/* ============================================
   MOBILE RESPONSIVE STYLES
   Breakpoint: 768px and below
   All mobile rules are contained here.
   Desktop layout is unaffected above 768px.
   ============================================ */

/* Elements that only exist for mobile — hidden on desktop */
.mobile-header {
    display: none;
}

.mobile-preview-btn {
    display: none;
}

@media (max-width: 768px) {

    /* Mobile CSS custom properties */
    :root {
        --mobile-header-height: 56px;
        --safe-area-top: env(safe-area-inset-top, 0px);
        --safe-area-bottom: env(safe-area-inset-bottom, 0px);
        --safe-area-left: env(safe-area-inset-left, 0px);
        --safe-area-right: env(safe-area-inset-right, 0px);
    }

    /* Prevent horizontal scroll */
    body {
        overflow-x: hidden;
    }

    /* Prevent iOS double-tap zoom on interactive elements */
    button, a, .deck-card, .category-item {
        touch-action: manipulation;
    }

    /* Prevent text selection on tap-heavy elements */
    .rating-btn, .deck-card, .card-content, .category-item {
        -webkit-user-select: none;
        user-select: none;
    }

/* Ensure minimum font size to prevent iOS auto-zoom on inputs */
    input, textarea, select {
        font-size: 16px !important;
    }

    /* Mobile header bar */
    .mobile-header {
        display: flex;
        align-items: center;
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        height: var(--mobile-header-height);
        background: var(--card-bg);
        border-bottom: 1px solid var(--border-color);
        z-index: 500;
        padding: 0 1rem;
        gap: 1rem;
    }

    .mobile-header-title {
        font-size: 1.2rem;
        font-weight: 600;
        color: var(--primary-color);
    }

    .mobile-hamburger-btn {
        background: none;
        border: none;
        font-size: 1.4rem;
        color: var(--text-color);
        cursor: pointer;
        padding: 8px;
        border-radius: 4px;
        line-height: 1;
    }

    /* Push app-container below the fixed header */
    .app-container {
        flex-direction: column;
        margin-top: var(--mobile-header-height);
    }

    /* Sidebar hidden by default on mobile */
    .app-container > nav.sidebar {
        display: none;
        position: fixed;
        top: var(--mobile-header-height);
        left: 0;
        right: 0;
        bottom: 0;
        width: 100%;
        z-index: 400;
        overflow-y: auto;
    }

    /* Sidebar visible when open */
    .app-container > nav.sidebar.sidebar-open {
        display: flex;
    }

    /* Main content takes full width on mobile */
    .main-content {
        width: 100%;
        margin-top: 0;
        height: calc(100dvh - var(--mobile-header-height) - var(--safe-area-top));
        overflow-y: auto;
    }

    /* Hide management UI on mobile */
    #add-category-btn,
    #add-deck-btn,
    #import-deck-btn,
    .deck-menu-btn,
    .category-menu-btn,
    .preview-card-delete {
        display: none !important;
    }

    /* Mobile preview button — visible on mobile only */
    .mobile-preview-btn {
        display: block;
        margin-top: 0.75rem;
        padding: 0.5rem 1rem;
        background: var(--secondary-color);
        color: var(--text-color);
        border: 1px solid var(--border-color);
        border-radius: 4px;
        font-size: 0.9rem;
        cursor: pointer;
        width: 100%;
        text-align: center;
    }

/* ---- Phase 5: Study screen ---- */

    /* Compact study header */
    .study-header {
        margin-bottom: 0.75rem;
        padding: 0.6rem 0.75rem;
        flex-wrap: wrap;
        gap: 0.5rem;
        flex-shrink: 0;
    }

    .study-info {
        gap: 0.5rem;
        flex-wrap: wrap;
    }

    .study-info span {
        font-size: 0.9rem;
    }

    #study-mode-select {
        font-size: 0.85rem;
        padding: 0.25rem 0.5rem;
    }

    #end-study-btn {
        font-size: 0.85rem;
        padding: 0.4rem 0.75rem;
    }

    /* Study mode buttons — wrap on mobile */
    .study-mode-buttons {
        flex-shrink: 0;
    }

    .study-mode-selection {
        gap: 0.5rem;
    }

    .study-mode-btn {
        font-size: 0.85rem;
        padding: 0.5rem 0.75rem;
        min-width: unset;
        flex: 1;
    }

    /* Study screen — fixed height, no overflow on mobile */
    #study-screen.active {
        overflow: hidden;
        justify-content: flex-start;
        height: calc(100dvh - var(--mobile-header-height));
        max-height: calc(100dvh - var(--mobile-header-height));
        flex-direction: column;
        padding: 0.75rem;
    }

    /* Compact study header — never shrink */
    .study-header {
        flex-shrink: 0;
        margin-bottom: 0.75rem;
        padding: 0.6rem 0.75rem;
        flex-wrap: wrap;
        gap: 0.5rem;
    }

    /* Study mode buttons — never shrink */
    .study-mode-buttons {
        flex-shrink: 0;
    }

    /* Card fills all remaining space */
    .study-card {
        width: 100%;
        max-width: 100%;
        padding: 0;
        flex: 1;
        display: flex;
        flex-direction: column;
        min-height: 0;
    }

    /* Card content fills the card, scrolls if needed */
    .card-content {
        flex: 1;
        min-height: 0;
        max-height: none;
        padding: 1.25rem;
        margin-bottom: 0.75rem;
        border-radius: 8px;
        overflow-y: auto;
    }

