/* ---------- Global Variables ---------- */
:root {
    /* Brand colours */
    --unit-blue: rgb(102, 153, 204);
    --unit-green: rgb(109, 247, 109);
    --unit-blue-accent: rgb(102, 215, 239);
    --unit-blue-accent-hover: rgb(0, 178, 218);
    --footer-bg: #333;
    --text-dark: #000;
    --text-light: #fff;

    /* Spacing scale */
    --space-s: 8px;
    --space-m: 20px;
    --space-l: 40px;
}

/* ---------- Base ---------- */
body {
    font-family: sans-serif, Arial;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
}

/* ---------- Header ---------- */
.header {
    position: relative;
    width: 100%;
    height: 600px;
    margin: -65px 0 0 0;
    background: url('images/index/placeholder.jpg') center/cover no-repeat;
    display: flex;
    align-items: center;      /* vertically centers the text block */
    justify-content: center;  /* horizontally centers it */
}

/* ---------- Home Header Section ---------- */
.home-header {
    max-width: 800px;
    margin: 70px 30px 0px 30px;
    text-align: center;
    color: var(--text-light);
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(10px);
    border-radius: 15px;
    padding: 40px 50px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.2);
}

.home-header h1 {
    font-size: 64px;
    margin-bottom: var(--space-m);
}

.home-header p {
    font-size: 24px;
    margin: 50px auto;
}

@media (max-width: 850px) {
    .header {
        height: 500px;
        margin: -65px 0 0 0;
    }

    .home-header {
        padding: 15px 20px;
    }

    .home-header h1 {
        font-size: 40px;
        padding-bottom: 15px;
    }

    .home-header p {
        font-size: 18px;
        margin-top: 20px;
    }
}

@media (max-width: 480px) {
    .header {
        height: 600px;
        margin: -65px 0 0 0;
    }
}


/* ---------- Navigation Bar ---------- */
.navbar-container {
    position: sticky;
    top: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;    
    background: var(--text-light);
    border-radius: 40px;
    padding: 2px 20px;
    margin: 0 auto;
    max-width: 1050px;
    height: 60px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
    z-index: 1000;
}

.logo-image {
    height: 40px;
    width: auto;
    max-width: 100%;
}

.navbar-pill a {
    padding: 12px 20px;
    font-size: 18px;
    color: var(--text-dark);
    text-decoration: none;
    border: 2px solid transparent;
    border-radius: 60px;
    background-color: transparent;
    transition: background-color 0.3s ease-in-out, color 0.3s ease-in-out;
}

.navbar-pill a:hover {
    background-color: var(--unit-green);
    color: var(--text-dark);
}

.navbar-pill a.active {
    background-color: var(--unit-blue-accent);
    color: var(--text-dark);
}

a.active:hover {
    background-color: var(--unit-blue-accent-hover);
    color: var(--text-dark);
}


/* ---------- About Section ---------- */
.about-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    grid-template-rows: auto 1fr auto;
    gap: var(--space-m);
    min-height: 400px;
    background-color: var(--text-light);
    padding: var(--space-m) var(--space-l) var(--space-l) var(--space-l);
}

.about-section h2 {
    grid-column: span 2;
    text-align: center;
    font-size: 36px;
}

.about-section p {
    grid-column: 1;
    grid-row: 2;
    text-align: justify;
    font-size: 18px;
    margin: 0 auto;
    max-width: 400px;
    line-height: 1.6;
    overflow-wrap: break-word;
}

.about-section .learn-more-btn {
    grid-column: 1;
    grid-row: 3;
    justify-self: center;
    align-self: center;
    padding: 10px 20px;
    font-size: 18px;
    background-color: var(--unit-blue);
    color: var(--text-light);
    border: none;
    border-radius: 30px;
    cursor: pointer;
    border: 2px solid var(--unit-blue);
    transition: background-color 0.3s ease-in-out;
}

.about-section .learn-more-btn:hover {
    background-color: var(--text-light);
    color: var(--unit-blue);
}

.about-section img {
    grid-column: 2;
    grid-row: 2 / span 2;
    width: 100%;
    height: auto;
    border-radius: 10px;
}

@media (max-width: 800px) {
    .about-section {
        grid-template-columns: 1fr;
        grid-template-rows: auto auto auto auto;
        text-align: center;
    }

    .about-section p {
        grid-column: 1;
        grid-row: 2;
        max-width: 100%;
    }

    .about-section img {
        grid-column: 1;
        grid-row: 3;
        margin-top: var(--space-m);
    }

    .about-section .learn-more-btn {
        grid-column: 1;
        grid-row: 4;
        margin-top: var(--space-m);
    }
}

/* ---------- Sponsors Section ---------- */
.sponsor-section {
    background-image: url('images/index/Sponsor-Backdrop.jpeg');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;

    padding: var(--space-m);
    text-align: center;
}

.sponsor-section h2 {
    color: var(--text-light);
    font-size: 40px;
    margin-bottom: var(--space-l);
}

