body {
    font-family: Arial, Helvetica, sans-serif;
    box-sizing: border-box;
    padding: 0;
    margin: 0;
    display: grid;
}
header {
    background-color: rgb(29, 28, 28);
    width: 100%;
    height: 100px;
    color: aliceblue;
    font-weight: 300;
    font-size: 20px;
    align-items: center;
    text-align: center;
}
.banner {
    width: 100%;
    height: 300px;
    background-image: url(../../images/phonebgrd.jpg);
    background-size: 100%;
}
.banner h2 {
    color: rgb(223, 215, 114);
    font-weight: 300;
    font-size: 50px;
    text-align: center;
    line-height: 200px;
    text-shadow: 3px 3px 4px gray;
}
.noiDung {
    margin-top: 20px;
    width: 100%;
    height: 200px;
    display: flex;
    justify-content: space-around;
    align-items: center;
}
.card {
    width: 30%;
    height: 180px;
    box-shadow: 3px 3px 4px gray;
    border-radius: 15px;
    border: 1px solid rgb(11, 11, 11);
    padding: 10px;
    display: flex;
    justify-content: center;
    flex-direction: column;
}
.footer {
    margin-top: 20px;
    width: 100%;
    height: 200px;
    background-color: rgb(5, 146, 19);
    color: aliceblue;
    font-weight: 300px;
    font-size: 20px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}
button {
    width: 100px;
    height: 40px;
    border-radius: 10px;
    font-size: 18px;
    text-align: center;
}