style.css

* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    text-transform: uppercase;
}

a {
    text-decoration: none;
}

li {
    list-style: none;
}

body {
    /*background: url("bg.jpg") center / cover no-repeat;*/
    /*height: 100vh;*/
    /*backdrop-filter: blur(5px);*/
    font-family: 'Roboto';
}


.input {
    outline: none;
    border: none;
    /*border-bottom: 1.5px solid white;*/
    border-bottom: 1.5px solid black;
    transition: border 0.3s;
    margin: 20px;
    background: none;
    position: relative;
}

.input::placeholder {
    position: absolute;
    left: 0;
    top: 0;
    transition: 0.3s;
}

.input:focus::placeholder {
    font-size: 8px;
    color: #009dff;
}

.input:focus {
    border-bottom: 1.5px solid #009dff;
}


.input2 {
    outline: none;
    border: none;
    /*border-bottom: 1.5px solid white;*/
    border-bottom: 1.5px solid black;
    transition: border 0.3s;
    margin: 20px;
    background: none;
    position: relative;
}

.input2::placeholder {
    position: absolute;
    left: 0;
    top: 0;
    transition: 0.3s;
}

.input2:focus::placeholder {
    font-size: 8px;
    color: #009dff;
}

.input2:focus {
    border-bottom: 1.5px solid #009dff;
}

.link {
    margin: 20px;
    display: block;
    color: #009dff;
}

.buttons {
    display: flex;
}

.reset {
    display: block;
    margin: 20px;
    color: #009dff;
}

.counter {
    font-size: 20px;
    color: red;
    margin: 20px;
}

.calculator-options {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
}

.plus-text {
    display: inline-block;
    margin: 20px;
    color: white;
    background: #00bc06;
    padding: 10px;
    border-radius: 4px;
    font-size: 20px;
    transition: 0.3s;
}

.subtraction-text {
    margin-left: 20px;
    display: inline-block;
    margin: 20px;
    color: white;
    background: #00bc06;
    padding: 10px;
    border-radius: 4px;
    font-size: 20px;
    transition: 0.3s;
}

.plus-text.active-mode {
    background: red;
}

.subtraction-text.active-mode {
    background: red;
}

.multiply-text {
    display: inline-block;
    margin: 20px;
    color: white;
    background: #00bc06;
    padding: 10px;
    border-radius: 4px;
    font-size: 20px;
    transition: 0.3s;
}

.divide-text {
    margin-left: 20px;
    display: inline-block;
    margin: 20px;
    color: white;
    background: #00bc06;
    padding: 10px;
    border-radius: 4px;
    font-size: 20px;
    transition: 0.3s;
}

.multiply-text.active-mode {
    background: red;
}

.divide-text.active-mode {
    background: red;
}

.divide2-text {
    margin-left: 20px;
    display: inline-block;
    margin: 20px;
    color: white;
    background: #00bc06;
    padding: 10px;
    border-radius: 4px;
    font-size: 20px;
    transition: 0.3s;
}

.divide2-text.active-mode {
    background: red;
}

.plus {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.calculator-settings {
    display: inline-block;
    margin: 10px;
    background: white;
    padding: 5px;
    cursor: pointer;
}

.settings {
    position: fixed;
    left: -100%;
    top: 0;
    height: 100%;
    width: 25%;
    background: white;
    box-shadow: 2px 2px 20px 2px rgba(0, 0, 0, 0.2);
    overflow: auto;
    z-index: 2;
    transition: left 0.3s;
}

.settings.active {
    left: 0;
}

.settings-menu {
    padding: 20px;
}

.settings-title {
    text-align: center;
    font-size: 25px;
    font-weight: 600;
}

.setting {
    margin-top: 50px;
    text-align: center;
    font-size: 18px;
    color: #00bc06;
}


.setting1-options {}

.setting1-option1 {}

.setting1-option img {
    max-width: 100%;
    width: 230px;
    height: 130px;
    cursor: pointer;
}

