/* ================================
   Claude Cowork 自然美学样式表
   ================================ */

:root {
    /* 核心色调：自然、柔和、高级 */
    --primary-h: 256;
    --primary-s: 85%;
    --primary-l: 65%;
    
    --primary-color: hsl(var(--primary-h), var(--primary-s), var(--primary-l));
    --primary-dark: hsl(var(--primary-h), var(--primary-s), 55%);
    --primary-soft: hsl(var(--primary-h), var(--primary-s), 96%);
    
    --accent-color: #FF8F70; /* 暖色点缀，如晨曦 */
    
    /* 文字颜色：柔和的深灰，非纯黑 */
    --text-primary: #2D3342;
    --text-secondary: #5F6B7C;
    --text-light: #8896AB;
    
    /* 背景体系 */
    --bg-body: #F8F9FA; /* 极淡的灰白，像纸张 */
    --bg-surface: rgba(255, 255, 255, 0.7);
    --bg-surface-solid: #FFFFFF;
    
    /* 装饰性元素 */
    --glass-border: 1px solid rgba(255, 255, 255, 0.6);
    --surface-border: 1px solid rgba(230, 232, 236, 0.6);
    
    /* 阴影：弥散、柔和 */
    --shadow-xs: 0 2px 8px rgba(0, 0, 0, 0.02);
    --shadow-sm: 0 4px 16px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 8px 30px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 20px 60px rgba(45, 51, 66, 0.08);
    --shadow-glow: 0 0 40px rgba(107, 78, 230, 0.15);
    
    /* 倒角：更自然的曲线 */
    --radius-sm: 12px;
    --radius-md: 20px;
    --radius-lg: 32px;
    --radius-full: 999px;
    
    --max-width: 1140px;
    --transition: all 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
}

/* 基础重置与排版 */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
    height: 100%;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    line-height: 1.7;
    color: var(--text-primary);
    background-color: var(--bg-body);
    /* 自然光感背景 */
    background-image: 
        radial-gradient(circle at 10% 5%, hsla(var(--primary-h), 80%, 90%, 0.6) 0%, transparent 40%),
        radial-gradient(circle at 90% 10%, hsla(30, 80%, 92%, 0.6) 0%, transparent 40%),
        radial-gradient(circle at 50% 50%, hsla(var(--primary-h), 60%, 97%, 0.4) 0%, transparent 60%),
        radial-gradient(circle at 90% 90%, hsla(200, 70%, 95%, 0.6) 0%, transparent 40%);
    background-attachment: fixed;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 32px;
}

/* ================================
   玻璃拟态导航栏
   ================================ */
.header {
    position: fixed;
    top: 20px; /* 悬浮感 */
    left: 50%;
    transform: translateX(-50%);
    width: calc(100% - 48px);
    max-width: var(--max-width);
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: var(--glass-border);
    border-radius: var(--radius-full);
    z-index: 1000;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.header.scrolled {
    top: 10px;
    padding: 0 10px;
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
    padding: 0 24px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

.logo img {
    border-radius: 10px;
    box-shadow: 0 4px 10px rgba(107, 78, 230, 0.2);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 8px;
    background: rgba(0,0,0,0.03);
    padding: 4px;
    border-radius: var(--radius-full);
}

.nav-menu a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    padding: 8px 20px;
    border-radius: var(--radius-full);
    transition: var(--transition);
    font-size: 0.95rem;
    display: block;
}

.nav-menu a:hover {
    color: var(--text-primary);
    background: #fff;
    box-shadow: var(--shadow-xs);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: 5px;
}

.mobile-menu-btn span {
    width: 20px;
    height: 2px;
    background-color: var(--text-primary);
    transition: var(--transition);
}

/* ================================
   Hero 区域：大气、留白
   ================================ */
.hero {
    padding: 200px 0 120px;
    text-align: center;
    position: relative;
}

.hero h1 {
    font-size: clamp(2.5rem, 6vw, 4rem);
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 24px;
    letter-spacing: -0.03em;
    background: linear-gradient(135deg, var(--text-primary) 30%, var(--primary-color) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: fadeUp 1s cubic-bezier(0.2, 0.8, 0.2, 1) forwards;
}

