/* --- CSS Reset & Basic Styles --- */
:root {
    --primary-color: #3B82F6;
    --primary-hover-color: #2563EB;
    --dark-text-color: #1F2937;
    --light-text-color: #6B7286;
    --bg-light-gray: #F9FAFB;
    --border-color: #E5E7EB;
    --error-color: #EF4444;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
    line-height: 1.6;
    color: var(--dark-text-color);
    background-color: #fff;
    min-width: 320px;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: var(--primary-color);
}

a:hover {
    color: var(--primary-hover-color);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    width: 100%;
    box-sizing: border-box;
}

/* --- Buttons --- */
.btn {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 8px;
    font-weight: 500;
    text-align: center;
    transition: all 0.3s ease;
    border: 1px solid transparent;
    cursor: pointer;
}

.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
}

.btn-primary:hover {
    background-color: var(--primary-hover-color);
    color: #fff;
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
}

.btn-secondary {
    background-color: #fff;
    color: var(--primary-color);
    border-color: var(--border-color);
}

.btn-secondary:hover {
    background-color: var(--bg-light-gray);
    color: var(--primary-hover-color);
}

.btn-block {
    display: block;
    width: 100%;
}


/* --- Header --- */
.main-header {
    background-color: #fff;
    border-bottom: 1px solid var(--border-color);
    padding: 15px 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

.main-header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 24px;
    font-weight: 700;
    color: var(--dark-text-color);
}

.main-nav ul {
    list-style: none;
    display: flex;
    gap: 30px;
}

.main-nav a {
    font-weight: 500;
    color: var(--light-text-color);
}

.main-nav a.active,
.main-nav a:hover {
    color: var(--primary-color);
}

.header-actions {
    display: flex;
    gap: 15px;
}

/* --- Footer --- */
.main-footer {
    background-color: var(--dark-text-color);
    color: #fff;
    padding: 40px 0;
    text-align: center;
    margin-top: auto; /* Push footer to the bottom */
}

.footer-links {
    margin-bottom: 20px;
}

.footer-links a {
    color: #fff;
    margin: 0 15px;
    opacity: 0.8;
    transition: opacity 0.3s ease;
}

.footer-links a:hover {
    opacity: 1;
}

.footer-info {
    opacity: 0.6;
    font-size: 14px;
}

.footer-info p {
    margin-bottom: 5px;
}

/* --- Authentication Form Styles --- */
.auth-wrapper {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.auth-container {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-grow: 1;
    padding: 40px 0;
    background-color: var(--bg-light-gray);
}

.auth-card {
    background-color: #fff;
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.05);
    width: 100%;
    max-width: 420px;
}

.auth-header {
    text-align: center;
    margin-bottom: 30px;
}

.auth-header h1 {
    font-size: 28px;
    margin-bottom: 10px;
}

.auth-header p {
    color: var(--light-text-color);
}

.auth-header p a {
    font-weight: 500;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-weight: 500;
    margin-bottom: 8px;
}

.form-control {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

.form-text {
    text-align: right;
    margin-top: 10px;
}

/* --- Homepage Styles --- */
.main-header {
    background: #fff;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    padding: 1rem 0;
}

.main-header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.main-nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
    margin: 0;
    padding: 0;
    flex-wrap: wrap;
}

.main-nav a {
    color: var(--dark-text-color);
    font-weight: 500;
}

.header-actions {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    align-items: center;
}

.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 5rem 0;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.hero-actions {
    display: flex;
    gap: 1rem;
}

.btn-large {
    padding: 16px 32px;
    font-size: 1.1rem;
}

.btn-outline {
    background: transparent;
    border: 2px solid white;
    color: white;
}

.btn-outline:hover {
    background: white;
    color: var(--primary-color);
}

.hero-placeholder {
    text-align: center;
}

.features {
    padding: 5rem 0;
    background: var(--bg-light-gray);
}

.features h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
}

.pricing {
    padding: 5rem 0;
}

.pricing h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
}

.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    max-width: 900px;
    margin: 0 auto;
}

.pricing-card {
    background: white;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    text-align: center;
    position: relative;
}

.pricing-card.featured {
    border-color: var(--primary-color);
    transform: scale(1.05);
}

.pricing-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.price {
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

.price span {
    font-size: 1rem;
    color: var(--light-text-color);
}

.pricing-card ul {
    list-style: none;
    margin-bottom: 2rem;
}

.pricing-card li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.main-footer {
    background: var(--dark-text-color);
    color: white;
    padding: 3rem 0 1rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    margin-bottom: 1rem;
}

