/* CSS Variables and Themes */
:root {
    --font-family-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    --font-family-serif: "Times New Roman", "STSong", "SimSun", Georgia, serif;

    /* Font Sizes */
    --font-size-base: 16px;
    --font-size-small: 14px;
    --font-size-large: 18px;

    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;

    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;

    /* Header & Footer Heights */
    --header-height: 60px;
    --footer-height: 64px;
    --icp-height: 32px;
}

/* Theme: Elegant Gray (Default) */
[data-theme="elegant-gray"], :root {
    --color-primary: #8B7E74;
    --color-primary-light: #A39791;
    --color-primary-dark: #6D615A;
    --color-accent: #B8A398;
    --color-accent-light: #E8DDD8;
    --color-accent-2: #9FB8AD;
    --color-bg: #FAFAF8;
    --color-bg-secondary: #F5F5F3;
    --color-surface: #FFFFFF;
    --color-text: #2C2C2C;
    --color-text-secondary: #6B6B6B;
    --color-text-tertiary: #999999;
    --color-border: #E5E5E3;
    --color-hover: #F0EBE8;
}

/* Theme: Warm Rose */
[data-theme="warm-rose"] {
    --color-primary: #C9A0A0;
    --color-primary-light: #D9B8B8;
    --color-primary-dark: #B88888;
    --color-accent: #E6C4B8;
    --color-accent-light: #F5E5DC;
    --color-accent-2: #B8A9C9;
    --color-bg: #FFF8F5;
    --color-bg-secondary: #FFF0EB;
    --color-surface: #FFFFFF;
    --color-text: #2C2C2C;
    --color-text-secondary: #6B6B6B;
    --color-text-tertiary: #999999;
    --color-border: #F0DDD5;
    --color-hover: #FFEEE8;
}

/* Theme: Mint Fresh */
[data-theme="mint-fresh"] {
    --color-primary: #89B0A8;
    --color-primary-light: #A3C4BD;
    --color-primary-dark: #6F9C93;
    --color-accent: #B8D4CF;
    --color-accent-light: #DCF0ED;
    --color-accent-2: #C9D9B8;
    --color-bg: #F5FAFA;
    --color-bg-secondary: #EBF5F3;
    --color-surface: #FFFFFF;
    --color-text: #2C2C2C;
    --color-text-secondary: #6B6B6B;
    --color-text-tertiary: #999999;
    --color-border: #D5E8E5;
    --color-hover: #E3F2EF;
}

/* Theme: Lavender Dream */
[data-theme="lavender-dream"] {
    --color-primary: #A89BB8;
    --color-primary-light: #BEB3CC;
    --color-primary-dark: #9283A4;
    --color-accent: #C9B8D9;
    --color-accent-light: #E8DCED;
    --color-accent-2: #B8C9D9;
    --color-bg: #F8F5FA;
    --color-bg-secondary: #F0EBF5;
    --color-surface: #FFFFFF;
    --color-text: #2C2C2C;
    --color-text-secondary: #6B6B6B;
    --color-text-tertiary: #999999;
    --color-border: #E5D5F0;
    --color-hover: #EEE3F5;
}

/* Theme: Pearl White */
[data-theme="pearl-white"] {
    --color-primary: #B8B0A8;
    --color-primary-light: #CCC6C0;
    --color-primary-dark: #A49A90;
    --color-accent: #D4CFC9;
    --color-accent-light: #EBE8E5;
    --color-accent-2: #C9D4CF;
    --color-bg: #FEFEFE;
    --color-bg-secondary: #F8F8F6;
    --color-surface: #FFFFFF;
    --color-text: #2C2C2C;
    --color-text-secondary: #6B6B6B;
    --color-text-tertiary: #999999;
    --color-border: #EBEBEB;
    --color-hover: #F5F3F0;
}