.setting1-option {
    text-align: center;
    margin-top: 10px;
}

.setting1-option2 {}

.setting1-option3 {}

.setting1-option4 {
    width: 230px;
    height: 130px;
    text-align: center;
    cursor: pointer;
    margin: 10px auto;
    border: 2px solid #009dff;
}

body.bg1 {
    background: url("img1.jpg") center / cover no-repeat;
    height: 100vh;
}

body.bg1 .setting1-option1 img {
    border: 2px solid #009dff;
}

body.bg1 .setting1-option4 {
    border: 2px solid black;
}

body.bg2 {
    background: url("img2.jpg") center / cover no-repeat;
    height: 100vh;
}

body.bg2 .setting1-option2 img {
    border: 2px solid #009dff;
}

body.bg2 .setting1-option4 {
    border: 2px solid black;
}

body.bg3 {
    background: url("bg.jpg") center / cover no-repeat;
    height: 100vh;
}

body.bg3 .setting1-option3 img {
    border: 2px solid #009dff;
}

body.bg3 .setting1-option4 {
    border: 2px solid black;
}

body.bg4 {
    background: white;
    height: 100vh;
}

body.bg4 .setting1-option4 img {
    border: 2px solid #009dff;
}

body.bg5 {
    background: url("img3.jpg") center / cover no-repeat;
    height: 100vh;
}

body.bg6 {
    background: url("img4.jpg") center / cover no-repeat;
    height: 100vh;
}

body.bg7 {
    background: url("img5.jpg") center / cover no-repeat;
    height: 100vh;
}

body.bg8 {
    background: url("img6.jpg") center / cover no-repeat;
    height: 100vh;
}

body.bg9 {
    background: url("img7.jpg") center / cover no-repeat;
    height: 100vh;
}

body.bg10 {
    background: url("img8.jpg") center / cover no-repeat;
    height: 100vh;
}

body.bg11 {
    background: url("img9.jpg") center / cover no-repeat;
    height: 100vh;
}

.setting2-option {
    margin-top: 10px;
    text-align: center;
    cursor: pointer;
}

.setting2-option1 {
    margin-top: 30px;
    font-family: 'Roboto';
}

.setting2-option2 {
    font-family: 'Oswald';
}

.setting2-option3 {
    font-family: 'Rubik Dirt';
}

body.main-font1 {
    font-family: 'Roboto';
}

body.main-font2 {
    font-family: 'Oswald';
}

body.main-font3 {
    font-family: 'Rubik Dirt';
}

@media (max-width: 1000px) {
    .settings {
        width: 50%;
    }
}

@media (max-width: 700px) {
    .buttons {
        flex-wrap: wrap;
    }
}

@media (max-width: 550px) {
    .settings {
        width: 100%;
    }
}

.store-link {
    display: flex;
    justify-content: center;
    margin-top: 20px;
    text-align: center;
    cursor: pointer;
    color: #009dff;
}

.store-link:hover {
    text-decoration: underline;
}

/*body.bg5 {*/
/*    background: url('img3.jpg') center / cover no-repeat;*/
/*    height: 100vh;*/
/*}*/

.back-link {
    display: inline-block;
    margin: 20px;
    color: #009dff;
    cursor: pointer;
}

.back-link:hover {
    text-decoration: underline;
}

.images {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    padding: 20px;
}

.image img {
    max-width: 100%;
    height: 300px;
    width: 350px;
    margin-left: 30px;
    cursor: pointer;
    margin-top: 20px;
}

.images-title {
    text-align: center;
    font-weight: 700;
    font-size: 30px;
}

.modal-window {
    position: absolute;
    left: 0;
    top: 0;
    background: white;
    z-index: 2;
    display: none;
    overflow: auto;
}

.modal-window.opened {
    display: block;
}

.range-wrap {
    margin-top: 30px;
}
.range-input::-webkit-slider-runnable-track {
    background: rgb(229, 229, 229);
    border-radius: 10px;
}


/*.dark-theme_area {*/
/*    max-width: 60px;*/
/*    background: rgb(229, 229, 229);*/
/*    height: 30px;*/
/*    border-radius: 25px;*/
/*    margin: 20px auto;*/
/*    position: relative;*/
/*    cursor: pointer;*/
/*}*/

/*.dark-theme_circle {*/
/*    background: #0275ff;*/
/*    width: 30px;*/
/*    height: 30px;*/
/*    border-radius: 50%;*/
/*    transition: 0.3s;*/
/*}*/

/*.dark-theme_circle.darkTheme {*/
/*    margin-left: 30px;*/
/*}*/

/*body.darkTheme {*/
/*    background: #1c1c1c;*/
/*    color: white;*/
/*}*/

/*.settings.darkTheme {*/
/*    background: black;*/
/*}*/

.save-button {
    display: flex;
    justify-content: center;
    color: #009dff;
    cursor: pointer;
    margin-top: 30px;
}

.save-button:hover {
    text-decoration: underline;
}