#app {
    display: flex;
    flex-direction: column;
    height: 100%;
    width: 100%;
}
.tabs {
    display: flex;
    background-color: #333;
    color: white;
    flex-shrink: 0;
    padding: 5px;
    justify-content: space-around;
}
.tab-button {
    flex-grow: 1;
    padding: 10px 5px;
    text-align: center;
    cursor: pointer;
    border: 1px solid #555;
    background-color: #444;
    color: white;
    font-size: 16px;
    border-radius: 5px;
    margin: 0 5px;
    transition: background-color 0.2s, border-color 0.2s;
}
.tab-button:hover {
    background-color: #666;
}
.tab-button.active {
    background-color: #007bff;
    border-color: #007bff;
}
.tab-content {
    flex-grow: 1;
    overflow-y: auto;
}
#home.tab-content, #history.tab-content {
    padding: 20px;
}
#products.tab-content {
    padding: 0;
}
#stock.tab-content {
    display: flex;
    flex-direction: column;
    padding: 10px;
    box-sizing: border-box;
}