:root {
    /* Colours */
    --clr-primary-faintest: rgb(235, 242, 248);
    --clr-primary-faint: rgb(233, 246, 255);
    --clr-primary-lighter: rgb(87, 188, 255);
    --clr-primary: rgb(48, 154, 224);
    --clr-primary-darker: rgb(31, 101, 147);

    --clr-dark-grey: rgb(65, 64, 66);
    --clr-white: rgb(255, 255, 255);

    /* Font Styling */

        /* Font Weight */
        --fw-light: 300;
        --fw-regular: 400;
        --fw-medium: 500;
        --fw-semi-bold: 600;
        --fw-bold: 700;
        --fw-extra-bold: 800;

    /* Padding and Spacing */
    --padding-site-mobile: 0.5rem;
    --padding-site-desktop: 2rem;

    --padding-content-mobile: 0.5rem;
    --padding-content-desktop: 1rem;

    --site-width: 100rem;
}

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

html {
    font-family: "Montserrat", sans-serif;
    font-optical-sizing: auto;
    font-weight: var(--fw-regular);
    font-style: normal;
}

body {
    color: var(--clr-dark-grey);
}

h1, h2, h3, h4, h5 {
    margin: 0.5rem auto;
}

h2 {
    font-size: 2rem;
    margin: 2rem 0rem;
    font-weight: var(--fw-extra-bold);
}

p {
    margin: 0.25rem auto;
    line-height: 1.5rem;
}

a {
    text-decoration: none;
}

.test {
    border: 1px solid red;
}

@media screen and (min-width: 768px) {
    h2 {
        font-size: 2.5rem;
    }
}

@media screen and (min-width: 1040px) {
    h2 {
        font-size: 3rem;
    }
}

/* Image Styling */

img {
    display: block;
    width: 100%;
}

/* Hide & Unhide */

.hidden {
    display: none;
}

.desktop {
    display: none;
}

@media screen and (min-width: 768px) {
    .desktop {
        display: block;
    }

    .mobile {
        display: none;
    }
}

/* Colour Classes */

.main_colour {
    color: var(--clr-primary);
}

/* header */
header {
    top: 0;
    left: 0;
    padding: var(--padding-site-mobile);
    position: relative;
    width: 100%;
}

header a {
    color: var(--clr-dark-grey);
}

header nav {
    width: 100%;
    height: 100%;
    padding: var(--padding-content-mobile);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
    max-width: var(--site-width);
}

header nav ul {
    display: flex;
    list-style: none;
}

header nav ul li {
    margin-left: 1.5rem;
    font-size: 0.9rem;
    font-weight: var(--fw-bold);
    text-transform: uppercase;
}

header nav .logo {
    font-size: 1.2rem;
    font-weight: var(--fw-extra-bold);
    text-transform: uppercase;
}

@media screen and (min-width: 768px) {
    header {
        padding: 0.5rem var(--padding-site-desktop);
    }

    header nav {
        padding: var(--padding-content-desktop);
    }

    header nav ul li {
        font-size: 1.2rem;
    }

    header nav .logo {
        font-size: 1.5rem;
    }
}

/* Main Body Styling */

main section:first-of-type > .container {
    margin-top: 5rem;
}

section {
    margin: 5rem auto;
}

.container {
    width: 100%;
    height: 100%;
}

.content_container {
    width: 100%;
    height: 100%;
    padding: var(--padding-site-mobile);
    margin: 0 auto;
    max-width: var(--site-width);
}

.content_container .content_wrapper {
    display: flex;
    flex-direction: column;
    width: 100%;
    height: 100%;

}

.content_container .content_wrapper .content_box {
    width: 100%;
    height: 100%;
    justify-content: center;
    align-items: center;
    margin: auto;
    padding: var(--padding-content-mobile);
}

.centered_text {
    text-align: center;
}

@media screen and (min-width: 768px) {
    main section:first-of-type > .container {
        margin-top: 8rem;
    }

    .content_container {
        padding: var(--padding-site-desktop);
    }

    .content_container .content_wrapper {
        flex-direction: row;
    }

    .content_container .content_wrapper .content_box {
        padding: var(--padding-content-desktop);
    }
}

/* Grid Styling */
.content_container .content_wrapper .content_grid {
    display: grid;
    grid-template-columns: auto;
    gap: 20px;
    width: 100%;
    height: 100%;
    padding: var(--padding-content-desktop);
}

