/* =========================================
           1. 基础视觉系统
           ========================================= */
:root {
    --primary-green: #3D7D56;
    --primary-blue: #1A3A59;
    --academic-red: #8B0000;
    --paper-bg: #F9F7F2;
    --accent-gold: #D4AF37;
    --text-main: #2C3E50;
    --text-sub: #606F7B;
    --font-serif: "Georgia", "Times New Roman", "Songti SC", serif;
    --shadow-soft: 0 20px 40px rgba(0,0,0,0.05);
    --shadow-hover: 0 25px 50px rgba(0,0,0,0.12);
}

* { margin: 0; padding: 0; box-sizing: border-box; font-family: "Microsoft YaHei", sans-serif; }
body { background-color: #fff; color: var(--text-main); line-height: 1.7; overflow-x: hidden; }
a { text-decoration: none; color: inherit; transition: 0.3s; }
ul { list-style: none; padding: 0; margin: 0; }
button { font-family: inherit; }
/* =========================================
       3. 页面内容
       ========================================= */
.page-wrapper { padding-top: 70px; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; position: relative; }

/* Hero */
.academic-hero {
    background: linear-gradient(rgba(26, 58, 89, 0.9), rgba(139, 0, 0, 0.4));
    background-size: cover; background-position: center;
    height: 500px; color: white; display: flex; flex-direction: column; justify-content: center; align-items: center; text-align: center;
}
.hero-tag { border: 1px solid var(--accent-gold); color: var(--accent-gold); padding: 6px 20px; border-radius: 30px; font-size: 0.85rem; letter-spacing: 2px; margin-bottom: 25px; text-transform: uppercase; }
.hero-title { font-family: var(--font-serif); font-size: 3.5rem; margin-bottom: 20px; font-weight: normal; letter-spacing: 1px; text-shadow: 0 4px 20px rgba(0,0,0,0.5); }
.hero-sub { font-size: 1.1rem; max-width: 700px; opacity: 0.95; line-height: 1.6; }

/* 1. 旗舰峰会规划 (Summit Planning) */
.summit-section { padding: 100px 20px; background: white; }
.summit-card {
    display: flex; background: #fff; border-radius: 12px; overflow: hidden; box-shadow: var(--shadow-soft); border: 1px solid #eee;
    max-width: 1100px; margin: 0 auto;
}
.summit-img { width: 50%; background: url('/uploads/20251219/9f5e731f004d38f7c11bf0456664afb3.avif') center/cover; position: relative; }

/* 日期：待定 */
.summit-status-badge {
    position: absolute; top: 30px; left: 30px; background: var(--academic-red); color: #fff;
    padding: 8px 20px; text-align: center; border-radius: 4px; font-weight: bold; box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    font-size: 0.9rem; letter-spacing: 1px;
}

.summit-content { padding: 60px; width: 50%; display: flex; flex-direction: column; justify-content: center; }
.summit-label { color: var(--primary-blue); font-weight: bold; letter-spacing: 1px; font-size: 0.9rem; text-transform: uppercase; margin-bottom: 15px; display: block; }
.summit-title { font-family: var(--font-serif); font-size: 2.2rem; color: var(--text-main); margin-bottom: 20px; line-height: 1.3; }
.summit-desc { font-size: 1rem; color: var(--text-sub); margin-bottom: 30px; line-height: 1.6; }
.summit-meta { display: flex; gap: 20px; margin-bottom: 30px; font-size: 0.9rem; color: #666; }
.meta-item span { font-weight: bold; color: var(--primary-green); margin-right: 5px; }

.btn-register { display: inline-block; background: var(--primary-blue); color: white; padding: 12px 30px; border-radius: 30px; font-weight: bold; transition: 0.3s; text-align: center; max-width: 200px; text-decoration: none; }
.btn-register:hover { background: #2c3e50; box-shadow: 0 5px 15px rgba(44, 62, 80, 0.3); }

/* 2. 专题研讨会计划 (Planned Seminars) */
.forum-section { padding: 100px 20px; background: var(--calm-lavender); }
.section-head { text-align: center; margin-bottom: 60px; }
.section-title { font-family: var(--font-serif); font-size: 2.5rem; color: var(--primary-blue); margin-bottom: 15px; }
.section-desc { color: var(--text-sub); }

.forum-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; max-width: 1200px; margin: 0 auto; }
.forum-card { background: white; border-radius: 8px; overflow: hidden; transition: 0.3s; border: 1px solid #eee; }
.forum-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-hover); border-color: var(--accent-gold); }

