.25rem 0.75rem;
    border-radius: 15px;
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: uppercase;
}

.badge-success {
    background: rgba(39, 174, 96, 0.1);
    color: #27ae60;
}

.badge-warning {
    background: rgba(243, 156, 18, 0.1);
    color: #f39c12;
}

.badge-danger {
    background: rgba(231, 76, 60, 0.1);
    color: #e74c3c;
}

.badge-info {
    background: rgba(52, 152, 219, 0.1);
    color: #3498db;
}

/* Grid Layout */
.grid {
    display: grid;
    gap: 1.5rem;
}

.grid-2 {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

.grid-4 {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

/* Utility Classes */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }

.p-1 { padding: 0.5rem; }
.p-2 { padding: 1rem; }
.p-3 { padding: 1.5rem; }

.d-none { display: none; }
.d-block { display: block; }
.d-flex { display: flex; }

.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.align-center { align-items: center; }

.w-full { width: 100%; }
.h-full { height: 100%; }

/* Enhanced UI Components */
.screen-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: white;
    border-radius: 15px;
    box-shadow: 0 8px 32px rgba(0,0,0,0.1);
    overflow: hidden;
    margin: 0 auto;
    max-width: 1400px;
    width: 100%;
}

/* Desktop Layout Optimization for 1920x1080 */
@media (min-width: 1920px) {
    .sidebar {
        width: 350px;
    }

    .header {
        padding: 1.5rem 3rem;
    }

    .content-area {
        padding: 2.5rem;
    }

    .nav-section-title {
        font-size: 0.9rem;
        padding: 1.25rem 2rem 0.75rem;
    }

    .nav-link {
        padding: 1rem 2rem;
        font-size: 1rem;
    }
}

/* Ensure proper layout proportions */
.main-content {
    min-height: calc(100vh - 80px);
}

.sidebar {
    min-height: calc(100vh - 80px);
}

.content-area {
    min-height: calc(100vh - 80px);
}

.screen-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 1.5rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.screen-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.screen-header .header-actions {
    display: flex;
    gap: 1rem;
}

.screen-content {
    flex: 1;
    padding: 2rem;
    overflow-y: auto;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: white;
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    border: 1px solid rgba(0,0,0,0.05);
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 30px rgba(0,0,0,0.12);
}

.stat-icon {
    font-size: 2rem;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.stat-content {
    flex: 1;
}

.stat-number {
    font-size: 2rem;
    font-weight: bold;
    color: #2c3e50;
    line-height: 1;
}

.stat-label {
    font-size: 0.9rem;
    color: #7f8c8d;
    margin-top: 0.25rem;
}

.table-container {
    background: white;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    overflow: hidden;
    margin-top: 1rem;
}

.table-header {
    background: #f8f9fa;
    padding: 1rem 1.5rem;
    border-bottom: 1px solid #e9ecef;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.table-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: #2c3e50;
}

/* Welcome Screen */
.welcome-screen {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 60vh;
    text-align: center;
    padding: 2rem;
}

.welcome-content h1 {
    font-size: 2.5rem;
    color: #2c3e50;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.welcome-content p {
    font-size: 1.2rem;
    color: #7f8c8d;
    max-width: 600px;
    margin: 0 auto;
}

/* Loading States */
.loading {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 40vh;
    font-size: 1.2rem;
    color: #7f8c8d;
}

.loading::before {
    content: '';
    width: 20px;
    height: 20px;
    border: 2px solid #ddd;
    border-top: 2px solid #667eea;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-right: 1rem;
}

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

/* Responsive Design */
@media (max-width: 1200px) {
    .stats-grid {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    }
}

@media (max-width: 768px) {
    .main-content {
        padding: 1rem;
    }
    
    .screen-header {
        padding: 1rem;
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .stat-card {
        padding: 1rem;
    }
}