/* ============================================
   MOBILE NAVIGATION - Complete Implementation
   ============================================ */

/* =========================================================
   RESPONSIVE NAVIGATION — V1.1.1 / V1.1.3
   ========================================================= */

@media (max-width: 1000px) {
    .grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }

    .metric-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .sidebar-layout {
        grid-template-columns: 1fr;
    }

    .side-nav-card {
        position: static;
    }

    .side-nav {
        display: grid;
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 6px;
    }

    .side-nav-link {
        min-height: 46px;
    }

    .hero h1 {
        font-size: clamp(3rem, 12vw, 5.2rem);
    }
}

@media (max-width: 900px) {
    .nav-shell {
        position: relative;
    }

    .nav-toggle {
        display: grid;
        place-items: center;
        gap: 5px;
        width: 44px;
        height: 44px;
        padding: 10px;
        border: 1px solid var(--line);
        border-radius: 12px;
        background: var(--surface);
        cursor: pointer;
    }

    .nav-toggle span {
        display: block;
        width: 22px;
        height: 2px;
        border-radius: 2px;
        background: #ddd;
        transform-origin: center;
        transition:
            transform .25s ease,
            opacity .2s ease,
            background-color .2s ease;
    }

    .nav-toggle:hover span {
        background: var(--accent);
    }

    .nav-toggle[aria-expanded="true"] span:nth-child(1) {
        transform: translateY(7px) rotate(45deg);
    }

    .nav-toggle[aria-expanded="true"] span:nth-child(2) {
        opacity: 0;
        transform: scaleX(.3);
    }

    .nav-toggle[aria-expanded="true"] span:nth-child(3) {
        transform: translateY(-7px) rotate(-45deg);
    }

    .nav-links {
        position: absolute;
        left: 0;
        right: 0;
        top: calc(100% + 10px);
        display: flex;
        flex-direction: column;
        align-items: stretch;
        gap: 6px;
        padding: 10px;
        border: 1px solid var(--line);
        border-radius: 16px;
        background: rgba(20,22,22,.96);
        backdrop-filter: blur(18px);
        -webkit-backdrop-filter: blur(18px);
        box-shadow: 0 18px 50px rgba(0,0,0,.28);

        opacity: 0;
        visibility: hidden;
        transform: translateY(-8px) scale(.98);
        transform-origin: top right;
        pointer-events: none;

        transition:
            opacity .22s ease,
            transform .22s ease,
            visibility .22s ease;
    }

    .nav-links.open {
        opacity: 1;
        visibility: visible;
        transform: translateY(0) scale(1);
        pointer-events: auto;
    }

    .nav-links .nav-link,
    .nav-links .nav-button {
        width: 100%;
        text-align: left;
    }

    .nav-links .nav-link {
        padding: 12px 14px;
    }

    .nav-links .nav-button {
        text-align: center;
    }

    .header-context {
        flex: 1;
        justify-content: flex-end;
    }

    .context-pill {
        display: none;
    }

    .admin-course-stack {
        display: grid;
        grid-template-columns: 1fr;
        gap: 18px;
    }

    .admin-course-stack > .card {
        width: 100%;
    }

    .admin-student-stack {
        display: grid;
        gap: 18px;
    }

    .admin-student-stack > .card {
        margin-top: 0 !important;
    }
}

@media (max-width: 700px) {
    :root {
        --container-padding: 1rem;
    }

    .site-header {
        top: 8px;
        margin-top: 8px;
    }

    .nav-shell {
        min-height: 62px;
    }

    .grid-4,
    .grid-3,
    .grid-2 {
        grid-template-columns: 1fr;
    }

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

    .section-head,
    .dashboard-head {
        align-items: flex-start;
        flex-direction: column;
    }

    .lesson-row {
        grid-template-columns: 26px 1fr;
    }

    .lesson-actions {
        grid-column: 2;
    }

    .lesson-title {
        font-size: .96rem;
    }

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

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

    .course-hero {
        padding-top: 30px;
    }

    .form-card {
        padding: 20px;
    }

    .btn-group {
        width: 100%;
    }

    .btn-group .btn {
        flex: 1 1 auto;
    }
}