responsive.css

@media screen and (max-width:458px) {
    html {
        font-size: 80%;
    }

    .filter {
        justify-content: space-evenly;
    }

    #all,
    #pending,
    #completed,
    #deleted,
    #clearAll {
        height: 23px;
        padding: 1px;
        margin: 10px auto;
    }

    #pending {
        width: 5rem;
    }

    #completed {
        width: 6rem;
    }

    #clearAll {
        width: 4rem;
        font-size: 0.87rem;
    }

    #deleted {
        width: 5rem;
    }

    #inputTask {
        height: 30px;
        margin: 15px 3px;
        padding-left: 10px;
    }

    #addBtn {
        height: 30px;
        margin: 15px 3px;
    }

    #date {
        height: 30px;
        margin: 15px 0px;
        padding-left: 4px;
    }
}

@media screen and (max-width:380px) {
    html {
        font-size: 71%;
    }

    #inputTask {
        height: 23px;
        margin: 12px 3px;
        padding-left: 10px;
        font-size: 8px;
    }

    #addBtn {
        height: 23px;
        font-size: 6px !important;
        margin: 12px 3px;
        font-weight: normal;
    }

    #date {
        height: 23px;
        margin: 12px 0px;
        font-size: 5.5px;
        padding-left: 4px;
    }

    #all,
    #pending,
    #completed,
    #deleted,
    #clearAll {
        height: 21px;
        padding: 1px;
        margin: 10px auto;
        font-size: 9px;
    }

    #list-container li {
        margin-bottom: 4px;
    }

    h1 {
        margin-bottom: 5px;
    }
}

@media screen and (max-width:320px) {
    html {
        font-size: 65%;
    }

    #all,
    #pending,
    #completed,
    #deleted,
    #clearAll {
        font-size: 8px;
    }
}

@media screen and (max-width:275px) {
    html {
        font-size: 47%;
    }

    * {
        overflow: hidden;
    }

    #clearAll {
        width: 4rem;
        font-size: 0.7rem;
    }
}