/* Theme: Coral Pink */
[data-theme="coral-pink"] {
    --color-primary: #D9A89B;
    --color-primary-light: #E6BFB3;
    --color-primary-dark: #CC9183;
    --color-accent: #F0C4B8;
    --color-accent-light: #FAE5DD;
    --color-accent-2: #B8D4C9;
    --color-bg: #FFF8F6;
    --color-bg-secondary: #FFF0EB;
    --color-surface: #FFFFFF;
    --color-text: #2C2C2C;
    --color-text-secondary: #6B6B6B;
    --color-text-tertiary: #999999;
    --color-border: #F0DDD5;
    --color-hover: #FFEEE5;
}

/* Font Size Classes */
.font-small {
    --font-size-base: 14px;
    --font-size-small: 12px;
    --font-size-large: 16px;
}

.font-large {
    --font-size-base: 18px;
    --font-size-small: 16px;
    --font-size-large: 20px;
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: var(--font-size-base);
    -webkit-text-size-adjust: 100%;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family-sans);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    overflow-x: hidden;
    padding-bottom: calc(var(--footer-height) + var(--icp-height));
}

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
    z-index: 100;
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    height: 100%;
    padding: 0 var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header-left {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.logo {
    height: 36px;
    width: auto;
    object-fit: contain;
}

.site-title {
    font-family: var(--font-family-serif);
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--color-primary);
    letter-spacing: 0.5px;
}

.header-nav {
    display: flex;
    gap: var(--spacing-sm);
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    background: transparent;
    border: none;
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    cursor: pointer;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

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

.nav-btn i {
    font-size: 1.1rem;
}

/* Settings Panel */
.settings-panel {
    position: fixed;
    top: 0;
    right: -100%;
    width: 100%;
    max-width: 400px;
    height: 100vh;
    background: var(--color-surface);
    box-shadow: var(--shadow-lg);
    z-index: 200;
    transition: right var(--transition-base);
    overflow-y: auto;
}

.settings-panel.active {
    right: 0;
}

.settings-content {
    padding: var(--spacing-lg);
}

.settings-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
}

.settings-header h3 {
    font-family: var(--font-family-serif);
    font-size: 1.3rem;
    color: var(--color-primary);
}

.close-btn {
    background: transparent;
    border: none;
    font-size: 1.5rem;
    color: var(--color-text-secondary);
    cursor: pointer;
    padding: var(--spacing-xs);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

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

.settings-section {
    margin-bottom: var(--spacing-xl);
}

.settings-section h4 {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1rem;
    font-weight: 500;
    color: var(--color-text);
    margin-bottom: var(--spacing-md);
}

.settings-section h4 i {
    color: var(--color-primary);
}

.theme-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-sm);
}

.theme-btn,
.size-btn,
.style-btn,
.length-btn {
    padding: var(--spacing-md);
    background: var(--color-bg-secondary);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text);
    font-size: 0.9rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.theme-btn:hover,
.size-btn:hover,
.style-btn:hover,
.length-btn:hover {
    border-color: var(--color-primary);
    background: var(--color-hover);
}

.theme-btn.active,
.size-btn.active,
.style-btn.active,
.length-btn.active {
    border-color: var(--color-primary);
    background: var(--color-primary);
    color: var(--color-surface);
}

.font-size-btns,
.ai-style-btns,
.ai-length-btns {
    display: flex;
    gap: var(--spacing-sm);
}

.font-size-btns .size-btn,
.ai-style-btns .style-btn,
.ai-length-btns .length-btn {
    flex: 1;
}

/* Main Content */
.main-content {
    margin-top: var(--header-height);
    min-height: calc(100vh - var(--header-height) - var(--footer-height) - var(--icp-height));
}

.page {
    display: none;
    animation: fadeIn var(--transition-base);
}

.page.active {
    display: block;
}

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

.page-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg) var(--spacing-md);
}

.page-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    font-family: var(--font-family-serif);
    font-size: 1.8rem;
    font-weight: 500;
    color: var(--color-primary);
    margin-bottom: var(--spacing-lg);
}

.page-title i {
    font-size: 1.6rem;
}

/* Hero Section */
.hero-section {
    padding: var(--spacing-xl) var(--spacing-md);
    text-align: center;
    background: linear-gradient(135deg, var(--color-bg) 0%, var(--color-bg-secondary) 100%);
}

