:root {
    /* 颜色体系：矿盐白 + 工业灰 + 盐湖蓝 + 安全绿 */
    --color-primary: #0E7490; /* 盐湖蓝 */
    --color-secondary: #059669; /* 安全绿 */
    --color-ink: #1F2937; /* 深色正文 */
    --color-muted: #4B5563; /* 次级文字 */
    --color-accent: #F59E0B; /* 强调色（数据/高亮信息） */
    --color-surface: #FFFFFF;
    --color-surface-elevated: #F8FAFC;
    --color-border: #E5E7EB;
    --color-background-light: #F8FAFC; /* 兼容旧变量名 */
    --color-background-white: #FFFFFF; /* 兼容旧变量名 */
    --color-text-dark: #1F2937; /* 兼容旧变量名 */
    --color-text-light: #FFFFFF; /* 兼容旧变量名 */
    --color-divider: #D1D5DB;
    --color-hero-overlay: rgba(15, 23, 42, 0.45);

    /* 字体系统 */
    --font-family-main: "Alibaba PuHuiTi", "HarmonyOS Sans", "PingFang SC", "Microsoft YaHei", sans-serif;
    --font-family-heading: "Alibaba PuHuiTi", "HarmonyOS Sans", "PingFang SC", "Microsoft YaHei", sans-serif;
    --font-size-base: 16px;
    --font-size-h1: 2.6rem;
    --font-size-h2: 2rem;
    --font-size-h3: 1.5rem;
    --font-size-small: 0.9rem;

    /* 间距系统 (8pt 网格) */
    --spacing-xxs: 4px;
    --spacing-xs: 8px;
    --spacing-sm: 12px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 40px;
    --spacing-xxl: 64px;

    /* 形状与阴影 */
    --border-radius-sm: 4px;
    --border-radius: 8px;
    --border-radius-lg: 12px;
    --border-radius-base: 4px; /* 兼容旧变量名 */
    --border-radius-large: 12px; /* 兼容旧变量名 */
    --shadow-soft: 0 10px 30px rgba(0, 0, 0, 0.08);
    --shadow-card: 0 6px 18px rgba(15, 23, 42, 0.08);
    --shadow-strong: 0 12px 32px rgba(15, 23, 42, 0.15);
    --box-shadow-base: 0 6px 18px rgba(15, 23, 42, 0.08); /* 兼容旧变量名 */
    --box-shadow-card: 0 6px 18px rgba(15, 23, 42, 0.08); /* 兼容旧变量名 */
    --box-shadow-hover: 0 12px 32px rgba(15, 23, 42, 0.15); /* 兼容旧变量名 */

    /* 布局尺寸 */
    --max-width: 1280px;
    --topbar-height: 44px;
    --header-height: 72px;
}

/* 基础与排版 */
* { box-sizing: border-box; margin: 0; padding: 0; }

html {
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-ink);
    font-family: var(--font-family-main);
    background: var(--color-surface-elevated);
    scroll-behavior: smooth;
}

body {
    background: var(--color-surface-elevated);
    color: var(--color-ink);
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color 0.25s, opacity 0.25s;
}
a:hover { color: #0b5e73; }

img { max-width: 100%; height: auto; display: block; }

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-family-heading);
    color: #0b1728;
    line-height: 1.25;
    margin-bottom: var(--spacing-md);
}
h1 { font-size: var(--font-size-h1); }
h2 { font-size: var(--font-size-h2); }
h3 { font-size: var(--font-size-h3); }

p { margin-bottom: var(--spacing-md); color: var(--color-ink); }

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

[id] {
    scroll-margin-top: calc(var(--topbar-height) + var(--header-height) + 16px);
}

.page-main {
    padding-top: calc(var(--topbar-height) + var(--header-height) + var(--spacing-lg));
}

/* 按钮 */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 12px 18px;
    border-radius: var(--border-radius);
    font-weight: 600;
    border: 1px solid transparent;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
}
.btn-primary {
    background: linear-gradient(135deg, #0E7490, #0b5e73);
    color: #fff;
    box-shadow: var(--shadow-soft);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: var(--shadow-strong); }
.btn-secondary {
    background: #fff;
    color: var(--color-primary);
    border-color: var(--color-primary);
}
.btn-secondary:hover { background: #e0f2fe; }
.btn-ghost {
    background: transparent;
    color: var(--color-ink);
    border-color: var(--color-divider);
}
.btn-ghost:hover { border-color: var(--color-primary); color: var(--color-primary); }
.btn-large { padding: 14px 22px; font-size: 1.05rem; }

/* 顶部与导航 */
.header {
    position: fixed;
    inset: 0 0 auto 0;
    z-index: 1000;
    backdrop-filter: blur(6px);
}

