/* ========================================
   Nullab - 靠谱的技术服务
   Slate 岩板灰系 - 现代、专业、高级感
   ======================================== */

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

:root {
    /* 主色 - 克制深蓝 */
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --primary-subtle: #eff6ff;
    
    /* 文本 - Slate 岩石灰 */
    --text-main: #0f172a;   /* Slate 900 - 接近黑但有质感 */
    --text-body: #334155;   /* Slate 700 - 正文灰 */
    --text-muted: #64748b;  /* Slate 500 - 辅助灰 */
    
    /* 背景 - 极简冷淡 */
    --bg-page: #f8fafc;     /* Slate 50 - 极淡冷灰 */
    --bg-card: #ffffff;     /* 纯白卡片 */
    --bg-alt: #f1f5f9;      /* Slate 100 - 浅灰分隔 */
    
    /* 边框 */
    --border: #e2e8f0;      /* Slate 200 */
    --border-hover: #cbd5e1; /* Slate 300 */
    
    /* 阴影 - 柔和弥散 */
    --shadow-sm: 0 1px 2px 0 rgb(15 23 42 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(15 23 42 / 0.1), 0 2px 4px -2px rgb(15 23 42 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(15 23 42 / 0.1), 0 4px 6px -4px rgb(15 23 42 / 0.1);
    
    --radius: 16px;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased; /* 让字体更清晰 */
}

body {
    font-family: 'Noto Sans SC', system-ui, -apple-system, sans-serif;
    color: var(--text-body);
    line-height: 1.6;
    background: var(--bg-page);
    font-size: 16px;
}

/* 导航 */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    padding: 1.2rem 2rem;
    transition: all 0.3s ease;
}

.nav.scrolled {
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    padding: 0.8rem 2rem;
}

.nav-container {
    max-width: 1000px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.4rem;
    font-weight: 800;
    color: var(--text-main);
    text-decoration: none;
    letter-spacing: -0.5px;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 2.5rem;
}

.nav-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-links a:hover {
    color: var(--text-main);
}

.nav-cta {
    background: var(--text-main); /* 黑色按钮更高级 */
    color: white !important;
    padding: 0.6rem 1.4rem;
    border-radius: 100px;
    font-size: 0.9rem !important;
    transition: transform 0.2s !important;
}

.nav-cta:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

/* Hero */
.hero {
    min-height: 75vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 8rem 2rem 4rem;
    position: relative;
    overflow: hidden;
}

/* 增加一点点高级的背景装饰 */
.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    height: 100%;
    background: radial-gradient(circle, rgba(37,99,235,0.05) 0%, rgba(248,250,252,0) 70%);
    z-index: -1;
}

.hero-content {
    max-width: 720px;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 1.5rem;
    color: var(--text-main);
    letter-spacing: -1px;
}

.highlight {
    color: var(--primary);
    position: relative;
    white-space: nowrap;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-muted);
    margin-bottom: 2.5rem;
    line-height: 1.8;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-tags {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.8rem;
    margin-bottom: 3rem;
}

.tag {
    background: white;
    padding: 0.5rem 1.2rem;
    border-radius: 100px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-muted);
    border: 1px solid var(--border);
}

.btn-primary {
    display: inline-flex;
    align-items: center;
    background: var(--primary);
    color: white;
    padding: 1rem 2.5rem;
    border-radius: 100px;
    font-size: 1.1rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s ease;
    box-shadow: 0 4px 6px -1px rgba(37, 99, 235, 0.2);
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(37, 99, 235, 0.3);
}

/* Section 通用 */
.section-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 6rem 2rem;
}

.section-title {
    font-size: 2.25rem;
    font-weight: 800;
    text-align: center;
    margin-bottom: 1rem;
    color: var(--text-main);
    letter-spacing: -0.5px;
}

.section-subtitle {
    text-align: center;
    color: var(--text-muted);
    margin-bottom: 4rem;
    font-size: 1.1rem;
}

/* 服务卡片 */
.services {
    background: white; /* 纯白背景显干净 */
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 2rem;
}

.service-card {
    background: var(--bg-page); /* 卡片用浅灰，形成微妙反差 */
    border-radius: var(--radius);
    padding: 2rem;
    transition: all 0.3s ease;
    border: 1px solid transparent;
}

.service-card:hover {
    background: white;
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--border);
}

.service-card.special {
    background: var(--primary-subtle);
    border: 1px solid rgba(37,99,235,0.1);
}

