* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

:root {
    --primary-blue: #0A2463;
    --accent-red: #E63946;
    --accent-teal: #2A9D8F;
    --accent-yellow: #E9C46A;
    --accent-blue: #264653;
    --text-dark: #000000;
    --text-light: #FFFFFF;
    --bg-light: #FFFFFF;
    --bg-dark: #000000;
    --transition: all 0.35s cubic-bezier(0.32, 0.01, 0.15, 1);
}

html {
    scroll-behavior: smooth;
}

body {
    color: var(--text-dark);
    background: var(--bg-light);
    line-height: 1.6;
    overflow-x: hidden;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ========== 导航栏 ========== */
.navbar {
    position: sticky;
    top: 0;
    width: 100%;
    background: var(--bg-light);
    border-bottom: 5px solid var(--primary-blue);
    z-index: 999;
    box-shadow: 0 2px 12px rgba(0,0,0,0.05);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo {
    /* 1. 设置背景图（替换为你的图片路径） */
    background: url("../img/LOGO.png") no-repeat center / contain;
    /* 2. 隐藏原文字 */
    text-indent: -9999px;
    /* 3. 必须设置宽高（根据你的logo尺寸调整，示例宽100px高40px） */
    width: 150px;
    height: 60px;
    /* 若原样式有字体样式，需清空 */
    font-size: 0;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 28px;
    align-items: center;
}

.nav-menu a {
    font-size: 16px;
    font-weight: 500;
    position: relative;
}

.nav-menu a::after {
    content: "";
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-blue);
    transition: var(--transition);
}

.nav-menu a:hover::after {
    width: 100%;
}

.nav-icons {
    display: flex;
    gap: 24px;
    align-items: center;
    font-size: 22px;
    cursor: pointer;
}

/* ========== Hero 区域 ========== */
.hero {
    background: var(--bg-dark);
    color: var(--text-light);
    padding: 100px 0;
    position: relative;
    overflow: hidden;
    min-height: 520px;
    display: flex;
    align-items: center;
}

.hero::after {
    content: '';
    position: absolute;
    right: 5%;
    top: 50%;
    transform: translateY(-50%);
    width: 42%;
    height: 85%;
    background: url('data:image/svg+xml;utf8,<svg viewBox="0 0 400 400" xmlns="http://www.w3.org/2000/svg"><path d="M350 380 Q300 300 380 150" stroke="%23E9C46A" stroke-width="8" fill="none"/><path d="M370 360 Q320 280 390 100" stroke="%23264653" stroke-width="8" fill="none"/><path d="M390 340 Q340 260 370 80" stroke="%23E63946" stroke-width="8" fill="none"/><circle cx="380" cy="70" r="8" fill="%23264653"/><circle cx="395" cy="120" r="10" fill="%232A9D8F"/><circle cx="400" cy="180" r="12" fill="%23E63946"/><circle cx="370" cy="30" r="8" fill="%23E9C46A"/></svg>') no-repeat right center;
    background-size: contain;
    opacity: 0.9;
    transition: var(--transition);
}

.hero-content {
    max-width: 600px;
    padding: 0 20px;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeUp 1s 0.2s forwards;
}

.hero h1 {
    font-size: 38px;
    line-height: 1.3;
    margin-bottom: 24px;
    font-weight: 600;
}

/* ========== 介绍区域 ========== */
.intro {
    padding: 56px 24px;
    max-width: 1200px;
    margin: 0 auto;
    opacity: 0;
    transform: translateY(20px);
    animation: fadeUp 1s 0.4s forwards;
}

.intro p {
    font-size: 21px;
    font-weight: 600;
    color: var(--primary-blue);
    line-height: 1.5;
}

/* ========== 催化剂区域 ========== */
.catalyst {
    padding: 0 24px 70px;
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
    align-items: center;
    border-bottom: 1px solid #eee;
    padding-bottom: 70px;
}

