:root {
    --primary-color: #00aaff;
    --secondary-color: #0077b6;
    --bg-color: #0a192f;
    --text-color: #ccd6f6;
    --light-text-color: #8892b0;
    --card-bg-color: #112240;
    --font-family: 'Poppins', sans-serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

/* --- Header & Nav --- */
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(10, 25, 47, 0.85);
    backdrop-filter: blur(10px);
    transition: top 0.3s;
}

nav {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

nav .logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;

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

nav .logo img{
  width: 170px;
}

nav ul {
    list-style: none;
    display: flex;
    gap: 2rem;
}

nav ul li a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 400;
    transition: color 0.3s ease;
}

nav ul li a:hover {
    color: var(--primary-color);
}

/* --- Buttons --- */
.btn {
    padding: 0.75rem 1.5rem;
    border-radius: 5px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    display: inline-block;
}

.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
    border: 1px solid var(--primary-color);
}
.btn-primary:hover {
    background-color: transparent;
    color: var(--primary-color);
}

.btn-secondary {
    background-color: transparent;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}
.btn-secondary:hover {
    background-color: var(--primary-color);
    color: #fff;
}

.btn-large {
    font-size: 1.2rem;
    padding: 1rem 2.5rem;
}

/* --- Hero Section --- */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    overflow: hidden;
}

#threejs-container {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    padding: 2rem;
}

.hero h1 {
    font-size: 4rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: #fff;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-color);
    max-width: 700px;
    margin: 0 auto 2rem;
}

/* --- General Content Sections --- */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 6rem 2rem;
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    color: #fff;
    margin-bottom: 0.5rem;
}

.divider {
    width: 80px;
    height: 4px;
    background: var(--primary-color);
    margin: 0 auto;
    border-radius: 2px;
}

/* --- About Section --- */
.about-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
/*     align-items: center; */
}

.about-text p {
    margin-bottom: 1rem;
    color: var(--light-text-color);
}
.about-text strong {
    color: var(--primary-color);
}
.about-image img {
    width: 100%;
    border-radius: 8px;
    box-shadow: 0 10px 30px -15px rgba(2,12,27,0.7);
}
.about-image .caption {
    font-size: 0.9rem;
    text-align: center;
    color: var(--light-text-color);
    margin-top: 1rem;
}

/* --- Tracks Section --- */
.tracks-container {
    display: grid;
    /* grid-template-columns: 1fr 1fr; */
    gap: 2rem;
}
.track-card {
    background-color: var(--card-bg-color);
    padding: 2rem;
    border-radius: 8px;
    border-left: 4px solid var(--primary-color);
    box-shadow: 0 10px 30px -15px rgba(2,12,27,0.7);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.track-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px -15px rgba(2,12,27,0.7);
}
.track-card h3 {
    color: #fff;
    margin-bottom: 1rem;
}
.track-card p {
    color: var(--light-text-color);
}

/* --- Timeline Section --- */
.timeline {
    position: relative;
    max-width: 700px;
    margin: 0 auto;
}
.timeline::after {
    content: '';
    position: absolute;
    width: 2px;
    background-color: var(--card-bg-color);
    top: 0;
    bottom: 0;
    left: 20px;
}
.timeline-item {
    padding: 1rem 0 2rem 50px;
    position: relative;
}
.timeline-dot {
    content: '';
    position: absolute;
    left: 14px;
    top: 1.2rem;
    width: 15px;
    height: 15px;
    border-radius: 50%;
    background-color: var(--primary-color);
    border: 2px solid var(--bg-color);
    z-index: 1;
}
.timeline-date {
    font-weight: 600;
    color: var(--primary-color);
}
.timeline-content h4 {
    font-weight: 600;
    color: #fff;
    margin-top: 0.25rem;
}

/* --- Participation Section --- */
.participation-steps {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-bottom: 4rem;
}
.step {
    text-align: center;
    padding: 1.5rem;
}
.step-number {
    width: 50px;
    height: 50px;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0 auto 1rem;
}
.step h4 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    color: #fff;
}
.step p {
    color: var(--light-text-color);
}
.register-cta {
    text-align: center;
    background: var(--card-bg-color);
    padding: 3rem;
    border-radius: 8px;
}
.register-cta p {
    max-width: 600px;
    margin: 0 auto 2rem;
}

/* --- Organizers Section --- */
.organizers-grid{
    display:grid;
    grid-template-columns:repeat(auto-fill,minmax(220px,1fr));
    gap:1.5rem;
    margin-top:2rem;
}

