body { padding-top: 56px; }
.left-aligned { margin-left: auto; }
.bg-dark { background-color: #343a40 !important; }
.bg-hero { background-color: #45b06cff; }

/* CALLOUT */
.bd-callout { padding:1.25rem; margin-top:1.25rem; margin-bottom:1.25rem; border:1px solid #e9ecef; border-left-width:.25rem; border-radius:.25rem }
.bd-callout h4 { margin-bottom: 1.25rem }
.bd-callout p:last-child { margin-bottom:0 }
.bd-callout code { border-radius:.25rem }
.bd-callout+.bd-callout { margin-top:-.25rem }
.bd-callout-info { border-left-color:#5bc0de }
.bd-callout-warning { border-left-color:#f0ad4e }
.bd-callout-danger { border-left-color:#d9534f }

/* footer */
footer a { color: white; font-weight: bold; text-decoration: none; }
footer a:hover { color: white; text-decoration: underline; }


:root {
    --primary: #1a3a5f;
    --secondary: #2d6b9a;
    --accent: #5ea1fc;
    --accent-dark: #4a8ef7;
    --light: #e8f4fc;
    --lighter: #f5fbff;
    --dark: #0a1e33;
    --text: #333;
    --text-light: #666;
    --white: #ffffff;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    --transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.1);
}

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

body {
    background-color: var(--lighter);
    color: var(--text);
    overflow-x: hidden;
    position: relative;
    font-family: 'Open Sans', sans-serif;
    line-height: 1.6;
}

h1,
h2,
h3,
h4,
h5 {
    font-family: 'Montserrat', sans-serif;
    font-weight: 700;
    line-height: 1.3;
}

body::before {
    content: "";
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 10% 20%, rgba(94, 161, 252, 0.1) 0%, rgba(26, 58, 95, 0.05) 100%);
    z-index: -1;
}



/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.animate {
    animation: fadeInUp 0.8s ease forwards;
}

.delay-1 {
    animation-delay: 0.1s;
}

.delay-2 {
    animation-delay: 0.2s;
}

.delay-3 {
    animation-delay: 0.3s;
}

.delay-4 {
    animation-delay: 0.4s;
}

/* Responsive Design */
@media (max-width: 992px) {
    .section-background img:first-child {
        width: 70%;
    }

    .section-background img:nth-child(2) {
        width: 30%;
    }

    .about-content {
        flex-direction: column;
        gap: 40px;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: rgba(26, 58, 95, 0.95);
        flex-direction: column;
        justify-content: center;
        padding: 20px 5%;
        gap: 25px;
        z-index: 999;
        backdrop-filter: blur(5px);
    }

    .nav-links.active {
        display: flex;
    }

    .mobile-menu-btn {
        display: block;
    }

    .hero-btns {
        flex-direction: column;
        align-items: center;
    }

    .section {
        padding: 80px 5%;
    }

    .footer-content {
        gap: 40px;
    }

    /* 移动端下拉菜单样式 */
    .dropdown-menu {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        background: transparent;
        padding: 0;
        margin-left: 20px;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.3s ease;
    }

    .dropdown.active .dropdown-menu {
        max-height: 500px;
    }

    .dropdown-menu a {
        padding: 8px 15px;
        font-size: 1rem;
    }

    .dropdown-toggle .fa-chevron-down {
        transition: transform 0.3s ease;
    }

    .dropdown.active .dropdown-toggle .fa-chevron-down {
        transform: rotate(180deg);
    }
}

@media (max-width: 480px) {
    .logo-text {
        font-size: 1.5rem;
    }

    .hero {
        min-height: 600px;
    }

    .section {
        padding: 70px 5%;
    }

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

.sponsor-link {
    color: #fff;
    text-decoration: none;
}

.sponsor-link:hover {
    text-decoration: underline;
}

.section-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    pointer-events: none;
    z-index: 1;
    overflow: hidden;
}

.section-background img {
    height: auto;
    opacity: 1;
    transition: opacity 0.3s ease;
}

.section-background img:first-child {
    width: 30%;
    object-fit: contain;
    margin-left: 0;
}

.section-background img:nth-child(2) {
    width: 30%;
    object-fit: contain;
    margin: 0;
}

.section-background img:nth-child(3) {
    width: 30%;
    object-fit: contain;
    margin-right: 0;
}

/* 确保内容在图片上层 */
.section-title,
.about-content {
    position: relative;
    z-index: 2;
}

/* 响应式调整 */
@media (max-width: 768px) {
    .section {
        padding: 80px 5%;
    }

    .section-background {
        flex-direction: column;
        align-items: center;
    }

    .section-background img {
        width: 70% !important;
        margin: 20px 0 !important;
    }
}