.top-bar {
    height: var(--topbar-height);
    background: #0b1728;
    color: #E5E7EB;
    display: flex;
    align-items: center;
}
.utility-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-lg);
}
.brand-badge {
    background: rgba(255, 255, 255, 0.08);
    color: #E5E7EB;
    border: 1px solid rgba(255, 255, 255, 0.12);
    padding: 4px 10px;
    border-radius: var(--border-radius);
    font-weight: 600;
    letter-spacing: 0.5px;
}
.utility-text { margin-left: var(--spacing-sm); color: #cdd3db; }

.utility-right {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}
.site-search {
    display: inline-flex;
    align-items: center;
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.16);
    border-radius: var(--border-radius);
    padding: 4px 8px 4px 10px;
}
.site-search input {
    background: transparent;
    border: none;
    color: #fff;
    outline: none;
    width: 180px;
}
.site-search input::placeholder { color: #b6c2d1; }
.site-search button {
    border: none;
    background: transparent;
    color: #fff;
    cursor: pointer;
    padding: 4px;
}
.link-portal, .link-hotline {
    color: #E5E7EB;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xxs);
}
.link-hotline i { color: var(--color-secondary); }

.nav-shell {
    background: var(--color-surface);
    box-shadow: 0 6px 24px rgba(15, 23, 42, 0.08);
}
.nav-container {
    height: var(--header-height);
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.logo {
    font-size: 1.8rem;
    font-weight: 800;
    color: #0b1728;
    letter-spacing: 0.5px;
}
.logo span { color: var(--color-primary); }

.nav-menu {
    list-style: none;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}
.nav-item { position: relative; }
.nav-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 10px 14px;
    border-radius: var(--border-radius);
    color: var(--color-ink);
    font-weight: 600;
}
.nav-link:hover { background: #E0F2FE; color: #0b5e73; }

.dropdown-menu {
    display: none;
    position: absolute;
    top: calc(100% - 6px);
    left: 0;
    min-width: 180px;
    background: #fff;
    box-shadow: var(--shadow-card);
    list-style: none;
    padding: 10px 0;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    z-index: 100;
}
.nav-item:hover > .dropdown-menu { display: block; }
.dropdown-item a {
    display: block;
    padding: 10px 16px;
    color: var(--color-ink);
    font-weight: 500;
}
.dropdown-item a:hover { background: #E0F2FE; color: #0b5e73; }

.menu-toggle {
    display: none;
    font-size: 1.6rem;
    cursor: pointer;
}

/* 栅格与卡片 */
.grid {
    display: grid;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}
.grid-2-cols { grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); }
.grid-3-cols { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.grid-4-cols { grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); }

.card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-card);
}
.tag {
    display: inline-block;
    padding: 4px 10px;
    border-radius: var(--border-radius);
    background: #E0F2FE;
    color: #0b5e73;
    font-weight: 600;
    font-size: var(--font-size-small);
}

/* 首页模块 */
.hero {
    position: relative;
    min-height: 72vh;
    background-size: cover;
    background-position: center;
    display: flex;
    align-items: center;
    color: #fff;
}
.hero::before {
    content: "";
    position: absolute;
    inset: 0;
    background: var(--color-hero-overlay);
}
.hero-content {
    position: relative;
    z-index: 1;
    max-width: 720px;
    padding: var(--spacing-xl) var(--spacing-lg);
    backdrop-filter: blur(4px);
}
.hero h1 { color: #fff; text-shadow: 0 10px 30px rgba(0,0,0,0.35); }
.hero p { color: #E5E7EB; font-size: 1.05rem; }
.cta-group { display: flex; gap: var(--spacing-md); flex-wrap: wrap; margin-top: var(--spacing-lg); }
.hero-badges { display: flex; flex-wrap: wrap; gap: var(--spacing-sm); margin-top: var(--spacing-md); }
.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xxs);
    padding: 8px 12px;
    border-radius: var(--border-radius);
    background: rgba(255, 255, 255, 0.12);
    color: #fff;
    border: 1px solid rgba(255, 255, 255, 0.2);
    font-weight: 600;
}

.stat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    margin-top: -60px;
    position: relative;
    z-index: 2;
}
.stat-card {
    background: #fff;
    border: 1px solid var(--color-border);
    border-left: 4px solid var(--color-primary);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-strong);
}
.stat-number {
    font-size: 2rem;
    font-weight: 800;
    color: var(--color-primary);
}
.stat-label { color: var(--color-muted); }

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}
.section-title p { color: var(--color-muted); max-width: 780px; margin: var(--spacing-sm) auto 0; }

.product-system {
    background: #fff;
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-card);
    border: 1px solid var(--color-border);
}
.tab-nav {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}
.tab-btn {
    padding: 10px 16px;
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
    background: var(--color-surface-elevated);
    cursor: pointer;
    font-weight: 700;
    color: var(--color-muted);
    transition: all 0.2s ease;
}
.tab-btn.active {
    background: linear-gradient(135deg, #0E7490, #0b5e73);
    color: #fff;
    border-color: transparent;
    box-shadow: var(--shadow-soft);
}
.tab-pane { display: none; }
.tab-pane.active { display: block; }

