body {
    font-family: 'Montserrat', sans-serif;
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    background-color: #f4f4f4;
    color: #333;
    line-height: 1.6;
}

header {
    background: #333;
    color: #fff;
    padding: 1rem 0;
    position: sticky;
    top: 0;
    width: 100%;
    z-index: 1000;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

nav .logo a {
    color: #fff;
    text-decoration: none;
    font-weight: bold;
    font-size: 1.5rem;
}

nav ul {
    list-style: none;
    display: flex;
    margin: 0;
    padding: 0;
}

nav ul li {
    margin-left: 20px;
}

nav ul li a {
    color: #fff;
    text-decoration: none;
    transition: color 0.3s ease;
}

nav ul li a:hover {
    color: #00aaff;
}

main {
    padding: 0;
}

section {
    padding: 60px 20px;
    max-width: 1000px;
    margin: 0 auto;
    text-align: center;
}

#hero {
    background: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.5)), url('https://cdn.pixabay.com/photo/2017/02/25/19/03/artificial-intelligence-2099072_1920.jpg') no-repeat center center/cover;
    color: #fff;
    height: 80vh;
    display: flex;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 0 20px;
}

#hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

#hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
}

.cta-button {
    background: #00aaff;
    color: #fff;
    padding: 15px 30px;
    text-decoration: none;
    border-radius: 5px;
    font-weight: bold;
    transition: background-color 0.3s ease;
}

.cta-button:hover {
    background: #0077cc;
}

h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: #333;
}

#about, #signup {
    background-color: #fff;
}

.schedule-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
    text-align: left;
    margin-top: 40px;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.schedule-item {
    background: #fff;
    padding: 15px 25px;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    display: grid;
    grid-template-columns: 120px 1fr 150px 80px;
    gap: 20px;
    align-items: center;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.schedule-item:hover {
    transform: translateY(-3px);
    box-shadow: 0 4px 10px rgba(0,0,0,0.15);
}

.schedule-item .date {
    font-weight: bold;
    color: #333;
}

.schedule-item .topic {
    font-weight: 600;
}

.schedule-item .speaker {
    color: #555;
    font-style: italic;
}

.schedule-item .details-link {
    background: #00aaff;
    color: #fff;
    padding: 8px 12px;
    text-decoration: none;
    border-radius: 5px;
    font-weight: bold;
    text-align: center;
    transition: background-color 0.3s ease;
}

.schedule-item .details-link:hover {
    background: #0077cc;
}

.schedule-item.status-past {
    opacity: 0.7;
}

.schedule-item.status-past .topic {
    text-decoration: line-through;
}

footer {
    text-align: center;
    padding: 20px;
    background: #333;
    color: #fff;
}

@media(max-width: 768px) {
    nav {
        flex-direction: column;
    }

    nav ul {
        margin-top: 1rem;
        flex-direction: column;
        align-items: center;
    }

    nav ul li {
        margin: 10px 0;
    }

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

    .schedule-item {
        grid-template-columns: 1fr;
        gap: 10px;
        text-align: center;
    }

    .schedule-item .date, .schedule-item .topic, .schedule-item .speaker {
        margin-bottom: 5px;
    }
}