.forum-top { height: 160px; background: #ddd; position: relative; background-size: cover; background-position: center; }
.forum-cat { position: absolute; bottom: 0; left: 0; background: rgba(26, 58, 89, 0.9); color: white; padding: 5px 15px; font-size: 0.75rem; font-weight: bold; text-transform: uppercase; }

.forum-body { padding: 25px; }
.forum-status { font-size: 0.8rem; color: var(--accent-gold); margin-bottom: 10px; display: block; font-weight: bold; text-transform: uppercase; }
.forum-title { font-size: 1.2rem; font-weight: bold; color: var(--text-main); margin-bottom: 10px; line-height: 1.4; }
.forum-link { color: var(--primary-green); font-size: 0.9rem; font-weight: bold; display: flex; align-items: center; gap: 5px; margin-top: 15px; text-decoration: none; }

/* 3. 重点学术课题 (Key Academic Projects) */
.project-section { padding: 100px 20px; background: white; }
.project-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 40px; max-width: 1100px; margin: 0 auto; }

.project-card { padding: 40px 30px; border: 1px solid #eee; border-radius: 12px; background: #FAFBFC; transition: 0.3s; position: relative; overflow: hidden; }
.project-card:hover { box-shadow: var(--shadow-soft); background: white; border-color: var(--primary-blue); }
.project-card::before { content: ''; position: absolute; top: 0; left: 0; width: 100%; height: 5px; background: var(--primary-blue); }

.proj-icon { font-size: 2.5rem; margin-bottom: 20px; display: block; color: var(--primary-blue); }
.proj-title { font-size: 1.4rem; font-weight: bold; color: var(--text-main); margin-bottom: 15px; font-family: var(--font-serif); }
.proj-desc { color: var(--text-sub); font-size: 0.95rem; line-height: 1.6; margin-bottom: 20px; }
.proj-status { font-size: 0.8rem; background: rgba(61, 125, 86, 0.1); color: var(--primary-green); padding: 4px 10px; border-radius: 4px; font-weight: bold; }

/* 4. 征集与合作 (CTA Section) - 视觉重构 */
.cta-section {
    padding: 120px 20px;
    background: linear-gradient(rgba(15, 32, 53, 0.9), rgba(26, 58, 89, 0.85)),
    url('https://images.unsplash.com/photo-1454165804606-c3d57bc86b40?q=80&w=2670&auto=format&fit=crop');
    background-size: cover;
    background-position: center;
    background-attachment: fixed; /* 视差效果 */
    color: white;
    position: relative;
}
.cta-section::before {
    content: ''; position: absolute; top: 0; left: 0; width: 100%; height: 100%;
    background: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAQAAAAECAYAAACp8Z5+AAAAGklEQVQIW2NkYGD4D8SMYHwGCBClABAAMMwc+F/0/h8AAAAASUVORK5CYII='); /* 微纹理 */
    opacity: 0.1;
}

.cta-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 80px; max-width: 1000px; margin: 60px auto 0; text-align: left; position: relative; z-index: 1; }

.cta-col {
    padding: 20px; border-left: 1px solid rgba(255,255,255,0.2);
    transition: 0.3s;
}
.cta-col:hover { border-left-color: var(--accent-gold); background: rgba(255,255,255,0.05); }

.cta-icon { font-size: 2.5rem; margin-bottom: 20px; display: block; color: var(--accent-gold); }
.cta-col h3 { font-size: 1.8rem; color: white; margin-bottom: 15px; font-family: var(--font-serif); }
.cta-col p { color: rgba(255,255,255,0.8); font-size: 1rem; margin-bottom: 30px; line-height: 1.8; }

.btn-cta {
    border: 1px solid rgba(255,255,255,0.5); color: white; padding: 12px 35px; border-radius: 30px;
    transition: 0.3s; font-size: 0.9rem; text-decoration: none; display: inline-block; font-weight: bold;
}
.btn-cta:hover { border-color: var(--accent-gold); color: var(--primary-blue); background: var(--accent-gold); }

@media (max-width: 1024px) {
    .summit-card { flex-direction: column; }
    .summit-img, .summit-content { width: 100%; }
    .summit-img { height: 300px; }
    .forum-grid { grid-template-columns: repeat(2, 1fr); }
    .project-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
    .hero-title { font-size: 1.5rem; }
    .section-title { font-size: 1.5rem; }
    .summit-title { font-size: 1.2rem; }
    .forum-grid, .project-grid { grid-template-columns: 1fr; }
    .cta-grid { grid-template-columns: 1fr; gap: 40px; }
    .cta-col { border-left: none; border-top: 1px solid rgba(255,255,255,0.2); padding-top: 30px; }
    .footer-grid { grid-template-columns: 1fr; text-align: center; }
}