.organizer-card{
    /* background:var(--card-bg-color); */
    /* border-left:4px solid var(--primary-color); */
    border-radius:8px;
    padding:1.5rem;
    /* box-shadow:0 10px 30px -15px rgba(2,12,27,0.7); */
    transition:transform .3s ease,box-shadow .3s ease;
}

.organizer-card:hover{
    transform:translateY(-8px);
    /* box-shadow:0 20px 40px -15px rgba(2,12,27,0.7); */
}

.organizer-card h4{
    font-size:1.1rem;
    font-weight:600;
    color:#fff;
    margin-bottom:0.3rem;
}

.organizer-card p{
    font-size:0.95rem;
    color:var(--light-text-color);
}



/* --- Footer --- */
footer {
    background-color: #020c1b;
    padding: 3rem 2rem;
    text-align: center;
}
.sponsors {
    margin-bottom: 2rem;
}
.sponsors h3 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}
.sponsors p {
    color: var(--light-text-color);
}
.footer-bottom {
    border-top: 1px solid var(--card-bg-color);
    padding-top: 2rem;
    font-size: 0.9rem;
    color: var(--light-text-color);
}
.footer-bottom a {
    color: var(--light-text-color);
    text-decoration: none;
}
.footer-bottom a:hover {
    color: var(--primary-color);
}

/* --- Animations --- */
.animate-on-load {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeIn 0.8s ease-out forwards;
}
.animate-on-load:nth-child(2) { animation-delay: 0.2s; }
.animate-on-load:nth-child(3) { animation-delay: 0.4s; }

.animate-on-scroll {
    opacity: 0;
    transform: translateY(50px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}
.animate-on-scroll.is-visible {
    opacity: 1;
    transform: translateY(0);
}

@keyframes fadeIn {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* --- Responsive Design --- */
@media (max-width: 900px) {
    .about-content, .tracks-container {
        grid-template-columns: 1fr;
    }
    .about-image {
        grid-row: 1;
        max-width: 300px;
        margin: 0 auto;
    }
}

@media (max-width: 768px) {
    nav ul { display: none; }
    .hero h1 { font-size: 3rem; }
    .hero p { font-size: 1.1rem; }
    .participation-steps { grid-template-columns: 1fr; }
    .organizers-list {
        display: flex;
        flex-direction: column;
        gap: 1rem;
    }
}

/* --- Expanded Track Card Styles --- */
.section-subtitle {
    max-width: 800px;
    margin: 1rem auto 0;
    font-size: 1.1rem;
    color: var(--light-text-color);
}

.track-card {
    display: flex;
    flex-direction: column;
}

.track-details {
    margin-top: 1.5rem;
    text-align: left;
}

.track-details h4 {
    color: var(--primary-color);
    font-size: 1.1rem;
    font-weight: 600;
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
    border-bottom: 1px solid var(--card-bg-color);
    padding-bottom: 0.25rem;
}

.track-details p {
    color: var(--light-text-color);
    margin-bottom: 1rem;
}

/* Style for inline math code */
.track-details p code, .track-details li code {
    background-color: rgba(0, 170, 255, 0.1);
    color: var(--primary-color);
    padding: 2px 5px;
    border-radius: 4px;
    font-family: 'Courier New', Courier, monospace;
}

.track-details ol {
    list-style-position: inside;
    padding-left: 1rem;
    color: var(--light-text-color);
}

.track-details ol li {
    margin-bottom: 1rem;
}

.track-details ol li::marker {
    font-weight: bold;
    color: var(--primary-color);
}

.math-formula {
    background-color: #020c1b;
    border: 1px solid var(--card-bg-color);
    border-radius: 8px;
    padding: 1rem;
    margin: 1rem 0;
    overflow-x: auto;
    text-align: center;
}

/* Ensure MathJax text color is correct */
mjx-container {
    color: var(--text-color) !important;
}


/* ---------- Mobile fix for “Challenge Tracks” section ---------- */
@media (max-width: 768px) {
  .navRegisterBtn{
    display: none;
  }

  /* 1. Stack the cards and let the column shrink */
  .tracks-container{
      display:grid;
      /* minmax(0,1fr) lets the track shrink below its min-content width   */
      grid-template-columns:minmax(0,1fr);
      gap:1.5rem;
  }

  /* 2. Make sure long equations or inline code never push the card wider */
  .track-card{
      width:100%;
      box-sizing:border-box;
      overflow-wrap:anywhere;   /* break extremely long tokens         */
      word-break:break-word;
      padding:1.5rem 1rem;      /* a little narrower side-padding      */
  }