.catalyst-text h2 {
    font-size: 34px;
    color: var(--primary-blue);
    margin-bottom: 22px;
    font-weight: 700;
}

.catalyst-text p {
    font-size: 16px;
    margin-bottom: 32px;
    line-height: 1.7;
    color: #333;
}

.btn {
    display: inline-block;
    padding: 13px 38px;
    background: var(--primary-blue);
    color: var(--text-light);
    font-size: 16px;
    font-weight: 600;
    border-radius: 0;
    transition: var(--transition);
    border: none;
    cursor: pointer;
}

.btn:hover {
    background: #071a4d;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(10,36,99,0.2);
}

.catalyst-image {
    background: url('data:image/svg+xml;utf8,<svg viewBox="0 0 400 300" xmlns="http://www.w3.org/2000/svg"><rect width="400" height="300" fill="%23f0f0f0"/><circle cx="300" cy="150" r="50" fill="%23fff" stroke="%23000" stroke-width="2"/><path d="M300 100 Q300 150 300 200" stroke="%23000" stroke-width="2" fill="none"/><path d="M250 50 Q300 100 350 50" stroke="%23E9C46A" stroke-width="6" fill="none"/><path d="M230 70 Q300 120 370 70" stroke="%23264653" stroke-width="6" fill="none"/><path d="M210 90 Q300 140 390 90" stroke="%23E63946" stroke-width="6" fill="none"/><path d="M190 110 Q300 160 410 110" stroke="%232A9D8F" stroke-width="6" fill="none"/><circle cx="320" cy="40" r="6" fill="%23E9C46A"/><circle cx="340" cy="30" r="6" fill="%23264653"/><circle cx="360" cy="50" r="6" fill="%232A9D8F"/><circle cx="380" cy="70" r="6" fill="%23E63946"/></svg>') no-repeat center center;
    background-size: contain;
    height: 310px;
    border-radius: 6px;
    transition: var(--transition);
}

.catalyst-image:hover {
    transform: scale(1.02);
}

/* ========== 开放科学区域 ========== */
.open-science {
    padding: 70px 24px;
    max-width: 1200px;
    margin: 0 auto;
}

.open-science h2 {
    font-size: 34px;
    color: var(--primary-blue);
    margin-bottom: 22px;
    font-weight: 700;
}

.open-science-intro {
    font-size: 16px;
    margin-bottom: 44px;
    line-height: 1.7;
    color: #333;
}

.science-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 34px;
    margin-bottom: 50px;
}

.science-card {
    transition: var(--transition);
    padding: 6px;
}

.science-card:hover {
    transform: translateY(-6px);
}

.science-card h3 {
    font-size: 22px;
    color: var(--primary-blue);
    padding-bottom: 10px;
    border-bottom: 4px solid var(--accent-red);
    margin-bottom: 22px;
    font-weight: 600;
}

.science-card h4 {
    font-size: 18px;
    margin-bottom: 16px;
    font-weight: 600;
}

.science-card p {
    font-size: 16px;
    line-height: 1.7;
    color: #333;
}

.read-more {
    text-align: center;
    margin-bottom: 70px;
    border-bottom: 1px solid #eee;
    padding-bottom: 70px;
}

/* ========== 侧边导航区域 ========== */
.side-nav {
    max-width: 1200px;
    margin: 0 auto 70px;
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 0;
    box-shadow: 0 4px 16px rgba(0,0,0,0.06);
}

.side-nav-menu {
    background: var(--primary-blue);
    color: var(--text-light);
    padding: 46px;
    font-size: 18px;
    font-weight: 600;
}

.side-nav-menu ul {
    list-style: none;
}

.side-nav-menu li {
    margin-bottom: 16px;
    transition: var(--transition);
    cursor: pointer;
}

