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

body {
    background-color: #0f172a;
    color: #f8fafc;
    line-height: 1.6;
}

.container {
    width: 85%;
    max-width: 1100px;
    margin: 0 auto;
}

.section-title {
    text-align: center;
    font-size: 28px;
    margin-bottom: 40px;
    color: #38bdf8;
}

/* --- 1. HEADER (Flexbox) --- */
.header {
    background-color: #1e293b;
    border-bottom: 1px solid #334155;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    font-size: 22px;
    font-weight: bold;
    color: #38bdf8;
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: 25px;
}

.nav-links a {
    color: #cbd5e1;
    text-decoration: none;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: #38bdf8;
}

.btn-login {
    background-color: #38bdf8;
    color: #0f172a;
    padding: 8px 16px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: bold;
}

/* --- 2. HERO --- */
.hero {
    background: linear-gradient(rgba(15, 23, 42, 0.8), rgba(15, 23, 42, 0.8)), 
                url(https://cdn.upanhlaylink.com/i/6gxOjngD.png) center/cover;
    padding: 100px 0;
    text-align: center;
}

.hero-content h1 {
    font-size: 38px;
    margin-bottom: 15px;
    color: #ffffff;
}

.hero-content p {
    font-size: 16px;
    color: #94a3b8;
    margin-bottom: 25px;
}

.btn-primary {
    display: inline-block;
    background-color: #8b5cf6;
    color: #ffffff;
    padding: 12px 25px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: bold;
    border: none;
    cursor: pointer;
}

.btn-primary:hover {
    background-color: #7c3aed;
}

/* --- 3. PRODUCTS (CSS Grid) --- */
.products {
    padding: 80px 0;
}

.product-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.product-card {
    background-color: #1e293b;
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid #334155;
    transition: transform 0.3s;
}

.product-card:hover {
    transform: translateY(-5px);
}

.product-card img {
    width: 100%;
    height: 160px;
    object-fit: cover;
}

.card-body {
    padding: 20px;
}

.card-body h3 {
    font-size: 18px;
    margin-bottom: 8px;
}

.card-body p {
    color: #94a3b8;
    font-size: 14px;
    margin-bottom: 15px;
}

.price-box {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.price {
    color: #38bdf8;
    font-weight: bold;
    font-size: 18px;
}

.btn-buy {
    background-color: #22c55e;
    color: #ffffff;
    padding: 6px 12px;
    border-radius: 4px;
    text-decoration: none;
    font-size: 14px;
    font-weight: bold;
}

.btn-buy:hover {
    background-color: #16a34a;
}

/* --- 4. ABOUT US (Flexbox) --- */
.about {
    padding: 80px 0;
    background-color: #111827;
}

.about-flex {
    display: flex;
    gap: 30px;
}

.about-box {
    flex: 1;
    background-color: #1e293b;
    padding: 30px;
    border-radius: 8px;
    border: 1px solid #334155;
    text-align: center;
}

.about-box h3 {
    margin-bottom: 12px;
    color: #38bdf8;
}

.about-box p {
    color: #94a3b8;
    font-size: 14px;
}

/* --- 5. CONTACT (Flexbox) --- */
.contact {
    padding: 80px 0;
}

.contact-flex {
    display: flex;
    gap: 50px;
    background-color: #1e293b;
    padding: 40px;
    border-radius: 8px;
    border: 1px solid #334155;
}

.contact-info {
    flex: 1;
}

.contact-info h3 {
    margin-bottom: 20px;
    color: #38bdf8;
}

.contact-info p {
    margin-bottom: 12px;
    color: #94a3b8;
}

.contact-form {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.contact-form input,
.contact-form textarea {
    width: 100%;
    padding: 12px;
    background-color: #0f172a;
    border: 1px solid #334155;
    border-radius: 6px;
    color: #ffffff;
}

.contact-form input:focus,
.contact-form textarea:focus {
    outline: none;
    border-color: #38bdf8;
}

/* --- 6. FOOTER --- */
.footer {
    background-color: #0b0f19;
    text-align: center;
    padding: 25px 0;
    border-top: 1px solid #1e293b;
    color: #64748b;
    font-size: 14px;
}

/* --- RESPONSIVE ĐƠN GIẢN CHO ĐIỆN THOẠI --- */
@media (max-width: 768px) {
    .product-grid {
        grid-template-columns: 1fr;
    }
    .about-flex, .contact-flex {
        flex-direction: column;
    }
    .nav-links {
        display: none;
    }
}