body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}

header {
    background-color: #003366;
    color: white;
    padding: 10px 20px;
}

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

nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
    padding: 0;
    margin: 0;
}

nav ul li {
    margin: 0 15px;
}

nav ul li a {
    text-decoration: none;
    color: white;
    font-weight: bold;
}

nav ul li a:hover {
    text-decoration: underline;
}
.banner {
    position: relative;
    text-align: center;
}

.banner img {
    width: 100%;
    height: auto;
}

.banner h2 {
    position: absolute;
    top: 40%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: white;
    background-color: rgba(0, 0, 0, 0.5);
    padding: 10px 20px;
    border-radius: 8px;
}
.trangchuaanh {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 20px;
    padding: 20px;
}

.anh {
    width: 220px;
    text-align: center;
}

.anh img {
    width: 100%;
    border-radius: 10px;
}
section.MuonSach,
section.TraSach {
    padding: 20px;
    background-color: #f2f2f2;
    border-radius: 10px;
    margin: 20px;
}

section h1 {
    text-align: center;
}

label {
    display: block;
    margin-top: 10px;
    font-weight: bold;
}

input {
    width: 100%;
    padding: 8px;
    margin-top: 5px;
}

button {
    margin-top: 15px;
    padding: 10px 15px;
    background-color: #003366;
    color: white;
    border: none;
    border-radius: 5px;
}

button:hover {
    background-color: #0055aa;
}
.Gioithieu,
.LienHe {
    text-align: center;
    padding: 30px;
}

.LienHe a {
    display: block;
    color: black;
    text-decoration: none;
    margin: 5px 0;
}
.menu-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background-color: white;
    margin: 4px 0;
}

@media (max-width: 768px) {
    .dau {
        flex-direction: column;
        text-align: center;
    }

    nav ul {
        flex-direction: column;
        display: none;
        background-color: #003366;
        width: 100%;
    }

    nav ul.show {
        display: flex;
    }

    nav ul li {
        margin: 10px 0;
    }

    .menu-toggle {
        display: flex;
    }

    .banner h2 {
        font-size: 18px;
        padding: 5px;
    }

    .trangchuaanh {
        flex-direction: column;
        align-items: center;
    }

    .anh {
        width: 90%;
    }
}