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

@keyframes zoomInOut {
    0% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.2);
    }
    100% {
        transform: scale(1);
    }
}

body {
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background: url('1920.png') no-repeat center center fixed;
    background-size: cover;
}

/* CSS cho điện thoại */
@media screen and (max-width: 768px) {
    body {
        background: url('750.png') no-repeat center center fixed;
        background-size: cover;
        padding: 10px;
    }

    .container {
        width: 100%;
        padding: 10px;
    }

    .logo {
        margin-bottom: 20px;
    }

    .logo img {
        max-width: 250px;
        width: 100%;
    }

    .iphone {
        margin: 20px 0;
    }

    .iphone img {
        max-height: 250px;
        width: auto;
    }

    .buttons {
        flex-direction: column;
        gap: 15px;
    }

    .btn img {
        max-width: 180px;
        width: 100%;
    }
}

/* CSS cho điện thoại nhỏ */
@media screen and (max-width: 375px) {
    .logo img {
        max-width: 200px;
    }

    .iphone img {
        max-height: 200px;
    }

    .btn img {
        max-width: 150px;
    }
}

.container {
    text-align: center;
    padding: 20px;
}

.logo {
    margin-bottom: 30px;
    animation: zoomInOut 2s ease-in-out infinite;
}

.logo:hover {
    transform: scale(1.3);
    filter: brightness(1.2);
}

.logo img {
    max-width: 500px;
    height: auto;
}

.iphone {
    margin: 30px 0;
}

.iphone img {
    max-width: 100%;
    height: auto;
    max-height: 500px;
}

.buttons {
    display: flex;
    flex-direction: column;
    gap: 20px;
    align-items: center;
}

@media (min-width: 769px) {
    .buttons {
        flex-direction: row;
        justify-content: center;
        gap: 40px;
    }
}

.btn {
    display: inline-block;
    animation: zoomInOut 2s ease-in-out infinite;
}

.btn:nth-child(2) {
    animation-delay: 1s;
}

.btn:hover {
    transform: scale(1.4);
    filter: brightness(1.2);
}

.btn img {
    max-width: 200px;
    height: auto;
}