/* ==========================================================================
   全局变量与基础重置
   ========================================================================== */
:root {
    --primary-color: #1e3a8a;      /* 高级深蓝 */
    --primary-light: #7ba3c6;      /* 雾霾蓝/冰蓝 */
    --bg-color: #fbfbfc;           /* 奶白/极浅灰背景 */
    --white: #ffffff;
    --text-main: #1f2937;          /* 沉稳深灰 */
    --text-muted: #4b5563;         /* 柔和次级文字 */
    --border-color: #e5e7eb;
    --card-shadow: 0 8px 24px rgba(30, 58, 138, 0.06); /* 带有主色调的轻微阴影 */
    --transition: all 0.3s ease;
}

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

body {
    font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-main);
    background-color: var(--bg-color);
    -webkit-font-smoothing: antialiased;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

ul {
    list-style: none;
}

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

/* ==========================================================================
   导航栏 Header
   ========================================================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(8px);
    z-index: 1000;
    transition: var(--transition);
    border-bottom: 1px solid transparent;
}

.header.scrolled {
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    border-bottom: 1px solid var(--border-color);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary-color);
    letter-spacing: 1px;
}

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

.nav-link {
    font-size: 15px;
    font-weight: 500;
    color: var(--text-muted);
}

.nav-link:hover, .nav-link.active {
    color: var(--primary-color);
}

.menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    color: var(--text-main);
    cursor: pointer;
}

/* ==========================================================================
   公共组件 (按钮、页面头部)
   ========================================================================== */
.btn {
    display: inline-block;
    padding: 12px 28px;
    background-color: var(--primary-color);
    color: var(--white);
    border-radius: 4px;
    font-size: 15px;
    font-weight: 500;
    border: 1px solid var(--primary-color);
}

.btn:hover {
    background-color: #172d6d;
    color: var(--white);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(30, 58, 138, 0.2);
}

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

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

.page-header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-light) 100%);
    padding: 140px 0 80px;
    text-align: center;
    color: var(--white);
}

.page-header h1 {
    font-size: 36px;
    margin-bottom: 16px;
    font-weight: 600;
}

.page-header p {
    font-size: 16px;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto;
}

.section-title {
    text-align: center;
    font-size: 28px;
    font-weight: 600;
    margin-bottom: 40px;
    color: var(--text-main);
}

/* ==========================================================================
   首页特定模块
   ========================================================================== */
.hero {
    height: 100vh;
    min-height: 600px;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, #1e3a8a 0%, #2a5298 100%);
    color: var(--white);
    text-align: center;
    padding-top: 70px;
}

.hero h1 {
    font-size: 42px;
    margin-bottom: 24px;
    font-weight: 700;
}

.hero h2 {
    font-size: 22px;
    font-weight: 400;
    margin-bottom: 20px;
    opacity: 0.9;
}

.hero p {
    font-size: 16px;
    max-width: 700px;
    margin: 0 auto 40px;
    line-height: 1.8;
    color: var(--bg-color);
}

.section-padding {
    padding: 80px 0;
}

.about-preview {
    background-color: var(--white);
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.about-content p {
    font-size: 16px;
    color: var(--text-muted);
    margin-bottom: 30px;
    line-height: 1.8;
}

/* 卡片网格布局 */
.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.card {
    background: var(--white);
    padding: 40px 30px;
    border-radius: 8px;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 30px rgba(30, 58, 138, 0.1);
}

.card-icon {
    width: 48px;
    height: 48px;
    background-color: rgba(30, 58, 138, 0.05);
    color: var(--primary-color);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    margin-bottom: 20px;
}

.card h3 {
    font-size: 20px;
    margin-bottom: 16px;
    color: var(--text-main);
}

.card p {
    color: var(--text-muted);
    font-size: 15px;
}

.cta-section {
    text-align: center;
    background-color: var(--white);
    border-top: 1px solid var(--border-color);
}

.cta-section p {
    font-size: 18px;
    margin-bottom: 24px;
    color: var(--text-main);
}

/* ==========================================================================
   业务介绍流程
   ========================================================================== */
.process-list {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    position: relative;
    padding-top: 20px;
}

.process-list::before {
    content: '';
    position: absolute;
    top: 35px;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--border-color);
    z-index: 1;
}

.process-item {
    flex: 1;
    text-align: center;
    position: relative;
    z-index: 2;
    padding: 0 10px;
}

.process-step {
    width: 32px;
    height: 32px;
    background-color: var(--primary-color);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
    font-weight: bold;
    box-shadow: 0 0 0 6px var(--bg-color);
}

.process-item h4 {
    margin-bottom: 8px;
    color: var(--text-main);
}

.process-item p {
    font-size: 14px;
    color: var(--text-muted);
}

/* ==========================================================================
   页脚 Footer
   ========================================================================== */
.footer {
    background-color: #111827;
    color: #9ca3af;
    padding: 60px 0 20px;
    text-align: center;
}

.footer h3 {
    color: var(--white);
    font-size: 18px;
    margin-bottom: 12px;
}

.footer p {
    margin-bottom: 12px;
    font-size: 14px;
}

.footer-bottom {
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid #374151;
    font-size: 13px;
}

.footer-bottom a {
    color: var(--primary-light);
}

.footer-bottom a:hover {
    color: var(--white);
}

/* ==========================================================================
   响应式设计
   ========================================================================== */
@media (max-width: 992px) {
    .grid-3, .grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }
    .process-list {
        flex-direction: column;
    }
    .process-list::before {
        top: 0;
        left: 25px;
        width: 2px;
        height: 100%;
    }
    .process-item {
        display: flex;
        text-align: left;
        margin-bottom: 30px;
        align-items: flex-start;
    }
    .process-step {
        margin: 0 20px 0 0;
        flex-shrink: 0;
        box-shadow: 0 0 0 6px var(--bg-color);
    }
}

@media (max-width: 768px) {
    .menu-toggle {
        display: block;
    }
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background-color: var(--white);
        flex-direction: column;
        align-items: center;
        padding-top: 40px;
        transition: var(--transition);
        box-shadow: 0 10px 15px rgba(0,0,0,0.05);
    }
    .nav-menu.active {
        left: 0;
    }
    .grid-3, .grid-4 {
        grid-template-columns: 1fr;
    }
    .hero h1 {
        font-size: 32px;
    }
    .page-header {
        padding: 100px 0 60px;
    }
    .section-padding {
        padding: 50px 0;
    }
}