.side-nav-menu li:hover {
    padding-left: 6px;
    opacity: 0.9;
}

.side-nav-image {
    background: url('data:image/svg+xml;utf8,<svg viewBox="0 0 600 300" xmlns="http://www.w3.org/2000/svg"><rect width="600" height="300" fill="%23000"/><path d="M100 150 Q200 100 300 150 Q400 200 500 150" stroke="%23fff" stroke-width="8" fill="none" opacity="0.7"/><path d="M100 150 Q200 200 300 150 Q400 100 500 150" stroke="%23fff" stroke-width="8" fill="none" opacity="0.7"/><path d="M450 250 Q500 200 550 100" stroke="%23E9C46A" stroke-width="6" fill="none"/><path d="M470 240 Q520 190 570 80" stroke="%23264653" stroke-width="6" fill="none"/><path d="M490 230 Q540 180 590 60" stroke="%23E63946" stroke-width="6" fill="none"/><path d="M510 220 Q560 170 610 40" stroke="%232A9D8F" stroke-width="6" fill="none"/><circle cx="580" cy="30" r="6" fill="%23264653"/><circle cx="595" cy="60" r="8" fill="%232A9D8F"/><circle cx="600" cy="90" r="10" fill="%23E63946"/><circle cx="570" cy="20" r="6" fill="%23E9C46A"/></svg>') no-repeat center center;
    background-size: cover;
    height: 320px;
    transition: var(--transition);
}

/* ========== 页脚 ========== */
.footer {
    background: var(--primary-blue);
    color: var(--text-light);
    padding: 60px 24px;
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 36px;
}

.footer-logo {
    /* 1. 设置背景图（替换为你的图片路径） */
    background: url("../img/BottomLogo.png") no-repeat center / contain;
    /* 2. 隐藏原文字 */
    text-indent: -9999px;
    /* 3. 必须设置宽高（根据你的logo尺寸调整，示例宽100px高40px） */
    width: 300px;
    height: 120px;
    /* 若原样式有字体样式，需清空 */
    font-size: 0;
    margin-bottom: 40px;
    margin-right: 40px;
}

.footer-social {
    display: flex;
    gap: 16px;
    font-size: 24px;
    margin-bottom: 22px;
}

.footer-info {
    font-size: 14px;
    line-height: 1.6;
    opacity: 0.9;
    margin-left: 35px;
}

.footer-column h4 {
    font-size: 18px;
    margin-bottom: 18px;
    font-weight: 600;
}

.footer-column ul {
    list-style: none;
}

.footer-column li {
    margin-bottom: 10px;
    font-size: 15px;
    opacity: 0.9;
    transition: var(--transition);
}

.footer-column li:hover {
    padding-left: 4px;
    opacity: 1;
}

.footer-form {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.footer-form input {
    padding: 13px;
    font-size: 15px;
    border: none;
    border-radius: 4px;
    outline: none;
}

.footer-form .btn {
    background: var(--text-light);
    color: var(--primary-blue);
    align-self: flex-start;
    border: none;
    cursor: pointer;
}

.footer-form .btn:hover {
    background: #f0f0f0;
}

/* ========== 返回顶部 ========== */
.back-to-top {
    position: fixed;
    bottom: 36px;
    right: 36px;
    width: 52px;
    height: 52px;
    background: var(--primary-blue);
    color: var(--text-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    opacity: 0;
    visibility: hidden;
}

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

.back-to-top:hover {
    transform: translateY(-4px);
    box-shadow: 0 6px 18px rgba(0,0,0,0.2);
}

/* ========== 动画 ========== */
@keyframes fadeUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: 0.9s ease;
}

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

/* ========== 移动端适配 ========== */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }

    .hero h1 {
        font-size: 28px;
    }

    .hero::after {
        display: none;
    }

    .catalyst {
        grid-template-columns: 1fr;
        gap: 36px;
    }

    .science-grid {
        grid-template-columns: 1fr;
    }

    .side-nav {
        grid-template-columns: 1fr;
    }

    .footer-container {
        grid-template-columns: 1fr;
        gap: 40px;
    }
}