  /* 3. If a MathJax block is still wider, scroll ​inside​ the box, not the page */
  .math-formula{
      overflow-x:auto;
      font-size:0.85rem;        /* slightly smaller text on mobiles    */
  }

  /* 4. Give the whole page a bit more breathing room */
  .container{
      padding:4rem 1rem;
  }
}













/* ─────────────────────────────────────────
   Spectral “build-the-cube” loader
────────────────────────────────────────── */
#loading-overlay{
    position:fixed; inset:0;
    background:var(--bg-color);
    display:flex; flex-direction:column;
    align-items:center; justify-content:center;
    z-index:5000;
    transition:opacity .6s ease, visibility .6s;
}
#loading-overlay.hidden{ opacity:0; visibility:hidden; }

/* stacked slices, tilted a little for 3-D look */
.spectral-loader{
    display:flex; flex-direction:column; gap:2px;
    transform:rotateX(60deg) rotateZ(45deg);
    perspective:800px;
}
.slice{
    width:80px; height:4px;
    background:#fff;
    transform:scaleX(0);
    transform-origin:left center;
    animation:sliceFill 1.2s forwards;
}
@keyframes sliceFill{ to{ transform:scaleX(1); } }

.loading-text{
    margin-top:1rem;
    font-size:.95rem;
    color:var(--light-text-color);
    letter-spacing:.05em; font-weight:600;
}










.hyper-button {
            /* --- Basic Button Appearance --- */
            margin-top: 1em;
            position: relative;
            display: inline-block;
            padding: 1.25rem 3rem;
            border: none;
            border-radius: 10px;
            cursor: pointer;
            outline: none;
            
            /* --- Font and Text --- */
            font-family: "Segoe UI", system-ui, sans-serif;
            font-size: 1.5rem;
            font-weight: 700;
            color: #fff;
            text-shadow: 0 2px 5px rgba(0, 0, 0, 0.25);
            
            /* --- The Hyperspectral Gradient --- */
            /* This is the top face of our button. The animated gradient creates a "scanning" effect. */
            background: #272727;
            background-size: 250% 100%; /* Gradient is wider than the button to allow for animation */
            
            /* --- Core Animation Setup --- */
            /* We transition the transform (for the lift) and the box-shadow (for the layers) */
            transition: 
                transform 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94),
                box-shadow 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94),
                background-position 0.6s ease;
            
            text-decoration: none;
        }

        /* 
         * =================================================
         *      HOVER STATE: The "Hypercube" Layer Reveal
         * =================================================
        */
        .hyper-button:hover {
            /* --- 1. Lift the button up --- */
            transform: translateY(-12px);

            /* --- 2. Animate the "spectral scan" on the top face --- */
            background-position: 100% 0;

            /* --- 3. Reveal the 3D spectral layers using box-shadow --- */
            /* This is the key to the effect. We stack multiple solid-color shadows
               with increasing vertical offsets to create the illusion of depth. */
            box-shadow:
                0  4px  0 #FF0000,  /* Red    */
                0 8px  0 #00FF00,  /* Green  */
                0 16px  0 #0000FF,  /* Blue   */
                0 32px 30px rgba(0,0,0,0.3);
        }
        
        .hyper-button:active {
            /* A subtle press-down effect */
            transform: translateY(-2px);
            box-shadow: 
                0 2px 0 #7b2cbf,
                0 4px 0 #2980b9,
                0 6px 0 #16a085,
                0 8px 15px rgba(0, 0, 0, 0.3);
            transition-duration: 0.1s;

        }


/* ──────────────────────────────────
   Additions for circular portraits
────────────────────────────────── */
.organizer-card{
    text-align:center;              /* keep everything nicely centred  */
}

.organizer-photo{
    width:120px;
    height:120px;
    border-radius:50%;
    object-fit:cover;
    display:block;
    margin:0 auto 1rem;
    border:3px solid var(--primary-color);
    box-shadow:0 6px 15px -5px rgba(2,12,27,0.6);
}


/* ──────────────────────────────────
   Additions for Leaderboard section
────────────────────────────────── */

/* Tabs -------------------------------------------------- */
.leaderboard-tabs{
    width:100%;
    max-width:900px;
    margin:0 auto 2rem;
    text-align:center;
    position:relative;
}
.leaderboard-tabs input[type="radio"]{
    display:none;
}
.leaderboard-tabs label{
    display:inline-block;
    margin: 0 0 1em .25rem;
    padding:.5rem 1.25rem;
    font-weight:600;
    cursor:pointer;
    border-radius:6px;
    background:var(--card-bg-color);
    color:var(--text-color);
    transition:background .3s ease,color .3s ease;
}
.leaderboard-tabs input:checked + label{
    background:var(--primary-color);
    color:#fff;
}

