/* ============================================
   PREMIUM READING LAYOUT - Grid Moderno
   ============================================ */

:root {
    /* Typography Scale */
    --font-reading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-size-base: clamp(16px, 2vw, 18px);
    --font-size-reading: clamp(18px, 2.5vw, 22px);
    --font-size-heading: clamp(24px, 4vw, 32px);
    --line-height-reading: 1.75;
    --line-height-tight: 1.5;
    
    /* Spacing Scale */
    --space-xs: clamp(0.5rem, 1vw, 0.75rem);
    --space-sm: clamp(0.75rem, 1.5vw, 1rem);
    --space-md: clamp(1rem, 2vw, 1.5rem);
    --space-lg: clamp(1.5rem, 3vw, 2.5rem);
    --space-xl: clamp(2rem, 4vw, 4rem);
    
    /* Colors Premium */
    --color-bg: #fafafa;
    --color-paper: #ffffff;
    --color-text: #1a1a1a;
    --color-text-light: #666666;
    --color-accent: #6366f1;
    --color-accent-hover: #4f46e5;
    --color-border: #e5e7eb;
    --color-highlight: #fef3c7;
    
    /* Shadows Premium */
    --shadow-soft: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-medium: 0 4px 16px rgba(0, 0, 0, 0.08);
    --shadow-strong: 0 8px 32px rgba(0, 0, 0, 0.12);
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============================================
   LAYOUT GRID - Leitura + Painel IA
   ============================================ */

.reader-layout {
    display: grid;
    grid-template-columns: 1fr;
    grid-template-rows: auto 1fr;
    min-height: 100vh;
    background: var(--color-bg);
}

/* Desktop: 2 colunas (conteúdo + painel IA) */
@media (min-width: 1024px) {
    .reader-layout {
        grid-template-columns: 1fr 420px;
        grid-template-rows: auto 1fr;
    }
    
    .reader-layout.has-ai-panel {
        grid-template-columns: 1fr 420px;
    }
}

/* Header do Leitor */
.reader-header {
    grid-column: 1 / -1;
    background: var(--color-paper);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-md);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-md);
    box-shadow: var(--shadow-soft);
    position: sticky;
    top: 0;
    z-index: 50;
}

/* Área de Leitura */
.reader-content-area {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-lg);
    padding: var(--space-xl);
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
}

@media (min-width: 1024px) {
    .reader-content-area {
        grid-template-columns: minmax(0, 800px) 1fr;
        justify-content: center;
    }
}

/* Container do Texto */
.reader-text-container {
    max-width: 100%;
    margin: 0 auto;
}

/* Texto do Capítulo - Tipografia Premium */
.reader-text {
    font-family: var(--font-reading);
    font-size: var(--font-size-reading);
    line-height: var(--line-height-reading);
    color: var(--color-text);
    background: var(--color-paper);
    padding: var(--space-xl);
    border-radius: var(--space-sm);
    box-shadow: var(--shadow-soft);
    max-width: 65ch; /* Largura ótima para leitura */
    margin: 0 auto;
    position: relative;
}

.reader-text .chapter-title {
    font-size: clamp(24px, 3vw, 28px);
    font-weight: 600;
    margin-bottom: var(--space-lg);
    color: var(--color-accent);
    line-height: var(--line-height-tight);
    border-bottom: 2px solid var(--color-border);
    padding-bottom: var(--space-sm);
}

.reader-text .text-block {
    margin-bottom: var(--space-lg);
    text-align: justify;
    hyphens: auto;
    -webkit-hyphens: auto;
    word-spacing: 0.1em;
    line-height: var(--line-height-reading);
    text-indent: 1.5em;
    padding: var(--space-sm) 0;
}

.reader-text .text-block:first-of-type {
    text-indent: 0;
    font-weight: 500;
}

.reader-text .text-block:last-child {
    margin-bottom: 0;
}

/* Seleção de Texto - Highlight */
.reader-text ::selection {
    background: var(--color-highlight);
    color: var(--color-text);
}

.reader-text .highlighted {
    background: var(--color-highlight);
    padding: 2px 4px;
    border-radius: 3px;
    cursor: pointer;
    transition: background var(--transition-fast);
}

.reader-text .highlighted:hover {
    background: #fde68a;
}

/* ============================================
   PAINEL IA - Desktop Side Panel
   ============================================ */

.ai-panel {
    display: none;
    grid-column: 2;
    background: var(--color-paper);
    border-left: 1px solid var(--color-border);
    flex-direction: column;
    height: 100vh;
    position: sticky;
    top: 0;
    box-shadow: -4px 0 16px rgba(0, 0, 0, 0.04);
}

@media (min-width: 1024px) {
    .reader-layout.has-ai-panel .ai-panel {
        display: flex;
    }
}

.ai-panel-header {
    padding: var(--space-md);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: linear-gradient(135deg, var(--color-accent) 0%, #8b5cf6 100%);
    color: white;
}

.ai-panel-header h3 {
    font-size: var(--font-size-base);
    font-weight: 600;
    margin: 0;
}

.ai-panel-close {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background var(--transition-fast);
}

.ai-panel-close:hover {
    background: rgba(255, 255, 255, 0.3);
}

.ai-panel-messages {
    flex: 1;
    overflow-y: auto;
    padding: var(--space-md);
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
    -webkit-overflow-scrolling: touch;
}

.ai-panel-input-area {
    padding: var(--space-md);
    border-top: 1px solid var(--color-border);
    background: var(--color-bg);
    flex-shrink: 0;
}

