/* Mobile Styles (< 768px) */
@media (max-width: 767px) {
    /* Navigation */
    .nav-toggle {
        display: flex;
    }

    .nav-links {
        position: fixed;
        top: 60px;
        right: -100%;
        flex-direction: column;
        background-color: rgba(44, 44, 44, 0.98);
        width: 100%;
        max-width: 300px;
        height: calc(100vh - 60px);
        padding: var(--spacing-xl) var(--spacing-lg);
        gap: var(--spacing-md);
        align-items: flex-start;
        transition: right var(--transition-medium);
        box-shadow: var(--shadow-lg);
    }

    .nav-links.active {
        right: 0;
    }

    .nav-links .btn-cta {
        width: 100%;
        text-align: center;
    }

    /* Hero */
    .hero {
        background-attachment: scroll;
        min-height: 100vh;
        padding: var(--spacing-xl) 0;
    }

    .hero-title {
        font-size: var(--font-size-3xl);
    }

    .hero-subtitle {
        font-size: var(--font-size-md);
    }

    .hero-details {
        flex-direction: column;
        gap: var(--spacing-sm);
    }

    /* Sections */
    .section {
        padding: var(--spacing-2xl) 0;
    }

    .section-title {
        font-size: var(--font-size-2xl);
        margin-bottom: var(--spacing-lg);
    }

    /* About */
    .about-content {
        grid-template-columns: 1fr;
    }

    .about-text {
        font-size: var(--font-size-sm);
    }

    .about-text .lead {
        font-size: var(--font-size-md);
    }

    /* Speakers */
    .speakers-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }

    .speaker-placeholder {
        width: 150px;
        height: 150px;
    }

    .speaker-initials {
        font-size: var(--font-size-3xl);
    }

    /* Registration */
    .registration-content {
        grid-template-columns: 1fr;
    }

    .registration-form {
        padding: var(--spacing-lg);
    }

    .registration-info {
        margin-bottom: var(--spacing-lg);
    }

    /* Footer */
    .footer-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }

    /* Container */
    .container {
        --container-padding: 16px;
    }
}

/* Tablet Styles (768px - 899px) */
@media (min-width: 768px) and (max-width: 899px) {
    /* Hero */
    .hero-title {
        font-size: var(--font-size-5xl);
    }

    .hero-subtitle {
        font-size: var(--font-size-lg);
    }

    /* About */
    .about-content {
        grid-template-columns: 1fr 1fr;
        gap: var(--spacing-xl);
    }

    /* Speakers */
    .speakers-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-xl);
    }

    /* Registration */
    .registration-content {
        grid-template-columns: 1fr 1fr;
    }

    /* Footer */
    .footer-content {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Desktop Styles (>= 900px) */
@media (min-width: 900px) {
    /* Navigation */
    .navbar .container {
        padding: 0 var(--spacing-xl);
    }

    /* Hero */
    .hero-title {
        font-size: var(--font-size-hero);
    }

    .hero-subtitle {
        font-size: var(--font-size-2xl);
    }

    /* About */
    .about-content {
        grid-template-columns: 1.2fr 1fr;
        gap: var(--spacing-3xl);
    }

    /* Speakers */
    .speakers-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: var(--spacing-2xl);
    }

    /* Registration */
    .registration-content {
        grid-template-columns: 1fr 1.2fr;
        gap: var(--spacing-3xl);
    }

    /* Footer */
    .footer-content {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* Large Desktop (>= 1400px) */
@media (min-width: 1400px) {
    :root {
        --container-max-width: 1320px;
    }

    .hero-title {
        font-size: 80px;
    }

    .section-title {
        font-size: var(--font-size-4xl);
    }
}

/* Accessibility - Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }

    .hero {
        background-attachment: scroll;
    }
}

/* Print Styles */
@media print {
    .navbar,
    .nav-toggle,
    .btn,
    .footer,
    .modal {
        display: none !important;
    }

    .hero {
        background-image: none !important;
        min-height: auto;
        padding: var(--spacing-lg) 0;
    }

    .hero-overlay {
        display: none;
    }

    .hero-content {
        color: var(--color-dark);
    }

    .section {
        page-break-inside: avoid;
    }
}