.footer-section ul {
    list-style: none;
}

.footer-section a {
    color: #ccc;
}

.footer-bottom {
    border-top: 1px solid #444;
    padding-top: 1rem;
    text-align: center;
    color: #ccc;
}

/* --- Responsive --- */
@media (max-width: 1024px) {
    .hero .container {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }
    
    .features-grid {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    }
    
    .pricing-grid {
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    }
}

@media (max-width: 768px) {
    .main-nav {
        display: none;
    }
    
    .header-actions .btn-secondary {
        display: none;
    }
    
    .main-header .container {
        flex-wrap: wrap;
        gap: 1rem;
    }

    .auth-card {
        padding: 30px;
    }

    .hero {
        padding: 3rem 0;
    }

    .hero h1 {
        font-size: 2rem;
        line-height: 1.3;
    }
    
    .hero p {
        font-size: 1rem;
    }

    .hero-actions {
        justify-content: center;
        flex-direction: column;
        align-items: center;
        gap: 0.5rem;
    }
    
    .btn-large {
        padding: 14px 28px;
        font-size: 1rem;
        width: 100%;
        max-width: 280px;
    }

    .features-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .features {
        padding: 3rem 0;
    }
    
    .features h2 {
        font-size: 2rem;
    }

    .pricing-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .pricing {
        padding: 3rem 0;
    }
    
    .pricing h2 {
        font-size: 2rem;
    }

    .pricing-card.featured {
        transform: none;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 1.5rem;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero h1 {
        font-size: 1.5rem;
    }
    
    .feature-card, .pricing-card {
        padding: 1.5rem;
    }
    
    .main-header {
        padding: 0.5rem 0;
    }
    
    .logo {
        font-size: 1.2rem;
    }
}
/* --- Chat Page Styles (scoped to .chat-wrapper) --- */
.chat-wrapper {
    display: flex;
    min-height: calc(100vh - 0px);
    background-color: #fff;
    position: relative; /* 为了容纳绝对定位的折叠按钮 */
}

.chat-wrapper .chat-sidebar {
    width: 280px;
    border-right: 1px solid var(--border-color);
    padding: 20px;
    background: #fff;
    display: flex;
    flex-direction: column;
    gap: 20px;
    transition: width 0.3s ease, margin-left 0.3s ease;
    position: relative;
    min-width: 280px;
    z-index: 5;
}

.chat-wrapper .chat-sidebar.collapsed {
    width: 0;
    min-width: 0;
    padding: 0;
    margin-left: -280px; /* 替代transform，避免层级问题 */
    opacity: 0;
    pointer-events: none;
}

.chat-wrapper .sidebar-toggle {
    position: absolute;
    top: 20px;
    right: -40px;
    width: 40px;
    height: 40px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 0 8px 8px 0;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    z-index: 100; /* 提高层级，确保可见 */
    transition: all 0.3s ease;
    box-shadow: 2px 2px 8px rgba(0,0,0,0.15); /* 增加阴影提升视觉层次 */
}

.chat-wrapper .sidebar-toggle:hover {
    background: var(--primary-hover-color);
    transform: scale(1.05);
}

.chat-wrapper .sidebar-toggle.collapsed {
    position: fixed;
    left: 0;
    top: 20px;
    right: auto;
    border-radius: 0 8px 8px 0;
    z-index: 999; /* 折叠状态时保证最高层级 */
}

.chat-wrapper .chat-sidebar-header {
    display: flex;
    gap: 10px;
}

.chat-wrapper .book-select-section .select-label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--light-text-color);
}

.chat-wrapper .conversations-section .section-title {
    font-size: 14px;
    color: var(--light-text-color);
    margin-bottom: 10px;
}

.chat-wrapper .conversation-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
    max-height: 40vh;
    overflow: auto;
}

.chat-wrapper .conversation-item {
    padding: 10px 12px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.2s;
}

.chat-wrapper .conversation-item:hover {
    background: var(--bg-light-gray);
}

.chat-wrapper .conversation-title {
    font-weight: 600;
}

.chat-wrapper .conversation-meta {
    font-size: 12px;
    color: var(--light-text-color);
}

.chat-wrapper .chat-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    padding: 24px;
    background: var(--bg-light-gray);
    position: relative;
    max-width: calc(100% - 280px); /* 防止溢出 */
    transition: max-width 0.3s ease; /* 平滑过渡 */
}

/* 侧边栏折叠时主内容区域扩展 */
.chat-wrapper .chat-sidebar.collapsed + .chat-main {
    max-width: 100%;
}

