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

/* ================= ROOT ================= */
:root {
    --blue-main: #1e88e5;
    --blue-dark: #1565c0;
    --blue-light: #e3f2fd;
    --white: #ffffff;
    --text-dark: #333;
    --shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
}

/* ================= BODY ================= */
body {
    font-family: 'Segoe UI', Arial, sans-serif;
    background-color: var(--blue-light);
    max-width: 1200px;
    margin: auto;

    display: grid;
    grid-template-columns: 72% 28%;
    gap: 24px;
}

/* ================= HEADER ================= */
header {
    grid-column: 1 / span 2;
    background: linear-gradient(135deg, var(--blue-main), var(--blue-dark));
    color: var(--white);
    padding: 28px 20px;
    text-align: center;
    font-size: 28px;
    font-weight: 700;
    letter-spacing: 1px;
}

/* ================= NAV ================= */
nav {
    grid-column: 1 / span 2;
    background-color: var(--white);
    padding: 14px 0;
    box-shadow: var(--shadow);
}

nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
    gap: 40px;
}

nav ul li a {
    color: var(--blue-dark);
    text-decoration: none;
    font-weight: 600;
    position: relative;
}

nav ul li a::after {
    content: "";
    position: absolute;
    width: 0;
    height: 3px;
    background-color: var(--blue-main);
    left: 0;
    bottom: -6px;
    transition: 0.3s;
}

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

/* ================= PRODUCT LIST ================= */
.product-list {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    padding: 20px;
}

/* ================= PRODUCT CARD ================= */
.product-card {
    background-color: var(--white);
    border-radius: 14px;
    padding: 18px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: 0.3s;
}

.product-card:hover {
    transform: translateY(-6px);
}

.product-card img {
    width: 100%;
    border-radius: 12px;
    margin-bottom: 14px;
}

.product-card h3 {
    font-size: 18px;
    color: var(--text-dark);
    margin-bottom: 6px;
}

.product-card p {
    font-size: 14px;
    color: #666;
    margin-bottom: 6px;
}

.product-card span {
    font-weight: 700;
    color: var(--blue-dark);
}

/* ================= BUTTON ================= */
.button {
    background: linear-gradient(135deg, var(--blue-main), var(--blue-dark));
    color: var(--white);
    border: none;
    padding: 12px 24px;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    font-size: 15px;
    font-weight: 600;
    border-radius: 30px;
    margin-top: 10px;
    transition: 0.3s;
}

.button:hover {
    opacity: 0.9;
    transform: scale(1.05);
}

/* ================= SIDEBAR ================= */
.sidebar {
    background: linear-gradient(180deg, var(--blue-main), var(--blue-dark));
    color: var(--white);
    padding: 24px;
    border-radius: 16px;
    box-shadow: var(--shadow);
}

.sidebar img {
    width: 100%;
    margin-bottom: 20px;
}

.social-icons a {
    display: block;
    color: var(--white);
    text-decoration: none;
    padding: 10px 0;
    font-weight: 500;
    transition: 0.3s;
}

.social-icons a:hover {
    padding-left: 10px;
    opacity: 0.9;
}

/* ================= FOOTER ================= */
.footer {
    grid-column: 1 / span 2;
    background-color: #0d47a1;
    color: var(--white);
    padding: 30px 20px;
    text-align: center;

    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.footer-item {
    font-size: 14px;
    opacity: 0.9;
}

/* ================= RESPONSIVE ================= */
@media (max-width: 768px) {
    body {
        grid-template-columns: 1fr;
    }

    header,
    nav,
    .sidebar,
    .footer {
        grid-column: 1;
    }

    .product-list {
        grid-template-columns: 1fr;
    }

    .footer {
        grid-template-columns: 1fr;
    }
}
/* ================= POST (DÙNG CHUNG CHO MỌI BÀI VIẾT) ================= */
.post {
    grid-column: 1 / span 2;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    padding: 40px;
    background: white;
    border-radius: 20px;
    box-shadow: var(--shadow);
    margin: 30px 0;
}

.post-image img {
    width: 100%;
    border-radius: 16px;
}

.post-title {
    color: var(--blue-dark);
    margin-bottom: 16px;
}

.post-text {
    color: #444;
    line-height: 1.7;
    margin-bottom: 18px;
}

.post-features {
    list-style: none;
    margin: 20px 0;
}

.post-features li {
    margin-bottom: 8px;
    font-size: 15px;
}

.post-price {
    font-size: 24px;
    font-weight: 700;
    color: #d32f2f;
    margin: 20px 0;
}

.post-actions {
    display: flex;
    gap: 16px;
    margin-top: 10px;
}

/* RESPONSIVE POST */
@media (max-width: 768px) {
    .post {
        grid-template-columns: 1fr;
    }
}
/* ================= SOCIAL ICONS ================= */
.social-icons {
    margin-top: 15px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.social-icons a {
    text-decoration: none;
    font-size: 1.1rem;
    color: #ffffff;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: 0.3s;
}

.social-icons a:hover {
    color: #fb8500;
    padding-left: 10px;
}

/* ICON STYLE */
.social-icons i {
    font-size: 1.4rem;
    width: 25px;
    text-align: center;
}

/* MÀU RIÊNG CHO TỪNG MXH */
.fa-facebook { color: #006eff; }
.fa-twitter { color: #1DA1F2; }
.fa-instagram { color: #E4405F; }
.fa-linkedin { color: #0A66C2; }
.fa-tiktok { color: #000000; }