/* ================= 1. 基础重置 ================= */
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: "Helvetica Neue", Helvetica, Arial, "Microsoft Yahei", sans-serif;
    background-color: #f9f9f9; color: #333; overflow-x: hidden;
}
a { text-decoration: none; transition: all 0.3s ease; }
ul { list-style: none; }

/* ================= 通用区块标题 ================= */
.section-header { text-align: center; padding: 80px 5% 40px; background: #fff; }
.section-header h2 { font-size: 28px; font-weight: 300; letter-spacing: 2px; color: #111; margin-bottom: 10px; }
.section-header p { color: #888; font-size: 14px; letter-spacing: 1px; text-transform: uppercase; }

/* ================= 2. 导航栏样式 ================= */
header {
    background: rgba(0, 0, 0, 0.8); backdrop-filter: blur(10px);
    position: fixed; top: 0; width: 100%; z-index: 100;
    display: flex; justify-content: space-between; align-items: center;
    padding: 0 5%; height: 60px;
}
.logo { color: #ffffff; font-size: 20px; font-weight: 300; letter-spacing: 2px; }
.nav-1 { display: flex; align-items: center; }
.nav-1 > li > a {
    display: block; padding: 0 20px; height: 60px; line-height: 60px;
    color: #cccccc; font-size: 14px; letter-spacing: 1px; cursor: pointer;
}
.nav-1 > li:hover > a { color: #ffffff; }

.lang-switch {
    background: transparent; border: 1px solid #ccc; color: #ccc;
    padding: 4px 10px; border-radius: 4px; cursor: pointer;
    font-size: 12px; margin-left: 15px; transition: 0.3s;
}
.lang-switch:hover { background: #fff; color: #000; }

/* ================= 3. 底部样式 ================= */
.footer { background-color: #111111; color: #ffffff; padding: 60px 5%; text-align: center; font-size: 14px; color: #888; }
.footer-content { max-width: 1200px; margin: 0 auto; display: flex; flex-direction: column; gap: 20px; }
.footer-links { display: flex; justify-content: center; gap: 30px; margin-bottom: 15px; flex-wrap: wrap; }
.footer-links a { color: #cccccc; font-size: 14px; letter-spacing: 1px; transition: color 0.3s; }
.footer-links a:hover { color: #ffffff; }
.footer-slogan { font-size: 12px; color: #555555; letter-spacing: 2px; text-transform: uppercase; margin-top: 5px; }

/* ================= 4. 公共自适应 (移动端) ================= */
@media (max-width: 768px) {
    header { flex-direction: column; height: auto; padding: 10px 0; }
    .nav-1 { width: 100%; justify-content: center; flex-wrap: wrap; margin-top: 10px; }
    .nav-1 > li > a { height: 40px; line-height: 40px; padding: 0 10px; }
    .footer-links { gap: 15px; }
}

/* ================= 高级渐变色占位符样式 ================= */
        .gradient-box {
            width: 100%;
            display: block;
        }
        /* 适配产品卡的尺寸 */
        .product-card .gradient-box {
            height: 250px;
            margin-bottom: 20px;
        }
        /* 适配底部研发实力的尺寸 */
        .feature-image .gradient-box {
            height: 400px;
            border-radius: 8px;
            box-shadow: 0 15px 30px rgba(0,0,0,0.1);
        }

        /* 为翎航科技定制的 5 款硬核渐变色 */
        /* 1. 钛金灰 (高级工业感) */
        .grad-titanium { background: linear-gradient(135deg, #434343 0%, #000000 100%); }
        /* 2. 赛博蓝 (底层代码/航天感) */
        .grad-cyber-blue { background: linear-gradient(135deg, #0062ff 0%, #00195a 100%); }
        /* 3. 极光青 (新能源/农业生态感) */
        .grad-aurora { background: linear-gradient(135deg, #00f2fe 0%, #4facfe 100%); }
        /* 4. 霓虹紫 (载人飞行/未来城市感) */
        .grad-neon-purple { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); }
        /* 5. 引擎红 (动力/极限性能感) */
        .grad-engine-red { background: linear-gradient(135deg, #ff0844 0%, #ffb199 100%); }