/* Panels ------------------------------------------------ */
.leaderboard-panels{
    position:relative;
}
.leaderboard-panel{
    display:none;
}
#tab-track1:checked ~ .leaderboard-panels .leaderboard-panel:nth-child(1),
#tab-track2:checked ~ .leaderboard-panels .leaderboard-panel:nth-child(2){
    display:block;
    animation:fadeIn .4s ease-out;
}

/* Table ------------------------------------------------- */
.leaderboard-table-wrapper{
    overflow-x:auto;
}
.leaderboard-table{
    width:100%;
    min-width:620px;
    border-collapse:collapse;
}
.leaderboard-table thead tr{
    background:var(--card-bg-color);
}
.leaderboard-table th,
.leaderboard-table td{
    padding:.75rem 1rem;
    text-align:left;
}
.leaderboard-table th{
    color:var(--primary-color);
    font-weight:700;
    border-bottom:2px solid var(--card-bg-color);
}
.leaderboard-table tbody tr:nth-child(even){
    background:rgba(255,255,255,.03);
}
.leaderboard-table tbody tr:hover{
    background:rgba(0,170,255,.08);
}
.leaderboard-table td{
    color:var(--light-text-color);
}

/* Medal colours ---------------------------------------- */
.gold-row   { background:rgba(255,215,0,0.10) !important; }
.silver-row { background:rgba(192,192,192,0.10) !important; }
.bronze-row { background:rgba(205,127,50,0.10) !important; }

/* Small fade-in used for panel switch ------------------ */
@keyframes fadeIn{
    from{ opacity:0; transform:translateY(20px); }
    to  { opacity:1; transform:translateY(0); }
}

/* ──────────────────────────────────
   Share-button & modal additions
────────────────────────────────── */

/* 1. Button tweaks inside the nav */
.navShareBtn{
    margin-left:1rem;
}

/* Hide on small screens just like the Register button */
@media (max-width:768px){
    .navShareBtn{ display:none; }
}

/* 2. Modal overlay */
.share-modal{
    position:fixed; inset:0;
    background:rgba(0,0,0,.6);
    display:flex; align-items:center; justify-content:center;
    visibility:hidden; opacity:0;
    transition:opacity .3s ease, visibility .3s ease;
    z-index:6000;
}
.share-modal.open{
    visibility:visible; opacity:1;
}

/* 3. Modal box */
.share-modal-content{
    background:var(--card-bg-color);
    border-radius:8px;
    padding:2rem;
    width:90%; max-width:480px;
    text-align:center;
    box-shadow:0 20px 40px -15px rgba(2,12,27,0.8);
    position:relative;
}

.share-modal-close{
    position:absolute; top:12px; right:14px;
    font-size:1.75rem; line-height:1;
    color:var(--light-text-color);
    cursor:pointer;
    transition:color .2s ease;
}
.share-modal-close:hover{ color:var(--primary-color); }

.modal-subtitle{
    color:var(--light-text-color);
    margin:.25rem 0 1.25rem;
}

/* 4. Input + copy button */
.share-input-group{
    display:flex;
}
.share-input-group input{
    flex:1;
    border:1px solid var(--primary-color);
    border-radius:5px 0 0 5px;
    padding:.75rem 1rem;
    background:rgba(255,255,255,0.05);
    color:var(--text-color);
    font-family:var(--font-family);
    font-size:1rem;
}
.share-input-group input:focus{
    outline:none;
    box-shadow:0 0 0 2px var(--primary-color);
}
.share-input-group button{
    border-radius:0 5px 5px 0;
}



/* ──────────────────────────────────
   FAQ section
────────────────────────────────── */
.faq-container{
    max-width:800px;
    margin:0 auto;
}

.faq-item{
    border-bottom:1px solid var(--card-bg-color);
    margin-bottom:1.5rem;
    padding-bottom:1.5rem;
}

.faq-question{
    font-size:1.1rem;
    font-weight:600;
    cursor:pointer;
    color:var(--primary-color);
    transition:color .25s ease, padding-left .25s ease;
}
.faq-question:hover{
    color:#fff;
    padding-left:.25rem;
}

.faq-answer{
    display:none;
    margin-top:.75rem;
    color:var(--light-text-color);
    line-height:1.7;
}

.faq-item.open .faq-answer{
    display:block;
    animation:fadeIn .3s ease-out;
}