/* AI 学习指南 - 共享样式 */

/* ========== 基础设置 ========== */
@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@400;500;600;700;900&display=swap');

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

:root {
    --color-primary: #3b82f6;
    --color-primary-dark: #2563eb;
    --color-secondary: #8b5cf6;
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-danger: #ef4444;
    --color-pink: #ec4899;
    
    --color-blue-light: #dbeafe;
    --color-orange-light: #fef3c7;
    --color-green-light: #d1fae5;
    --color-pink-light: #fce7f3;
    
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    
    --bg-light: #f8fafc;
    --bg-white: #ffffff;
    --border-color: #e2e8f0;
    
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: var(--bg-light);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

.page-wrapper {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

a {
    text-decoration: none;
    color: inherit;
}

/* ========== 按钮样式 ========== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 15px;
    transition: all var(--transition-fast);
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    color: white;
    box-shadow: 0 4px 14px rgba(59, 130, 246, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(59, 130, 246, 0.5);
}

.btn-secondary {
    background: var(--bg-white);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

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

/* ========== 顶部导航 ========== */
.main-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 16px 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 20px;
    font-weight: 700;
    color: var(--text-primary);
}

.nav-logo i {
    font-size: 24px;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    gap: 32px;
}

.nav-links a {
    color: var(--text-secondary);
    font-weight: 500;
    transition: color var(--transition-fast);
}

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

/* ========== Hero 区域 ========== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 120px 24px 80px;
    position: relative;
    overflow: hidden;
}

.hero-content {
    text-align: center;
    max-width: 800px;
    position: relative;
    z-index: 10;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    background: var(--color-blue-light);
    color: var(--color-primary);
    border-radius: 50px;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 24px;
}

.hero h1 {
    font-size: 56px;
    font-weight: 900;
    line-height: 1.1;
    margin-bottom: 20px;
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--color-primary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 20px;
    color: var(--text-secondary);
    margin-bottom: 40px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-bottom: 60px;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 60px;
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 36px;
    font-weight: 900;
    color: var(--color-primary);
}

.stat-label {
    font-size: 14px;
    color: var(--text-muted);
}

/* 装饰卡片 */
.hero-decoration {
    position: absolute;
    inset: 0;
    pointer-events: none;
}

.floating-card {
    position: absolute;
    width: 60px;
    height: 60px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    box-shadow: var(--shadow-xl);
}

.floating-card i {
    color: white;
}

.card-1 {
    background: linear-gradient(135deg, #4285f4, #34a853);
    top: 20%;
    left: 10%;
    animation: float 6s ease-in-out infinite;
}

.card-2 {
    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    top: 30%;
    right: 15%;
    animation: float 8s ease-in-out infinite 1s;
}

.card-3 {
    background: linear-gradient(135deg, #ec4899, #f59e0b);
    bottom: 25%;
    left: 15%;
    animation: float 7s ease-in-out infinite 0.5s;
}

.card-4 {
    background: linear-gradient(135deg, #1e293b, #475569);
    bottom: 30%;
    right: 10%;
    animation: float 5s ease-in-out infinite 1.5s;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

/* ========== 模块概览 ========== */
.modules-section {
    padding: 100px 24px;
    max-width: 1200px;
    margin: 0 auto;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 40px;
    font-weight: 800;
    margin-bottom: 16px;
}

.section-header p {
    font-size: 18px;
    color: var(--text-secondary);
}

.modules-grid {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.module-card {
    display: flex;
    align-items: center;
    gap: 24px;
    padding: 28px;
    background: var(--bg-white);
    border-radius: var(--radius-xl);
    border: 2px solid var(--border-color);
    transition: all var(--transition-normal);
    cursor: pointer;
}

.module-card:hover {
    transform: translateX(8px);
    border-color: var(--color-primary);
    box-shadow: var(--shadow-xl);
}

.module-icon {
    width: 72px;
    height: 72px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    flex-shrink: 0;
}

.module-icon i {
    color: white;
}

.module-icon.blue {
    background: linear-gradient(135deg, #3b82f6, #2563eb);
}

.module-icon.orange {
    background: linear-gradient(135deg, #f59e0b, #d97706);
}

.module-icon.green {
    background: linear-gradient(135deg, #10b981, #059669);
}

