:root {
    --primary-color: #0066cc;
    --secondary-color: #00ccff;
    --accent-color: #ff6600;
    --dark-color: #1a1a2e;
    --light-color: #f8f9fa;
    --text-color: #333333;
    --text-light: #666666;
    --white: #ffffff;
    --gray-light: #f5f5f5;
    --gray: #e0e0e0;
    --gray-dark: #9e9e9e;
}

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

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

a {
    text-decoration: none;
    color: var(--primary-color);
    transition: color 0.3s ease;
}

a:hover {
    color: var(--secondary-color);
}

ul, ol {
    list-style: none;
}

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

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 2rem;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 0;
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
}

.btn-primary {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    color: white;
    padding: 0.75rem 2rem;
    font-size: 1.1rem;
    border-radius: 50px;
    transition: all 0.3s ease;
    display: inline-block;
    font-weight: 500;
    text-align: center;
    vertical-align: middle;
    cursor: pointer;
    user-select: none;
    border: 1px solid transparent;
}

.btn-primary:hover {
    background-color: var(--secondary-color);
    border-color: var(--secondary-color);
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0, 102, 204, 0.2);
    color: white;
}

.text-center {
    text-align: center;
}

.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 1rem; }
.mt-4 { margin-top: 1.5rem; }
.mt-5 { margin-top: 2rem; }
.mt-6 { margin-top: 3rem; }

.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 1.5rem; }
.mb-5 { margin-bottom: 2rem; }
.mb-6 { margin-bottom: 3rem; }

.py-1 { padding-top: 0.25rem; padding-bottom: 0.25rem; }
.py-2 { padding-top: 0.5rem; padding-bottom: 0.5rem; }
.py-3 { padding-top: 1rem; padding-bottom: 1rem; }
.py-4 { padding-top: 1.5rem; padding-bottom: 1.5rem; }
.py-5 { padding-top: 2rem; padding-bottom: 2rem; }
.py-6 { padding-top: 3rem; padding-bottom: 3rem; }

.px-1 { padding-left: 0.25rem; padding-right: 0.25rem; }
.px-2 { padding-left: 0.5rem; padding-right: 0.5rem; }
.px-3 { padding-left: 1rem; padding-right: 1rem; }
.px-4 { padding-left: 1.5rem; padding-right: 1.5rem; }
.px-5 { padding-left: 2rem; padding-right: 2rem; }
.px-6 { padding-left: 3rem; padding-right: 3rem; }

.text-muted {
    color: var(--text-light);
}

.badge {
    display: inline-block;
    padding: 0.25em 0.4em;
    font-size: 75%;
    font-weight: 700;
    line-height: 1;
    text-align: center;
    white-space: nowrap;
    vertical-align: baseline;
    border-radius: 0.25rem;
}

.bg-primary {
    background-color: var(--primary-color) !important;
}

.text-white {
    color: var(--white) !important;
}

.bg-light {
    background-color: var(--gray-light) !important;
}

.shadow-sm {
    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075) !important;
}

.shadow {
    box-shadow: 0 0.5rem 1rem rgba(0, 0, 0, 0.15) !important;
}

.rounded-lg {
    border-radius: 0.5rem !important;
}

/* 导航栏样式 */
.navbar {
    padding: 1rem 0;
    transition: all 0.3s ease;
}

.navbar-dark .navbar-nav .nav-link {
    color: rgba(255, 255, 255, 0.8);
    padding: 0.5rem 1rem;
    position: relative;
}

.navbar-dark .navbar-nav .nav-link:hover,
.navbar-dark .navbar-nav .nav-link.active {
    color: var(--secondary-color);
}

.navbar-dark .navbar-nav .nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--secondary-color);
    transition: all 0.3s ease;
    transform: translateX(-50%);
}

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

/* 页脚样式 */
.footer {
    background: #0f172a;
    color: white;
    padding: 50px 0 20px;
}

.footer-links li {
    margin-bottom: 10px;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    transition: color 0.3s ease;
}

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

.social-icons a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    color: white;
    margin-right: 10px;
    transition: all 0.3s ease;
}

.social-icons a:hover {
    background: var(--primary-color);
    transform: translateY(-3px);
}

/* 表单样式 */
.form-control {
    display: block;
    width: 100%;
    padding: 0.375rem 0.75rem;
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.5;
    color: var(--text-color);
    background-color: var(--white);
    background-clip: padding-box;
    border: 1px solid var(--gray);
    appearance: none;
    border-radius: 0.375rem;
    transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

.form-control:focus {
    color: var(--text-color);
    background-color: var(--white);
    border-color: var(--secondary-color);
    outline: 0;
    box-shadow: 0 0 0 0.25rem rgba(0, 204, 255, 0.25);
}

/* 响应式样式 */
@media (max-width: 992px) {
    .section-title {
        font-size: 2rem;
    }
}

@media (max-width: 768px) {
    .section-title {
        font-size: 1.75rem;
    }

    .btn-primary {
        padding: 0.6rem 1.5rem;
        font-size: 1rem;
    }
}

@media (max-width: 576px) {
    .section-title {
        font-size: 1.5rem;
    }

    .container {
        padding: 0 15px;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.animate-fade-in {
    animation: fadeIn 0.8s ease forwards;
}

/* 时间线样式 */
.timeline {
    position: relative;
    padding-left: 30px;
}

.timeline::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 3px;
    height: 100%;
    background: linear-gradient(to bottom, var(--primary-color), var(--secondary-color));
}

.timeline-item {
    position: relative;
    margin-bottom: 30px;
    padding-bottom: 10px;
}

.timeline-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: -36px;
    width: 15px;
    height: 15px;
    border-radius: 50%;
    background: var(--primary-color);
    border: 3px solid white;
}

.timeline-date {
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.timeline-content {
    padding: 10px 0;
}