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

body{

    font-family:"Times New Roman", serif;
    background:white;
}

table{

    margin:40px auto;
    border-collapse:collapse;
}

th,td{

    border:1px solid black;
    width:100px;
    height:40px;
    text-align:center;
    font-size:18px;
}

th{

    color:#CC6666;
    background:#F8F4EA;
}

/* TKWeb */
.tkweb{

    background:#99CC33;
}

/* LTĐT */
.ltdt{

    background:#FFD11A;
}

/* HĐH */
.hdh{

    background:#6FA8DC;
}

/* CSDL */
.csdl{

    background:#E6B8B7;
}

/* TK CSDL */
.csdl2{

    background:#A2C4C9;
}
.back{
    text-align:center;
    margin:35px 0;
}

.back a{

    display:inline-block;

    padding:12px 25px;

    background:linear-gradient(135deg,#4CAF50,#2E8B57);

    color:white;

    text-decoration:none;

    border-radius:30px;

    font-size:18px;

    font-weight:bold;

    box-shadow:0 5px 10px rgba(0,0,0,.2);

    transition:.3s;
}

.back a:hover{

    background:linear-gradient(135deg,#2E8B57,#4CAF50);

    transform:translateY(-3px);

    box-shadow:0 8px 18px rgba(0,0,0,.3);
}