/* ============================================
   Enhanced UI Styles & Mobile Responsiveness
   ============================================ */

/* Improved Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
    letter-spacing: -0.02em;
    font-weight: 700;
}

.book-title {
    letter-spacing: -0.01em;
}

/* Enhanced User Stats (Gamification) */
.user-stats {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

.user-stat-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-md);
    background: rgba(99, 102, 241, 0.1);
    transition: all var(--transition-base);
}

.user-stat-item:hover {
    background: rgba(99, 102, 241, 0.2);
    transform: translateY(-2px);
}

.stat-icon {
    font-size: 1.25rem;
}

.stat-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

.stat-value {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
}

/* XP Progress Bar */
.xp-progress-container {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    min-width: 120px;
}

.xp-progress-bar {
    height: 6px;
    background: var(--bg-secondary);
    border-radius: 999px;
    overflow: hidden;
    position: relative;
}

.xp-progress-fill {
    height: 100%;
    background: var(--gradient-primary);
    border-radius: 999px;
    transition: width var(--transition-slow);
    position: relative;
}

.xp-progress-fill::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    animation: shimmer 2s infinite;
}

.xp-text {
    font-size: 0.7rem;
    color: var(--text-secondary);
    display: flex;
    justify-content: space-between;
}

/* Level Badge */
.level-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    border-radius: 50%;
    font-size: 1.25rem;
    font-weight: 800;
    color: white;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
    position: relative;
}

.level-badge::before {
    content: '';
    position: absolute;
    inset: -3px;
    border-radius: 50%;
    background: linear-gradient(135deg, #6366f1, #a855f7, #ec4899);
    z-index: -1;
    opacity: 0.5;
    filter: blur(8px);
}

/* Streak Counter */
.streak-counter {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    background: linear-gradient(135deg, rgba(251, 146, 60, 0.1), rgba(239, 68, 68, 0.1));
    border: 1px solid rgba(251, 146, 60, 0.3);
    border-radius: var(--radius-md);
}

.streak-flame {
    font-size: 1.25rem;
    animation: flameFlicker 2s ease-in-out infinite;
}

@keyframes flameFlicker {

    0%,
    100% {
        transform: scale(1);
        opacity: 1;
    }

    50% {
        transform: scale(1.1);
        opacity: 0.9;
    }
}

.streak-count {
    font-size: 1rem;
    font-weight: 700;
    color: #f97316;
}

/* Enhanced Notifications */
.notification {
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    backdrop-filter: blur(12px);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    min-width: 300px;
}

.notification-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.notification-content {
    flex: 1;
}

.notification-title {
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.notification-message {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* Improved Button Styles */
.btn {
    position: relative;
    overflow: hidden;
    min-height: 44px;
    /* Touch-friendly */
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn:active::before {
    width: 300px;
    height: 300px;
}

/* Enhanced Card Hover Effects */
.book-card,
.word-card,
.stat-card {
    transition: all var(--transition-base);
}

.book-card:hover,
.word-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

/* Better Modal Backdrop */
.modal {
    backdrop-filter: blur(12px);
    animation: fadeIn 0.3s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

/* ============================================
   Mobile Responsiveness
   ============================================ */

/* Tablet (768px - 1023px) */
@media (max-width: 1023px) {
    .header-content {
        flex-wrap: wrap;
        gap: var(--spacing-md);
    }

    .search-container {
        order: 3;
        flex: 1 1 100%;
    }

    .books-grid {
        grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    }

    .stats-grid {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    }

    .user-stats {
        flex-wrap: wrap;
        justify-content: center;
    }
}

/* Mobile (< 768px) */
@media (max-width: 767px) {

    /* Typography scaling */
    body {
        font-size: 14px;
    }

    h1 {
        font-size: 1.5rem;
    }

    h2 {
        font-size: 1.25rem;
    }

    h3 {
        font-size: 1.1rem;
    }

    /* Header */
    .header-content {
        padding: var(--spacing-sm) var(--spacing-md);
        flex-direction: column;
        align-items: stretch;
    }

    .logo {
        font-size: 1.25rem;
        text-align: center;
    }

    .header-actions {
        justify-content: center;
        width: 100%;
    }

    .search-container {
        width: 100%;
        max-width: none;
    }

    /* Navigation Tabs */
    .nav-tabs {
        flex-wrap: wrap;
        justify-content: center;
        gap: var(--spacing-sm);
    }

