:root {
    --gold: #d4af37;
    --red: #7b1e1e;
    --dark: #111;
    --light: #f5f5f5;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
html{
    scroll-behavior: smooth;
}
body {
    font-family: "Bona Nova SC", serif;
    background: var(--dark);
    color: var(--light);
    line-height: 1.7;
}

.hero {
    height: 70vh; /* 50% màn hình */
    min-height: 420px;
    background-image:
        linear-gradient(
            rgba(0,0,0,0.75),
            rgba(0,0,0,0.85)
        ),
        url("hero.png");
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    border-bottom: 4px solid rgba(212,175,55,0.4);
}



.hero-content {
    text-align: center;
    max-width: 900px;
    padding: 20px;
    position: relative;
}
.hero-content strong{
    color: var(--gold);
    font-weight: 700;
}


.hero h1 {
    font-size: 3.2rem;
    color: var(--gold);
    letter-spacing: 4px;
    text-shadow:
        0 0 10px rgba(212,175,55,0.4),
        0 0 30px rgba(0,0,0,0.8);
    margin-bottom: 15px;
}


.hero p {
    font-size: 1.1rem;
    color: #ddd;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    margin-bottom: 25px;
}


.section {
    padding: 80px 20px;
    max-width: 1100px;
    margin: auto;
    text-align: center;
}

.section.dark {
    background: #0d0d0d;
}

.section h2 {
    font-size: 2.3rem;
    color: var(--gold);
    margin-bottom: 30px;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px,1fr));
    gap: 30px;
}

.feature-box {
    border: 1px solid rgba(212,175,55,0.3);
    padding: 30px;
    border-radius: 10px;
    transition: 0.3s;
}

.feature-box:hover {
    transform: translateY(-10px);
    border-color: var(--gold);
}

.btn-download {
    display: inline-block;
    padding: 14px 42px;
    border-radius: 0;
    background:
        linear-gradient(135deg, #b8962e, #ffd700);
    color: #000;
    font-weight: 900;
    letter-spacing: 2px;
    text-decoration: none;
    border: 2px solid #5a4a15;
    box-shadow:
        inset 0 0 10px rgba(255,255,255,0.3),
        0 10px 25px rgba(0,0,0,0.6);
    position: relative;
}
.btn-download::after {
    content: "➤";
    margin-left: 10px;
}

.btn-download:hover {
    background: linear-gradient(135deg, #ffd700, #ffec8b);
}

.btn-zalo {
    display: inline-block;
    padding: 1px 17px;
    background: linear-gradient(135deg, #0172b1, #0172b1);
    font-weight: 900;
    letter-spacing: 2px;
    text-decoration: none;
    border: 2px solid #0172b1;
    position: relative;
    color: #fff;
    border-radius: 25px;
}
.btn-zalo:hover {
    background: linear-gradient(135deg, #bdfff0, #10bdff);
}


.video-wrapper {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    max-width: 1000px;
    margin: auto;
}

.video-wrapper iframe {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
}

footer {
    padding: 30px;
    text-align: center;
    background: #000;
    opacity: 0.7;
}

/* ===== Scroll Animation ===== */
.fade-in {
    opacity: 0;
    transform: translateY(40px);
    transition: all 1s ease;
}

.fade-in.show {
    opacity: 1;
    transform: translateY(0);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.2rem;
    }
}

/* ===== HEADER ===== */
.main-header {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 999;
    background: rgba(10,10,10,0.9);
    backdrop-filter: blur(6px);
    border-bottom: 1px solid rgba(212,175,55,0.3);
}

.header-container {
    max-width: 1200px;
    margin: auto;
    padding: 10px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-weight: 900;
    color: var(--gold);
    font-size: 1.2rem;
    letter-spacing: 2px;
    display: flex;
    align-items: center;
}

.nav {
    display: flex;
    gap: 25px;
    align-items: center;
}

.nav a {
    color: #fff;
    text-decoration: none;
    font-size: 1rem;
    position: relative;
}

.nav a::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -6px;
    width: 0;
    height: 2px;
    background: var(--gold);
    transition: 0.3s;
}

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

.nav-download {
    color: #000 !important;
    background: linear-gradient(45deg, var(--gold), #ffd700);
    padding: 6px 16px;
    border-radius: 20px;
    font-weight: bold;
}

/* ===== MOBILE ===== */
.menu-toggle {
    display: none;
    font-size: 1.8rem;
    cursor: pointer;
    color: var(--gold);
}

@media (max-width: 768px) {
    .nav {
        position: absolute;
        top: 65px;
        right: 0;
        background: #111;
        flex-direction: column;
        width: 200px;
        padding: 20px;
        gap: 15px;
        display: none;
        border-left: 1px solid rgba(212,175,55,0.3);
    }

    .nav.active {
        display: flex;
    }

    .menu-toggle {
        display: block;
    }
}