/* Color Variables */
:root {
    --primary-color: #2e3a87; /* 深靛蓝 - 学术/宇宙 */
    --secondary-color: #f4623a; /* 活力橙 - 强调 */
    --text-main: #212529;
    --text-muted: #6c757d;
    --bg-light: #f8f9fa;
}

body {
    font-family: 'Inter', sans-serif;
    color: var(--text-main);
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Inter', sans-serif;
    font-weight: 700;
}

a { color: var(--primary-color); text-decoration: none; transition: 0.2s; }
a:hover { color: var(--secondary-color); }

/* Navigation */
#mainNav {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 0.5rem 1rem rgba(0, 0, 0, 0.05);
    padding: 1rem 0;
}
#mainNav .navbar-brand { color: var(--primary-color); }
#mainNav .nav-link { color: var(--text-main); font-weight: 600; padding: 0.5rem 1rem; }
#mainNav .nav-link:hover { color: var(--secondary-color); }

/* Masthead / Hero */
header.masthead {
    padding-top: 10rem;
    padding-bottom: 6rem;
    /* 确保你的 assets/img 文件夹里有 lensing.png */
    background: linear-gradient(to bottom, rgba(26, 30, 46, 0.7) 0%, rgba(26, 30, 46, 0.9) 100%), url("../assets/img/WebbBulletCluster.jpg");
    background-position: center;
    background-size: cover;
    min-height: 100vh;
    display: flex;
    align-items: center;
}
.avatar-img {
    width: 180px;
    height: 180px;
    border-radius: 50%;
    border: 4px solid rgba(255,255,255,0.8);
    object-fit: cover;
}

/* Sections */
.page-section { padding: 2rem 0; }
.section-heading { font-size: 2.5rem; margin-bottom: 1rem; color: var(--primary-color); }
.divider-primary { max-width: 3.25rem; border-width: 0.2rem; border-color: var(--secondary-color); margin: 1.5rem auto; opacity: 1; border-style: solid; }
.divider-light { max-width: 3.25rem; border-width: 0.2rem; border-color: #fff; margin: 1.5rem auto; opacity: 1; border-style: solid; }
.divider { max-width: 3.25rem; border-width: 0.2rem; border-color: #fff; margin: 1.5rem auto; opacity: 1; border-style: solid; }

/* --- Research Card Style --- */
.research-card {
    background: #fff;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 10px 30px rgba(0,0,0,0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    margin-bottom: 3rem; 
}
.research-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0,0,0,0.12);
}
.research-img-wrapper {
    height: 100%;
    min-height: 300px; 
    overflow: hidden;
}
.research-img-wrapper img {
    width: 100%;
    height: 100%;
    object-fit: cover; 
    transition: transform 0.5s ease;
}
.research-card:hover .research-img-wrapper img {
    transform: scale(1.05); 
}
.research-body {
    padding: 2.5rem;
    display: flex;
    flex-direction: column;
    justify-content: center;
    height: 100%;
}
.research-title {
    color: var(--primary-color);
    font-size: 1.75rem;
    margin-bottom: 1rem;
}
.research-desc {
    font-size: 1.05rem;
    line-height: 1.7;
    color: #555;
    margin-bottom: 1.5rem;
}
.research-tag {
    display: inline-block;
    padding: 0.35em 0.8em;
    font-size: 0.85em;
    font-weight: 600;
    color: var(--primary-color);
    background-color: rgba(46, 58, 135, 0.1); 
    border-radius: 20px;
    margin-right: 0.5rem;
    margin-bottom: 0.5rem;
}

/* --- Education --- */
#education-md h3 { color: var(--text-main); margin-top: 1.5rem; font-size: 1.4rem; margin-bottom: 0.5rem;}
#education-md p { margin-bottom: 0.2rem; }
#education-md strong { color: var(--primary-color); }
#education-md li { color: var(--text-muted); margin-bottom: 0.5rem; }

/* --- Awards (Dark Theme) --- */
#awards-md { color: rgba(255,255,255,0.8); text-align: left; }
#awards-md h3 { color: #fff; margin-top: 1.5rem; font-size: 1.2rem;}
#awards-md ul { list-style: none; padding-left: 0; }
#awards-md li { margin-bottom: 0.5rem; border-bottom: 1px solid rgba(255,255,255,0.1); padding-bottom: 0.5rem;}

/* 自定义首页 Hero 区域的大按钮样式 */
header.masthead .btn-xl {
    /* 之前调整大小的代码 */
    font-size: 1.5rem;      
    padding: 1.5rem 3rem;   
    
    /* --- 新增：修改颜色 --- */
    background-color: #000000;  /* 这里填你想要的背景颜色代码 */
    border-color: #ff5733;      /* 建议和背景色保持一致 */
    color: #ffffff;             /* 字体颜色（通常是白色） */
}

/* --- 新增：修改鼠标悬停时的颜色 (可选) --- */
header.masthead .btn-xl:hover {
    background-color: #c70039;  /* 鼠标放上去变深一点 */
    border-color: #c70039;
}

/* 强制增加最大宽度 */
@media (min-width: 1200px) {
    .container {
        max-width: 1400px !important; /* 原来通常是 1140px */
    }
}
/* 或者直接让它占屏幕的 90% */
/* .container {
    max-width: 90% !important;
} 
*/
/* 图片说明文字样式 */
.figure-caption {
    color: #555;
    font-style: italic; /* 斜体，更有学术感 */
    background: #f8f9fa; /* 浅灰背景 */
    padding: 5px 10px;
    border-radius: 5px;
    display: inline-block;
}

/* 弹窗中的公式间距 */
.modal-body p {
    margin-bottom: 1.5rem; /* 让段落之间松一点 */
    line-height: 1.8;
}
/* --- Research Card Interactive Style --- */
.research-card {
    cursor: pointer; /* 鼠标放上去变小手 */
    position: relative;
}

/* 鼠标悬停时，稍微加深阴影，提示可点击 */
.research-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 1rem 3rem rgba(0,0,0,0.15) !important;
}

/* 弹窗样式微调 */
.modal-content {
    border-radius: 1rem;
    border: none;
    box-shadow: 0 1rem 3rem rgba(0,0,0,0.3);
}