:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --background-color: #f5f6fa;
    --text-color: #2c3e50;
    --border-color: #dcdde1;
    --danger-color: #e74c3c;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    --info-color: #3498db;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
}

h1, h2, h3, h4, h5, h6 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

a {
    color: var(--secondary-color);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

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

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

.btn {
    padding: 8px 15px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background 0.3s ease;
    font-weight: 500;
}

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

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

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

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

.btn:hover {
    opacity: 0.9;
}

.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
    color: var(--text-color);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 8px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    color: var(--text-color);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--secondary-color);
}

.table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
    background: white;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

.table th,
.table td {
    padding: 12px;
    border: 1px solid var(--border-color);
    text-align: left;
}

.table th {
    background: var(--primary-color);
    color: white;
    font-weight: 600;
}

.table tr:nth-child(even) {
    background: #f8f9fa;
}

.table tr:hover {
    background: #f1f1f1;
}

.alert {
    padding: 15px;
    border-radius: 5px;
    margin-bottom: 20px;
}

.alert-success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

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

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
}

.modal-content {
    background: white;
    width: 90%;
    max-width: 500px;
    margin: 50px auto;
    padding: 20px;
    border-radius: 10px;
    position: relative;
}

.modal-close {
    position: absolute;
    top: 10px;
    right: 10px;
    font-size: 24px;
    cursor: pointer;
    color: var(--text-color);
}

@media (max-width: 768px) {
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .table {
        display: block;
        overflow-x: auto;
    }
}

/* Transaction specific styles */
.sale {
    color: var(--success-color);
}

.purchase {
    color: var(--danger-color);
}

.payment {
    color: var(--warning-color);
}

.receipt {
    color: var(--info-color);
}

.empty-state {
    text-align: center;
    padding: 40px;
    background: white;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    margin-top: 20px;
}

.empty-state i {
    font-size: 48px;
    color: #ddd;
    margin-bottom: 20px;
}

.empty-state p {
    color: var(--text-color);
    font-size: 18px;
}

/* Action buttons */
.action-buttons {
    display: flex;
    gap: 10px;
}

.action-buttons .btn {
    padding: 6px 12px;
    font-size: 14px;
}

/* Form sections */
.form-section {
    background: white;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    margin-bottom: 20px;
}

.form-section h3 {
    margin-bottom: 20px;
    color: var(--primary-color);
}

/* Responsive grid */
.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 15px;
}

.game-container {
    max-width: 800px;
    margin: 50px auto;
    padding: 20px;
    background: white;
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
}

#tic-tac-toe {
    text-align: center;
}

.board {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin: 20px auto;
    max-width: 300px;
}

.cell {
    aspect-ratio: 1;
    background: var(--background-color);
    border: 2px solid var(--primary-color);
    border-radius: 5px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2em;
    cursor: pointer;
    transition: all 0.3s ease;
}

.cell:hover {
    background: var(--secondary-color);
    color: white;
}

.status {
    margin: 20px 0;
    font-size: 1.2em;
    font-weight: bold;
}

.hidden-section {
    margin-top: 20px;
    padding: 20px;
    background: var(--background-color);
    border-radius: 5px;
}

.hidden-section input {
    padding: 10px;
    margin-right: 10px;
    border: 1px solid var(--primary-color);
    border-radius: 5px;
}

.hidden-section button {
    padding: 10px 20px;
    background: var(--secondary-color);
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background 0.3s ease;
}

.hidden-section button:hover {
    background: var(--primary-color);
}