@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

:root {
    /* Elegant Academic Palette */
    --primary-text: #1e293b;    /* Slate 800 - Deep Blue-Grey */
    --secondary-text: #475569;  /* Slate 600 */
    --muted-text: #94a3b8;      /* Slate 400 */
    --accent-color: #334155;    /* Slate 700 - Very professional dark grey/blue */
    --highlight-color: #0369a1; /* Sky 700 - Subtle highlight for links */
    
    --bg-color: #ffffff;
    --sidebar-bg: #f8fafc;      /* Slate 50 */
    --border-color: #e2e8f0;    /* Slate 200 */
    
    --sidebar-width: 300px;
}

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

body {
    font-family: 'Inter', 'Microsoft YaHei', 'Segoe UI', Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--primary-text);
    line-height: 1.65;
    font-size: 15px;
}

a {
    color: var(--highlight-color);
    text-decoration: none;
    transition: color 0.15s ease;
}

a:hover {
    text-decoration: underline;
    color: #0c4a6e;
}

/* Layout */
.app-container {
    display: flex;
    max-width: 1280px;
    margin: 0 auto;
    min-height: 100vh;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background: var(--sidebar-bg);
    padding: 40px 30px;
    position: fixed;
    height: 100vh;
    overflow-y: auto;
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    z-index: 10;
}

.profile-header {
    margin-bottom: 30px;
    text-align: center; /* Center align text */
    width: 100%;
}

.profile-img {
    width: 160px;
    height: 160px;
    border-radius: 12px;
    object-fit: cover;
    margin: 0 auto 15px; /* Center image */
    display: block;
    border: 3px solid #fff;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}

.profile-name {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: 6px;
    line-height: 1.2;
}

.chinese-name {
    font-family: "KaiTi", "STKaiti", "楷体", "Microsoft YaHei", serif;
    font-size: 1.5rem; /* Larger for calligraphy effect */
    font-weight: normal;
    margin-top: 8px;
    letter-spacing: 4px; /* Space out characters */
    color: #333;
}

.profile-title {
    font-size: 0.9rem;
    color: var(--secondary-text);
    margin-bottom: 20px;
    line-height: 1.4;
}

.lang-btn {
    display: inline-block;
    margin-top: 5px;
    padding: 5px 18px;
    background-color: #fff;
    color: var(--accent-color);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    transition: all 0.2s;
    text-decoration: none;
}

.lang-btn:hover {
    background-color: var(--highlight-color);
    color: #fff;
    border-color: var(--highlight-color);
    text-decoration: none;
    transform: translateY(-2px);
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

/* Sidebar Navigation */
.nav-menu {
    list-style: none;
    margin: 20px 0;
    border-top: 1px solid var(--border-color);
    padding-top: 20px;
}

.nav-menu li {
    margin-bottom: 4px;
}

.nav-link {
    display: flex;
    align-items: center;
    padding: 10px 15px; /* More padding for click area */
    color: var(--secondary-text);
    font-size: 0.9rem;
    font-weight: 500;
    transition: all 0.2s ease; /* Smooth transition */
    border-radius: 8px; /* Rounded corners */
    margin-bottom: 2px;
}

.nav-link i {
    width: 24px;
    text-align: center;
    margin-right: 10px;
    color: var(--muted-text);
    font-size: 0.95rem; /* Slightly larger icon */
    transition: color 0.2s;
}

.nav-link:hover {
    color: var(--highlight-color); /* Darker blue text */
    background-color: #e0f2fe; /* Light blue background */
    transform: translateX(5px); /* Slide right */
    text-decoration: none;
}

.nav-link:hover i {
    color: var(--highlight-color);
}

.nav-link.active {
    color: var(--highlight-color);
    background-color: #e0f2fe; /* Active state background */
    font-weight: 600;
}

.nav-link.active i {
    color: var(--highlight-color);
}

/* Sidebar Contact */
.contact-info {
    margin-top: auto;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
    font-size: 0.85rem;
    color: var(--secondary-text);
}

.contact-item {
    margin-bottom: 8px;
    display: flex;
    align-items: flex-start;
    gap: 12px;
    line-height: 1.4;
}

.contact-item i {
    margin-top: 3px;
    color: var(--muted-text);
    width: 16px;
    text-align: center;
}

.social-links {
    display: flex;
    flex-direction: column; /* Vertical stack */
    gap: 8px;
    margin-bottom: 25px;
    width: 100%;
}

