style.css

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    outline: none;
    background-color: #ecf0f3;
    font-family: coolvetica, sans-serif
}

.container {
    height: 90vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #ecf0f3;
}

.calc{
    box-shadow: 6px 6px 13px rgb(186, 186, 186),
                6px 6px 13px rgba(0,0,0,.16);
    border-radius: 28px;
    padding: 16px;
    display: grid;
    grid-template-columns: repeat(4,66px)
}

input{
    grid-column: span 4;
    height: 68px;
    width: 258px;
    box-shadow: inset -6px -6px 13px #fff,
                inset 6px 6px 13px rgba(0,0,0,.16);
    background-color: #ecf0f3;
    border: none;
    border-radius: 32px;
    color: rgb(92, 92, 92);
    text-align: end;
    margin: 40px 0px 30px 0px;
    padding: 20px;
    font-size: 40px;
}

button{
    box-shadow: inset 6px 6px 13px #fff,
                6px 6px 13px rgba(0,0,0,.16);
    background-color: #ecf0f3;
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    margin: 10px;
    font-weight: bold;
    font-size: 20px;
    color: rgb(92, 92, 92);
}

.equal{
    width: 120px;
    border-radius: 42px;
    box-shadow: inset 6px 6px 13px #fff,
                6px 6px 13px rgba(0,0,0,.16);
    background-color: #ecf0f3;
    border: none;
    border-radius: 32px;
}

.equal:active{
    box-shadow:inset -6px -6px 13px #fff,
            inset 6px 6px 13px rgba(0,0,0,.16);
    background-color: #ecf0f3;
    border: none;
    border-radius: 32px;
}

button:active{
    box-shadow: inset -6px -6px 13px #fff,
                inset 6px 6px 13px rgba(0,0,0,.16);
}

.footer{
  text-align: center;
}

.footer p {
    display: flex;
    justify-content: center;
    align-items: center;
}


footer a {
    display: inline-block;
    padding: 10px;
    text-decoration: none;
    color: black;
}