/* ========== 主题变量（品牌主色取自 logo：#1d2d64） ========== */
:root {
    --brand: #1d2d64;
    --brand-dark: #14204a;
    --brand-deep: #16224e;
    --brand-light: #2a3f80;
    --brand-soft: rgba(29, 45, 100, 0.08);
    --ink: #141c3a;
    --text: #3a4256;
    --muted: #6b7280;
    --line: #d8ddea;
    --surface: #ffffff;
    --bg: #e9edf6;
    --bg-alt: #e2e7f3;
    --on-dark: #ffffff;
    --on-dark-muted: #c3cbde;
    --shadow: 0 2px 12px rgba(20, 28, 58, 0.08);
    --shadow-hover: 0 12px 30px rgba(29, 45, 100, 0.22);
}

/* ========== CSS Reset & Base ========== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: "Microsoft Yahei", "PingFang SC", "Helvetica Neue", sans-serif;
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ========== 导航栏 ========== */
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 999;
    padding: 20px 0;
    background-color: var(--brand);
    box-shadow: 0 2px 14px rgba(13, 20, 48, 0.28);
    transition: all 0.3s ease;
}

header.transparent {
    background-color: rgba(29, 45, 100, 0.82);
    box-shadow: none;
}

header.scrolled {
    background-color: var(--brand);
    box-shadow: 0 2px 14px rgba(13, 20, 48, 0.28);
}

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

.logo {
    font-size: 24px;
    font-weight: 700;
    color: var(--on-dark);
    text-decoration: none;
}

.logo img {
    display: block;
    height: 64px;
    width: auto;
}

.footer-brand {
    display: inline-block;
    margin-bottom: 14px;
}

.footer-brand img {
    display: block;
    height: 56px;
    width: auto;
}

.nav-list {
    display: flex;
    gap: 40px;
    list-style: none;
}

.nav-list li a {
    color: rgba(255, 255, 255, 0.82);
    text-decoration: none;
    font-size: 15px;
    font-weight: 400;
    transition: color 0.3s;
}

.nav-list li a:hover,
.nav-list li a.active {
    color: var(--on-dark);
}

/* ========== 页面头部（子页共用） ========== */
.page-header {
    padding: 140px 0 70px;
    text-align: center;
    background: linear-gradient(135deg, var(--brand) 0%, var(--brand-deep) 55%, #0f1838 100%);
    color: var(--on-dark);
}

.page-header h1 {
    font-size: 36px;
    margin-bottom: 12px;
    color: var(--on-dark);
}

.page-header p {
    color: var(--on-dark-muted);
    max-width: 600px;
    margin: 0 auto;
}

/* ========== 通用区块 ========== */
.section {
    padding: 80px 0;
}

.section-title {
    font-size: 28px;
    text-align: center;
    margin-bottom: 60px;
    font-weight: 600;
    color: var(--ink);
}

.section-subtitle {
    font-size: 24px;
    margin-bottom: 40px;
    font-weight: 600;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--line);
    color: var(--ink);
}

/* ========== 通用按钮 ========== */
.btn-primary {
    display: inline-block;
    padding: 12px 32px;
    background-color: var(--brand);
    color: #fff;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
}

.btn-primary:hover {
    background-color: var(--brand-dark);
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(29, 45, 100, 0.35);
}

.btn-outline {
    display: inline-block;
    padding: 12px 32px;
    border: 1px solid var(--brand);
    color: var(--brand);
    border-radius: 6px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
}

.btn-outline:hover {
    background-color: var(--brand);
    color: #fff;
    transform: translateY(-2px);
}

/* 深色区域上的次要按钮 */
.on-dark .btn-outline,
.banner .btn-outline {
    border-color: rgba(255, 255, 255, 0.7);
    color: #fff;
}

.on-dark .btn-outline:hover,
.banner .btn-outline:hover {
    background-color: #fff;
    color: var(--brand);
}

/* ========== 通用卡片悬停效果 ========== */
.card-hover {
    background: var(--surface);
    border: 1px solid #e3e8f4;
    border-radius: 16px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
}

.card-hover:hover {
    transform: translateY(-4px);
    border-color: rgba(29, 45, 100, 0.25);
    box-shadow: var(--shadow-hover);
}

/* ========== 页脚 ========== */
footer {
    background: var(--brand-deep);
    padding: 60px 0 30px;
    margin-top: 40px;
    color: var(--on-dark-muted);
}

.footer-wrap {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 40px;
}

.footer-col {
    flex: 1;
    min-width: 200px;
}

.footer-col h3 {
    font-size: 18px;
    margin-bottom: 20px;
    color: var(--on-dark);
}

.footer-col p,
.footer-col a {
    color: var(--on-dark-muted);
    font-size: 14px;
    text-decoration: none;
    line-height: 2;
}

.footer-col a:hover {
    color: var(--on-dark);
}

.copyright {
    text-align: center;
    margin-top: 50px;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.14);
    color: #8f9ab5;
    font-size: 13px;
}

/* ========== 滚动渐入动画 ========== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease;
}

.fade-in.show {
    opacity: 1;
    transform: translateY(0);
}

/* ========== 占位图片样式 ========== */
.placeholder-img {
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

/* ========== Banner 水平滚动背景 ========== */
.banner-scroll-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: 0 center;
    background-repeat: repeat-x;
    animation: bgScrollLeft 40s linear infinite;
    z-index: 0;
}

@keyframes bgScrollLeft {
    0% { background-position: 0 center; }
    100% { background-position: -1920px center; }
}

/* ========== 自适应 ========== */
@media(max-width: 992px) {
    .section-title {
        font-size: 24px;
    }
    .page-header h1 {
        font-size: 32px;
    }
    .nav-list {
        display: none;
    }
}

@media(max-width: 576px) {
    .section-title {
        font-size: 22px;
    }
    .page-header {
        padding: 110px 0 45px;
    }
    .page-header h1 {
        font-size: 28px;
    }
    .logo img {
        height: 48px;
    }
    .footer-brand img {
        height: 44px;
    }
}