/* CSS Variables for theming */
:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --text-color: #333;
    --bg-color: #ffffff;
    --bg-secondary: #f8f9fa;
    --border-color: #e0e0e0;
    --link-color: #2980b9;
    --link-hover: #1f5f8b;
    --shadow: rgba(0, 0, 0, 0.1);
    --shadow-hover: rgba(0, 0, 0, 0.15);
    --transition: all 0.3s ease;
}

/* Dark mode variables */
.dark-mode {
    --primary-color: #ecf0f1;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --text-color: #e0e0e0;
    --bg-color: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --border-color: #404040;
    --link-color: #5dade2;
    --link-hover: #85c1e9;
    --shadow: rgba(0, 0, 0, 0.3);
    --shadow-hover: rgba(0, 0, 0, 0.4);
}

/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.7;
    color: var(--text-color);
    background-color: var(--bg-color);
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    color: var(--primary-color);
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: 1rem;
    transition: color 0.3s ease;
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

h2 {
    font-size: 2rem;
    margin-top: 2.5rem;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border-color);
}

h3 {
    font-size: 1.5rem;
    margin-top: 1.5rem;
    margin-bottom: 1rem;
}

p {
    margin-bottom: 1rem;
    text-align: justify;
}

a {
    color: var(--link-color);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--link-hover);
    text-decoration: underline;
}

em {
    font-style: italic;
    color: var(--secondary-color);
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Navigation */
.navbar {
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    transition: var(--transition);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.theme-toggle {
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    width: 2.5rem;
    height: 2.5rem;
    font-size: 1.25rem;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background: var(--bg-secondary);
    transform: rotate(15deg);
}

/* Hero section */
.hero {
    background: linear-gradient(135deg, var(--secondary-color) 0%, #1f5f8b 100%);
    color: white;
    padding: 4rem 0;
    margin-bottom: 3rem;
}

.hero-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 3rem;
}

.hero-left {
    flex: 1;
}

.hero-right {
    flex: 0 0 auto;
    text-align: right;
}

.hero h1 {
    color: white;
    font-size: 3rem;
    margin-bottom: 0;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.hero .subtitle {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
    opacity: 0.95;
}

.hero .conference-info {
    font-size: 1.1rem;
    opacity: 0.9;
    margin-bottom: 0;
}

/* Content sections */
.content {
    padding: 2rem 0;
}

.section {
    margin-bottom: 3rem;
}

.section:last-child {
    margin-bottom: 0;
}

/* Presenters grid */
.presenters-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 1.5rem;
}

.presenter {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid var(--secondary-color);
    transition: var(--transition);
    text-align: center;
}

.presenter:hover {
    box-shadow: 0 4px 12px var(--shadow);
    transform: translateY(-2px);
}

.presenter-photo {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    object-fit: cover;
    display: block;
    margin: 0 auto 1.5rem auto;
    border: 3px solid var(--secondary-color);
    box-shadow: 0 2px 8px var(--shadow);
}

.presenter h3 {
    margin-top: 0;
    color: var(--secondary-color);
    text-align: center;
}

.presenter .affiliation {
    font-weight: 500;
    color: var(--text-color);
    opacity: 0.8;
    margin-bottom: 0.5rem;
    text-align: center;
}

.presenter .email {
    margin-bottom: 1rem;
    font-size: 0.95rem;
    text-align: center;
}

.presenter .bio-content {
    text-align: left;
}

/* Learning outcomes */
.outcomes-list {
    list-style: none;
    padding-left: 0;
    margin-top: 1rem;
}

.outcomes-list li {
    padding: 0.75rem 0;
    padding-left: 1.5rem;
    position: relative;
    border-bottom: 1px solid var(--border-color);
}

.outcomes-list li:last-child {
    border-bottom: none;
}

.outcomes-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--secondary-color);
    font-weight: bold;
    font-size: 1.2rem;
}

/* Modules */
.module {
    background: var(--bg-secondary);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid var(--secondary-color);
    transition: var(--transition);
}

.module:hover {
    box-shadow: 0 2px 8px var(--shadow);
}

.module h3 {
    margin-top: 0;
    color: var(--secondary-color);
}

/* Schedule table */
.schedule-note {
    margin-bottom: 1.5rem;
    font-style: italic;
    color: var(--text-color);
    opacity: 0.8;
}

.schedule-table {
    overflow-x: auto;
    margin-top: 1.5rem;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: var(--bg-secondary);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 8px var(--shadow);
}

thead {
    background: var(--secondary-color);
    color: white;
}

th {
    padding: 1rem;
    text-align: left;
    font-weight: 600;
}

td {
    padding: 1rem;
    border-top: 1px solid var(--border-color);
}

tbody tr {
    transition: var(--transition);
}

tbody tr:hover {
    background: var(--bg-color);
}

tbody tr td:first-child {
    font-weight: 500;
    white-space: nowrap;
    width: 150px;
}

tbody em {
    display: block;
    margin-top: 0.5rem;
    font-size: 0.9rem;
    opacity: 0.8;
    font-style: italic;
}

/* Activities */
.activity {
    background: var(--bg-secondary);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid var(--accent-color);
}

.activity h3 {
    margin-top: 0;
    color: var(--accent-color);
}

/* Materials */
.materials-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.material-item {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: 8px;
    text-align: center;
    transition: var(--transition);
}

.material-item:hover {
    box-shadow: 0 4px 12px var(--shadow);
    transform: translateY(-2px);
}

.material-item h3 {
    margin-top: 0;
    color: var(--secondary-color);
}

.material-item p {
    margin-bottom: 0;
    text-align: center;
}

.material-item em {
    color: var(--text-color);
    opacity: 0.7;
    display: block;
    text-align: center;
}

/* Footer */
footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    margin-top: 4rem;
    text-align: center;
}

footer p {
    margin-bottom: 0.5rem;
    color: var(--text-color);
    opacity: 0.8;
}

footer .acknowledgment {
    font-size: 0.9rem;
    font-style: italic;
}

/* Responsive design */
@media (max-width: 768px) {
    .container {
        padding: 0 1rem;
    }

    .hero-content {
        flex-direction: column;
        text-align: center;
        gap: 2rem;
    }

    .hero-right {
        text-align: center;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .hero .subtitle {
        font-size: 1.25rem;
    }

    h2 {
        font-size: 1.75rem;
    }

    h3 {
        font-size: 1.25rem;
    }

    .presenters-grid {
        grid-template-columns: 1fr;
    }

    .presenter-photo {
        width: 120px;
        height: 120px;
    }

    .materials-list {
        grid-template-columns: 1fr;
    }

    table {
        font-size: 0.9rem;
    }

    tbody tr td:first-child {
        width: 100px;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 2rem 0;
    }

    .hero h1 {
        font-size: 1.75rem;
    }

    .hero .subtitle {
        font-size: 1.1rem;
    }

    table {
        font-size: 0.85rem;
    }

    th, td {
        padding: 0.75rem 0.5rem;
    }
}

/* Print styles */
@media print {
    .navbar,
    .theme-toggle,
    footer {
        display: none;
    }

    .hero {
        background: white;
        color: black;
        border-bottom: 2px solid black;
    }

    .hero h1 {
        color: black;
        text-shadow: none;
    }

    a {
        color: black;
        text-decoration: underline;
    }
}