.grid_item {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
    height: 100%;
    padding: var(--padding-content-desktop);
    border-radius: 1rem;
    box-shadow: rgba(100, 100, 111, 0.2) 0px 7px 29px 0px;
    transition: 1s ease;
}

.grid_item:hover {
    scale: 1.01;
    box-shadow: rgba(48, 154, 224, 0.2) 0px 7px 29px 0px;
    cursor: pointer;
}

.grid_item a {
    color: var(--clr-dark-grey);
}

.grid_item img {
    aspect-ratio: 1 / 1;
    object-fit: contain;
    width: 100%;
    height: auto;
    transition: 10s ease;
}

.grid_item span {
    font-weight: var(--fw-extra-bold);
    margin: 0 auto;
    min-width: 100%;
    border: 1px solid red;
}

.grid_item p {
    text-align: center;
    font-weight: var(--fw-extra-bold);
    margin: 0 auto;
    min-width: 100%;
}

@media screen and (min-width: 768px) {
    .content_container .content_wrapper .content_grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* Form Inputs for Calculator */

.action_group {
    display: flex;
    flex-direction: column;
    margin: 0.5rem auto 1.5rem auto;
}

.action_group label {
    font-weight: var(--fw-bold);
    font-size: 1.2rem;
    caret-color: transparent;
}

.action_group input {
    padding: 0.5rem 0;
    font-size: 1rem;
    color: var(--clr-dark-grey);
    background: none;
    border: none;
    border-bottom: 2px solid transparent;
    border-image: linear-gradient(0.25turn, rgb(31, 101, 147) 0%, rgb(48, 154, 224) 50%, transparent 95%);
    border-image-slice: 1;
    outline: none;
    width: 100%;
}

.action_group > button {
    padding: 1rem;
    width: fit-content;
    background: var(--clr-primary);
    border: none;
    border-radius: 0.75rem;
    color: var(--clr-white);
    transition: 0.3s ease;
    text-transform: uppercase;
    font-weight: var(--fw-semi-bold);
}

.action_group > button:hover {
    background: var(--clr-primary-darker);
    cursor: pointer;
}

input::-webkit-outer-spin-button,
input::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

input[type=number]{
    -moz-appearance: textfield;
}

@media screen and (min-width: 768px) {
    .action_group input {
        border-image: linear-gradient(0.25turn, rgb(31, 101, 147) 0%, rgb(48, 154, 224) 25%, transparent 50%);
        border-image-slice: 1;
    }
}

/* Radio buttons for action_group */

.radio_button_group {
    margin: 1rem 0;
    display: flex;
    flex-direction: column;
    justify-content: start;
}

.radio_button_group > div {
    display: flex;
    justify-content: start;
    padding: 0.25rem;
    align-items: center; 
    margin-right: 2rem;
}

.radio_button_group label {
    display: flex;
    font-size: 0.8rem;
    align-items: center;
    gap: 0.5rem;
}

.radio_button_group input[type="checkbox"] {
    appearance: none;
    font: inherit;
    width: 1.5rem;
    height: 1.5rem;
    min-width: 1.5rem;
    min-height: 1.5rem;
    background: var(--clr-white);
    border: none;
    border-radius: 60% 40% 38% 62% / 50% 58% 42% 50% ;
    box-shadow: inset 3px 3px 3px rgba(0, 0, 0, 0.06),
                2px 4px 2px rgba(0, 0, 0, 0.1);
    margin: 0;
    transform: translateY(0.11rem);
    display: grid;
    place-content: center;
    cursor: pointer;
    transition: 0.4s ease;
}

.radio_button_group input[type="checkbox"]::before {
    content: "";
    width: 0.65rem;
    height: 0.65rem;
    border-radius: 25%;
    transform: scale(0);
    transition: 0.2s transform ease;
    box-shadow: inset 1em 1em var(--clr-secondary);
    background-color: CanvasText;
    transition: 0.4s ease;
}

.radio_button_group input[type="checkbox"]:checked {
    background: var(--clr-primary-faint); 
    box-shadow: inset 3px 3px 3px rgba(0, 0, 0, 0.1),
                2px 4px 2px rgba(0, 0, 0, 0.2);
    scale: 1.075;
    border-radius: 47% 53% 35% 65% / 44% 52% 48% 56% ;
}

.radio_button_group input[type="checkbox"]:checked::before {
    background-color: var(--clr-primary-faint);
}

@media screen and (min-width: 768px) {
    .radio_button_group {
        flex-direction: row;
    }
}