.service-emoji {
    font-size: 2.5rem;
    margin-bottom: 1.2rem;
    display: block;
}

.service-card h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.8rem;
    color: var(--text-main);
}

.service-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.service-price {
    display: inline-block;
    background: white;
    padding: 0.4rem 0.8rem;
    border-radius: 6px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-main);
    box-shadow: var(--shadow-sm);
}

.service-card.special .service-price {
    background: rgba(255,255,255,0.6);
    color: var(--primary);
}

.price-note {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-top: 3rem;
    opacity: 0.8;
}

/* 评价 */
.reviews {
    background: var(--bg-page);
}

.reviews-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.review-card {
    background: white;
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
}

.review-content p {
    font-size: 1rem;
    color: var(--text-body);
    line-height: 1.8;
    margin-bottom: 1.5rem;
    font-style: italic;
}

.review-author {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--bg-alt);
}

.author-avatar {
    font-size: 2rem;
    background: var(--bg-alt);
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
}

.author-info {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.author-name {
    font-weight: 700;
    font-size: 0.95rem;
    color: var(--text-main);
}

.author-tag {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-weight: 500;
}

/* 为什么选我 */
.why-me {
    background: white;
}

.why-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 3rem;
    margin-top: 2rem;
}

.why-item {
    text-align: center;
}

.why-icon {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
    display: inline-block;
    background: var(--primary-subtle);
    width: 80px;
    height: 80px;
    line-height: 80px;
    border-radius: 24px;
}

.why-item h3 {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 0.8rem;
    color: var(--text-main);
}

.why-item p {
    font-size: 0.95rem;
    color: var(--text-muted);
}

/* 流程 */
.process {
    background: var(--bg-page);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.process-steps {
    display: flex;
    align-items: flex-start;
    justify-content: center;
    flex-wrap: wrap;
    gap: 2rem;
    position: relative;
}

.process-step {
    flex: 1;
    min-width: 200px;
    max-width: 240px;
    text-align: center;
    background: white;
    padding: 2rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
    position: relative;
    z-index: 1;
}

.step-num {
    width: 40px;
    height: 40px;
    background: var(--text-main);
    color: white;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 1.1rem;
    margin: 0 auto 1.5rem;
    box-shadow: var(--shadow-md);
}

.step-text h3 {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-main);
}

.process-arrow {
    display: none; /* 新设计不需要箭头 */
}

/* 联系 */
.contact {
    background: white;
    padding: 8rem 2rem;
}

.contact-box {
    text-align: center;
    max-width: 560px;
    margin: 0 auto;
    background: var(--text-main); /* 深色卡片 */
    color: white;
    padding: 3.5rem 2rem;
    border-radius: 24px;
    box-shadow: var(--shadow-lg);
}

.contact-box h2 {
    font-size: 2rem;
    margin-bottom: 1rem;
    font-weight: 800;
}

.contact-box > p {
    opacity: 0.8;
    margin-bottom: 2.5rem;
    font-size: 1.1rem;
}

.wechat-box {
    background: rgba(255,255,255,0.1);
    border: 1px solid rgba(255,255,255,0.2);
    border-radius: 16px;
    padding: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
    backdrop-filter: blur(10px);
}

.wechat-label {
    color: rgba(255,255,255,0.6);
    font-size: 0.9rem;
}

.wechat-id {
    font-size: 1.4rem;
    font-weight: 700;
    color: white;
    letter-spacing: 1px;
}

.copy-btn {
    background: white;
    color: var(--text-main);
    border: none;
    padding: 0.6rem 1.2rem;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.copy-btn:hover {
    background: var(--bg-alt);
}

.contact-tip {
    font-size: 0.9rem;
    opacity: 0.5;
}

/* Footer */
.footer {
    background: white;
    text-align: center;
    padding: 2rem;
    color: var(--text-muted);
    font-size: 0.9rem;
    border-top: 1px solid var(--border);
}

/* 响应式 */
@media (max-width: 768px) {
    .nav-links a:not(.nav-cta) {
        display: none;
    }
    
    .hero {
        min-height: auto;
        padding: 7rem 1.5rem 4rem;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .section-container {
        padding: 4rem 1.5rem;
    }
    
    .services-grid, .reviews-grid, .why-grid {
        grid-template-columns: 1fr;
    }
    
    .wechat-box {
        flex-direction: column;
        gap: 1rem;
    }
    
    .copy-btn {
        width: 100%;
    }
}