    /* Rating section — never shrink */
    .rating-section {
        flex-shrink: 0;
        padding-top: 0.5rem;
    }

    .card-text {
        font-size: 1.1rem;
    }

    /* Flip button — full width */
    #flip-card-btn {
        width: 100%;
        padding: 0.9rem;
        font-size: 1rem;
        margin-bottom: 0.75rem;
    }

    /* Rating section */
    .rating-section {
        padding-top: 0.5rem;
        padding-bottom: var(--safe-area-bottom);
        flex-shrink: 0;
    }

    .rating-section p {
        font-size: 0.95rem;
        margin-bottom: 0.6rem;
        text-align: center;
    }

    /* Rating buttons — single row on mobile */
    .rating-buttons {
        display: flex;
        flex-direction: row;
        gap: 0.4rem;
    }

    .rating-btn {
        min-width: unset;
        flex: 1;
        padding: 0.75rem 0.25rem;
        font-size: 0.8rem;
        min-height: 48px;
    }

    /* ---- Phase 4: Browse screens ---- */

    /* Reduce screen padding on mobile */
    .screen {
        padding: 1rem;
        overflow-y: auto;
        height: calc(100dvh - var(--mobile-header-height) - var(--safe-area-top));
        flex: none;
    }

    /* Screen header */
    .screen-header {
        margin-bottom: 1rem;
        padding-bottom: 0.75rem;
    }

    .screen-header h2 {
        font-size: 1.3rem;
    }

    /* Welcome screen */
    #welcome-screen h2 {
        font-size: 1.5rem;
    }

    #welcome-screen p {
        font-size: 1rem;
    }

    /* Deck grid — single column on mobile */
    .decks-grid {
        grid-template-columns: 1fr;
        gap: 0.75rem;
    }

    /* Deck cards — larger tap targets */
    .deck-card {
        padding: 1rem;
    }

    .deck-card h3 {
        font-size: 1.1rem;
    }

    /* Home overview deck lines — stack vertically on mobile */
    .deck-line {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
        padding: 0.75rem 0;
    }

    .deck-actions {
        width: 100%;
        justify-content: flex-start;
    }

    /* Study and Preview action links — larger touch targets */
    .deck-action-link {
        padding: 0.6rem 1rem;
        font-size: 0.9rem;
        min-height: 44px;
        display: inline-flex;
        align-items: center;
        justify-content: center;
        flex: 1;
    }

/* Category screen header actions */
    .category-actions {
        gap: 0.5rem;
    }

    /* ---- Phase 6: Sidebar mobile polish ---- */

    /* Sidebar header — larger tap targets */
    .sidebar-header {
        padding: 1rem;
    }

    .sidebar-header .header-top h1 {
        font-size: 1.3rem;
    }

    /* Hamburger menu button in sidebar — larger tap target */
    .hamburger-btn {
        padding: 10px;
        font-size: 1.3rem;
    }

    /* Theme selector — full width, easier to tap */
    .theme-selector select {
        width: 100%;
        padding: 0.6rem;
        font-size: 1rem;
    }

    /* Sidebar stats — comfortable spacing */
    .sidebar-stats {
        margin-top: 0.75rem;
        padding-top: 0.75rem;
    }

    .sidebar-stat {
        font-size: 1rem;
        margin-bottom: 0.6rem;
    }

    /* Sidebar content scrollable */
    .sidebar-content {
        flex: 1;
        overflow-y: auto;
        padding: 1rem;
    }

    /* Category items — larger tap targets */
    .category-item {
        padding: 1rem;
        font-size: 1rem;
        margin-bottom: 0.4rem;
    }

    /* Hamburger dropdown menu — full width on mobile */
    .hamburger-menu {
        position: fixed;
        top: var(--mobile-header-height);
        left: 0;
        right: 0;
        width: 100%;
        border-radius: 0;
        z-index: 600;
    }

.hamburger-menu .menu-item {
        padding: 1rem 1.25rem;
        font-size: 1rem;
    }

    /* ---- Phase 7: iPhone safe areas & final polish ---- */

    /* Mobile header — account for iPhone notch */
    .mobile-header {
        padding-top: var(--safe-area-top);
        height: calc(var(--mobile-header-height) + var(--safe-area-top));
        padding-left: calc(1rem + var(--safe-area-left));
        padding-right: calc(1rem + var(--safe-area-right));
    }

    /* Push content below taller header on notch devices */
    .app-container {
        margin-top: calc(var(--mobile-header-height) + var(--safe-area-top));
    }

    /* Sidebar — account for safe areas */
    .app-container > nav.sidebar {
        top: calc(var(--mobile-header-height) + var(--safe-area-top));
        padding-bottom: var(--safe-area-bottom);
    }

    /* Rating buttons — account for iPhone home bar */
    .rating-section {
        padding-bottom: var(--safe-area-bottom);
    }

    /* Study screen height — account for safe areas */
    #study-screen.active {
        height: calc(100dvh - var(--mobile-header-height) - var(--safe-area-top));
        max-height: calc(100dvh - var(--mobile-header-height) - var(--safe-area-top));
    }

    /* Toast notifications — avoid notch area */
    .toast {
        top: calc(20px + var(--safe-area-top));
        right: calc(20px + var(--safe-area-right));
    }

    /* Modal — full width with safe area padding */
    .modal-content {
        width: calc(100% - 2rem);
        max-width: 100%;
        margin: 1rem;
        max-height: calc(90vh - var(--safe-area-top) - var(--safe-area-bottom));
    }
}