.module-icon.pink {
    background: linear-gradient(135deg, #ec4899, #db2777);
}

.module-content {
    flex: 1;
}

.module-number {
    display: inline-block;
    font-size: 12px;
    font-weight: 700;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.module-content h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 8px;
}

.module-content p {
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.module-tags {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.module-tags span {
    padding: 4px 12px;
    background: var(--bg-light);
    border-radius: 50px;
    font-size: 12px;
    font-weight: 500;
    color: var(--text-secondary);
}

.module-arrow {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--bg-light);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    color: var(--text-muted);
    transition: all var(--transition-fast);
}

.module-card:hover .module-arrow {
    background: var(--color-primary);
    color: white;
    transform: translateX(4px);
}

/* ========== 关于部分 ========== */
.about-section {
    padding: 100px 24px;
    background: var(--bg-white);
}

.about-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.about-text h2 {
    font-size: 36px;
    font-weight: 800;
    margin-bottom: 20px;
}

.about-text p {
    font-size: 16px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 32px;
}

.about-features {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.feature {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 500;
}

.feature i {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    background: var(--color-blue-light);
    color: var(--color-primary);
    display: flex;
    align-items: center;
    justify-content: center;
}

.about-visual {
    display: flex;
    justify-content: center;
}

.visual-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
}

.grid-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    padding: 20px;
    background: var(--bg-light);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.grid-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.grid-item i {
    font-size: 32px;
    color: var(--color-primary);
}

.grid-item span {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-secondary);
}

/* ========== 页脚 ========== */
.main-footer {
    padding: 60px 24px;
    background: var(--text-primary);
    color: white;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    text-align: center;
}

.footer-brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 12px;
}

.footer-brand i {
    font-size: 24px;
    color: var(--color-primary);
}

.footer-content > p {
    color: var(--text-muted);
    margin-bottom: 24px;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 32px;
}

.footer-links a {
    color: var(--text-muted);
    font-size: 14px;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: white;
}

/* ========== 子页面通用样式 ========== */
.page-header {
    padding: 140px 24px 60px;
    text-align: center;
    background: linear-gradient(180deg, var(--bg-white) 0%, var(--bg-light) 100%);
}

.page-header h1 {
    font-size: 48px;
    font-weight: 800;
    margin-bottom: 16px;
}

.page-header p {
    font-size: 18px;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.page-content {
    padding: 60px 24px;
    max-width: 1000px;
    margin: 0 auto;
}

.content-section {
    margin-bottom: 60px;
}

.content-section h2 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 24px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.content-section h2 i {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
}

.content-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.info-card {
    padding: 24px;
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    transition: all var(--transition-fast);
}

.info-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.info-card h3 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.info-card p {
    color: var(--text-secondary);
    font-size: 14px;
    line-height: 1.7;
}

.code-block {
    background: #1e293b;
    border-radius: var(--radius-md);
    padding: 20px;
    overflow-x: auto;
    font-family: 'Fira Code', 'Consolas', monospace;
    font-size: 14px;
    line-height: 1.6;
    margin: 16px 0;
}

.code-block code {
    color: #e2e8f0;
}

.step-list {
    counter-reset: step;
}

.step-item {
    display: flex;
    gap: 20px;
    padding: 24px;
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    margin-bottom: 16px;
    transition: all var(--transition-fast);
}

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

.step-number {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--color-primary);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 14px;
    flex-shrink: 0;
}

.step-content h3 {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 8px;
}

.step-content p {
    color: var(--text-secondary);
    font-size: 14px;
    line-height: 1.7;
}

/* ========== 响应式设计 ========== */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 36px;
    }
    
    .hero-subtitle {
        font-size: 16px;
    }
    
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .hero-stats {
        gap: 30px;
    }
    
    .stat-number {
        font-size: 28px;
    }
    
    .nav-links {
        display: none;
    }
    
    .module-card {
        flex-direction: column;
        text-align: center;
    }
    
    .module-arrow {
        display: none;
    }
    
    .about-content {
        grid-template-columns: 1fr;
    }
    
    .visual-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-links {
        flex-wrap: wrap;
        gap: 16px;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 100px 16px 60px;
    }
    
    .hero h1 {
        font-size: 28px;
    }
    
    .modules-section {
        padding: 60px 16px;
    }
    
    .page-header {
        padding: 120px 16px 40px;
    }
    
    .page-header h1 {
        font-size: 32px;
    }
}