* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 0;
    font-family: "Inter";
    line-height: 1.75;
    overflow-x: hidden;
}

h2 {
    color: #1D3F16;
}

h3 {
    color: #4B6D52;
}

a {
    text-decoration: none;
    color: black;
}

.importance, 
.ethics, 
.public-involvement, 
.join-us, 
.discoveries, 
.quote, 
.references {
    margin-bottom: 130px;
    padding: 0 56px;
}

button:hover {
    cursor: pointer;
}

header {
    min-height: 100vh;
    width: 100%;
    margin-bottom: 130px;
}

header h1 {
    margin: 15px 0 8px 0;
    font-size: 55px;
    font-weight: 900;
    line-height: 1.5;
    letter-spacing: -1px;
}

.top-side {    
    padding: 15px 0;
    background-image: url("./images/image-header-Picsart-AiImageEnhancer.png");
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;

    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.top-side h1 {
    text-align: center;
    color: #1D3F16;
}

.nav-btns {
    margin: 1rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    row-gap: 12px;
}

.top-side-btns {
    display: flex;
    column-gap: 12px;
}

.bottom-side-btns {
    display: flex;
    column-gap: 12px;
    padding: 0;
}

.nav-btns button {
    margin: 0;
    padding: 0 25px;
    font-weight: 600;
    color: white;
    background-color: #3E5743;
    border: none;
    border-radius: 150px;
    font-size: 16px;
    width: 200px;
    height: 50px;
    transition: all 0.3s ease;
}

.nav-btns button:hover {
    background-color: transparent;
    color: #3E5743;
    border: 1px solid #3E5743;
}

.bottom-side {
    width: 100%;
    display: flex;
    justify-content: space-evenly;
    align-items: center;
    column-gap: 56px;
    background-color: #A9CA9E;
    padding: 15px  56px;
}

.importance h2 {
    text-align: center;
}

.importance-btns {
    display: flex;
    justify-content: center;
    column-gap: 45px;
    position: relative;
}

.gray-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background-color: rgba(128, 128, 128, 0.702);
    z-index: 999;
}

.close-btn {
    border-radius: 50%;
    color: #ffff;
    border: 2px solid #ffff;
    background-color: transparent;
    font-size: 16px;
    font-weight: bold;
    height: 30px;
    width: 30px;
    margin: 0;
    position: absolute;
    right: 30px;
}

.popup {
    display: none;
    opacity: 0;
    transform: scale(0.95);
    transition: opacity 0.3s ease, transform 0.3s ease;
    position: absolute;
    background-color: #44624a;
    padding: 25px 50px;
    border-radius: 16px;
    z-index: 2;
    color: white;
    max-width: 600px;
}

.popup.show {
    display: block;
    opacity: 1;
    transform: scale(1);
}

.overlay {
    display: none;
    position: fixed;
    top: 0; left: 0;
    width: 100%;
    height: 100vh;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 1;
}
.overlay.show {
    display: block;
}

.importance-btns > button {
    width: 250px;
    height: 250px;
    border: 2px solid #A9CA9E;
    border-radius: 18px 36px 18px 36px;
    font-size: 22px;
    font-weight: 600;
    text-align: center;
    position: relative;
    transition: all 0.3s ease;
}

.importance-btns button:hover {
    transform: scale(1.05);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.2);
    border-color: #3E5743;
}

.health {
    background-image: url("./images/Health.png");
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
    border: none;
}

.environment {
    background-image: url("./images/Environment.png");
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
    border: none;
}

.food {
    background-image: url("./images/Food.png");
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
    border: none;
}

.biotechnology {
    background-image: url("./images/Biotech.png");
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
    border: none;
}

.public-involvement > div {
    margin-bottom: 40px;
}

.images {
    display: flex;
    justify-content: space-evenly;
}

.images > div {
    width: 250px;
}

.images > div > img {
    width: 100%;
    height: 200px;
    transition: all 0.3s ease;
}

.images > div > img:hover {
    cursor: pointer;
    transform: scale(1.05);
}

.images > div > p {
    margin-top: 8px;
    padding: 0 16px;
    text-align: center;
}

