@media (max-width: 768px) {
    .liquid-container {
        padding: 16px;
        gap: 16px;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }

    .glass-header {
        padding: 12px 16px;
    }

    .glass-nav {
        display: none;
    }

    .glass-hamburger {
        display: block !important;
    }

    .glass-nav.mobile-menu-open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: var(--lg-glass-bg);
        backdrop-filter: var(--lg-glass-blur);
        -webkit-backdrop-filter: var(--lg-glass-blur);
        border: 1px solid var(--lg-glass-border);
        box-shadow: var(--lg-glass-shadow);
        padding: 16px;
        z-index: 200;
    }

    .glass-nav.mobile-menu-open::before {
        content: '';
        position: fixed;
        top: 0;
        left: 0;
        width: 100vw;
        height: 100vh;
        background: rgba(0, 0, 0, 0.5);
        z-index: -1;
    }

    .glass-nav.mobile-menu-open .menu {
        flex-direction: column;
        width: 100%;
    }

    .glass-nav.mobile-menu-open a {
        padding: 12px 0;
        width: 100%;
    }

    .glass-nav.mobile-menu-open .user-menu {
        margin-left: 0;
        width: 100%;
        flex-direction: row;
        justify-content: flex-start;
        padding-top: 12px;
        border-top: 1px solid var(--lg-glass-border);
    }

    .user-menu {
        margin-left: 0;
    }

    .header-container {
        position: relative;
        display: flex;
        align-items: center;
    }

    .leaderboard-tabs {
        overflow-x: auto;
        display: flex;
        flex-wrap: nowrap;
        gap: 4px;
        -webkit-overflow-scrolling: touch;
        scrollbar-width: thin;
        padding-bottom: 4px;
    }

    .leaderboard-tab {
        white-space: nowrap;
        flex-shrink: 0;
    }

    .leaderboard-tab-btn {
        white-space: nowrap;
        flex-shrink: 0;
    }

    .studycore-table {
        font-size: 0.875rem;
    }

    .achievement-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }

    .glass-footer {
        padding: 24px 16px;
    }

    .footer-widgets {
        flex-direction: column;
        gap: 24px;
    }

    .footer-widgets .widget {
        width: 100%;
    }

    .glass-footer .footer-container {
        flex-direction: column;
        gap: 24px;
    }

    .footer-navigation {
        width: 100%;
    }

    .footer-navigation .footer-menu {
        flex-direction: column;
        gap: 8px;
    }

    .glass-nav.mobile-menu-open .glass-menu {
        display: flex;
        flex-direction: column;
    }

    .glass-nav.mobile-menu-open .menu-item {
        width: 100%;
    }

    .glass-nav.mobile-menu-open .sub-menu {
        position: static;
        box-shadow: none;
        background: rgba(255, 255, 255, 0.03);
        border: 1px solid var(--lg-glass-border);
        border-radius: var(--lg-radius-sm);
        padding: 8px;
        margin: 4px 0 4px 16px;
    }

    .site-branding {
        flex-shrink: 0;
    }

    .notifications-link .notification-count {
        font-size: 0.65rem;
        min-width: 18px;
        height: 18px;
    }
}

@media (max-width: 480px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }

    .timer-display {
        font-size: 2.5rem;
    }

    .timer-controls {
        flex-direction: column;
        gap: 8px;
    }

    .timer-btn {
        width: 100%;
    }

    .leaderboard-tabs {
        overflow-x: auto;
        display: flex;
        flex-wrap: nowrap;
    }

    .leaderboard-tab-btn {
        white-space: nowrap;
        flex-shrink: 0;
    }

    .studycore-table {
        font-size: 0.8rem;
    }

    .studycore-table th:nth-child(2),
    .studycore-table td:nth-child(2) {
        display: none;
    }

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

    .glass-input {
        width: 100%;
        box-sizing: border-box;
    }

    .studycore-form-group {
        width: 100%;
    }

    .form-group {
        width: 100%;
    }

    form {
        width: 100%;
    }

    form .glass-input {
        width: 100%;
        box-sizing: border-box;
    }

    form label,
    form input,
    form select,
    form textarea {
        width: 100%;
        box-sizing: border-box;
    }

    .glass-back-to-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
    }

    body.studycore-theme h1 {
        font-size: 1.5rem;
    }

    body.studycore-theme h2 {
        font-size: 1.25rem;
    }

    .glass-card {
        padding: 16px;
    }

    .glass-button {
        width: 100%;
    }

    .liquid-container .glass-card .glass-button {
        width: 100%;
    }

    .glass-header {
        padding: 10px 12px;
    }

    .glass-hamburger {
        font-size: 1.3rem;
    }

    .user-menu .glass-button {
        padding: 6px 12px;
        font-size: 0.8rem;
    }

