<div id="wrap">
    <header id="header">
        <div class="container"></div>
    </header>
    <nav id="nav">
        <div class="container"></div>
    </nav>
    <main id="main">
        <div class="contents container">
            <div class="cont1"></div>
            <div class="cont2"></div>
            <div class="cont3"></div>
            <div class="cont4"></div>
        </div>
    </main>
    <footer id="footer">
        <div class="container"></div>
    </footer>
</div>

*{
    box-sizing: 0;
    padding: 0;
    margin: 0;
}
#header {
    height: 100px;
    background-color: #EEEBE9;
}
#nav {
    height: 100px;
    background-color: #B9AAA5;
}
#main {
    height: 780px;
    background-color: #886F65;
}
#footer {
    height: 100px;
    background-color: #3E2723;
}
.container {
    width: 1200px;
    height: inherit;
    margin: 0 auto;
    background-color: rgba(0,0,0,0.3);
}
.contents {
    display: grid;
    grid-template-areas: 
    "cont1 cont1"
    "cont2 cont2"
    "cont3 cont4"
    ;
    grid-template-columns: 50% 50%; 
    grid-template-rows: 100px 200px 480px;
}
.contents .cont1 {
    background-color: #74574A;
    grid-area: cont1;
}
.contents .cont2 {
    background-color: #684D43;
    grid-area: cont2;
}
.contents .cont3 {
    background-color: #594139;
    grid-area: cont3;
}
.contents .cont4 {
    background-color: #4A352F;
    grid-area: cont4;
}

@media (max-width: 1220px) {
    .container {
        width: 96%;
    }
    .contents {
        display: grid;
        grid-template-areas: 
        "cont1 cont2 cont2"
        "cont1 cont3 cont4"
        ;
        grid-template-columns: 1fr 2fr;
        grid-template-rows: 390px 390px
    }
}
@media (max-width: 768px) {
    .container {
        width: 100%;
    }
    .contents {
        display: grid;
        grid-template-areas: 
        "cont1 cont2"
        "cont1 cont3"
        "cont1 cont4"
        ;
        grid-template-columns: 30% 70%; 
        grid-template-rows: repeat(3, 1fr);
    }
}
@media (max-width: 480px) {
    .contents {
        display: grid;
        grid-template-areas: 
        "cont1"
        "cont2"
        "cont3"
        "cont4"
        ;
        grid-template-columns: 100%; 
        grid-template-rows: 150px 210px 210px 210px;
    }
}