/* ========== 全局样式 ========== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #fff;
}

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

/* ========== 导航栏 ========== */
.navbar {
    background-color: #1e2a36;
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 1rem 0;
}

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

.logo {
    color: white;
    font-size: 1.5rem;
    font-weight: bold;
    text-decoration: none;
}

.logo i {
    margin-right: 8px;
}

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.nav-links a {
    color: white;
    text-decoration: none;
    transition: 0.3s;
}

.nav-links a:hover,
.nav-links a.active {
    color: #ffc107;
}

/* 移动端菜单 */
.menu-toggle {
    display: none;
    background: none;
    border: none;
    color: white;
    font-size: 1.5rem;
    cursor: pointer;
}

@media (max-width: 768px) {
    .menu-toggle {
        display: block;
    }
    .nav-links {
        display: none;
        width: 100%;
        flex-direction: column;
        align-items: center;
        gap: 1rem;
        margin-top: 1rem;
    }
    .nav-links.show {
        display: flex;
    }
}

/* ========== 按钮 ========== */
.btn {
    display: inline-block;
    padding: 10px 24px;
    border-radius: 30px;
    text-decoration: none;
    font-weight: 500;
    transition: 0.3s;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background-color: #005c99;
    color: white;
}

.btn-primary:hover {
    background-color: #004466;
    transform: translateY(-2px);
}

.btn-outline {
    border: 2px solid #005c99;
    color: #005c99;
    background: transparent;
}

.btn-outline:hover {
    background-color: #005c99;
    color: white;
}

/* ========== 首页 Hero ========== */
.hero {
    background: linear-gradient(rgba(0,0,0,0.6), rgba(0,0,0,0.6)), url('https://picsum.photos/id/104/1920/600') center/cover no-repeat;
    color: white;
    text-align: center;
    padding: 120px 0;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
}

/* ========== 通用区块 ========== */
.section-title {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 2rem;
    position: relative;
    padding-bottom: 15px;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background-color: #005c99;
    margin: 12px auto 0;
}

/* 卡片网格 */
.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin: 40px 0;
}

.card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.08);
    transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.12);
}

.card img {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.card-body {
    padding: 1.5rem;
}

.card-title {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
}

/* ========== 页脚 ========== */
.footer {
    background-color: #1e2a36;
    color: #ccc;
    padding: 40px 0 20px;
    margin-top: 60px;
}

.footer .container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.footer h4 {
    color: white;
    margin-bottom: 1rem;
}

.footer a {
    color: #ccc;
    text-decoration: none;
}

.footer a:hover {
    color: white;
}

.copyright {
    text-align: center;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid #444;
    font-size: 0.85rem;
}

/* ========== 产品页面筛选 ========== */
.filter-buttons {
    text-align: center;
    margin-bottom: 30px;
}

.filter-btn {
    background: #f0f0f0;
    border: none;
    padding: 8px 20px;
    margin: 0 5px;
    border-radius: 30px;
    cursor: pointer;
    transition: 0.3s;
}

.filter-btn.active,
.filter-btn:hover {
    background-color: #005c99;
    color: white;
}

/* ========== 联系表单 ========== */
.contact-form {
    background: #f9f9f9;
    padding: 2rem;
    border-radius: 12px;
}

.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 6px;
    font-family: inherit;
}

.form-group textarea {
    resize: vertical;
}

/* ========== 关于页面 ========== */
.about-section {
    padding: 60px 0;
}

.stats {
    display: flex;
    justify-content: space-around;
    text-align: center;
    margin: 40px 0;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: bold;
    color: #005c99;
}