style.css

@import url('https://fonts.googleapis.com/css2?family=Spartan:wght@700&display=swap');

:root {
    --text-white: hsl(0, 0%, 100%);

    /* theme 1 */

    --bg-desaturated-blue-1: hsl(222, 26%, 31%);
    --bg-desaturated-blue-2: hsl(223, 31%, 20%);
    --bg-desaturated-blue-3: hsl(224, 36%, 15%);
    --key-desaturated-blue-1: hsl(225, 21%, 49%);
    --key-desaturated-blue-2: hsl(224, 28%, 35%);
    --key-red: hsl(6, 63%, 50%);
    --key-dark-red: hsl(6, 70%, 34%);
    --key-light-grayish-orange: hsl(30, 25%, 89%);
    --key-grayish-orange: hsl(28, 16%, 65%);
    --text-dark-grayish-blue: hsl(221, 14%, 31%);

    /* theme 2 */

    --bg-light-gray: hsl(0, 0%, 90%);
    --bg-grayish-red: hsl(0, 5%, 81%);
    --bg-very-light-gray: hsl(0, 0%, 93%);
    --key-dark-cyan: hsl(185, 42%, 37%);
    --key-very-dark-cyan: hsl(185, 58%, 25%);
    --key-orange: hsl(25, 98%, 40%);
    --key-dark-orange: hsl(25, 99%, 27%);
    --key-light-grayish-yellow: hsl(45, 7%, 89%);
    --key-dark-grayish-orange: hsl(35, 11%, 61%);
    --text-dark-grayish-yellow: hsl(60, 10%, 19%);

    /* theme 3 */

    --bg-dark-violet-1: hsl(268, 75%, 9%);
    --bg-dark-violet-2: hsl(268, 71%, 12%);
    --key-dark-violet: hsl(281, 89%, 26%);
    --key-vivid-magenta: hsl(285, 91%, 52%);
    --key-pure-cyan: hsl(176, 100%, 44%);
    --key-soft-cyan: hsl(177, 92%, 70%);
    --key-very-dark-violet: hsl(268, 47%, 21%);
    --key-dark-magenta: hsl(290, 70%, 36%);
    --text-light-yellow: hsl(52, 100%, 62%);
    --text-very-dark-blue: hsl(198, 20%, 13%);
}

* {
    box-sizing: border-box;
}

body, #header, #calc-text, #screen, #result, #buttons, .button {
    transition: background-color 0.5s, color 0.5s, border-bottom 0.5s;
}

body {
    font-family: 'Spartan', sans-serif;
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 2rem;
    transition: 1s ease;
}

#calculator {
    display: flex;
    flex-direction: column;
    width: 38%;
    height: 84vh;
}

#header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

#calc-text {
    font-size: 1.75rem;
}

#themes {
    display: flex;
}

#theme-selector {
    display: flex;
    padding: 0.3rem 0.2rem;
    border-radius: 5rem;
}

#theme-text-container #theme-text {
    padding-bottom: 0.3rem;
}

#theme-text-container {
    display: flex;
    align-items: flex-end;
    justify-content: flex-end;
}

#theme-labels {
    display: flex;
    font-size: 0.75rem;
}

#theme-labels p {
    margin: 0.2rem 0 0.2rem 0.8rem;
}

input[type='radio']:after {
    width: 15px;
    height: 15px;
    border-radius: 15px;
    border: none;
    top: -2px;
    left: -1px;
    position: relative;
    content: '';
    display: inline-block;
    visibility: visible;
    transition: color 0.3s;
    cursor: pointer;
    margin: 0;
}

input[type='radio']:checked:after {
    width: 15px;
    height: 15px;
    border-radius: 15px;
    top: -2px;
    left: -1px;
    position: relative;
    content: '';
    display: inline-block;
    visibility: visible;
}

#t1:checked:after {
    background-color: var(--key-red);
}

#t2:checked:after {
    background-color: var(--key-orange);
}

#t3:checked:after {
    background-color: var(--key-soft-cyan);
}

#theme-text {
    margin: 0 1rem 0 0;
    font-size: 0.75rem;
    align-self: flex-end;
}

#screen {
    height: 18vh;
    width: 100%;
    margin: 1rem 0;
    border-radius: 0.5rem;
}

#screen #result {
    text-align: right;
    line-height: 16vh;
    font-size: 2.5rem;
    margin: 0 2rem 0 0;
}

#buttons {
    width: 100%;
    height: 100%;
    border-radius: 0.5rem;
    padding: 1.5rem;
    display: grid;
    grid-gap: 1.5rem;
    grid-template-columns: 1fr 1fr 1fr 1fr;
}

