@media screen and (max-width:425px){
    body{
        overflow-x: hidden;
        /* FUNGSI KUNCI MUTLAK: Mengubah jatah baris grid desktop (64px) menjadi 60px.
           Ini menutup ruang hampa 4px secara instan sehingga gap putih lenyap permanen! */
        grid-template-rows: 60px 1fr; 
    }

    /* =========================
       NAVBAR
       ========================= */
    header{
        height: 60px;
        background-color: var(--warna-primer);
        position: relative;
        z-index: 100;
    }

    nav{
        padding: 0 .8rem;
        display: flex;
        justify-content: space-between;
        align-items: center;
        height: 100%;
        background-color: var(--warna-primer);
    }

    /* .menu{
        display: none;
    } */

    .nav-left{
        display: flex;
        align-items: center;
        gap: .5rem;
    }

    .nav-left .ri-menu-line{
        display: block;
        font-size: 1.3rem;
        color: #fff;
        cursor: pointer;
    }

    nav .img img{
        width: 30px;
        margin: 0;
        padding: 0;
    }

    .icon{
        display: flex;
        align-items: center;
        gap: .6rem;
        color: #fff;
    }

    .icon i{
        display: block;
        font-size: 12px;
        color: #fff;
    }

    .icon img{
        width: 30px;
        height: 30px;
        object-fit: cover;
        border-radius: 50%;
        margin: 0;
        padding: 0;
    }

    main {
        margin-top: 0;
        padding-top: 0;
        height: 100%;
    }   
    
    .container-1 {
        height: 280px !important;
        padding: 2rem 1rem; /* Padding internal diseimbangkan */
        
        /* Margin top dikembalikan ke nol bersih karena fondasi Grid body di atas sudah rapat sempurna */
        margin-top: 0; 

        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        text-align: center;

        background-position: center;
        background-size: cover;
        background-repeat: no-repeat;
    }

    .container-1 .wellcome {
        line-height: 1.1 !important;
        margin-top: 0 !important; 
        padding-top: 0;
    }

    .container-1 .wellcome h1 {
        font-size: 1.8rem; 
        line-height: 1.1;
        margin: 0 !important; 
    }

    .container-1 .wellcome .infolearn {
        font-size: 1.8rem;
        margin: 0 !important;
    }

    .container-1 .kata-kata {
        width: 100%;
        max-width: 290px;
        margin: 0.6rem auto 1.2rem auto; 
        font-size: .65rem; 
        line-height: 1.4;
    }

    .container-1 .btn {
        display: flex;
        justify-content: center;
        align-items: center;
        gap: 0.6rem;
        width: 100%;
    }

    .container-1 .btn button {
        width: auto; 
        height: 34px; 
        padding: 0 1rem; 
        font-size: .65rem; 
        font-weight: 600;
        border-radius: 8px;
        display: inline-flex;
        align-items: center;
        justify-content: center;
        column-gap: 6px; 
        white-space: nowrap; 
    }

    .container-2{
        height: auto;
        display: flex;
        flex-direction: column;
        padding: 1rem;
        gap: 1.25rem;
    }

    .container-2 .about-us{
        order: 1;
        line-height: normal;
    }

    .container-2 .about-us h2{
        font-size: 2rem;
        line-height: 1.2;
    }

    .container-2 .about-us h2.infolearn{
        font-size: 1.15rem;
        margin-top: .2rem;
    }

    .container-2 .about-us p{
        font-size: .72rem;
        line-height: 1.7;
        margin: .8rem 0 1rem;
    }

    .container-2 .about-us button{
        width: 110px;
        height: 32px;
        border-radius: 10px;
        font-size: .7rem;
    }

    .container-2 .card-about{
        order: 2;
        width: 100%;
        height: auto;
        display: flex;
        justify-content: center;
    }

    .container-2 .card-about .card{
        width: 100%;
        max-width: none;
        height: 320px;
        border-radius: 16px;
        background-size: cover;
        background-position: center;
    }

    .container-3,
    .container-4{
        padding: 1rem;
    }

    .container-3 .title h2,
    .container-4 .title h2{
        font-size: 1.3rem;
    }

    .container-3 .title .learn-more p,
    .container-4 .title .learn-more p{
        font-size: .65rem;
    }

    .container-3 .title .learn-more a,
    .container-4 .title .learn-more a{
        font-size: .65rem;
    }

    .container-3 .course{
        grid-template-columns: 1fr;
        gap: 12px;
    }

    .container-3 .course .course-recomend{
        grid-column: auto;
        flex-direction: column;
        min-height: auto;
    }

    .container-3 .course .course-recomend img{
        width: 100%;
        height: 160px;
        border-radius: 14px 14px 0 0;
    }

    .container-3 .course .course-recomend .course-detail{
        width: 100%;
        padding: .8rem;
    }

    .container-3 .course .card-course:nth-child(3),
    .container-3 .course .card-course:nth-child(4),
    .container-3 .course .card-course:nth-child(5){
        display: none;
    }

    .container-3 .course .course-populer{
        grid-column: auto;
        grid-row: auto;
        min-height: auto;
        padding: .8rem;
    }

    .container-4{
        grid-template-columns: 1fr;
    }

    .container-4 .title{
        grid-column: auto;
    }

    /* FOOTER */
    footer .footer-content{
        flex-direction: column;
        gap: 1.5rem;
        padding: 1rem;
    }

    footer .footer-content .social-side{
        text-align: left;
    }

    footer .footer-content .brand-side h3,
    footer .footer-content .social-side h3{
        font-size: .8rem;
    }

    footer .footer-content ul li a{
        font-size: .65rem;
    }

    footer .footer-copyright p{
        font-size: .55rem;
    }
}