.img-popup {
    display: none;
    position: fixed;
    z-index: 2;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: #44624a;
    padding: 30px;
    border-radius: 16px;
    color: white;
    width: 80%;
    max-width: 80%;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}

.img-popup.show {
    display: block;
}

.ethics-left-side {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.ethics-left-side p {
    width: 600px;
}

.ethics-left-side > img {
    margin: auto;
    width: 280px;
    height: 280px;
    box-shadow: 15px 15px 4px 0 #A9CA9E;
}

.join-us {
    width: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    text-align: center;
    background-color: #A9CA9E;
    padding-top: 50px;
    padding-bottom: 50px;
}

.join-us h2 {
    margin: 0;
}

.join-us > p {
    margin: auto;
    width: 800px;
}

.join-us-image-link {
    margin-top: 36px;
    display: flex;
    column-gap: 2px;
    justify-content: center;
}

.left-image img,
.right-image img {
    transition: all 0.3s ease;
    position: relative;
}

.left-image img:hover,
.right-image img:hover {
    cursor: pointer;
    opacity: 0.5;
}

.left-image p,
.right-image p {
    position: absolute;
    display: none;
    top: 50%;
    left: 50%;
    z-index: 0;
}

.left-image img:hover p {
    display: block;
}

.discovery-info > div {
    display: flex;
    align-items: center;
    margin-bottom: 32px;
}

.left-text {
    width: 550px;
}

.right-text {
    width: 550px;
}

.discovery-info img {
    margin: auto;
    width: 250px;
    height: 250px;
    border: 2px solid #A9CA9E;
    border-radius: 16px 32px 16px 32px;
    box-shadow: 12px 12px 4px 0 #44624A;
}

.quote {
    width: 80%;
    margin: auto;
    margin-bottom: 130px;
    padding: 12px 16px;
    border-left: 8px solid #44624A;
    background-color: #A9CA9E;
    text-align: center;
}

.quote p {
    margin: 0;
}

.quote .name {
    margin-top: 6px;
}

.references ul {
    list-style-type: disc;
    padding-left: 20px;
    line-height: 1.8;
    font-size: 16px;
}

#references li {
    margin-bottom: 10px;
}

footer {
    display: flex;
    justify-content: center;
    align-items: center;
    column-gap: 16px;
    background-color: #44624A;
    color: white;
    padding: 20px;
}

footer a {
    color: white;
}

footer p {
    margin: 0;
}

.names {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.footer-links {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.foot-link {
    display: flex;
    column-gap: 16px;
}

/* Media Queries for Responsiveness */

@media (max-width: 768px) {
    .top-side-btns, .bottom-side-btns {
        flex-direction: column;
        align-items: center;
    }

    .nav-btns button {
        width: 150px;
        font-size: 14px;
        height: 40px;
    }

    .importance-btns > button {
        width: 200px;
        height: 200px;
        font-size: 18px;
    }

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

    .images > div {
        width: 90%;
        margin-bottom: 16px;
    }

    .ethics-left-side p, .left-text, .right-text {
        width: 100%;
    }

    .join-us > p {
        width: 90%;
    }

    .discovery-info > div {
        flex-direction: column;
        align-items: center;
    }

    footer {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 30px;
    }

    .top-side h1 {
        font-size: 24px;
    }

    .importance-btns > button {
        width: 150px;
        height: 150px;
        font-size: 16px;
    }

    .join-us > p {
        width: 100%;
    }

    .discovery-info img {
        width: 200px;
        height: 200px;
    }
}

.scroll-up {
    position: fixed;
    bottom: 30px;
    right: 30px;
    display: none;
    background-color: #44624a;
    border: none;
    padding: 16px;
    border-radius: 50%;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
    z-index: 1000;
    cursor: pointer;
    transition: all 0.3s ease;
    opacity: 0.9;
  }
  
  .scroll-up.show {
    display: block;
  }
  
  .scroll-up:hover {
    transform: scale(1.1);
    background-color: #2f4a35;
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.3);
    opacity: 1;
  }
  
  .scroll-up img {
    width: 24px;
    height: 24px;
    filter: invert(1); /* make white icons show on dark background */
  }