* {
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    margin: 0;
    padding: 0;
    background: url(../images/background.png);
    background-repeat: no-repeat;
    background-attachment: fixed;
    background-size: cover;
}

/* Math, other page */
.item-body li,
.item-body a {
    font-size: 18px;
}
/*..................*/

a {
    text-decoration: none;
}

.container {
    max-width: 960px;
    margin: auto;
    padding: 50px 0px;
}

.calculateBtn {
    margin-top: 15px;
    padding: 10px 15px;
    font-size: 18px;
    border-radius: 10px;
    color: white;
    border: none;
    background-color: rgba(43, 119, 59, 0.719);
    cursor: pointer;
    display: inline-block;
    transition-duration: 0.5s;
}

.calculateBtn:hover {
    background-color: #4F8026;
}

.all-input {
    margin-bottom: 10px;
    padding: 5px;
    padding-left: 10px;
    width: 200px;
    font-size: 18px;
    outline: none;
    border-radius: 10px;
    border: 2px solid gray;
    display: block;
}

.all-input:focus {
    border: 2px solid green;
}

.all-select {
    margin-bottom: 10px;
    padding: 5px;
    width: auto;
    font-size: 18px;
    outline: none;
    border-radius: 10px;
    border: 2px solid gray;
}

.all-select:focus {
    border: 2px solid green;
}

.alert {
    width: auto;
    margin: 20px 0px;
    background-color: #F2DEDE;
    border: 1px solid #EBCCD1;
    border-radius: 5px;
    color: #A94465;
    padding: 10px;
    display: none;
}

.closebtn {
    margin-left: 15px;
    font-weight: bold;
    float: right;
    cursor: pointer;
}

.closebtn:hover {
    color: black;
}

.item-title {
    color: #2060a0;
}

/*...................*/
/* Header           */
/*.................*/
.head {
    width: 100%;
    background-color: #003366;
}

.header-body {
    max-width: 960px;
    margin: auto;
    padding: 20px 0px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 24px;
    font-weight: bold;
    color: white;
}

.nav-list {
    list-style: none;
    display: flex;
    align-items: center;
    gap: 15px;
    margin: 0;
}

.nav-link:link,
.nav-link:visited {
    display: inline-block;
    text-decoration: none;
    font-size: 18px;
    font-weight: bold;
    color: #ffffff;
    padding: 10px 15px;
    border: 2px solid transparent;
}

.nav-list a:hover {
    background-color: white;
    color: #003366;
    transition-duration: 0.5s;
}

.active:link,
.active:visited {
    border: 2px solid white;
}

.menu-btn {
    display: none;
    padding: 4px 12px;
    font-size: 24px;
    border: 1px solid #E0E1E5;
    border-radius: 5px;
}
.menu-btn i {
    color: #7D7E80;
    height: 20px;
    width: 20px;
}
/* Moblie nav  */
.mobile-menu{
    background-color: rgb(238, 238, 238);
    padding: 20px 0px;
    display: none;
}
.mobile-nav-list{
    list-style: none;
    margin: 0;
    padding: 0;
}
.mobile-nav-link:link,
.mobile-nav-link:visited {
    display: inline-block;
    color: black;
}
.mobile-menu li:nth-last-child(n+2){
    border-bottom: 1px solid rgb(216, 216, 216);
}
/*...................*/
/* Home page        */
/*.................*/

/* Basic Calculator */
.calculator {
    height: auto;
    width: 300px;
    padding: 20px;
    padding-top: 0;
    margin: auto;
    margin-bottom: 30px;
    display: flex;
    justify-content: center;
    border-radius: 20px;
    box-shadow: 0 15px 53px 14px rgb(0 0 0 / 10%);
}

.cal-input input,
.display {
    width: 50px;
    height: 50px;
    font-size: 24px;
    font-weight: bold;
    border-radius: 10px;
    background-color: rgb(68, 66, 66);
    transition-duration: 0.3s;
    color: #fff;
    border-style: none;
    cursor: pointer;
}

.cal-input input:hover {
    transform: scale(1.05);
    opacity: 0.5;
}

.display {
    width: 240px;
    padding: 5px 10px;
    background-color: aquamarine;
    border: 2px solid rgb(204, 207, 207);
    box-sizing: border-box;
    color: black;
    cursor: text;
    outline: none;
    display: block;
}

.display:hover {
    transform: scale(1);
    opacity: 1;
}

.calculator h2 {
    text-align: center;
}

.cal-input {
    display: grid;
    grid-template-columns: auto auto auto auto;
    grid-gap: 10px;
}


/*................*/
/*      Tab      */
/*..............*/

.tabs {
    display: flex;
    flex-wrap: wrap;
}

.tabs label {
    order: 1;
    display: block;
    padding: 1rem 2rem;
    margin: 0px 0.4rem;
    margin-bottom: 0.4rem;
    margin-left: 0;
    cursor: pointer;
    background: rgb(211, 210, 210);
    font-weight: bold;
    transition: background ease 0.5s;
    border-radius: 5px;
}

.tabs label:hover {
    background-color: thistle;
}

.tabs .tab {
    order: 99;
    flex-grow: 1;
    width: 100%;
    display: none;
    padding-bottom: 10px;
    background-color: transparent;
}

.tabs input[type="radio"] {
    display: none;
}

.tabs input[type="radio"]:checked+label {
    background: #8B0000;
    color: white;
}

.tabs input[type="radio"]:checked+label+.tab {
    display: block;
}