/* 右侧工具栏优化 - 改为内联而非绝对定位，避免挤压 */
.chat-wrapper .chat-tools{
    position: absolute;
    right: 24px;
    top: 80px; /* 调整位置避开标题 */
    width: 300px;
    max-width: 25vw; /* 响应式宽度限制 */
    background: #fff;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    box-shadow: 0 8px 24px rgba(0,0,0,0.08);
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
    z-index: 10;
    transition: opacity 0.3s ease, transform 0.3s ease;
}

.chat-wrapper .chat-tools-header{
    display: flex;
    justify-content: center;
}

.chat-wrapper .chat-tools-tabs{
    display: flex;
    gap: 8px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 8px;
}

.chat-wrapper .chat-tools-tabs .tools-tab{
    flex: 1;
    background: transparent;
    border: none;
    padding: 8px 10px;
    border-radius: 8px;
    cursor: pointer;
    color: var(--light-text-color);
    font-size: 14px;
}

.chat-wrapper .chat-tools-tabs .tools-tab.active{
    background: var(--bg-light-gray);
    color: var(--dark-text-color);
}

.chat-wrapper .chat-tools-body{
    max-height: 45vh;
    overflow: auto;
}

.chat-wrapper .hidden{ 
    display:none; 
}

/* 调整右侧列表的间距以适配容器 */
.chat-wrapper .chat-tools .conversation-list{ 
    max-height: none;
    gap: 6px;
}

.chat-wrapper .chat-tools .conversation-item {
    padding: 8px 10px;
    font-size: 14px;
}

/* 小屏隐藏右侧工具栏，避免遮挡 */
@media (max-width: 1200px){
    .chat-wrapper .chat-tools{ 
        display: none; 
    }
}

.chat-wrapper .chat-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
    flex-wrap: wrap;
    gap: 12px;
}

.chat-wrapper .chat-header-right{
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.chat-wrapper .chat-title {
    font-size: 20px;
    margin: 0;
}

.chat-wrapper .chat-status {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--light-text-color);
}

.chat-wrapper .status-indicator {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #10B981;
    display: inline-block;
}

.chat-wrapper .message-list {
    flex: 1;
    background: #fff;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 20px;
    overflow: auto;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.02);
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.chat-wrapper .welcome-message {
    display: flex;
    gap: 12px;
    align-items: flex-start;
    color: var(--light-text-color);
    align-self: center; /* 居中对齐 */
    max-width: 600px;
    text-align: center;
}

.chat-wrapper .welcome-avatar {
    font-size: 22px;
}

.chat-wrapper .welcome-content h3 {
    font-size: 18px;
    margin-bottom: 6px;
    color: var(--dark-text-color);
}

.chat-wrapper .message {
    display: flex;
    gap: 12px;
    align-items: flex-end;
    margin: 8px 0;
    max-width: 100%;
}

.chat-wrapper .message .message-content {
    max-width: 70%;
    padding: 12px 16px;
    border-radius: 16px;
    line-height: 1.7;
    font-size: 15px;
    word-wrap: break-word;
    overflow-wrap: break-word;
}

.chat-wrapper .message-user {
    justify-content: flex-end;
    margin-left: auto; /* 用户消息右对齐 */
}

.chat-wrapper .user-message {
    background: #DCF4FF;
    border: 1px solid #BEE3F8;
    border-radius: 16px 16px 4px 16px;
}

.chat-wrapper .user-avatar {
    font-size: 18px;
    order: 2; /* 头像在右侧 */
}

.chat-wrapper .message-assistant {
    justify-content: flex-start;
    margin-right: auto; /* AI消息左对齐 */
}

.chat-wrapper .ai-message {
    background: #F6F6F7;
    border: 1px solid var(--border-color);
    border-radius: 16px 16px 16px 4px;
}

.chat-wrapper .ai-avatar {
    font-size: 18px;
    order: 1; /* 头像在左侧 */
}

.chat-wrapper .system-message {
    background: #FFF7ED;
    border: 1px dashed #F59E0B;
    color: #92400E;
    border-radius: 12px;
    padding: 10px 12px;
    align-self: center; /* 系统消息居中 */
    max-width: 80%;
    text-align: center;
}

.chat-wrapper .message-time {
    font-size: 12px;
    color: var(--light-text-color);
    margin-top: 6px;
}