.hero-title {
    font-family: var(--font-family-serif);
    font-size: 2rem;
    font-weight: 500;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    letter-spacing: 1px;
}

.hero-subtitle {
    font-size: 1.1rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-lg);
}

.hero-decorative-line {
    max-width: 300px;
    margin: 0 auto;
    color: var(--color-primary);
}

/* Content Section */
.content-section {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg) var(--spacing-md);
}

.section-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    font-family: var(--font-family-serif);
    font-size: 1.5rem;
    font-weight: 500;
    color: var(--color-primary);
    margin-bottom: var(--spacing-lg);
}

.section-title i {
    font-size: 1.4rem;
}

/* Outline Styles */
.outline-container {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
}

.chapter {
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--color-border);
}

.chapter:last-child {
    border-bottom: none;
}

.chapter-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    padding: var(--spacing-md);
    background: var(--color-bg-secondary);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-md);
    transition: all var(--transition-fast);
}

.chapter-header:hover {
    background: var(--color-hover);
}

.chapter-title {
    font-family: var(--font-family-serif);
    font-size: 1.3rem;
    font-weight: 500;
    color: var(--color-primary);
}

.toggle-icon {
    font-size: 1.2rem;
    color: var(--color-text-secondary);
    transition: transform var(--transition-fast);
}

.chapter.expanded .toggle-icon {
    transform: rotate(180deg);
}

.chapter-content {
    display: none;
    padding: var(--spacing-md);
}

.chapter.expanded .chapter-content {
    display: block;
}

.section-item {
    margin-bottom: var(--spacing-lg);
}

.section-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.section-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    background: var(--color-primary);
    color: var(--color-surface);
    border-radius: 50%;
    font-size: 0.85rem;
    font-weight: 500;
}

.section-title-text {
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--color-text);
}

.section-description {
    margin-left: 36px;
    color: var(--color-text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
}

.key-points {
    margin-left: 36px;
    margin-top: var(--spacing-sm);
}

.key-points ul {
    list-style: none;
    padding-left: 0;
}

.key-points li {
    position: relative;
    padding-left: var(--spacing-lg);
    margin-bottom: var(--spacing-xs);
    color: var(--color-text-secondary);
    font-size: 0.9rem;
}

.key-points li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--color-accent);
    font-weight: bold;
}

/* Chat Styles */
.chat-container {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
}

.chat-messages {
    min-height: 400px;
    max-height: 600px;
    overflow-y: auto;
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    background: var(--color-bg-secondary);
    border-radius: var(--radius-md);
}

.message {
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    max-width: 85%;
    animation: slideIn var(--transition-base);
}

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

.message.user {
    background: var(--color-primary);
    color: var(--color-surface);
    margin-left: auto;
}

.message.assistant {
    background: var(--color-surface);
    color: var(--color-text);
    box-shadow: var(--shadow-sm);
}

.message-content {
    line-height: 1.7;
}

.message-content p {
    margin-bottom: var(--spacing-sm);
}

.message-content p:last-child {
    margin-bottom: 0;
}

/* Markdown Styles */
.message-content h1,
.message-content h2,
.message-content h3 {
    font-family: var(--font-family-serif);
    color: var(--color-primary);
    margin: var(--spacing-md) 0 var(--spacing-sm);
}

.message-content h1 { font-size: 1.5rem; }
.message-content h2 { font-size: 1.3rem; }
.message-content h3 { font-size: 1.1rem; }

.message-content ul,
.message-content ol {
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

.message-content li {
    margin-bottom: var(--spacing-xs);
}

.message-content code {
    background: var(--color-bg-secondary);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 0.9em;
}

.message-content pre {
    background: var(--color-bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin: var(--spacing-sm) 0;
}

.message-content pre code {
    background: none;
    padding: 0;
}

.message-content blockquote {
    border-left: 3px solid var(--color-primary);
    padding-left: var(--spacing-md);
    margin: var(--spacing-sm) 0;
    color: var(--color-text-secondary);
    font-style: italic;
}

