/**
 * AISoBrand Global Style System
 * Version: 20260831
 * Philosophy: 简洁有力量 · 国际咨询机构调性
 * Reference: McKinsey whitespace + Accenture data-driven + BCG authority
 */

/* ===== 字体系统 ===== */
@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+SC:wght@400;600;700;900&display=swap');

:root {
    /* 品牌色 - 克制使用 */
    --primary: #D4743E;           /* 降饱和橙，用于关键点缀 */
    --primary-light: #E88B5A;     /*  hover 状态 */
    --primary-dark: #B85E2E;      /*  active/press */
    
    /* 中性色 */
    --text-dark: #1A1A2E;
    --text-body: #3D3D5C;
    --text-muted: #6B6B8A;
    --text-light: #9A9AB0;
    
    /* 背景色 - 两段式 */
    --bg-warm: #FFF9F5;           /* 暖白，前段用 */
    --bg-white: #FFFFFF;
    --bg-dark: #1A1A2E;           /* 深黑，后段用 */
    --bg-dark-elevated: #252540;
    
    /* 边框与分隔 */
    --border-light: rgba(0,0,0,0.06);
    --border-dark: rgba(255,255,255,0.08);
    
    /* 阴影 - 极克制 */
    --shadow-card: 0 2px 12px rgba(26,26,46,0.06);
    --shadow-hover: 0 8px 32px rgba(26,26,46,0.10);
    --shadow-dark: 0 4px 20px rgba(0,0,0,0.3);
    
    /* 圆角 - 小圆角体现专业 */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    
    /* 间距体系 - 大留白 */
    --space-xs: 8px;
    --space-sm: 16px;
    --space-md: 32px;
    --space-lg: 64px;
    --space-xl: 120px;
    --space-section: 140px;
    
    /* 字体栈 */
    --font-serif: 'Noto Serif SC', 'Songti SC', 'STSong', serif;
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', sans-serif;
    
    /* 容器 */
    --container-max: 1160px;
    --container-padding: 24px;
}

/* ===== 基础重置 ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    color: var(--text-dark);
    line-height: 1.7;
    background: var(--bg-white);
    overflow-x: hidden;
}

/* ===== 排版层级 - 衬线标题 ===== */
h1, h2, h3 {
    font-family: var(--font-serif);
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.2;
}

h1 {
    font-size: clamp(36px, 5vw, 56px);
    font-weight: 900;
}

h2 {
    font-size: clamp(28px, 3.5vw, 40px);
    font-weight: 700;
}

h3 {
    font-size: clamp(20px, 2.5vw, 24px);
    font-weight: 600;
}

p, li, td, th {
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.75;
    color: var(--text-body);
}

/* 正文强调 */
.lead {
    font-size: 18px;
    line-height: 1.8;
    color: var(--text-muted);
    max-width: 640px;
}

.caption {
    font-size: 13px;
    color: var(--text-light);
    letter-spacing: 0.02em;
}

/* ===== 容器 ===== */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

/* ===== 按钮体系 - 克制 ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 32px;
    font-size: 15px;
    font-weight: 600;
    text-decoration: none;
    border-radius: var(--radius-sm);
    transition: all 0.25s ease;
    cursor: pointer;
    border: none;
    font-family: var(--font-sans);
}

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

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

.btn-secondary {
    background: transparent;
    color: var(--text-dark);
    border: 1px solid var(--border-light);
}

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

.btn-ghost {
    background: transparent;
    color: var(--text-muted);
    padding: 12px 0;
    border-bottom: 1px solid transparent;
    border-radius: 0;
}

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

/* 深色背景按钮 */
.btn-dark .btn-primary {
    background: white;
    color: var(--text-dark);
}

.btn-dark .btn-primary:hover {
    background: var(--bg-warm);
}

/* ===== 区块系统 ===== */
.section {
    padding: var(--space-section) 0;
    position: relative;
}