.chat-wrapper .message-text p {
    margin: 0 0 8px 0;
}

.chat-wrapper .message-text p:last-child {
    margin-bottom: 0;
}

.chat-wrapper .chat-input-area {
    margin-top: 16px;
}

.chat-wrapper .input-container {
    display: flex;
    gap: 10px;
    align-items: flex-end;
    background: #fff;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 12px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}

.chat-wrapper .chat-textarea {
    flex: 1;
    min-height: 20px;
    max-height: 120px;
    border: none;
    resize: none;
    outline: none;
    font-size: 15px;
    line-height: 1.6;
    font-family: inherit;
}

.chat-wrapper .send-btn {
    background: var(--primary-color);
    color: #fff;
    border: none;
    border-radius: 10px;
    padding: 10px 14px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    min-width: 44px;
    height: 44px;
}

.chat-wrapper .send-btn:hover {
    background: var(--primary-hover-color);
    transform: translateY(-1px);
}

.chat-wrapper .send-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.chat-wrapper .send-icon {
    font-weight: 700;
    font-size: 16px;
}

.chat-wrapper .input-tips {
    margin-top: 8px;
    color: var(--light-text-color);
    font-size: 13px;
    text-align: center;
}

/* Thinking indicator */
.chat-wrapper .thinking .thinking-indicator {
    display: flex;
    align-items: center;
    gap: 10px;
}

.chat-wrapper .thinking-dots {
    display: inline-flex;
    gap: 6px;
}

.chat-wrapper .thinking-dots span {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: #9CA3AF;
    display: inline-block;
    animation: blink 1.2s infinite ease-in-out;
}

.chat-wrapper .thinking-dots span:nth-child(2) {
    animation-delay: 0.2s;
}

.chat-wrapper .thinking-dots span:nth-child(3) {
    animation-delay: 0.4s;
}

@keyframes blink {
    0%, 80%, 100% {
        opacity: 0.2;
        transform: translateY(0);
    }
    40% {
        opacity: 1;
        transform: translateY(-3px);
    }
}

.chat-wrapper .new-chat-pill{
    border-radius: 999px;
    padding: 8px 16px;
    font-weight: 600;
    font-size: 14px;
    transition: all 0.2s ease;
}

.chat-wrapper .new-chat-pill:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.25);
}

/* 响应式优化 */
@media (max-width: 768px) {
    .chat-wrapper {
        flex-direction: column;
    }
    
    .chat-wrapper .chat-sidebar {
        width: 100%;
        min-width: 100%;
        order: 2;
        border-right: none;
        border-top: 1px solid var(--border-color);
        padding: 16px;
    }
    
    .chat-wrapper .chat-sidebar.collapsed {
        display: none;
    }
    
    .chat-wrapper .sidebar-toggle {
        position: fixed;
        top: 10px;
        left: 10px;
        z-index: 1000;
    }
    
    .chat-wrapper .chat-main {
        max-width: 100%;
        order: 1;
        padding: 16px;
    }
    
    .chat-wrapper .chat-tools {
        display: none !important;
    }
    
    .chat-wrapper .message .message-content {
        max-width: 85%;
    }
    
    .chat-wrapper .welcome-message {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .chat-wrapper .chat-main {
        padding: 12px;
    }
    
    .chat-wrapper .message-list {
        padding: 16px;
    }
    
    .chat-wrapper .input-container {
        padding: 10px;
    }
    
    .chat-wrapper .chat-textarea {
        font-size: 16px; /* 防止iOS自动缩放 */
    }
}
@media (min-width: 1201px) {
  .chat-wrapper .chat-main {
    padding-right: 340px; /* 为右侧工具栏预留空间，避免遮挡 */
  }
  .chat-wrapper.tools-collapsed .chat-main {
    padding-right: 24px; /* 折叠时恢复默认内边距 */
  }
}

/* 右侧工具栏折叠开关按钮 */
.chat-wrapper .tools-toggle {
  position: fixed;
  right: 12px;
  top: 120px;
  width: 40px;
  height: 40px;
  border: none;
  border-radius: 8px 0 0 8px;
  background: var(--primary-color);
  color: #fff;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.chat-wrapper .tools-toggle:hover {
  background: var(--primary-hover-color);
}

@media (max-width: 1200px) {
  .chat-wrapper .tools-toggle { display: none; }
}
/* 居中列布局：消息列表与输入区域保持同宽且居中 */
.chat-wrapper .message-list,
.chat-wrapper .chat-input-area,
.chat-wrapper .chat-header {
  max-width: 960px;
  margin-left: auto;
  margin-right: auto;
}

/* 在超小屏时自然占满，无需额外规则，max-width会自动适配 */