:root {
    /* HP 风格设计系统 - 企业级色板 */
    --colors-primary: #024ad8;       /* HP 电力蓝 - 唯一信号色 */
    --colors-primary-deep: #0e3191;
    --colors-ink: #1a1a1a;          /* 墨黑 - 标题与正文 */
    --colors-ink-soft: #292929;
    --colors-canvas: #ffffff;       /* 纯白画布 */
    --colors-cloud: #f7f7f7;        /* 云灰 - 交替板块 */
    --colors-fog: #e8e8e8;          /* 雾灰 - 细分边框 */
    --colors-steel: #c2c2c2;        /* 钢灰 - 辅助信息 */
    --colors-on-ink: #ffffff;
    
    /* 间距系统 (8px 为基准) */
    --spacing-xs: 8px;
    --spacing-md: 16px;
    --spacing-xl: 24px;
    --spacing-xxl: 32px;
    --spacing-section: 80px;

    /* 形状规范 */
    --rounded-md: 4px;              /* 交互元素：按钮、输入框 */
    --rounded-xl: 16px;             /* 容器元素：卡片、图片 */
    
    /* 深度感知 */
    --shadow-soft: 0 4px 12px rgba(26, 26, 26, 0.05);
    
    --container-width: 1366px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-font-smoothing: antialiased;
}

body {
    /* 字体栈：西文优先 Inter，中文优先系统内置黑体 */
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background-color: var(--colors-canvas);
    color: var(--colors-ink);
    line-height: 1.6;
}

/* 标题层级 - 严格执行 500 字重规范 */
h1, h2, h3, h4 {
    font-weight: 500;
    line-height: 1.2;
    letter-spacing: -0.01em;
}

.display-xxl { font-size: clamp(2.5rem, 5vw, 4rem); }
.display-xl { font-size: clamp(2rem, 4vw, 3.2rem); }
.display-md { font-size: 2rem; }
.display-sm { font-size: 1.5rem; }
.body-md { font-size: 1rem; font-weight: 400; color: #3d3d3d; }
.caption-md { font-size: 0.875rem; font-weight: 400; color: #636363; }

/* 顶部公用条 */
.utility-strip {
    background: var(--colors-ink);
    color: var(--colors-on-ink);
    height: 40px;
    font-size: 12px;
    display: flex;
    align-items: center;
}

.utility-strip .container {
    display: flex;
    justify-content: flex-end;
    gap: 32px;
    width: 100%;
}

.utility-strip span {
    cursor: pointer;
    opacity: 0.8;
    transition: opacity 0.2s;
}

.utility-strip span:hover {
    opacity: 1;
}

/* 导航系统 */
nav {
    background: var(--colors-canvas);
    height: 72px;
    border-bottom: 1px solid var(--colors-fog);
    position: sticky;
    top: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
}

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 40px;
    width: 100%;
}

.nav-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-size: 22px;
    font-weight: 700;
    color: var(--colors-ink);
    text-decoration: none;
    letter-spacing: -0.5px;
    display: flex;
    align-items: center;
    gap: 6px;
}

.logo .brand-zh {
    color: var(--colors-primary);
    font-weight: 500;
}

.nav-links {
    display: flex;
    gap: 40px;
}

.nav-links a {
    text-decoration: none;
    color: var(--colors-ink);
    font-weight: 400;
    font-size: 15px;
    transition: color 0.2s;
}

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

/* 按钮规范 - 硬朗 4px 圆角 */
.button-primary {
    background: var(--colors-primary);
    color: white;
    padding: 12px 32px;
    border-radius: var(--rounded-md);
    text-decoration: none;
    font-weight: 600;
    font-size: 14px;
    text-transform: uppercase;
    letter-spacing: 0.7px;
    border: none;
    display: inline-block;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: pointer;
    text-align: center;
}

.button-primary:hover {
    background: var(--colors-primary-deep);
    box-shadow: 0 4px 12px rgba(2, 74, 216, 0.2);
}