/* Suggested Questions */
.suggested-questions {
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--color-bg-secondary);
    border-radius: var(--radius-md);
}

.suggested-questions h4 {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-sm);
}

.question-btn {
    display: block;
    width: 100%;
    text-align: left;
    padding: var(--spacing-sm) var(--spacing-md);
    margin-bottom: var(--spacing-xs);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text);
    font-size: 0.9rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.question-btn:hover {
    border-color: var(--color-primary);
    background: var(--color-hover);
}

.question-btn i {
    margin-right: var(--spacing-xs);
    color: var(--color-primary);
}

/* Chat Input */
.chat-input-container {
    display: flex;
    gap: var(--spacing-sm);
    align-items: flex-end;
}

#chatInput {
    flex: 1;
    padding: var(--spacing-md);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-family: var(--font-family-sans);
    font-size: var(--font-size-base);
    color: var(--color-text);
    background: var(--color-surface);
    resize: none;
    transition: border-color var(--transition-fast);
}

#chatInput:focus {
    outline: none;
    border-color: var(--color-primary);
}

.send-btn {
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--color-primary);
    color: var(--color-surface);
    border: none;
    border-radius: var(--radius-md);
    font-size: 1.2rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.send-btn:hover {
    background: var(--color-primary-dark);
    transform: translateY(-2px);
}

.send-btn:active {
    transform: translateY(0);
}

/* Image Generation */
.image-gen-container {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
}

.input-section {
    margin-bottom: var(--spacing-lg);
}

#imagePrompt {
    width: 100%;
    padding: var(--spacing-md);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-family: var(--font-family-sans);
    font-size: var(--font-size-base);
    color: var(--color-text);
    background: var(--color-surface);
    resize: vertical;
    margin-bottom: var(--spacing-md);
    transition: border-color var(--transition-fast);
}

#imagePrompt:focus {
    outline: none;
    border-color: var(--color-primary);
}

.generate-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    background: var(--color-primary);
    color: var(--color-surface);
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.generate-btn:hover {
    background: var(--color-primary-dark);
    transform: translateY(-2px);
}

.generate-btn i {
    font-size: 1.2rem;
}

.image-result {
    min-height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-bg-secondary);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-md);
}

.image-result img {
    max-width: 100%;
    border-radius: var(--radius-md);
}

.export-section {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
}

.export-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--color-bg-secondary);
    color: var(--color-text);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.export-btn:hover {
    border-color: var(--color-primary);
    background: var(--color-hover);
}

/* History */
.history-tabs {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

.history-tab {
    flex: 1;
    padding: var(--spacing-md);
    background: var(--color-bg-secondary);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text);
    font-size: 0.95rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.history-tab:hover {
    border-color: var(--color-primary);
    background: var(--color-hover);
}

.history-tab.active {
    border-color: var(--color-primary);
    background: var(--color-primary);
    color: var(--color-surface);
}

.history-list {
    display: none;
}

.history-list.active {
    display: block;
}

.history-item {
    background: var(--color-surface);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.history-item:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.history-item-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
}

.history-item-time {
    font-size: 0.85rem;
    color: var(--color-text-tertiary);
}

.history-item-content {
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
}

/* Footer */
.footer {
    position: fixed;
    bottom: var(--icp-height);
    left: 0;
    right: 0;
    height: var(--footer-height);
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    box-shadow: 0 -4px 12px rgba(0, 0, 0, 0.08);
    z-index: 90;
    backdrop-filter: blur(10px);
}

.footer-nav {
    display: flex;
    justify-content: space-around;
    align-items: center;
    height: 100%;
    max-width: 600px;
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

.footer-btn {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    background: transparent;
    border: none;
    color: var(--color-text-secondary);
    font-size: 0.75rem;
    cursor: pointer;
    transition: all var(--transition-base);
    flex: 1;
    border-radius: var(--radius-sm);
}

