:root {
    --primary: #2c3e50;
    --accent: #2980b9;
    --light: #f4f6f7;
    --white: #ffffff;
    --text: #333333;
    --border: #e0e0e0;
    --font-main: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

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

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

/* Navigation */
nav {
    background: var(--primary);
    color: var(--white);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.nav-container {
    max-width: 1100px;
    margin: auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
}

.nav-logo {
    font-weight: 700;
    font-size: 1.2rem;
}

.nav-links a {
    color: var(--white);
    text-decoration: none;
    margin-left: 20px;
    font-size: 0.95rem;
    font-weight: 500;
    transition: opacity 0.3s;
}

.nav-links a:hover {
    opacity: 0.8;
}

/* Hero Section */
header {
    background: linear-gradient(rgba(44, 62, 80, 0.9), rgba(44, 62, 80, 0.8)), url('https://source.unsplash.com/1600x900/?science,technology') no-repeat center center/cover;
    color: var(--white);
    text-align: center;
    padding: 5rem 20px;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    line-height: 1.2;
}

header h2 {
    font-size: 1.3rem;
    font-weight: 300;
    margin-bottom: 2rem;
    color: #ecf0f1;
}

.hero-subtitle {
    font-size: 0.9rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 1rem;
    font-weight: 600;
    opacity: 0.9;
}

/* Buttons */
.btn {
    display: inline-block;
    background: var(--accent);
    color: var(--white);
    padding: 12px 30px;
    text-decoration: none;
    border-radius: 4px;
    font-weight: 600;
    transition: background 0.3s ease;
}

.btn:hover {
    background: #3498db;
}

.btn-secondary {
    background: #7f8c8d;
}

.btn-secondary:hover {
    background: #95a5a6;
}

/* Sections */
section {
    padding: 4rem 20px;
    max-width: 1100px;
    margin: auto;
}

.bg-light {
    background-color: var(--light);
    /* Stretch background to full width */
    box-shadow: 0 0 0 100vmax var(--light);
    clip-path: inset(0 -100vmax); 
}

h3 {
    color: var(--primary);
    font-size: 1.8rem;
    margin-bottom: 2rem;
    text-align: center;
    position: relative;
}

h3::after {
    content: '';
    display: block;
    width: 50px;
    height: 3px;
    background: var(--accent);
    margin: 10px auto 0;
}

/* About Grid & Text */
#about p {
    text-align: center;
    max-width: 800px;
    margin: 0 auto 1.5rem;
    font-size: 1.1rem;
}

/* Tracks Grid */
.categories {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

.category-item {
    background: var(--white);
    border: 1px solid var(--border);
    padding: 1.5rem;
    border-radius: 6px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.category-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.category-item h4 {
    color: var(--accent);
    margin-bottom: 0.8rem;
    font-size: 1.1rem;
}

.category-item p {
    font-size: 0.95rem;
    color: #555;
}

/* Tables */
.table-container {
    overflow-x: auto;
}

.dates-table, .fees-table {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    border-collapse: collapse;
    background: var(--white);
    border: 1px solid var(--border);
}

.dates-table th, .fees-table th,
.dates-table td, .fees-table td {
    padding: 15px;
    border-bottom: 1px solid var(--border);
    text-align: left;
}

.dates-table th, .fees-table th {
    background-color: var(--light);
    font-weight: 600;
    color: var(--primary);
}

.fees-table th {
    background-color: var(--primary);
    color: var(--white);
}

/* Submission Box */
.submission-box {
    max-width: 800px;
    margin: auto;
    text-align: center;
}

.submission-list {
    text-align: left;
    list-style: none;
    margin-bottom: 2rem;
    padding: 2rem;
    background: var(--white);
    border-radius: 6px;
    border: 1px solid var(--border);
}

.submission-list li {
    margin-bottom: 1rem;
    padding-left: 1.5rem;
    position: relative;
}

.submission-list li::before {
    content: "•";
    color: var(--accent);
    font-weight: bold;
    position: absolute;
    left: 0;
}

/* Footer */
footer {
    background: var(--primary);
    color: var(--white);
    text-align: center;
    padding: 3rem 20px;
    margin-top: 0;
}

footer p {
    opacity: 0.8;
    font-size: 0.9rem;
}

/* Mobile Responsiveness */
@media (max-width: 768px) {
    header h1 { font-size: 1.8rem; }
    .nav-container { flex-direction: column; }
    .nav-links { margin-top: 1rem; }
    .nav-links a { margin: 0 10px; display: inline-block; }
    section { padding: 3rem 15px; }
}