.sponsor-section p {
    color: var(--text-dark);
    background-color: white;
    opacity: 0.8;
    padding: var(--space-m);
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    font-size: 23px;
    max-width: 600px;
    margin: 0 auto var(--space-l) auto;
}

.sponsor-section .sponsor-logos {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 30px;
    padding-bottom: var(--space-m);
}

.sponsor-section .sponsor-logos img {
    width: 100%;          /* image fills the flex/grid cell width */
    max-width: 200px;     /* never larger than 250px */
    aspect-ratio: 1 / 1;  /* keep square */
    height: auto;         /* let the aspect-ratio control height */
    object-fit: cover;
    border-radius: 10px;
}

@media (max-width: 480px) {

    .sponsor-section .sponsor-logos img {
        max-width: 140px;
    }
}


/* ---------- Publications Section ---------- */
.publications-section {
    padding: 30px var(--space-m);
    background: linear-gradient(to right, #974df8, #5deef8);
    text-align: center;
}

.publications-section h2 {
    color: var(--text-light);
    font-size: 40px;
    margin: 10px auto 30px auto;
}

.publication-item {
    margin-top: 30px;
    margin-bottom: 10px;
    flex: 0 0 300px;
    background: var(--text-light);
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
    padding: 10px;
    text-align: center;
    display: flex;
    flex-direction: column;
}

.publication-item h3 {
    font-size: 22px;
    margin: 10px 0;
    padding: 15px;
}

.publication-item img {
    width: 100%;
    max-width: 300px;
    height: 200px;
    object-fit: cover;
    border-radius: 5px;
    margin-bottom: 15px;
    align-self: center;
}

.publication-item p {
    font-size: 16px;
    color: #000000;
    margin: auto 0 10px 0;
    padding-bottom: 15px;
    line-height: 1.4;
}


.view-publications-btn, .view-sponsors-btn {
    margin-top: 30px;
    padding: 15px 20px;
    font-size: 18px;
    background-color: var(--unit-green);
    width: 250px;
    color: var(--text-dark);
    border: none;
    border-radius: 30px;
    cursor: pointer;
    transition: background-color 0.3s ease-in-out;
}

.view-publications-btn:hover, .view-sponsors-btn:hover {
    background-color: var(--text-light);
    color: var(--text-dark);
}

/* --- Slider layout --- */
.slider-container {
    display: flex;
    justify-content: center;
    align-items: center;
}

.slider-wrapper {
    overflow: hidden;
    width: 100%;
    max-width: calc(2 * 400px + 20px);
    margin: 0px 30px;
}

.slider {
    display: grid;
    grid-auto-flow: column;
    grid-auto-columns: minmax(400px, 1fr);
    grid-template-rows: 1fr;
    gap: 20px;
    transition: transform 0.5s ease-in-out;
    justify-content: start;
    padding-left: 0;
    margin-left: 0;
}

.slider-btn {
    background: rgba(0,0,0,0.7);
    color: var(--text-light);
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    font-size: 24px;
    cursor: pointer;
}

.slider-btn:disabled {
    opacity: 0.4;
    cursor: default;
}

/* ---------- Responsive Layout ---------- */
@media (max-width: 1050px) {
    .slider-container {
        justify-content: center;
    }

    .slider-wrapper {
        max-width: 400px;
        width: 100%;
        margin: 0 auto;
        padding: 0;
    }

    .slider {
        grid-auto-columns: minmax(100%, 1fr);
        gap: 20px;
    }

    .publication-item {
        flex: 0 0 100%;
        margin: 0 auto;
    }
}

/* Smaller tablets / large phones */
@media (max-width: 768px) {
    .slider-wrapper {
        max-width: 320px;
        width: 100%;
        margin: 0 auto;
        padding: 0;
    }
    
    .publication-item {
        max-width: 320px;
        padding: 20px;
    }

    .publication-item h3 {
        font-size: 20px;
    }

    .publication-item p {
        font-size: 14px;
    }

    .publication-item img {
        width: 100%;
        margin-bottom: 10px;
    }

    .view-publications-btn, .view-sponsors-btn {
        width: 200px;
        font-size: 16px;
        padding: 12px 18px;
    }

    .slider-btn {
        width: 40px;
        height: 40px;
        font-size: 20px;
    }
}

/* Small phones */
@media (max-width: 480px) {
    .slider-wrapper {
        max-width: 260px;
        width: 100%;
        margin: 0 auto;
        padding: 0;
    }
    
    .slider-container {
        justify-content: center;
        align-items: center;
    }
    .publication-item {
        max-width: 260px;
        padding: 15px;
        border-radius: 8px;
    }

    .publication-item h3 {
        font-size: 18px;
    }

    .publication-item p {
        font-size: 13px;
    }

    .publication-item img {
        width: 85%;
    }

    .view-publications-btn, .view-sponsors-btn {
        width: 180px;
        font-size: 15px;
        padding: 10px 15px;
    }
}



.left-arrow {
    left: 0;
    margin-right: 10px;
}

.right-arrow {
    right: 0;
    margin-left: 10px;
}