.footer-btn::after {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 3px;
    background: var(--color-primary);
    border-radius: 0 0 3px 3px;
    transition: width var(--transition-base);
}

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

.footer-btn.active {
    color: var(--color-primary);
    font-weight: 500;
}

.footer-btn.active::after {
    width: 60%;
}

.footer-btn i {
    font-size: 1.5rem;
    transition: transform var(--transition-fast);
}

.footer-btn:active i {
    transform: scale(0.9);
}

.footer-btn span {
    font-family: var(--font-family-sans);
}

/* ICP Footer */
.icp-footer {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: var(--icp-height);
    background: var(--color-bg-secondary);
    border-top: 1px solid var(--color-border);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 89;
}

.icp-content {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.7rem;
    color: var(--color-text-tertiary);
}

.icp-content span {
    opacity: 0.7;
}

.icp-separator {
    opacity: 0.4;
    margin: 0 var(--spacing-xs);
}

.icp-footer a {
    font-size: 0.7rem;
    color: var(--color-text-tertiary);
    text-decoration: none;
    opacity: 0.7;
    transition: all var(--transition-fast);
}

.icp-footer a:hover {
    opacity: 1;
    color: var(--color-primary);
}

/* Footer Mobile Optimization */
@media (max-width: 480px) {
    .icp-content {
        font-size: 0.65rem;
        gap: 4px;
    }

    .icp-separator {
        margin: 0 2px;
    }
}

/* Selection Popup */
.selection-popup {
    position: fixed;
    display: none;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    padding: var(--spacing-xs);
    z-index: 1000;
}

.selection-popup.active {
    display: flex;
    gap: var(--spacing-xs);
}

.popup-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    background: transparent;
    border: none;
    color: var(--color-text);
    font-size: 0.85rem;
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    white-space: nowrap;
}

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

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    flex-direction: column;
    gap: var(--spacing-md);
}

.loading-overlay.active {
    display: flex;
}

.loading-spinner {
    width: 48px;
    height: 48px;
    border: 4px solid rgba(255, 255, 255, 0.2);
    border-top-color: var(--color-surface);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-overlay p {
    color: var(--color-surface);
    font-size: 1rem;
}

/* Guide & About Content */
.guide-content,
.about-content {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
}

.guide-section,
.about-section {
    margin-bottom: var(--spacing-xl);
}

.guide-section:last-child,
.about-section:last-child {
    margin-bottom: 0;
}

.guide-section h3,
.about-section h3 {
    font-family: var(--font-family-serif);
    font-size: 1.2rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.guide-section p,
.about-section p {
    color: var(--color-text-secondary);
    line-height: 1.8;
    margin-bottom: var(--spacing-sm);
}

.guide-section ul {
    list-style: none;
    padding-left: 0;
}

.guide-section li {
    position: relative;
    padding-left: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    color: var(--color-text-secondary);
    line-height: 1.7;
}

.guide-section li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--color-primary);
    font-weight: bold;
}

.guide-section strong {
    color: var(--color-text);
}

.qr-code-section {
    margin-top: var(--spacing-lg);
    text-align: center;
}

.qr-code-section h4 {
    font-size: 1rem;
    color: var(--color-text);
    margin-bottom: var(--spacing-md);
}

.qr-code {
    max-width: 200px;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
}

/* Responsive Design */
@media (max-width: 768px) {
    .site-title {
        font-size: 0.95rem;
    }

    .nav-btn span {
        display: none;
    }

    .nav-btn {
        padding: var(--spacing-sm);
    }

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

    .hero-subtitle {
        font-size: 1rem;
    }

    .page-title {
        font-size: 1.4rem;
    }

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

    .settings-panel {
        max-width: 100%;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing-md: 12px;
        --spacing-lg: 20px;
        --spacing-xl: 28px;
    }

    .hero-title {
        font-size: 1.3rem;
    }

    .theme-grid {
        grid-template-columns: 1fr;
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Chapter Reader Styles */
.chapter-reader-content {
    max-width: 900px;
    margin: 0 auto;
}

