style.css

@import url("https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css");

* {
    box-sizing: border-box;
    padding: 0px;
    margin: 0px;
}

body {
    background-color: #DCD7C9;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    height: 100vh;
}

.main-container {
    display: grid;
    grid-template-columns: 1fr auto 1fr;

}

.button-container {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: end;
    margin-right: 80px;
}

button {
    background-color: #4A403A;
    color: white;
    border: none;
    background-size: cover;
    height: 50px;
    width: 100px;
    text-align: center;
    font-size: 20px;
    margin-bottom: 10px;
    transition-duration: 0.4s;
    box-shadow: rgba(0, 0, 0, 0.4) 0px 2px 4px, rgba(0, 0, 0, 0.3) 0px 7px 13px -3px, rgba(0, 0, 0, 0.2) 0px -3px 0px inset;
    border-radius: 10px;
}

button:hover {
    background-color: #D67D3E;
    color: white;
}

button:active {
    box-shadow: 0px 2px 4px 0px rgba(0, 0, 0, 0.06) inset;
}

.canvas {

    width: 602px;
    height: 602px;
    border-top: 2px solid #A75D5D;
    border-left: 2px solid #A75D5D;
    display: flex;
    flex-wrap: wrap;
    align-content: flex-start;
    box-shadow: rgba(0, 0, 0, 0.25) 0px 54px 55px, rgba(0, 0, 0, 0.12) 0px -12px 30px, rgba(0, 0, 0, 0.12) 0px 4px 6px, rgba(0, 0, 0, 0.17) 0px 12px 13px, rgba(0, 0, 0, 0.09) 0px -3px 5px;

}

#header {
    background-color: #A27B5C;
    height: 70px;
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: rgba(0, 0, 0, 0.35) 0px 5px 15px;
    font-size: 40px;
}

#bottom {
    background-color: #A27B5C;
    height: 70px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 20px;
    box-shadow: rgba(0, 0, 0, 0.35) 0px -5px 15px;
}

.filled {
    filter: brightness(90%);
}