style.css

html {
    box-sizing: border-box;
}

* {
    box-sizing: inherit;
    margin: 0;
    padding: 0;
}

body {
    background-color: cadetblue;
}

.container,
.second-container {
    margin: 30px;
    border: 2px red solid;
    padding: 50px;
}

.container {
    background-color: aquamarine;
}

#item_container,
#second_item_container{
    border: 2px red solid;
    padding: 50px;   
}

#item_container {
    background-color: burlywood;
}

#item_container a,
#second_item_container a {
    text-decoration: none;
}

.container .items-container,
.second-container .sweet-palette-container {
    display: flex;
    border: 2px red solid;
    padding: 50px;
    list-style: none;
}

.container .items-container {
    background-color: blue;
}

.red-item,
.green-item,
.blue-item {
    margin: 0 10px;
    border: 2px red solid;
    padding: 50px;
    color: crimson;
}

.red-item {
    background-color: lightcoral;
}

.green-item {
    background-color: lightgreen;
}

.blue-item {
    background-color: lightblue;
}

.second-container {
    background-color: gray;
}

#second_item_container {
    background-color:chartreuse ;
}

.sweet-palette-container {
    background-color: #4A3933;
}

.sweet-palette-container li {
    margin: 0 10px;
    border: 2px red solid;
    padding: 50px;
}

.second-container .sweet-palette-container .color-1 {
    background-color: #F0A500;
}

.second-container .sweet-palette-container .color-2 {
    background-color: #E45826;
}

.second-container .sweet-palette-container .color-3 {
    background-color: #E6D5B8;
}