.chapter-nav-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--color-border);
}

.back-to-outline-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text);
    font-size: 0.9rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.back-to-outline-btn:hover {
    background: var(--color-hover);
    border-color: var(--color-primary);
}

.chapter-info {
    font-family: var(--font-family-serif);
    font-size: 0.95rem;
    color: var(--color-text-secondary);
}

.chapter-article {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-sm);
    line-height: 1.9;
}

.loading-chapter {
    text-align: center;
    padding: var(--spacing-xl);
    color: var(--color-text-secondary);
}

.loading-chapter i {
    font-size: 2rem;
    color: var(--color-primary);
    animation: spin 1s linear infinite;
}

/* Markdown Content Styles */
.chapter-article h1 {
    font-family: var(--font-family-serif);
    font-size: 2rem;
    font-weight: 500;
    color: var(--color-primary);
    margin: var(--spacing-xl) 0 var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--color-border);
    line-height: 1.4;
}

.chapter-article h2 {
    font-family: var(--font-family-serif);
    font-size: 1.6rem;
    font-weight: 500;
    color: var(--color-primary);
    margin: var(--spacing-lg) 0 var(--spacing-md);
    line-height: 1.4;
}

.chapter-article h3 {
    font-family: var(--font-family-serif);
    font-size: 1.3rem;
    font-weight: 500;
    color: var(--color-text);
    margin: var(--spacing-lg) 0 var(--spacing-md);
    line-height: 1.4;
}

.chapter-article h4 {
    font-family: var(--font-family-serif);
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--color-text);
    margin: var(--spacing-md) 0 var(--spacing-sm);
}

.chapter-article p {
    margin-bottom: var(--spacing-md);
    text-align: justify;
    color: var(--color-text);
}

.chapter-article blockquote {
    margin: var(--spacing-lg) 0;
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--color-bg-secondary);
    border-left: 4px solid var(--color-primary);
    border-radius: var(--radius-md);
    color: var(--color-text-secondary);
    font-style: italic;
}

.chapter-article blockquote p {
    margin-bottom: 0;
}

.chapter-article ul,
.chapter-article ol {
    margin: var(--spacing-md) 0;
    padding-left: var(--spacing-xl);
}

.chapter-article li {
    margin-bottom: var(--spacing-sm);
    line-height: 1.8;
}

.chapter-article strong {
    color: var(--color-text);
    font-weight: 500;
}

.chapter-article em {
    color: var(--color-text-secondary);
}

.chapter-article hr {
    margin: var(--spacing-xl) 0;
    border: none;
    border-top: 1px solid var(--color-border);
}

.chapter-article table {
    width: 100%;
    margin: var(--spacing-lg) 0;
    border-collapse: collapse;
    font-size: 0.95rem;
}

.chapter-article th {
    background: var(--color-bg-secondary);
    padding: var(--spacing-md);
    text-align: left;
    font-weight: 500;
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.chapter-article td {
    padding: var(--spacing-md);
    border: 1px solid var(--color-border);
}

.chapter-article code {
    background: var(--color-bg-secondary);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 0.9em;
    color: var(--color-primary);
}

.chapter-article pre {
    background: var(--color-bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin: var(--spacing-md) 0;
}

.chapter-article pre code {
    background: none;
    padding: 0;
    color: var(--color-text);
}

/* Chapter Images Styles */
.chapter-article img {
    width: 100%;
    max-width: 100%;
    height: auto;
    display: block;
    margin: var(--spacing-xl) auto;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.chapter-article img:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* Responsive image styles */
@media (max-width: 768px) {
    .chapter-article img {
        margin: var(--spacing-lg) auto;
        border-radius: var(--radius-sm);
    }
}

@media (max-width: 480px) {
    .chapter-article img {
        margin: var(--spacing-md) 0;
        width: 100%;
    }
}

.chapter-nav-bottom {
    display: flex;
    justify-content: space-between;
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
}

.chapter-nav-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--color-primary);
    color: var(--color-surface);
    border: none;
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.chapter-nav-btn:hover {
    background: var(--color-primary-dark);
    transform: translateY(-2px);
}

