footer {
    color: var(--muted);
    font-size: 0.88rem;
    padding: 30px 22px 46px;
}

footer>* {
    text-align: center;
    max-width: var(--max);
    margin: 0 auto 10px;
}

footer a {
    color: var(--muted);
    text-decoration: underline;
}

.loading-spinner {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 40px;
}

.loading-spinner i {
    font-size: 2rem;
    color: var(--accent);
    animation: spin 1s linear infinite;
}

@keyframes spin {
    from {
        transform: rotate(0deg);
    }

    to {
        transform: rotate(360deg);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

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

.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition:
        opacity 0.6s ease,
        transform 0.6s ease;
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

.hero-title {
    animation: fadeInUp 0.8s ease forwards;
}

.hero-authors {
    animation: fadeInUp 0.8s ease 0.1s forwards;
    opacity: 0;
}

.hero-venue {
    animation: fadeInUp 0.8s ease 0.15s forwards;
    opacity: 0;
}

.hero-buttons {
    animation: fadeInUp 0.8s ease 0.2s forwards;
    opacity: 0;
}

@media (max-width: 640px) {
    h1.title {
        font-size: 1.9rem;
    }

    body {
        font-size: 15px;
    }

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

    .takeaways-grid.custom-width {
        flex-direction: column;
    }

    .problem-cards {
        grid-template-columns: 1fr;
    }

    nav.top ul {
        display: none;
    }

    nav.top .brand {
        font-size: 0.9rem;
    }
}

.wide {
    width: 100%;
    margin-left: 0;
    margin-right: 0;
}