    .nav-tab {
        padding: var(--spacing-sm) var(--spacing-md);
        font-size: 0.9rem;
    }

    /* Container */
    .container {
        padding: var(--spacing-lg) var(--spacing-md);
    }

    /* Statistics Grid */
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-md);
    }

    .stat-card {
        padding: var(--spacing-md);
    }

    .stat-icon {
        font-size: 1.5rem;
        width: 40px;
        height: 40px;
    }

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

    /* Controls */
    .controls-row {
        flex-direction: column;
        align-items: stretch;
    }

    .category-tabs {
        flex-wrap: wrap;
        justify-content: center;
    }

    .category-tab {
        flex: 1 1 auto;
        min-width: 100px;
        text-align: center;
    }

    .filter-controls {
        flex-direction: column;
        width: 100%;
    }

    .select-wrapper {
        width: 100%;
    }

    .select-input {
        width: 100%;
    }

    /* Books Grid - Single Column */
    .books-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    .book-card {
        padding: var(--spacing-md);
    }

    /* Vocabulary Grid - Single Column */
    .vocabulary-grid {
        grid-template-columns: 1fr;
    }

    /* User Stats - Stacked */
    .user-stats {
        flex-direction: column;
        width: 100%;
        padding: var(--spacing-md);
    }

    .user-stat-item {
        width: 100%;
        justify-content: space-between;
    }

    .xp-progress-container {
        width: 100%;
    }

    /* Modals - Full Width */
    .modal {
        padding: var(--spacing-sm);
    }

    .modal-content {
        max-width: 100%;
        width: 100%;
        padding: var(--spacing-lg);
        max-height: 95vh;
    }

    .modal-title {
        font-size: 1.5rem;
    }

    /* Forms */
    .form-row {
        flex-direction: column;
    }

    /* Buttons - Full Width on Mobile */
    .modal-actions {
        flex-direction: column-reverse;
    }

    .modal-actions .btn {
        width: 100%;
    }

    /* Data Management Section */
    .data-management {
        padding: var(--spacing-lg) var(--spacing-md) !important;
    }

    .data-management>div {
        flex-direction: column;
    }

    .data-management .btn {
        width: 100%;
    }

    /* Notifications */
    .notification {
        min-width: auto !important;
        max-width: calc(100vw - 2rem) !important;
        width: 90vw !important;
        padding: var(--spacing-sm) var(--spacing-md) !important;
        font-size: 0.85rem !important;
    }

    .notification-dropdown {
        width: calc(100vw - 2rem) !important;
        max-width: 350px !important;
        right: 1rem !important;
        left: 1rem !important;
    }

    .notification-container {
        padding: 0 0.5rem !important;
    }
}

/* Small Mobile (< 375px) */
@media (max-width: 374px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }

    .category-tab {
        font-size: 0.85rem;
        padding: var(--spacing-xs) var(--spacing-sm);
    }

    .book-title {
        font-size: 1.1rem;
    }
}

/* Landscape Mobile */
@media (max-width: 767px) and (orientation: landscape) {
    .header-content {
        flex-direction: row;
        flex-wrap: wrap;
    }

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

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

/* Touch Device Optimizations */
@media (hover: none) and (pointer: coarse) {

    /* Larger touch targets */
    .btn,
    .category-tab,
    .nav-tab {
        min-height: 48px;
        min-width: 48px;
    }

    /* Remove hover effects on touch devices */
    .book-card:hover,
    .word-card:hover,
    .stat-card:hover {
        transform: none;
    }

    /* Tap highlight */
    * {
        -webkit-tap-highlight-color: rgba(99, 102, 241, 0.2);
    }
}

/* Print Styles */
@media print {

    .header,
    .controls,
    .data-management,
    .modal,
    .notification-container {
        display: none !important;
    }

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

    body {
        background: white;
        color: black;
    }
}

/* Compact Gamification Panel */
.gamification-compact {
    display: flex;
    flex-direction: column;
    gap: 4px;
    width: 100%;
    max-width: 300px;
}

.xp-line {
    display: flex;
    align-items: center;
    gap: 8px;
}

.xp-progress-bar-compact {
    flex: 1;
    height: 10px;
    background: var(--bg-tertiary);
    /* Adaptable background */
    border: 1px solid var(--border-color);
    /* Visible border */
    border-radius: 999px;
    overflow: hidden;
    position: relative;
    min-width: 50px;
    /* Ensure it never collapses */
}