#reset, #eval {
    grid-column: span 2;
}

#del, #reset, #eval {
    font-size: 1.5rem;
}

.button {
    font-size: 1.75rem;
    font-family: 'Spartan', sans-serif;
    text-align: center;
    padding: 0.5rem 0;
    border-radius: 0.5rem;
    border: none;
    cursor: pointer;
}

.button:hover {
    opacity: .75;
}

/* theme 1 */

body.theme-1 {
    background-color: var(--bg-desaturated-blue-1);
    color: var(--text-white);
}

body.theme-1 input[type='radio']:after {
    background-color: var(--bg-desaturated-blue-2);
}

body.theme-1 #calc-text {
    color: var(--text-white);
}

body.theme-1 #theme-selector {
    background-color: var(--bg-desaturated-blue-2);
}

body.theme-1 #screen {
    background-color: var(--bg-desaturated-blue-3);
}

body.theme-1 #screen #result {
    color: var(--text-white);
}

body.theme-1 #buttons {
    background-color: var(--bg-desaturated-blue-2);
}

body.theme-1 .button {
    background-color: var(--key-light-grayish-orange);
    color: var(--text-dark-grayish-blue);
    border-bottom: 4px solid var(--key-grayish-orange);
}

body.theme-1 #eval {
    background-color: var(--key-red);
    color: var(--text-white);
    border-bottom: 4px solid var(--key-dark-red);
}

body.theme-1 #del, body.theme-1 .button#reset {
    background-color: var(--key-desaturated-blue-1);
    color: var(--text-white);
    border-bottom: 4px solid var(--key-desaturated-blue-2);
}

/* theme 2 */

body.theme-2 {
    background-color: var(--bg-light-gray);
    color: var(--text-dark-grayish-yellow);
}

body.theme-2 input[type='radio']:after {
    background-color: var(--bg-grayish-red);
}

body.theme-2 #calc-text {
    color: var(--text-dark-grayish-yellow);
}

body.theme-2 #theme-selector {
    background-color: var(--bg-grayish-red);
}

body.theme-2 #screen {
    background-color: var(--bg-very-light-gray);
}

body.theme-2 #screen #result {
    color: var(--text-dark-grayish-yellow);
}

body.theme-2 #buttons {
    background-color: var(--bg-grayish-red);
}

body.theme-2 .button {
    background-color: var(--key-light-grayish-yellow);
    color: var(--text-dark-grayish-yellow);
    border-bottom: 4px solid var(--key-dark-grayish-orange);
}

body.theme-2 #eval {
    background-color: var(--key-orange);
    color: var(--text-white);
    border-bottom: 4px solid var(--key-dark-orange);
}

body.theme-2 #del, body.theme-2 #reset {
    background-color: var(--key-dark-cyan);
    color: var(--text-white);
    border-bottom: 4px solid var(--key-very-dark-cyan);
}

/* theme 3 */

body.theme-3 {
    background-color: var(--bg-dark-violet-1);
    color: var(--text-light-yellow);
}

body.theme-3 input[type='radio']:after {
    background-color: var(--bg-dark-violet-2);
}

body.theme-3 #calc-text {
    color: var(--text-light-yellow);
}

body.theme-3 #theme-selector {
    background-color: var(--bg-dark-violet-2);
}

body.theme-3 #screen {
    background-color: var(--bg-dark-violet-2);
}

body.theme-3 #screen #result {
    color: var(--text-light-yellow);
}

body.theme-3 #buttons {
    background-color: var(--bg-dark-violet-2);
}

body.theme-3 .button {
    background-color: var(--key-very-dark-violet);
    color: var(--text-light-yellow);
    border-bottom: 4px solid var(--key-dark-magenta);
}

body.theme-3 #eval {
    background-color: var(--key-pure-cyan);
    color: var(--text-very-dark-blue);
    border-bottom: 4px solid var(--key-soft-cyan);
}

body.theme-3 #del, body.theme-3 #reset {
    background-color: var(--key-dark-violet);
    color: var(--text-white);
    border-bottom: 4px solid var(--key-vivid-magenta);
}

@media screen and (max-width: 768px) {
    #calculator {
        width: 80%;
    }
}

@media screen and (max-width: 375px) {
    #calculator {
        width: 90%;
    }

    #buttons {
        grid-gap: 1rem;
    }

    #screen {
        margin: 2rem 0;
    }

    #reset, #del {
        font-size: 1.1rem;
    }
}