/* BASE TYPOGRAPHY & COLORS */
:root {
    --primary-color: #0056b3;
    --text-color: #333333;
    --light-bg: #f4f7f6;
    --white: #ffffff;
    --border-color: #dddddd;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    margin: 0;
    padding: 0;
}

h1, h2, h3 {
    color: #111;
    margin-bottom: 15px;
}

/* CONTAINER LAYOUT */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 60px 20px;
}

.bg-light {
    background-color: var(--light-bg);
}

/* HERO SECTION */
.hero-section {
    background-image: linear-gradient(rgba(0, 0, 0, 0.7), rgba(0, 0, 0, 0.7)), url('../assets/images/hero-network.jpg');
    background-size: cover;
    background-position: center;
    color: var(--white);
    text-align: center;
    padding: 100px 20px;
}

.hero-section h1 {
    color: var(--white);
    font-size: 2.5rem;
    max-width: 900px;
    margin: 0 auto 20px;
}

.subtitle {
    font-size: 1.2rem;
    margin-bottom: 30px;
}

.deadline-note {
    margin-top: 30px;
    font-size: 1.1rem;
    color: #ffd700; /* Subtle gold for emphasis */
}

/* BUTTONS */
.btn {
    display: inline-block;
    padding: 12px 25px;
    text-decoration: none;
    border-radius: 5px;
    font-weight: bold;
    margin: 10px;
    transition: background 0.3s ease;
}

.primary-btn {
    background: var(--primary-color);
    color: var(--white);
}

.primary-btn:hover {
    background: #004494;
}

.secondary-btn {
    background: transparent;
    color: var(--white);
    border: 2px solid var(--white);
}

.secondary-btn:hover {
    background: var(--white);
    color: #111;
}

/* THEMES GRID */
.theme-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-top: 30px;
}

.theme-card {
    background: var(--white);
    padding: 25px;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    text-align: center;
}

.theme-card img {
    max-width: 60px;
    margin-bottom: 15px;
}

/* SCHEDULE TABLE */
.schedule-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

.schedule-table th, .schedule-table td {
    padding: 15px;
    border-bottom: 1px solid var(--border-color);
    text-align: left;
    vertical-align: top;
}

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

/* SPEAKER GRID */
.speaker-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 30px;
    margin-top: 30px;
}

.speaker-card {
    text-align: center;
}

.speaker-card img {
    width: 150px;
    height: 150px;
    object-fit: cover;
    border-radius: 50%; /* Makes headshots circular */
    margin-bottom: 15px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.speaker-card h3 {
    font-size: 1.1rem;
    margin-bottom: 5px;
}

.speaker-card .affiliation {
    font-size: 0.9rem;
    color: #666;
}

/* FOOTER */
footer {
    background: #222;
    color: #aaa;
    text-align: center;
    padding: 20px;
    font-size: 0.9rem;
}