/* ========== 通用样式 ========== */
:root {
    --primary-color: #1a5f7a;
    --secondary-color: #159895;
    --accent-color: #57c5b6;
    --dark-color: #002b5b;
    --light-color: #f8f9fa;
    --text-color: #333;
    --text-light: #666;
    --gradient-primary: linear-gradient(135deg, #1a5f7a 0%, #159895 100%);
    --gradient-dark: linear-gradient(135deg, #002b5b 0%, #1a5f7a 100%);
    --shadow-sm: 0 2px 10px rgba(0,0,0,0.1);
    --shadow-md: 0 5px 20px rgba(0,0,0,0.15);
    --shadow-lg: 0 10px 40px rgba(0,0,0,0.2);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Microsoft YaHei', 'Segoe UI', Tahoma, sans-serif;
    color: var(--text-color);
    line-height: 1.6;
    overflow-x: hidden;
}

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

img {
    max-width: 100%;
    height: auto;
}

/* ========== 导航栏 ========== */
.navbar {
    background: rgba(255,255,255,0.98) !important;
    box-shadow: var(--shadow-sm);
    padding: 0.8rem 0;
    transition: var(--transition);
}

.navbar.scrolled {
    padding: 0.5rem 0;
    box-shadow: var(--shadow-md);
}

.navbar-brand {
    font-weight: 700;
    font-size: 1.5rem;
    color: var(--primary-color) !important;
}

.navbar-brand span {
    color: var(--secondary-color);
}

.nav-link {
    font-weight: 500;
    color: var(--text-color) !important;
    padding: 0.5rem 1rem !important;
    position: relative;
    margin: 0 0.2rem;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: var(--transition);
    transform: translateX(-50%);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 80%;
}

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

/* 语言切换按钮 */
.lang-switch {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-left: 1rem;
}

.lang-btn {
    padding: 0.3rem 0.8rem;
    border: 1px solid var(--primary-color);
    background: transparent;
    color: var(--primary-color);
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.85rem;
    transition: var(--transition);
}

.lang-btn:hover,
.lang-btn.active {
    background: var(--primary-color);
    color: white;
}

/* ========== 页面标题区 ========== */
.page-header {
    background: var(--gradient-dark);
    padding: 120px 0 60px;
    color: white;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.page-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

.page-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    position: relative;
}

.page-header .breadcrumb {
    justify-content: center;
    background: transparent;
    margin-bottom: 0;
    position: relative;
}

.page-header .breadcrumb-item,
.page-header .breadcrumb-item a {
    color: rgba(255,255,255,0.8);
}

.page-header .breadcrumb-item.active {
    color: white;
}

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

.section-title {
    text-align: center;
    margin-bottom: 50px;
}

.section-title h2 {
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--dark-color);
    margin-bottom: 1rem;
    position: relative;
    display: inline-block;
}

.section-title h2::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: var(--gradient-primary);
    border-radius: 2px;
}

.section-title p {
    color: var(--text-light);
    font-size: 1.1rem;
    max-width: 600px;
    margin: 0 auto;
}

/* ========== 按钮样式 ========== */
.btn-primary-custom {
    background: var(--gradient-primary);
    border: none;
    padding: 12px 30px;
    color: white;
    border-radius: 30px;
    font-weight: 500;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.btn-primary-custom:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    color: white;
}

.btn-outline-custom {
    border: 2px solid var(--primary-color);
    padding: 10px 28px;
    color: var(--primary-color);
    border-radius: 30px;
    font-weight: 500;
    background: transparent;
    transition: var(--transition);
}

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

/* ========== 卡片样式 ========== */
.card-custom {
    border: none;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    height: 100%;
}

.card-custom:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
}

.card-custom .card-img-top {
    height: 200px;
    object-fit: cover;
}

.card-custom .card-body {
    padding: 1.5rem;
}

.card-custom .card-title {
    font-weight: 600;
    color: var(--dark-color);
    margin-bottom: 0.8rem;
}

/* ========== 页脚 ========== */
.footer {
    background: var(--dark-color);
    color: white;
    padding: 60px 0 0;
}

.footer-top {
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.footer h5 {
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: white;
    position: relative;
    padding-bottom: 10px;
}

.footer h5::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 40px;
    height: 2px;
    background: var(--accent-color);
}

.footer p,
.footer a {
    color: rgba(255,255,255,0.7);
    line-height: 2;
}

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

.footer-links {
    list-style: none;
    padding: 0;
}

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    display: flex;
    align-items: center;
    gap: 8px;
}

.footer-links a i {
    font-size: 0.8rem;
    color: var(--accent-color);
}

.footer-bottom {
    padding: 20px 0;
    text-align: center;
    color: rgba(255,255,255,0.5);
    font-size: 0.9rem;
}

.footer-contact i {
    color: var(--accent-color);
    margin-right: 10px;
    width: 20px;
}

/* ========== 返回顶部 ========== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 999;
    box-shadow: var(--shadow-md);
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-5px);
}

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

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

/* ========== 响应式 ========== */
@media (max-width: 991px) {
    .navbar-collapse {
        background: white;
        padding: 1rem;
        border-radius: 10px;
        margin-top: 1rem;
        box-shadow: var(--shadow-md);
    }
    
    .lang-switch {
        margin: 1rem 0 0;
        justify-content: center;
    }
    
    .page-header {
        padding: 100px 0 50px;
    }
    
    .page-header h1 {
        font-size: 2rem;
    }
    
    .section {
        padding: 60px 0;
    }
    
    .section-title h2 {
        font-size: 1.8rem;
    }
}

@media (max-width: 767px) {
    .page-header h1 {
        font-size: 1.6rem;
    }
    
    .section-title h2 {
        font-size: 1.5rem;
    }
    
    .footer-top {
        text-align: center;
    }
    
    .footer h5::after {
        left: 50%;
        transform: translateX(-50%);
    }
}