    .user-name {
        display: none;
    }

    .user-avatar {
        width: 28px;
        height: 28px;
    }

    .glass-nav.mobile-menu-open {
        padding: 12px;
    }

    .glass-nav.mobile-menu-open a {
        font-size: 0.9rem;
        padding: 10px 0;
    }

    .stat-value {
        font-size: 1.5rem;
    }

    .stat-icon {
        font-size: 1.5rem;
    }

    .stat-card {
        padding: 16px;
    }

    .glass-footer {
        padding: 20px 12px;
        margin-top: 32px;
    }

    .site-info p {
        font-size: 0.8rem;
    }

    .glass-footer .footer-menu a {
        font-size: 0.85rem;
    }

    .achievement-card {
        padding: 16px;
    }

    .achievement-icon {
        font-size: 2rem;
    }

    .leaderboard-tab-btn {
        font-size: 0.8rem;
        padding: 8px 14px;
    }

    .studycore-table thead th {
        font-size: 0.7rem;
        padding: 8px 6px;
    }

    .studycore-table tbody td {
        padding: 8px 6px;
        font-size: 0.8rem;
    }

    .rank-num {
        font-size: 0.85rem;
    }

    .studycore-avatar {
        width: 28px;
        height: 28px;
    }

    .timer-controls .timer-btn {
        padding: 10px 16px;
        font-size: 0.85rem;
    }

    .subject-selector {
        width: 100%;
        font-size: 0.85rem;
        padding: 10px 12px;
    }

    .studycore-form-group label {
        font-size: 0.85rem;
    }

    .studycore-form-group input,
    .studycore-form-group select,
    .studycore-form-group textarea {
        font-size: 0.85rem;
        padding: 10px 12px;
    }

    .progress-ring-container canvas {
        max-width: 140px;
        height: auto;
    }

    .site-title a {
        font-size: 1.1rem;
    }
}

@media (max-width: 768px) {
    .glass-nav .sub-menu {
        position: static;
        box-shadow: none;
        background: rgba(255, 255, 255, 0.03);
        border: 1px solid var(--lg-glass-border);
        border-radius: var(--lg-radius-sm);
        padding: 8px;
        margin: 4px 0 4px 16px;
        opacity: 1;
        visibility: visible;
        display: none;
    }

    .glass-nav .menu-item-has-children:hover .sub-menu,
    .glass-nav .page_item_has_children:hover .sub-menu {
        display: none;
    }

    .glass-nav .menu-item-has-children .sub-menu.open,
    .glass-nav .page_item_has_children .sub-menu.open {
        display: block;
    }

    .glass-nav .menu-item-has-children > a::after,
    .glass-nav .page_item_has_children > a::after {
        content: '\25BC';
        font-size: 0.6em;
        margin-left: 6px;
        display: inline-block;
        transition: transform var(--lg-transition);
    }

    .glass-nav .menu-item-has-children > a.open::after,
    .glass-nav .page_item_has_children > a.open::after {
        transform: rotate(180deg);
    }
}

@media (max-width: 768px) {
    .studycore-landing h1 {
        font-size: 2.2rem;
    }

    .studycore-landing .subtitle {
        font-size: 1rem;
    }

    .studycore-landing .hero-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }

    .studycore-landing .features {
        grid-template-columns: 1fr 1fr;
        gap: 16px;
    }

    .studycore-landing .cta-buttons {
        flex-direction: column;
        align-items: center;
    }

    .studycore-landing .cta-primary,
    .studycore-landing .cta-secondary {
        width: 100%;
        max-width: 300px;
        text-align: center;
    }

    .studycore-landing .leaderboard-preview {
        padding: 16px;
    }

    .studycore-landing .lb-rank {
        width: 30px;
        font-size: 0.85rem;
    }

    .studycore-landing .lb-points {
        font-size: 0.85rem;
    }
}

@media (max-width: 480px) {
    .studycore-landing h1 {
        font-size: 1.8rem;
    }

    .studycore-landing .hero-stats {
        grid-template-columns: 1fr 1fr;
        gap: 10px;
    }

    .studycore-landing .hero-stat {
        padding: 20px 12px;
    }

    .studycore-landing .hero-stat .number {
        font-size: 1.8rem;
    }

    .studycore-landing .features {
        grid-template-columns: 1fr;
        gap: 12px;
    }

    .studycore-landing .feature-card {
        padding: 20px;
    }

    .studycore-landing .lb-row {
        padding: 10px 0;
        flex-wrap: wrap;
    }

    .studycore-landing .lb-badge {
        display: none;
    }
}