/* Mobile first - base styles already handle phones */

/* Tablet */
@media (min-width: 768px) {
    .app-container {
        max-width: 700px;
        margin: 0 auto;
        padding-bottom: 110px;
    }

    .subject-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    .library-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    .bottom-nav {
        max-width: 700px;
        margin: 0 auto;
        left: 0;
        right: 0;
    }

    #chat-view {
        max-width: 700px;
        margin: 0 auto;
        left: 0;
        right: 0;
    }
}

/* Laptop / desktop */
@media (min-width: 1024px) {
    body {
        display: flex;
        justify-content: center;
        background: var(--gray-100);
    }

    .app-container {
        max-width: 860px;
        width: 100%;
        box-shadow: 0 0 40px rgba(0,0,0,0.06);
        background: var(--bg);
    }

    .subject-grid {
        grid-template-columns: repeat(4, 1fr);
    }

    .library-grid {
        grid-template-columns: repeat(4, 1fr);
    }

    .bottom-nav {
        max-width: 860px;
        margin: 0 auto;
        left: 0;
        right: 0;
    }

    #chat-view {
        max-width: 860px;
        margin: 0 auto;
        left: 0;
        right: 0;
        box-shadow: 0 0 40px rgba(0,0,0,0.12);
    }

    .nav-btn {
        font-size: 12px;
    }
}