.social-links a {
    display: flex;
    align-items: center;
    color: var(--secondary-text);
    font-size: 0.9rem;
    padding: 8px 12px;
    border-radius: 6px;
    transition: all 0.2s;
    background-color: #fff;
    border: 1px solid var(--border-color);
    text-decoration: none;
}

.social-links a i {
    width: 20px;
    text-align: center;
    margin-right: 10px;
    color: var(--accent-color);
}

.social-links a:hover {
    color: var(--highlight-color);
    border-color: var(--highlight-color);
    background-color: #f0f9ff;
    transform: translateX(3px); /* Slide right slightly */
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: 60px 70px;
}

/* Typography for Sections */
section {
    margin-bottom: 60px;
    scroll-margin-top: 40px;
}

.section-title {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--accent-color); /* Use the dark slate color */
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 12px;
    margin-bottom: 24px;
    letter-spacing: -0.01em;
    display: flex;
    align-items: center;
}

.section-title i {
    margin-right: 12px;
    color: var(--muted-text); /* Subtle icon color */
    font-size: 0.9em;
}

.subtitle {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-text);
    margin: 30px 0 15px;
    display: flex;
    align-items: center;
}

.subtitle::before {
    content: '';
    display: block;
    width: 4px;
    height: 18px;
    background: var(--muted-text);
    margin-right: 10px;
    border-radius: 2px;
}

/* Bio Text */
.bio-text {
    text-align: justify;
    margin-bottom: 20px;
    color: var(--secondary-text);
}

.bio-text p {
    margin-bottom: 12px; /* Adds space between paragraphs */
}

.bio-text p:last-child {
    margin-bottom: 0;
}

/* Timeline Style Lists (Education, News, etc) */
.news-list, .compact-list, .pub-list {
    list-style: none;
    padding-left: 20px;
    border-left: 2px solid var(--border-color); /* The timeline line */
    margin-left: 8px; /* Offset for the line */
}

/* News Specific */
.news-item {
    display: flex;
    align-items: baseline;
    margin-bottom: 12px;
    font-size: 0.95rem;
    position: relative;
}

.news-item::before {
    /* Timeline dot */
    content: '';
    position: absolute;
    left: -27px; /* Adjust based on padding + border */
    top: 6px;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #fff;
    border: 2px solid var(--muted-text);
}

.news-tag {
    font-weight: 600;
    font-size: 0.8rem;
    color: var(--secondary-text);
    min-width: 60px;
    flex-shrink: 0;
    margin-right: 15px;
    text-align: right;
    opacity: 0.8;
}

.news-content {
    color: var(--secondary-text);
}

/* Compact Lists (Teaching, Awards) */
.compact-list li {
    position: relative;
    padding-left: 0; /* Removed bullet padding */
    margin-bottom: 10px;
    color: var(--secondary-text);
}

/* Reusing the timeline styling for compact lists if desired, or keeping simple bullets */
/* Let's make compact-list simpler but cleaner */
.compact-list {
    border-left: none; /* Remove timeline line for simple lists to vary style */
    padding-left: 0;
    margin-left: 0;
}

.compact-list li {
    padding-left: 20px;
    position: relative;
}

.compact-list li::before {
    content: "•";
    color: var(--muted-text);
    position: absolute;
    left: 0;
    top: 0;
    font-weight: bold;
}

/* Publications - The Core */
.pub-list {
    border-left: none; /* No timeline line for papers */
    padding-left: 0;
    margin-left: 0;
}

.pub-item {
    margin-bottom: 15px;
    padding-left: 35px; /* Space for [1] */
    color: var(--secondary-text);
    line-height: 1.6;
    position: relative; /* For absolute index */
    display: block; /* Ensure block layout, not flex */
}

.pub-index {
    font-weight: 600;
    color: var(--muted-text);
    position: absolute;
    left: 0;
    top: 0;
    width: 30px;
    font-size: 0.9rem;
}

.highlight-author {
    font-weight: 700;
    color: var(--primary-text);
}

.red {
    color: #ef4444; /* Bright Red */
    font-weight: bold;
}

/* Responsive */
@media (max-width: 900px) {
    .app-container { flex-direction: column; }
    .sidebar { 
        width: 100%; 
        height: auto; 
        position: relative; 
        border-right: none; 
        border-bottom: 1px solid var(--border-color);
        padding: 30px 20px;
    }
    .main-content { margin-left: 0; padding: 40px 20px; }
    .nav-menu { display: none; } 
    .news-item { flex-direction: column; }
    .news-tag { text-align: left; margin-bottom: 4px; }
    .news-item::before { display: none; /* Hide dots on mobile */ }
    .news-list { border-left: none; padding-left: 0; }
}