.product-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: var(--spacing-lg);
}
.product-item {
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-card);
    transition: transform 0.25s ease, box-shadow 0.25s ease;
    height: 100%;
}
.product-item:hover { transform: translateY(-4px); box-shadow: var(--shadow-strong); }
.product-item img {
    height: 180px;
    object-fit: contain;
    margin: 0 auto var(--spacing-md);
}
.product-item h4 { color: #0b1728; }
.product-meta { color: var(--color-muted); font-size: var(--font-size-small); }

.process-lane {
    position: relative;
    padding: var(--spacing-xl);
    background: linear-gradient(120deg, rgba(14, 116, 144, 0.08), rgba(5, 150, 105, 0.06));
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--color-border);
}
.flow-track {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: var(--spacing-lg);
}
.flow-node {
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-card);
    position: relative;
    cursor: pointer;
    transition: transform 0.2s ease, border-color 0.2s ease;
}
.flow-node:hover { transform: translateY(-4px); border-color: var(--color-primary); }
.flow-node .node-step {
    width: 34px;
    height: 34px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: #E0F2FE;
    color: #0b5e73;
    font-weight: 800;
    margin-bottom: var(--spacing-sm);
}
.flow-detail {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: #fff;
    border: 1px dashed var(--color-border);
    border-radius: var(--border-radius);
    color: var(--color-muted);
    min-height: 120px;
}

.trace-box {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: var(--spacing-lg);
    align-items: center;
    background: linear-gradient(135deg, rgba(14, 116, 144, 0.12), rgba(5, 150, 105, 0.1));
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-card);
}
.trace-form {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}
.trace-form input {
    flex: 1 1 260px;
    padding: 12px;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    font-size: 1rem;
}
.trace-result {
    margin-top: var(--spacing-sm);
    color: var(--color-muted);
}

.news-columns {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
}
.news-block {
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-card);
}
.news-block h3 {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: #0b1728;
    border-left: 4px solid var(--color-primary);
    padding-left: var(--spacing-sm);
}
.news-item {
    border-bottom: 1px dashed var(--color-border);
    padding: var(--spacing-sm) 0;
}
.news-item:last-child { border-bottom: none; }
.news-item a { font-weight: 600; color: var(--color-ink); }
.news-item span {
    float: right;
    color: var(--color-muted);
    font-size: var(--font-size-small);
}

.timeline {
    display: flex;
    gap: var(--spacing-lg);
    overflow-x: auto;
    padding: var(--spacing-md) 0;
}
.timeline-step {
    min-width: 220px;
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-card);
    position: relative;
}
.timeline-step::before {
    content: "";
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 4px;
    height: 24px;
    background: var(--color-primary);
    border-radius: 2px;
}
.timeline-step h4 { margin-top: var(--spacing-md); }
.timeline-step p { color: var(--color-muted); }

/* 页脚 */
.footer {
    background: #0b1728;
    color: #E5E7EB;
    padding: var(--spacing-xxl) 0 var(--spacing-xl);
    margin-top: var(--spacing-xxl);
}
.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: var(--spacing-xl);
}
.footer h4 {
    color: #fff;
    margin-bottom: var(--spacing-md);
    letter-spacing: 0.5px;
}
.footer ul { list-style: none; }
.footer ul li a {
    color: #d1d5db;
    display: block;
    padding: 6px 0;
    font-size: var(--font-size-small);
}
.footer ul li a:hover { color: #fff; }
.footer .brand {
    font-weight: 800;
    font-size: 1.2rem;
}
.footer .hotline { color: #fff; font-weight: 700; }
.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-md);
    margin-top: var(--spacing-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.12);
    font-size: var(--font-size-small);
    color: #9CA3AF;
}

/* 响应式 */
@media (max-width: 1100px) {
    .trace-box { grid-template-columns: 1fr; }
}

@media (max-width: 992px) {
    .nav-menu {
        display: none;
        position: absolute;
        top: calc(var(--topbar-height) + var(--header-height));
        left: 0;
        width: 100%;
        background: #fff;
        flex-direction: column;
        box-shadow: var(--shadow-card);
        padding: var(--spacing-md);
    }
    .nav-menu.active { display: flex; }
    .nav-link { width: 100%; justify-content: space-between; }
    .dropdown-menu {
        position: static;
        box-shadow: none;
        border: none;
        padding-left: var(--spacing-md);
    }
    .menu-toggle { display: block; }
    .hero { min-height: 68vh; }
    .utility-container { flex-direction: column; align-items: flex-start; }
    .utility-right { width: 100%; justify-content: space-between; }
}

@media (max-width: 640px) {
    :root {
        --font-size-h1: 2.2rem;
        --font-size-h2: 1.6rem;
        --font-size-h3: 1.25rem;
    }
    .hero { min-height: 60vh; }
    .stat-grid { margin-top: var(--spacing-lg); }
    .cta-group { flex-direction: column; align-items: flex-start; }
    .page-main { padding-top: calc(var(--topbar-height) + var(--header-height) + var(--spacing-md)); }
}