/* Results Styling */
.results {
    height: 100%;
    display: flex;
    align-items: stretch !important;
}

.results_container {
    padding: 2rem;
    font-weight: var(--fw-medium);
    text-transform: uppercase;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    width: 550px;
    width: 100%;
    border-radius: 60% 40% 38% 62% / 50% 58% 42% 50% ;
    box-shadow: inset 15px 15px 15px rgba(0, 0, 0, 0.06),
                10px 25px 10px rgba(0, 0, 0, 0.1);
    transition: 0.5s ease;
}

.results_container:hover {
    scale: 1.01;
    background: var(--clr-primary-faint);
    border-radius: 47% 53% 35% 65% / 44% 52% 48% 56% ;
    box-shadow: inset 15px 15px 15px rgba(0, 0, 0, 0.06),
                10px 25px 10px rgba(0, 0, 0, 0.1);
}

.results_container .result_heading {
    font-weight: var(--fw-extra-bold);
}

.results_container > .main_result_container {
    font-size:  1rem;
    margin: 0.25rem auto;
    padding: 0.25rem;
    height: 100%;
    width: 100%;
}

.results_container > .main_result_container p {
    line-height: 2.2rem;
}

.results_container > .secondary_results_container {
    display: flex;
    flex-direction: row;
    width: 100%;
    height: 100%;
}

.results_container > .secondary_results_container > div {
    display: flex;
    flex-direction: row;
    width: 100%;
    height: 100%;
    font-size: 0.8rem;
    padding: 0.25rem;
}

.results_container > .secondary_results_container > div p {
    font-size: 0.8rem;
}

@media screen and (min-width: 360px) {
    .results_container {
        min-height: 400px;
        width: 100%;
    }

    .results_container > .main_result_container {
        font-size: 1.3rem;
        margin: 1rem auto;
    }

    .results_container > .secondary_results_container > div {
        font-size: 1.1rem;
    }
}

@media screen and (min-width: 768px) {
    .results_container {
        min-height: 500px;
        max-width: 650px;
        width: 100%;
    }

    .results_container > .main_result_container {
        font-size: 1.8rem;
        margin: 1rem auto;
    }

    .results_container > .main_result_container p {
        line-height: 2.5rem;
    }
}

@media screen and (min-width: 1080px) {
    .results_container {
        min-height: 650px;
        max-width: 650px;
        width: 100%;
    }

    .results_container > .main_result_container {
        font-size: 3rem;
        margin: 0.5rem auto;
    }

    .results_container > .main_result_container p {
        line-height: 3.5rem;
    }

    .results_container > .secondary_results_container > div p {
        font-size: 1rem;
    }
}

/* Water Tank Styling */

#water_tank_section {
    position: relative;
    background: linear-gradient(0deg, transparent 0%, rgb(225, 225, 225) 3%, rgb(238, 238, 238) 30%, transparent 50%);
    z-index: -5;
}

#water_tank_section h2 {
    text-align: center;
}

.water_tank {
    border: 8px solid #8d9d83;
    background: url(media_files/Water\ Image-01.png);
    background-size: 650px 520px;
    max-width: 650px;
    border-radius: 50% 50% 10% 10% / 25% 25% 10% 10%;
    aspect-ratio: 1 / 0.8;
    box-shadow: inset 15px 15px 15px rgba(0, 0, 0, 0.5),
                3px 5px 5px rgba(0, 0, 0, 0.4);
    margin: 0 auto;
    position: relative;
}

.water_tank_background {
    background: var(--clr-dark-grey);
    outline: 4px solid var(--clr-dark-grey);
    border-radius: 50% 50% 10% 10% / 25% 25% 10% 10%;
    aspect-ratio: 1 / 0.8;
    max-width: 650px;
    position: absolute; /* Absolute positioning to fill parent */
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: -1; /* Lower than the other elements */
}

.water_tank_text {
    color: var(--clr-white);
    position: absolute;
    width: 100%;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    font-size: 3rem;
    font-weight: var(--fw-extra-bold);
}

/* Footer Styling */
footer .container {
    background-color: var(--clr-primary);
    color: var(--clr-white);
}

footer a {
    color: var(--clr-white);
}

footer ul {
    list-style: none;
}

footer ul li {
    margin: 0.25rem 0
}

footer h2 {
    margin: 0.25rem 0
}

@media screen and (min-width: 768px) {
    footer .content_box:nth-of-type(2) {
        text-align: right;
    }
}