.hero-subtitle {
    font-size: clamp(1.1rem, 2.5vw, 1.35rem);
    color: var(--text-secondary);
    max-width: 680px;
    margin: 0 auto 48px;
    line-height: 1.6;
    animation: fadeUp 1s cubic-bezier(0.2, 0.8, 0.2, 1) 0.2s forwards;
    opacity: 0;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
    opacity: 0;
    animation: fadeUp 1s cubic-bezier(0.2, 0.8, 0.2, 1) 0.4s forwards;
}

/* 按钮美学：微渐变、柔光 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 16px 40px;
    font-size: 1.05rem;
    font-weight: 600;
    text-decoration: none;
    border-radius: var(--radius-full);
    transition: var(--transition);
    cursor: pointer;
    letter-spacing: 0.01em;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: #fff;
    box-shadow: 0 10px 20px rgba(107, 78, 230, 0.25);
    border: 1px solid rgba(255,255,255,0.1);
}

.btn-primary:hover {
    transform: translateY(-2px) scale(1.02);
    box-shadow: 0 15px 30px rgba(107, 78, 230, 0.35);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.6);
    backdrop-filter: blur(10px);
    color: var(--text-primary);
    border: 1px solid rgba(255, 255, 255, 0.8);
}

.btn-secondary:hover {
    background: #fff;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* ================================
   内容区块通用
   ================================ */
.section {
    padding: 100px 0;
    position: relative;
    z-index: 1;
}

.section-alt {
    position: relative;
}

/* 装饰性背景球 */
.section-alt::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 50% 50%, rgba(255,255,255,0.8), transparent);
    z-index: -1;
}

.section h2 {
    font-size: clamp(2rem, 4vw, 2.75rem);
    font-weight: 700;
    text-align: center;
    margin-bottom: 64px;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

.content-grid {
    max-width: 860px;
    margin: 0 auto;
}

/* ================================
   Bento Grid / 卡片设计
   ================================ */
.features-grid, .use-cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 32px;
}

.feature-card, .use-case {
    background: var(--bg-surface);
    backdrop-filter: blur(20px);
    border: var(--surface-border);
    border-radius: var(--radius-lg);
    padding: 40px;
    transition: var(--transition);
    height: 100%;
    display: flex;
    flex-direction: column;
}

.feature-card:hover, .use-case:hover {
    transform: translateY(-8px);
    background: var(--bg-surface-solid);
    box-shadow: var(--shadow-lg);
    border-color: transparent;
}

.feature-icon {
    width: 64px;
    height: 64px;
    border-radius: 18px;
    background: var(--primary-soft);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    margin-bottom: 24px;
    color: var(--primary-color);
    transition: var(--transition);
}

.feature-card:hover .feature-icon {
    transform: scale(1.1) rotate(5deg);
    background: var(--primary-color);
    color: #fff;
    box-shadow: 0 10px 20px rgba(107, 78, 230, 0.2);
}

.feature-card h3, .use-case h3 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.feature-card h4, .use-case h4 {
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--primary-color);
    background: var(--primary-soft);
    display: inline-block;
    padding: 4px 12px;
    border-radius: var(--radius-full);
    margin-bottom: 16px;
    font-weight: 600;
    align-self: flex-start;
}

.feature-card p, .use-case p {
    color: var(--text-secondary);
    font-size: 1.05rem;
    line-height: 1.7;
    margin-bottom: 0;
    flex-grow: 1;
}

/* Use Case 特殊样式 - 更像是一张张卡片 */
.use-case {
    border-left: none;
    position: relative;
    overflow: hidden;
}

.use-case::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 6px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    opacity: 0;
    transition: var(--transition);
}

.use-case:hover::before {
    opacity: 1;
}

/* ================================
   步骤设计：流动的连接
   ================================ */
.steps-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 40px;
    position: relative;
}

.step {
    background: #fff;
    border-radius: var(--radius-lg);
    padding: 40px;
    border: 1px solid rgba(0,0,0,0.03);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    position: relative;
    z-index: 2;
}