.ai-panel-input-area .chat-input-wrapper {
    display: flex;
    gap: var(--space-xs);
    align-items: flex-end;
}

.ai-panel-input-area .chat-input,
.ai-drawer .chat-input {
    flex: 1;
    min-height: 44px;
    max-height: 120px;
    padding: var(--space-sm) var(--space-md);
    border: 1px solid var(--color-border);
    border-radius: var(--space-sm);
    font-size: var(--font-size-base);
    font-family: var(--font-reading);
    resize: none;
    display: block !important;
    visibility: visible !important;
    opacity: 1 !important;
    width: 100%;
    background: var(--color-paper);
    color: var(--color-text);
    box-sizing: border-box;
}

.ai-panel-input-area .chat-input:focus,
.ai-drawer .chat-input:focus {
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
    outline: none;
}

/* ============================================
   DRAWER IA - Mobile
   ============================================ */

.ai-drawer {
    position: fixed;
    top: 0;
    right: 0;
    width: 100%;
    max-width: 420px;
    height: 100vh;
    background: var(--color-paper);
    box-shadow: var(--shadow-strong);
    transform: translateX(100%);
    transition: transform var(--transition-base);
    z-index: 1000;
    display: flex;
    flex-direction: column;
}

.ai-drawer.open {
    transform: translateX(0);
}

.ai-drawer-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background: rgba(0, 0, 0, 0.5);
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-base);
    z-index: 999;
}

.ai-drawer-overlay.active {
    opacity: 1;
    pointer-events: all;
}

@media (min-width: 1024px) {
    .ai-drawer {
        display: none;
    }
}

/* ============================================
   BOTÃO FLUTUANTE - Perguntar ao Livro
   ============================================ */

.btn-ask-book {
    position: fixed;
    bottom: var(--space-lg);
    right: var(--space-lg);
    width: 64px;
    height: 64px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--color-accent) 0%, #8b5cf6 100%);
    color: white;
    border: none;
    box-shadow: var(--shadow-strong);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    transition: transform var(--transition-base), box-shadow var(--transition-base);
    z-index: 100;
    visibility: visible;
    opacity: 1;
}

.btn-ask-book:hover {
    transform: scale(1.1);
    box-shadow: 0 12px 40px rgba(99, 102, 241, 0.4);
}

.btn-ask-book:active {
    transform: scale(0.95);
}

@media (min-width: 1024px) {
    .btn-ask-book {
        display: none;
    }
}

/* ============================================
   MENU DE AÇÕES - Seleção de Texto
   ============================================ */

.text-selection-menu {
    position: fixed;
    background: var(--color-paper);
    border-radius: var(--space-sm);
    box-shadow: var(--shadow-strong);
    padding: var(--space-xs);
    display: none;
    gap: var(--space-xs);
    z-index: 200;
    animation: slideUp 200ms ease-out;
}

.text-selection-menu.active {
    display: flex;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.text-selection-menu button {
    padding: var(--space-xs) var(--space-sm);
    border: none;
    background: var(--color-bg);
    color: var(--color-text);
    border-radius: var(--space-xs);
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: background var(--transition-fast);
    white-space: nowrap;
}

.text-selection-menu button:hover {
    background: var(--color-accent);
    color: white;
}

.text-selection-menu button:active {
    transform: scale(0.95);
}

/* ============================================
   MENSAGENS DO CHAT
   ============================================ */

.message {
    display: flex;
    gap: var(--space-sm);
    animation: fadeIn 300ms ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.message.user {
    flex-direction: row-reverse;
}

.message-avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    flex-shrink: 0;
}

.message.user .message-avatar {
    background: var(--color-accent);
    color: white;
}

.message.ai .message-avatar {
    background: var(--color-bg);
    color: var(--color-accent);
}

.message-content {
    flex: 1;
    background: var(--color-bg);
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--space-sm);
    max-width: 85%;
}

.message.user .message-content {
    background: var(--color-accent);
    color: white;
}

/* ============================================
   INPUT DO CHAT
   ============================================ */

.chat-input-wrapper {
    display: flex;
    gap: var(--space-xs);
    align-items: flex-end;
}

.chat-input {
    flex: 1;
    padding: var(--space-sm) var(--space-md);
    border: 1px solid var(--color-border);
    border-radius: var(--space-sm);
    font-size: var(--font-size-base);
    font-family: var(--font-reading);
    resize: none;
    min-height: 44px;
    max-height: 120px;
    transition: border-color var(--transition-fast);
    display: block;
    visibility: visible;
    opacity: 1;
    width: 100%;
    background: var(--color-paper);
    color: var(--color-text);
}

.chat-input:focus {
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.btn-send {
    padding: var(--space-sm) var(--space-md);
    background: var(--color-accent);
    color: white;
    border: none;
    border-radius: var(--space-sm);
    cursor: pointer;
    font-weight: 500;
    transition: background var(--transition-fast);
    white-space: nowrap;
}

.btn-send:hover {
    background: var(--color-accent-hover);
}

.btn-send:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* ============================================
   RESPONSIVE
   ============================================ */

@media (max-width: 768px) {
    .reader-content-area {
        padding: var(--space-md);
    }
    
    .reader-text {
        padding: var(--space-md);
        font-size: clamp(16px, 4vw, 18px);
    }
    
    .reader-header {
        flex-wrap: wrap;
        padding: var(--space-sm);
    }
}

/* ============================================
   UTILITÁRIOS
   ============================================ */

.loading {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-xl);
    color: var(--color-text-light);
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}