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

body{
    background:url("background.jpg");
    background-size:cover;
    background-position:center;
    height:100vh;
    display:flex;
    justify-content:center;
    align-items:flex-start;
}

.container{
    width:420px;
    text-align:center;
    margin-top:40px;
    padding:0 10px; /* cách lề trái phải 20px */
}

.logo img{
    width:110px;
    height:110px;
    border-radius:50%;
}

h1{
    margin-top:10px;
    font-size:24px;
    letter-spacing: 1px;
    font-weight: 800;
}

.desc{
    margin:10px 0 25px;
    color:#333;
    font-size:18px;
}

.btn{
    display:flex;
    align-items:center;
    gap:15px;
    text-decoration:none;
    color:white;
    font-size:18px;
    padding:20px 20px;
    border-radius:40px;
    margin:25px 0;
    transition:0.3s;

    box-shadow:
        0 4px 10px rgba(0,0,0,0.15),
        0 8px 25px rgba(0,0,0,0.15);
}
.btn:hover{
    transform:translateY(-2px);
    box-shadow:
        0 6px 15px rgba(0,0,0,0.35),
        0 10px 30px rgba(0,0,0,0.3);
}

.btn img{
    width:30px;
}

.btn:hover{
    transform:scale(1.03);
}

.red{
    background:#d51c1c;
}

.blue{
    background:#156c8e;
}

.green{
    background:#2cab4c;
}

.yellow{
    background:#e4c21a;
}

.pink{
    background:linear-gradient(90deg,#ff2ca3,#c02cff);
}
.footer{
    text-align:center;
    margin-top:40px;
    padding:20px;
    font-size:14px;
    color:#555;
}