.button-outline {
    background: transparent;
    color: var(--colors-primary);
    border: 1px solid var(--colors-primary);
    padding: 12px 32px;
    border-radius: var(--rounded-md);
    text-decoration: none;
    font-weight: 600;
    font-size: 14px;
    text-transform: uppercase;
    letter-spacing: 0.7px;
    display: inline-block;
    transition: all 0.2s;
    text-align: center;
}

.button-outline:hover {
    background: rgba(2, 74, 216, 0.04);
}

/* 核心 Hero 区域 - 带有蓝色切角装饰 */
.hero-section {
    padding: 100px 0;
    position: relative;
    overflow: hidden;
}

.hero-card {
    background: var(--colors-canvas);
    border-radius: var(--rounded-xl);
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 60px;
    align-items: center;
    position: relative;
}

.hero-content {
    padding-left: 0;
}

.hero-image-container {
    position: relative;
    height: 520px;
    background: var(--colors-cloud);
    border-radius: var(--rounded-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: visible;
}

/* 蓝色切角装饰 - 纯几何风格 */
.chevron-decoration {
    position: absolute;
    width: 120px;
    height: 100%;
    background: var(--colors-primary);
    z-index: -1;
    transform: skewX(-20deg);
}

.chevron-right { right: -60px; }

/* 板块节奏感控制 */
.section-cloud { background: var(--colors-cloud); padding: var(--spacing-section) 0; }
.section-white { background: var(--colors-canvas); padding: var(--spacing-section) 0; }

/* 网格系统 */
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 32px; }

/* 产品卡片 - 16px 圆角 */
.card-product {
    background: var(--colors-canvas);
    border-radius: var(--rounded-xl);
    padding: 48px 40px;
    box-shadow: var(--shadow-soft);
    display: flex;
    flex-direction: column;
    height: 100%;
    transition: transform 0.3s cubic-bezier(0.2, 1, 0.3, 1);
}

.card-product:hover { transform: translateY(-8px); }

.card-product .icon { width: 56px; height: 56px; margin-bottom: 32px; display: block; }
.card-product h3 { font-size: 22px; margin-bottom: 16px; }

/* 价格卡片规范 */
.card-pricing {
    background: var(--colors-canvas);
    border-radius: var(--rounded-xl);
    padding: 56px 48px;
    box-shadow: var(--shadow-soft);
    border: 1px solid var(--colors-fog);
    display: flex;
    flex-direction: column;
}

.card-pricing.featured {
    border-top: 6px solid var(--colors-primary);
    transform: scale(1.04);
    z-index: 5;
}

.price-stamp {
    font-size: 56px;
    font-weight: 500;
    margin: 32px 0;
    letter-spacing: -2px;
}

.price-stamp span { font-size: 16px; color: var(--colors-steel); letter-spacing: 0; }

/* 底部收尾板块 - 墨黑基调 */
.help-band {
    background: var(--colors-ink);
    color: var(--colors-on-ink);
    padding: 80px 0;
    text-align: center;
}

footer {
    background: var(--colors-ink);
    color: var(--colors-on-ink);
    padding: 80px 0;
    border-top: 1px solid var(--colors-ink-soft);
}

.footer-grid { display: grid; grid-template-columns: 1.5fr repeat(4, 1fr); gap: 60px; }
.footer-col h4 { font-size: 15px; font-weight: 600; margin-bottom: 32px; color: white; }
.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 14px; }
.footer-col a { color: var(--colors-steel); text-decoration: none; font-size: 14px; transition: color 0.2s; }
.footer-col a:hover { color: white; }

/* 销售徽章 */
.badge-sale {
    background: #ff5050;
    color: white;
    padding: 4px 12px;
    border-radius: 2px;
    font-size: 12px;
    font-weight: 700;
    display: inline-block;
    margin-bottom: 24px;
    letter-spacing: 1px;
}

/* 响应式调整 */
@media (max-width: 1100px) {
    .grid-4 { grid-template-columns: repeat(2, 1fr); }
    .hero-card { grid-template-columns: 1fr; text-align: center; }
    .hero-image-container { height: 400px; }
    .chevron-decoration { display: none; }
    .footer-grid { grid-template-columns: repeat(2, 1fr); }
    .card-pricing.featured { transform: scale(1); }
}