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

body{
    font-family: 'Segoe UI', sans-serif;
    background:#FFFFFF;
}

/* HEADER */
header{
    background:linear-gradient(to right,#a10f14,#c2181c);
    color:gold;
    text-align:center;
    padding:25px 0;
}

header h1{
    font-size:42px;
    letter-spacing:2px;
}

/* NAVIGATION */
nav{
    background:#8b0000;
    display:flex;
    justify-content:center;
}

nav a{
    color:white;
    text-decoration:none;
    padding:15px 20px;
    font-size:18px;
    transition:0.3s;
    position:relative;
}

nav a::after{
    content:"";
    position:absolute;
    width:0;
    height:2px;
    background:gold;
    left:0;
    bottom:5px;
    transition:0.3s;
}

nav a:hover::after{
    width:100%;
}

nav a:hover{
    color:gold;
}

/* MAIN CONTENT */
.container{
    width:70%;
    margin:40px auto;
    background:white;
    padding:40px;
    border-radius:10px;
    box-shadow:0 5px 15px rgba(0,0,0,0.1);
    text-align:center;
}

.container h2{
    margin-bottom:15px;
    font-size:28px;
}

.container p{
    margin-bottom:25px;
    color:#555;
}

/* FORM */
form{
    display:flex;
    flex-direction:column;
    gap:15px;
}

input, textarea{
    padding:12px;
    border:1px solid #ccc;
    border-radius:5px;
    font-size:16px;
}

input:focus, textarea:focus{
    border-color:#c2181c;
    outline:none;
}

button{
    background:#c2181c;
    color:white;
    padding:12px;
    border:none;
    border-radius:5px;
    font-size:16px;
    cursor:pointer;
    transition:0.3s;
}

button:hover{
    background:#8b0000;
}

/* FOOTER */
footer{
    background:#8b0000;
    color:white;
    text-align:center;
    padding:15px;
    margin-top:40px;
}

nav a.active{
    color: gold;
    font-weight: bold;
}

.container h3{
    margin-top:20px;
    color:hsl(359, 78%, 43%);
}

.container p{
    line-height:1.6;
}
nav {
    background: #b30000;
    padding: 15px;
    text-align: center;
}

nav a {
    color: white;
    margin: 0 15px;
    text-decoration: none;
    font-weight: bold;
}

nav a:hover {
    color: yellow;
}
iframe {
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    margin-top: 20px;
}
.banner {
    background-image: url("Screenshot 2026-03-01 140640.png");
    height: 400px;
    background-size: cover;
    background-position: center;
    display: flex;
    align-items: center;
    justify-content: center;
    color: red;
    font-size: 30px;
    font-weight: bold;
}
.anh-trangchu {
    width: 100%;
    max-width: 900px;
    display: block;
    margin: 20px auto;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.3);
}