/* 全局变量 - 悬疑探索风格 */
:root {
    --primary-color: #ff4757; /* 警示红 */
    --secondary-color: #2f3542; /* 深灰蓝 */
    --bg-color: #f1f2f6; /* 浅灰白 */
    --surface-color: #ffffff;
    --text-main: #2f3542;
    --text-light: #747d8c;
    --border-radius: 8px;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    --font-family: 'Helvetica Neue', Arial, sans-serif;
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.3s ease;
}

ul {
    list-style: none;
}

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

/* 顶部导航 */
.mystery-header {
    background: var(--surface-color);
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-flex {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--secondary-color);
}

.nav-links a {
    margin: 0 20px;
    font-weight: 500;
    color: var(--text-main);
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width 0.3s;
}

.nav-links a:hover::after, .nav-links a.active::after {
    width: 100%;
}

.btn-submit {
    background: var(--secondary-color);
    color: var(--white);
    padding: 8px 20px;
    border-radius: var(--border-radius);
    font-size: 0.9rem;
}

.btn-submit:hover {
    background: var(--primary-color);
}

/* 英雄区域 */
.hero-banner {
    padding: 80px 0;
    background: linear-gradient(135deg, #eef2f3 0%, #dce3e8 100%);
}

.hero-content {
    display: flex;
    align-items: center;
    gap: 50px;
}

.hero-text {
    flex: 1;
}

.tag-alert {
    display: inline-block;
    background: rgba(255, 71, 87, 0.1);
    color: var(--primary-color);
    padding: 5px 10px;
    border-radius: 4px;
    font-size: 0.8rem;
    font-weight: bold;
    margin-bottom: 15px;
}

.hero-text h1 {
    font-size: 3rem;
    color: var(--secondary-color);
    margin-bottom: 15px;
    line-height: 1.2;
}

.subtitle {
    font-size: 1.2rem;
    color: var(--text-light);
    margin-bottom: 30px;
}

.hero-btns {
    display: flex;
    gap: 15px;
}

.btn-primary {
    padding: 12px 30px;
    background: var(--primary-color);
    color: var(--white);
    border-radius: var(--border-radius);
    font-weight: bold;
}

.btn-primary:hover {
    background: #ff6b81;
    transform: translateY(-2px);
}

.btn-secondary {
    padding: 12px 30px;
    background: transparent;
    color: var(--secondary-color);
    border: 2px solid var(--secondary-color);
    border-radius: var(--border-radius);
    font-weight: bold;
}

.btn-secondary:hover {
    background: var(--secondary-color);
    color: var(--white);
}

.hero-img-box {
    flex: 1;
}

.hero-img-box img {
    width: 100%;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

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

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

.bg-dark {
    background: var(--secondary-color);
    color: var(--white);
}

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

.section-head h2 {
    font-size: 2.2rem;
    margin-bottom: 10px;
    color: var(--secondary-color);
}

.section-head.light h2 {
    color: var(--white);
}

.section-head p {
    color: var(--text-light);
}

.section-head.light p {
    color: #a4b0be;
}

/* 案例卡片 */
.case-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 30px;
}

.case-card {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform 0.3s;
}

.case-card:hover {
    transform: translateY(-5px);
}

.card-img {
    position: relative;
    height: 200px;
    overflow: hidden;
}

.card-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s;
}

.case-card:hover .card-img img {
    transform: scale(1.05);
}

.case-tag {
    position: absolute;
    top: 15px;
    right: 15px;
    background: rgba(0,0,0,0.7);
    color: var(--white);
    padding: 4px 10px;
    border-radius: 4px;
    font-size: 0.8rem;
}

.card-body {
    padding: 20px;
}

.card-body h3 {
    font-size: 1.3rem;
    margin-bottom: 10px;
    color: var(--secondary-color);
}

.desc {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 15px;
}

.read-link {
    color: var(--primary-color);
    font-weight: bold;
    font-size: 0.9rem;
}

/* 科学假说列表 */
.theory-list {
    max-width: 800px;
    margin: 0 auto;
}

.theory-item {
    background: rgba(255,255,255,0.05);
    padding: 25px;
    border-radius: var(--border-radius);
    margin-bottom: 20px;
    display: flex;
    align-items: flex-start;
    gap: 20px;
    border: 1px solid rgba(255,255,255,0.1);
}

.theory-icon {
    font-size: 2rem;
    background: rgba(255,255,255,0.1);
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
}

.theory-content h3 {
    font-size: 1.4rem;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.theory-content p {
    color: #dfe4ea;
    font-size: 0.95rem;
}

/* 页脚 */
.site-footer {
    background: #1e272e;
    color: #747d8c;
    padding: 60px 0 30px;
}

.footer-layout {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-col h4 {
    color: var(--white);
    margin-bottom: 20px;
    font-size: 1.2rem;
}

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

.footer-col ul li a:hover {
    color: var(--primary-color);
}

.copyright {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid rgba(255,255,255,0.05);
    font-size: 0.8rem;
}

/* 响应式适配 */
@media (max-width: 768px) {
    .header-flex {
        flex-direction: column;
        height: auto;
        padding: 15px 0;
        gap: 15px;
    }

    .nav-links {
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
        gap: 10px;
    }

    .hero-content {
        flex-direction: column-reverse;
        text-align: center;
    }

    .hero-btns {
        justify-content: center;
    }

    .theory-item {
        flex-direction: column;
        text-align: center;
        align-items: center;
    }

    .footer-layout {
        grid-template-columns: 1fr;
        text-align: center;
    }
}