*{
    margin:0;
    padding:0;
    box-sizing:border-box;
    font-family:Arial, sans-serif;
}

body{
    background:#fff;
    color:#1d3557;
}

/* Banner */
.banner{
    width:100%;
    height:100vh;
    min-height:500px;
    background:url("images/banner.PNG") center center;
    background-size:cover;
    position:relative;
}

.banner::before{
    content:"";
    position:absolute;
    inset:0;
    background:rgba(0,0,0,0.45);
}

.banner-content{
    position:absolute;
    top:50%;
    left:50%;
    transform:translate(-50%,-50%);
    text-align:center;
    color:white;
    width:90%;
    z-index:1;
}

.banner-content h1{
    font-size:50px;
    line-height:1.4;
}

/* Nút liên hệ */
.contact-fixed{
    position:fixed;
    right:20px;
    top:50%;
    transform:translateY(-50%);
    display:flex;
    flex-direction:column;
    gap:12px;
    z-index:999;
}

.contact-fixed a{
    width:60px;
    height:60px;
    display:block;
    border-radius:50%;
    overflow:hidden;
    box-shadow:0 4px 12px rgba(0,0,0,.3);
    transition:0.3s;
}

.contact-fixed a:hover{
    transform:scale(1.1);
}

.contact-fixed img{
    width:100%;
    height:100%;
    object-fit:cover;
}

/* Footer */
.footer{
    text-align:center;
    padding:20px;
    background:#0047AB;
    color:white;
    font-size:18px;
    font-weight:bold;
}

/* Mobile */
@media(max-width:768px){

    .banner{
        height:100vh;
    }

    .banner-content h1{
        font-size:32px;
    }

    .contact-fixed a{
        width:50px;
        height:50px;
    }
}
*{
    margin:0;
    padding:0;
    box-sizing:border-box;
    font-family:Arial,sans-serif;
}

body{
    background:#f7f9fc;
    color:#1d3557;
}

/* =========================
   BANNER
========================= */

.banner{
    width:100%;
    height:600px;
    background:url("images/banner.PNG") center center;
    background-size:cover;
    position:relative;
}

.banner::before{
    content:"";
    position:absolute;
    inset:0;
    background:rgba(0,0,0,.45);
}

.banner-content{
    position:absolute;
    top:50%;
    left:50%;
    transform:translate(-50%,-50%);
    text-align:center;
    color:white;
    width:90%;
    z-index:2;
}

.banner-content h1{
    font-size:48px;
    line-height:1.4;
    margin-bottom:20px;
}

.banner-content p{
    font-size:24px;
}

/* =========================
   SECTION
========================= */

.section{
    max-width:1200px;
    margin:0 auto;
    padding:70px 20px;
}

.section h2{
    text-align:center;
    color:#0056d6;
    font-size:38px;
    margin-bottom:40px;
}

/* =========================
   GRID
========================= */

.grid{
    display:grid;
    grid-template-columns:repeat(auto-fit,minmax(280px,1fr));
    gap:25px;
}

/* =========================
   CARD
========================= */

.card{
    background:white;
    padding:25px;
    border-radius:16px;
    border-top:4px solid #0056d6;
    box-shadow:0 4px 12px rgba(0,0,0,.08);
    transition:.3s;
}

.card:hover{
    transform:translateY(-5px);
    box-shadow:0 10px 25px rgba(0,0,0,.12);
}

.card h3{
    color:#0056d6;
    font-size:24px;
    margin-bottom:15px;
}

.card p{
    color:#444;
    line-height:1.7;
}

.card ul{
    padding-left:20px;
}

.card li{
    line-height:1.7;
    margin-bottom:8px;
}


/* =========================
   NÚT LIÊN HỆ NỔI
========================= */

.contact-fixed{
    position:fixed;
    right:20px;
    top:50%;
    transform:translateY(-50%);
    display:flex;
    flex-direction:column;
    gap:12px;
    z-index:999;
}

.contact-fixed a{
    width:60px;
    height:60px;
    display:block;
    border-radius:50%;
    overflow:hidden;
    box-shadow:0 4px 12px rgba(0,0,0,.3);
    transition:.3s;
}

.contact-fixed a:hover{
    transform:scale(1.1);
}

.contact-fixed img{
    width:100%;
    height:100%;
    object-fit:cover;
    display:block;
}

/* =========================
   FOOTER
========================= */

.footer{
    text-align:center;
    padding:25px;
    background:#0047AB;
    color:white;
    font-size:18px;
    font-weight:bold;
    margin-top:40px;
}

/* =========================
   MOBILE
========================= */

@media(max-width:768px){

    .banner{
        height:500px;
    }

    .banner-content h1{
        font-size:30px;
    }

    .banner-content p{
        font-size:18px;
    }

    .section{
        padding:50px 15px;
    }

    .section h2{
        font-size:28px;
    }

    .card{
        padding:20px;
    }

    .card h3{
        font-size:22px;
    }

    .register{
        margin:30px 15px;
        padding:25px;
    }

    .register h2{
        font-size:28px;
    }

    .contact-fixed a{
        width:50px;
        height:50px;
    }
}