.step:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.step-number {
    font-size: 4rem;
    font-weight: 900;
    color: rgba(107, 78, 230, 0.08); /* 巨大水印式数字 */
    position: absolute;
    top: 20px;
    right: 30px;
    line-height: 1;
    z-index: -1;
    transition: var(--transition);
}

.step:hover .step-number {
    color: rgba(107, 78, 230, 0.15);
    transform: scale(1.1);
}

.step h3 {
    margin-bottom: 12px;
    font-size: 1.25rem;
}

/* ================================
   FAQ：优雅的手风琴
   ================================ */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    background: #fff;
    border-radius: var(--radius-md);
    border: 1px solid rgba(0,0,0,0.03);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    overflow: hidden;
}

.faq-item:hover {
    box-shadow: var(--shadow-md);
    transform: scale(1.01);
}

.faq-item summary {
    padding: 24px 32px;
    cursor: pointer;
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--text-primary);
    display: flex;
    justify-content: space-between;
    align-items: center;
    list-style: none;
}

.faq-item summary::-webkit-details-marker {
    display: none;
}

.faq-item summary::after {
    content: '+';
    font-weight: 300;
    font-size: 1.5rem;
    color: var(--primary-color);
    transition: var(--transition);
}

.faq-item[open] summary::after {
    transform: rotate(45deg);
    color: var(--accent-color);
}

.faq-item[open] summary {
    border-bottom: 1px solid rgba(0,0,0,0.03);
}

.faq-item p {
    padding: 24px 32px;
    color: var(--text-secondary);
    background: var(--bg-body);
}

/* ================================
   CTA 区域：沉浸式
   ================================ */
.cta-section {
    margin: 80px 30px;
    background: linear-gradient(120deg, var(--primary-color), #8B6FFF);
    border-radius: var(--radius-lg);
    text-align: center;
    padding: 100px 24px;
    color: #fff;
    position: relative;
    overflow: hidden;
    box-shadow: 0 30px 60px -15px rgba(107, 78, 230, 0.4);
}

/* 装饰纹理 */
.cta-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.cta-section .container {
    position: relative;
    z-index: 2;
}

.cta-section h2 {
    color: #fff;
    margin-bottom: 24px;
    font-size: 2.5rem;
}

.cta-section p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.25rem;
    max-width: 600px;
    margin: 0 auto 48px;
}

.cta-buttons .btn-primary {
    background: #fff;
    color: var(--primary-color);
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
    border: none;
}

.cta-buttons .btn-primary:hover {
    background: #fff;
    transform: translateY(-3px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.2);
}

.cta-buttons .btn-secondary {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.4);
    color: #fff;
}

.cta-buttons .btn-secondary:hover {
    background: rgba(255, 255, 255, 0.2);
    border-color: #fff;
}

/* ================================
   Footer：极简
   ================================ */
.footer {
    background: #fff;
    padding: 80px 0 40px;
    border-top: 1px solid rgba(0,0,0,0.03);
}

.footer-brand {
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-bottom: 24px;
}

.footer-note {
    color: var(--text-light);
    margin-bottom: 40px;
}

.footer-bottom {
    border-top: 1px solid rgba(0,0,0,0.05);
    padding-top: 32px;
}

.footer-bottom p {
    color: var(--text-light);
}

/* ================================
   动画定义
   ================================ */
@keyframes fadeUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ================================
   响应式调整
   ================================ */
@media (max-width: 768px) {
    .header {
        width: calc(100% - 32px);
        top: 16px;
    }

    .nav-menu {
        position: absolute;
        top: 72px;
        left: 0;
        right: 0;
        flex-direction: column;
        background: #fff;
        padding: 16px;
        border-radius: 24px;
        box-shadow: var(--shadow-lg);
        transform: translateY(-20px);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition);
        gap: 0;
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .nav-menu a {
        padding: 16px;
        border-radius: 12px;
    }

    .mobile-menu-btn {
        display: flex;
    }

    .hero {
        padding: 160px 0 80px;
    }

    .hero h1 {
        font-size: 2.25rem;
    }
    
    .cta-section {
        margin: 40px 16px;
        padding: 60px 20px;
        border-radius: 32px;
    }
    
    .feature-card, .step, .use-case {
        padding: 30px 24px;
    }
}