.section-warm {
    background: var(--bg-warm);
}

.section-white {
    background: var(--bg-white);
}

.section-dark {
    background: var(--bg-dark);
    color: white;
}

.section-dark h1,
.section-dark h2,
.section-dark h3 {
    color: white;
}

.section-dark p,
.section-dark li {
    color: rgba(255,255,255,0.75);
}

/* 区块标题组 */
.section-header {
    text-align: center;
    margin-bottom: var(--space-lg);
}

.section-header h2 {
    margin-bottom: var(--space-sm);
}

.section-header .section-desc {
    font-size: 17px;
    color: var(--text-muted);
    max-width: 560px;
    margin: 0 auto;
}

/* 标签徽章 */
.tag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 0.03em;
}

.tag-primary {
    background: rgba(212,116,62,0.08);
    color: var(--primary);
}

.tag-dark {
    background: rgba(255,255,255,0.08);
    color: rgba(255,255,255,0.8);
    border: 1px solid var(--border-dark);
}

/* ===== 卡片系统 ===== */
.card {
    background: var(--bg-white);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-md);
    padding: var(--space-md);
    transition: all 0.3s ease;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
    border-color: rgba(212,116,62,0.15);
}

.card-dark {
    background: var(--bg-dark-elevated);
    border-color: var(--border-dark);
}

/* ===== 网格系统 ===== */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--space-md); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-md); }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--space-md); }

@media (max-width: 1024px) {
    .grid-4 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
    .section { padding: 80px 0; }
    :root { --container-padding: 16px; }
}

/* ===== 动效系统 - 统一克制 ===== */
.reveal {
    opacity: 0;
    transform: translateY(32px);
    transition: all 0.7s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }

/* Hero 渐入 */
@keyframes fadeUp {
    from { opacity: 0; transform: translateY(24px); }
    to { opacity: 1; transform: translateY(0); }
}

.hero-fade > * {
    opacity: 0;
    animation: fadeUp 0.7s ease forwards;
}

.hero-fade > *:nth-child(1) { animation-delay: 0.1s; }
.hero-fade > *:nth-child(2) { animation-delay: 0.2s; }
.hero-fade > *:nth-child(3) { animation-delay: 0.35s; }
.hero-fade > *:nth-child(4) { animation-delay: 0.5s; }

/* 分割线生长 */
@keyframes lineGrow {
    from { width: 0; }
    to { width: 48px; }
}

.section-divider {
    display: block;
    width: 0;
    height: 2px;
    background: var(--primary);
    margin: var(--space-sm) auto 0;
}

.section-divider.visible {
    animation: lineGrow 0.6s ease forwards;
}

/* 数字计数器 */
.counter {
    font-family: var(--font-serif);
    font-weight: 900;
    font-size: 40px;
    color: var(--primary);
}

.counter-dark {
    color: white;
}

/* ===== 客户 Logo 墙 ===== */
.logo-wall {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-lg);
    flex-wrap: wrap;
    padding: var(--space-md) 0;
    opacity: 0.5;
    filter: grayscale(100%);
    transition: all 0.3s ease;
}

.logo-wall:hover {
    opacity: 0.8;
}

.logo-wall img {
    height: 32px;
    width: auto;
    object-fit: contain;
    transition: all 0.3s ease;
}

.logo-wall img:hover {
    filter: grayscale(0%);
    opacity: 1;
}

/* ===== 品牌符号 SVG ===== */
.brand-symbol {
    display: inline-block;
    width: 32px;
    height: 32px;
    color: var(--primary);
}

.brand-symbol svg {
    width: 100%;
    height: 100%;
    fill: none;
    stroke: currentColor;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* ===== 导航栏覆盖 ===== */
.navbar-global {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 60px;
    background: rgba(255,255,255,0.92);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-light);
    z-index: 1000;
}

/* ===== 深色区域专用 ===== */
.dark-area .btn-secondary {
    border-color: var(--border-dark);
    color: rgba(255,255,255,0.8);
}

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

/* ===== 减弱动画偏好 ===== */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* ===== 打印样式 ===== */
@media print {
    .navbar, .footer, .btn, .reveal {
        display: none !important;
    }
    .section { padding: 20px 0; }
}