*{
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Space Mono';
    font-weight:900 !important
}

:root{
    --Strong-cyan: hsl(172, 67%, 45%);
    --Very-dark-cyan: hsl(183, 100%, 15%);
    --Dark-grayish-cyan: hsl(186, 14%, 43%);
    --Grayish-cyan: hsl(184, 14%, 56%);
    --Light-grayish-cyan: hsl(185, 41%, 84%);
    --Very-light-grayish-cyan: hsl(189, 41%, 97%);
    --White: hsl(0, 0%, 100%);
    --fontSize: 24px;
}

::placeholder{
    color: var(--Dark-grayish-cyan);
}

body{
    background-color: var(--Light-grayish-cyan);
}

/* -------- style classes --------- */

.white{
    color: var(--White);
}

.grey{
    color: var(--Grayish-cyan);
}

.cyan{
    color: var(--Strong-cyan);
}

.column{
    display: flex;
    flex-direction: column;
}

.space-between{
    display: flex;
    justify-content: space-between;
}


/* -------- header --------- */

header{
    display: flex;
    flex-direction: column;
    margin: var(--fontSize) 0;
    font-size: var(--fontSize);
    color: var(--Very-dark-cyan);
    letter-spacing: 10px;
    justify-content: center;
    align-items: center;
}

/* -------- main --------- */

main{
    display: flex;
    flex-direction: column;
    background-color: var(--White);
    border-top-left-radius: var(--fontSize);
    border-top-right-radius: var(--fontSize);
    padding: var(--fontSize);
}

/* -------- main container one --------- */

#main-container-one span{
    color: var(--Dark-grayish-cyan);
}

.tip-choice{
    display: grid;
    grid-template-columns: 50% 50%;
    grid-gap: 10px;
    margin: 10px 0 var(--fontSize) 0;
}

.custom{
    text-align: right;
    background-color: var(--Very-light-grayish-cyan);
    color: var(--Very-dark-cyan);
    font-size: var(--fontSize);
    text-align: center;
    border-radius: 4px;
    cursor: text;
    border: none;
}

.percentage{
    border: none;
    background-color: var(--Very-dark-cyan);
    font-size: var(--fontSize);
    color: var(--White);
    border-radius: 4px;
    padding: 6px;
    cursor: pointer;
}

.bill-input, .people-input{
    position: relative;
    margin-bottom: var(--fontSize);
}

.bill-input img, .people-input img{
    position: absolute;
    top:22px;
    left:18px;
}

.bill-input input, .people-input input{
    width: 100%;
    padding: 6px;
    text-align: right;
    margin-top: 6px;
    border-radius: 4px;
    border: none;
    background-color: var(--Very-light-grayish-cyan);
    color: var(--Very-dark-cyan);
    cursor: text;
    font-size: var(--fontSize);
    font-family: 'Space Mono';
}

/* -------- main container two --------- */

#main-container-two{
    display: flex;
    flex-direction: column;

    background-color: var(--Very-dark-cyan);
    padding: var(--fontSize);
    border-radius: 10px;
}

#main-container-two-top, #main-container-two-middle{
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--fontSize);
}

.amount{
    font-size: var(--fontSize);
}

#reset{
    padding: 10px;
    font-size: 1rem;
    width: 100%;
    border: none;
    border-radius: 4px;
    background-color: var(--Strong-cyan);
    color: var(--Very-dark-cyan);
    cursor: pointer;
}

#error-message{
    color: orangered !important;
}

/* -------- active states --------- */

#bill:focus, #people:focus{
    outline: none !important;
    border: 2px solid var(--Strong-cyan);
}

.percentage:hover{
    background-color: var(--Strong-cyan);
    color: var(--Very-dark-cyan);
}

#reset:hover{
    background-color: var(--Very-light-grayish-cyan);
    transition: 0.2s;
}

#reset:disabled{
    background-color: var(--Dark-grayish-cyan);
    cursor: not-allowed;
}

.custom.active{
    border: 2px solid var(--Strong-cyan);
}

.percentage.active{
    background-color: var(--Strong-cyan);
}

/* -------- media query --------- */

@media only screen and (min-width:768px) {
    main{
        flex-direction: row;
        width: 60%;
    }

    body{
        height: 100vh;
    }

    #main-container-one, #main-container-two{
        width: 50%;
    }

    #main-container-two{
        display: flex;
        flex-direction: column;
        gap: 2rem;
        margin-left: 20px;
    }

    #reset{
        margin-top: 52px;
    }

    .amount span{
        font-size: 36px;
    }

}

@media only screen and (min-width:600px) {
    body{
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
    }

    main{
        border-radius: var(--fontSize);
        width: 80%;
        box-shadow: 10px 10px 10px 3px rgba(0, 0, 0, 0.1);
    }

    .tip-choice{
        grid-template-columns: 1fr 1fr 33%;
    }
}