style.css

*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    font-family: sans-serif;
}
body{
    display: grid;
    place-items: center;
    height: 70vh;
}

.box{
    width: 500px;
    height: 350px;
    /* border: 1px solid black; */
    box-shadow: 0px 0px 50px lightblue;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 50px;
    
}

.variables{
    display: grid;
    grid-template-columns: 1fr 1fr;
    justify-items: end;
    gap: 20px 130px;
}
.result{
    font-size: 20px;
    letter-spacing: .4rem;
    position: relative;
}

.variables p{
    font-size: 20px;
}
#length{
    font-size: 15px;
    font-weight: bolder;
    border: 1px solid;
    width: 50px;
    height: 30px;
}
input{
    width: 60px;
    height: 30px;
    outline: none;
    border-radius: 5px;
}
#include-numbers, #include-special{
    accent-color: green;
    border-radius: 10px;
}
p{
    margin-left: 20px;
}

#submit{
    width: 110px;
    height: 50px;
    background: lightblue;
    outline: none;
    border: none;
   border-radius: 10px;
   padding: 3%;
   font-size: 20px;
}
#submit:active{
    font-size: 18px;
}

#copy-msg{
    font-size: 13px;
    letter-spacing: normal;
    position: absolute;
    top: 40px;
    left: 50px;
    animation: copy 3s ease-in-out  infinite  ;
    display: none;

}

@keyframes copy{
    25%{
        color: red;
    }
    50%{
        color: green;
    }
    75%{
        color: blue;
    }
    100%{
        color: black;
    }
}