/* ========== 全局基础样式 ========== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: "Microsoft YaHei", sans-serif;
    letter-spacing: 0.3px;
}

body {
    background: #0A1430;  /* 深蓝科技底色 */
    color: #ffffff;
    line-height: 1.75;
}

/* 居中限制宽度 */
.section {
    padding: 80px 20px;
    max-width: 1200px;
    margin: auto;
}

.center {
    text-align: center;
}

.max-600 {
    max-width: 600px;
    margin: 20px auto;
}

/* ========== 头部导航栏 ========== */
header {
    width: 100%;
    position: fixed;
    top: 0;
    left: 0;
    padding: 18px 40px;
    background: rgba(10, 20, 48, 0.85);
    display: flex;
    justify-content: space-between;
    align-items: center;
    backdrop-filter: blur(8px);
    z-index: 999;
    border-bottom: 1px solid rgba(255,255,255,0.08);
}

.logo {
    font-size: 20px;
    font-weight: 600;
    color: #fff;
}

nav a {
    color: #ffffff;
    margin-left: 24px;
    font-size: 15px;
    text-decoration: none;
    transition: 0.2s;
}

nav a:hover {
    color: #4DA3FF;
}

/* ========== 顶部横幅 ========== */
.hero {
    padding-top: 150px;
    padding-bottom: 120px;
    text-align: center;
    background: linear-gradient(180deg, #0F1C45 0%, #0A1430 100%);
}

.hero h1 {
    font-size: 42px;
    font-weight: 700;
    margin-bottom: 20px;
}

.hero p {
    font-size: 18px;
    max-width: 700px;
    margin: auto;
    opacity: 0.85;
}

/* 按钮通用样式 */
.btn {
    display: inline-block;
    background: #357BFF;
    padding: 13px 28px;
    color: #fff;
    text-decoration: none;
    border-radius: 6px;
    margin-top: 28px;
    font-size: 15px;
    transition: 0.25s;
}

.btn:hover {
    background: #1F5DE6;
}

.btn.small {
    padding: 10px 20px;
    font-size: 14px;
}

/* ========== 深色区域背景（统一设计语言） ========== */
.dark {
    background: #0F1C45;
    border-top: 1px solid rgba(255,255,255,0.06);
    border-bottom: 1px solid rgba(255,255,255,0.06);
}

/* ========== 核心产品卡片 ========== */
.card {
    background: rgba(255,255,255,0.04);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 12px;
    padding: 40px;
    margin-top: 40px;
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

.card h3 {
    margin-top: 30px;
    margin-bottom: 10px;
    font-size: 20px;
}

.card p {
    opacity: 0.9;
}

/* ========== 三列网格 ========== */
.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 22px;
    margin-top: 40px;
}

/* 白底卡片（亮色） */
.box-light {
    background: rgba(255,255,255,0.08);
    padding: 30px;
    border-radius: 10px;
    border: 1px solid rgba(255,255,255,0.12);
}

.box-light h3 {
    margin-bottom: 12px;
}

/* 深色盒子（场景应用） */
.box {
    background: rgba(255,255,255,0.03);
    padding: 32px;
    border-radius: 10px;
    border: 1px solid rgba(255,255,255,0.08);
}

/* ========== 联系我们 ========== */
#contact p {
    margin: 10px 0;
}

/* ========== 页脚 ========== */
footer {
    text-align: center;
    padding: 25px 10px;
    color: #cfcfcf;
    font-size: 14px;
    margin-top: 60px;
    border-top: 1px solid rgba(255,255,255,0.08);
}