.footer {
    background: #222;
    color: #fff;
    padding: 32px 0 16px 0;
    margin-top: 0px;
    font-size: 16px;
}
.footer-content {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-around;
    gap: 32px;
    max-width: 1200px;
    margin: 0 auto;
}
.footer-section {
    flex: 1 1 ;
    min-width: 200px;
    margin-bottom: 16px;
}
.footer-section h3 {
    margin-bottom: 12px;
    color: #a0a0a0;
    font-size: 20px;
}
.footer-section a {
    color: #ffda00;
    text-decoration: none;
    transition: color 0.2s;
}
.footer-section a:hover {
    color: #fff;
    text-decoration: underline;
}
.footer-bottom {
    text-align: center;
    margin-top: 24px;
    color: #bbb;
    font-size: 14px;
    letter-spacing: 1px;
}

/* Responsive Footer */
@media (max-width: 800px) {
    .footer-content {
        flex-direction: column;
        align-items: center;
        gap: 12px; /* tăng gap nhẹ để dễ đọc */
        padding: 0 12px;
    }

    .footer-section {
        width: 100%;           /* mỗi section chiếm toàn bộ chiều rộng */
        text-align: center;
        margin-bottom: 12px;
        padding: 0;
    }

    .footer-section h3 {
        margin-bottom: 6px;
        font-size: 17px;
    }

    .footer-section p,
    .footer-section a,
    .footer-links-list li {
        font-size: 14px;
        margin: 4px 0;
    }

    .footer-links-list {
        padding-left: 0;
        margin: 0;
        list-style: none;
    }

    .social-icon {
        display: inline-block;
        margin: 0 6px;
    }

    .social-icon img {
        width: 24px;
        height: 24px;
        margin: 0 2px;
    }

    .footer-bottom {
        margin-top: 10px;
        font-size: 12px;
        padding: 4px 0;
    }
}

/* --- Sticky Footer Styles --- */
html, body {
    height: 100%;
    margin: 0;
    padding: 0;
}
body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}
.main-content {
    flex: 1 0 auto;
    padding-bottom: 40px;
}
.footer {
    flex-shrink: 0;
    width: 100%;
    background: #222;
    color: #fff;
    padding: 32px 0 16px 0;
    margin-top: 0px;
    font-size: 16px;
}
.social-icon img {
    width: 28px;
    height: 28px;
    vertical-align: middle;
    margin: 0 4px;
    transition: transform 0.2s;
    filter: brightness(0) invert(1); 
}
.social-icon img:hover {
    transform: scale(1.15);
    filter: brightness(0) invert(1) drop-shadow(0 0 4px #ffda00);
}