.xp-progress-fill {
    height: 100%;
    background: var(--gradient-primary);
    border-radius: 999px;
    transition: width 0.5s ease;
    position: relative;
}

.xp-progress-fill::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    animation: shimmer 2s infinite;
}

.xp-text-compact {
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--text-accent);
    min-width: 50px;
    text-align: right;
}

.level-line {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
}

.level-text-compact {
    font-weight: 700;
    color: var(--text-primary);
}

.books-read-compact {
    color: var(--text-secondary);
    font-size: 0.8rem;
}

.streak-compact {
    margin-left: auto;
    font-weight: 600;
    color: #f97316;
    display: flex;
    align-items: center;
    gap: 4px;
    font-size: 0.8rem;
    background: rgba(249, 115, 22, 0.1);
    padding: 2px 6px;
    border-radius: 12px;
}

/* ============================================
   Direct Messaging & Chat Styles
   ============================================ */

.chat-modal-content {
    max-width: 900px !important;
    width: 95% !important;
    height: 80vh;
    display: flex;
    flex-direction: column;
    padding: 0 !important;
    overflow: hidden !important;
}

.chat-modal-content .modal-header {
    padding: var(--spacing-md) var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
}

.chat-layout {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* Sidebar */
.chat-sidebar {
    width: 300px;
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    background: var(--bg-secondary);
}

.conversations-list {
    flex: 1;
    overflow-y: auto;
}

.conversation-item {
    padding: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    cursor: pointer;
    transition: background 0.2s;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.conversation-item:hover {
    background: rgba(255, 255, 255, 0.05);
}

.conversation-item.active {
    background: rgba(99, 102, 241, 0.1);
    border-left: 3px solid var(--accent-primary);
}

.conv-avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    object-fit: cover;
}

.conv-info {
    flex: 1;
    overflow: hidden;
}

.conv-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 4px;
}

.conv-name {
    font-weight: 600;
    font-size: 0.95rem;
}

.conv-time {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.conv-last-msg {
    font-size: 0.85rem;
    color: var(--text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.conv-unread {
    background: var(--accent-primary);
    color: white;
    font-size: 0.7rem;
    padding: 2px 6px;
    border-radius: 10px;
    font-weight: bold;
}

/* Chat Main Area */
.chat-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: var(--bg-primary);
}

.chat-empty-state {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    gap: var(--spacing-md);
}

.chat-empty-state .empty-icon {
    font-size: 3rem;
    opacity: 0.3;
}

.chat-active-state {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.chat-target-header {
    padding: var(--spacing-sm) var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    background: var(--bg-secondary);
}

#chatTargetAvatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    object-fit: cover;
}

.chat-messages-area {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.message-bubble {
    max-width: 70%;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: 16px;
    font-size: 0.95rem;
    line-height: 1.4;
    position: relative;
}

.message-bubble.sent {
    align-self: flex-end;
    background: var(--accent-primary);
    color: white;
    border-bottom-right-radius: 4px;
}

.message-bubble.received {
    align-self: flex-start;
    background: var(--bg-secondary);
    color: var(--text-primary);
    border-bottom-left-radius: 4px;
    border: 1px solid var(--border-color);
}

.message-time {
    font-size: 0.7rem;
    opacity: 0.7;
    margin-top: 4px;
    text-align: right;
}

.chat-input-area {
    padding: var(--spacing-md) var(--spacing-lg);
    border-top: 1px solid var(--border-color);
    display: flex;
    gap: var(--spacing-md);
    align-items: flex-end;
    background: var(--bg-secondary);
}

#chatMessageInput {
    flex: 1;
    min-height: 40px;
    max-height: 120px;
    resize: none;
    border-radius: 20px;
    padding: 10px 15px;
}

/* Mobile Adjustments for Chat */
@media (max-width: 767px) {
    .chat-layout {
        position: relative;
    }

    .chat-sidebar {
        width: 100%;
        position: absolute;
        inset: 0;
        z-index: 2;
        transition: transform 0.3s;
    }

    .chat-sidebar.hidden {
        transform: translateX(-100%);
    }

    .chat-main {
        width: 100%;
    }
}