/* --- 全局变量和基本样式 --- */
:root {
    --bg-dark: #0a0c10;
    --bg-light: #1a1d24;
    --primary-color: #00f6ff;
    --secondary-color: #9747ff;
    --text-color: #e0e0e0;
    --text-muted: #888;
    --border-color: rgba(0, 246, 255, 0.2);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Poppins', 'Microsoft YaHei', sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-color);
    line-height: 1.6;
}

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

/* --- 头部和导航 --- */
.header {
    background: rgba(10, 12, 16, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    padding: 15px 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

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

.logo a {
    text-decoration: none;
    color: var(--primary-color);
    font-size: 1.8rem;
    font-weight: 700;
    text-shadow: 0 0 10px var(--primary-color);
}

.main-nav ul {
    list-style: none;
    display: flex;
}

.main-nav ul li {
    margin-left: 30px;
}

.main-nav a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 400;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.main-nav a:hover {
    color: var(--primary-color);
    text-shadow: 0 0 5px var(--primary-color);
}

/* --- 主视觉区域 (Hero Section) --- */
.hero-section {
    padding-top: 180px;
    padding-bottom: 120px;
    text-align: center;
    background: linear-gradient(rgba(10, 12, 16, 0.8), var(--bg-dark)), url('https://www.transparenttextures.com/patterns/cubes.png');
    background-size: cover;
}

.hero-section h1 {
    font-size: 3.5rem;
    font-weight: 700;
    color: #fff;
    text-shadow: 0 0 15px var(--primary-color), 0 0 25px var(--secondary-color);
    margin-bottom: 20px;
}

.hero-section .subtitle {
    font-size: 1.2rem;
    max-width: 600px;
    margin: 0 auto 40px;
    color: var(--text-muted);
}

.cta-button {
    display: inline-block;
    background: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    padding: 12px 30px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
}

.cta-button:hover {
    background: var(--primary-color);
    color: var(--bg-dark);
    box-shadow: 0 0 20px var(--primary-color);
}

/* --- 通用区块样式 --- */
.research-section, .team-section {
    padding: 80px 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 600;
    margin-bottom: 60px;
    color: #fff;
}

/* --- 卡片网格布局 --- */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.card {
    background: var(--bg-light);
    padding: 30px;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    transition: all 0.3s ease;
    text-align: center;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 30px rgba(0, 246, 255, 0.1);
}

.card h3 {
    color: var(--primary-color);
    font-size: 1.5rem;
    margin-bottom: 15px;
}

/* --- 团队部分特殊样式 --- */
.team-card {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.team-photo-placeholder {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    background-color: #333;
    border: 3px solid var(--secondary-color);
    margin-bottom: 20px;
}

.team-card h4 {
    color: #fff;
    font-size: 1.2rem;
    margin-bottom: 5px;
}

/* --- 页脚 --- */
.footer {
    background: var(--bg-light);
    text-align: center;
    padding: 20px 0;
    margin-top: 60px;
    border-top: 1px solid var(--border-color);
}

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