.chapter-nav-btn i {
    font-size: 1.1rem;
}

/* Concept Illustration Styles */
.concept-illustration {
    margin: var(--spacing-xl) auto;
    max-width: 800px;
    text-align: center;
    padding: var(--spacing-lg);
    background: linear-gradient(135deg, var(--color-bg) 0%, var(--color-bg-secondary) 100%);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
}

.concept-illustration:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--color-primary);
}

.concept-illustration svg {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 0 auto;
    cursor: pointer;
    transition: transform var(--transition-base);
}

.concept-illustration svg:hover {
    transform: scale(1.02);
}

.concept-illustration-caption {
    margin-top: var(--spacing-md);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--color-border);
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
    text-align: center;
}

.concept-illustration-title {
    font-family: var(--font-family-serif);
    font-size: 1rem;
    font-weight: 500;
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

.illustration-loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-xl);
    color: var(--color-text-secondary);
}

.illustration-loading i {
    font-size: 2rem;
    color: var(--color-primary);
    animation: spin 1s linear infinite;
}

.illustration-loading p {
    font-size: 0.9rem;
    margin: 0;
}

.illustration-error {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-lg);
    color: var(--color-text-tertiary);
    font-size: 0.9rem;
}

.illustration-error i {
    font-size: 1.5rem;
    opacity: 0.5;
}

/* Responsive - Mobile */
@media (max-width: 768px) {
    .concept-illustration {
        max-width: 100%;
        padding: var(--spacing-md);
        margin: var(--spacing-lg) 0;
    }

    .concept-illustration-caption {
        font-size: 0.85rem;
    }
}

/* Print Styles */
@media print {
    .header,
    .footer,
    .icp-footer,
    .settings-panel,
    .selection-popup,
    .chapter-nav-top,
    .chapter-nav-bottom {
        display: none !important;
    }

    .main-content {
        margin-top: 0;
    }

    body {
        padding-bottom: 0;
    }

    .chapter-article {
        box-shadow: none;
    }

    .concept-illustration {
        page-break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ddd;
    }
}

/* AI提示卡片样式 */
.ai-tips-card {
    background: linear-gradient(135deg, var(--color-primary-light) 0%, var(--color-bg-secondary) 100%);
    border: 1px solid var(--color-primary);
    border-left: 4px solid var(--color-primary);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-lg);
    overflow: hidden;
    animation: slideDown 0.3s ease;
}

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

.ai-tips-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-primary);
    color: white;
    font-weight: 500;
}

.ai-tips-header i:first-child {
    font-size: 1.1rem;
}

.ai-tips-header span {
    flex: 1;
}

.ai-tips-close {
    background: transparent;
    border: none;
    color: white;
    cursor: pointer;
    padding: var(--spacing-xs);
    border-radius: var(--radius-sm);
    transition: background var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.ai-tips-close:hover {
    background: rgba(255, 255, 255, 0.2);
}

.ai-tips-content {
    padding: var(--spacing-md);
}

.ai-tips-content p {
    margin: 0 0 var(--spacing-sm) 0;
    color: var(--color-text);
    font-size: 0.95rem;
}

.ai-tips-content ul {
    margin: var(--spacing-sm) 0;
    padding-left: 0;
    list-style: none;
}

.ai-tips-content li {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-xs) 0;
    color: var(--color-text-secondary);
    font-size: 0.9rem;
}

.ai-tips-content li i {
    color: var(--color-primary);
    font-size: 1rem;
    width: 20px;
    text-align: center;
}

.ai-tips-note {
    background: var(--color-surface);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-sm);
    margin-top: var(--spacing-md) !important;
    font-size: 0.85rem !important;
    color: var(--color-text-secondary) !important;
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-sm);
}

.ai-tips-note i {
    color: var(--color-accent);
    margin-top: 2px;
}

.ai-tips-content a {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 500;
}

.ai-tips-content a:hover {
    text-decoration: underline;
}