:root {
    /* 严格提取自 SquareRoot Theme 官方变量 */
    --primary-color: #151d2a;
    --text-main: #3f3f3f;
    --text-muted: #5a5a5a;
    --bg-white: #ffffff;
    --bg-light: #f7f7f7;
    --nav-height: 80px;
    --font-heading: 'Raleway', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    --font-body: 'Raleway', 'Helvetica Neue', Helvetica, Arial, sans-serif;
}

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

body {
    font-family: var(--font-body);
    font-size: 14px;
    font-weight: 500;
    color: var(--text-muted);
    line-height: 1.6em;
    letter-spacing: 1px;
    background-color: var(--bg-white);
    -webkit-font-smoothing: antialiased;
}

/* ================= Bilingual System CSS ================= */
body.lang-en .zh { display: none !important; }
body.lang-zh .en { display: none !important; }

/* 规避 AOS 和 overflow 并发带来的横向滚动条 */
.overflow-hidden { overflow: hidden; }

h1, h2, h3, h4, h5, h6, .nav-logo {
    font-family: var(--font-heading);
    color: var(--text-main);
    font-weight: 600;
    line-height: 1.6em;
}

a { text-decoration: none; color: var(--primary-color); transition: all 0.3s ease; }
a:hover { color: #333; }

/* ================= 导航条 ================= */
.navbar {
    position: fixed; top: 0; left: 0; right: 0;
    height: var(--nav-height);
    background: transparent;
    z-index: 1000;
    transition: all 0.4s ease;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}
.navbar.scrolled {
    background: #ffffff;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    height: 65px;
    border-bottom: none;
}
.nav-container {
    max-width: 1170px; margin: 0 auto; padding: 0 2rem;
    height: 100%; display: flex; justify-content: space-between; align-items: center;
}
.navbar.scrolled .nav-logo a, .navbar.scrolled .nav-links a { color: #4c4c4c; }
.nav-logo a { color: #fff; font-size: 24px; font-weight: 700; text-transform: uppercase; letter-spacing: 2px;}
.nav-links { list-style: none; display: flex; gap: 2.5rem; align-items: center;}
.nav-links a { font-size: 14px; font-weight: 600; color: #fff; text-transform: uppercase; letter-spacing: 1px;}
.nav-links a:hover, .navbar.scrolled .nav-links a:hover { color: var(--primary-color); }
.nav-links .btn-primary, .nav-links .btn-lang { 
    background: transparent; 
    border: 2px solid #fff;
    color: #fff !important; 
    padding: 0.5rem 1.4rem; 
    border-radius: 2px; 
}
.nav-links .btn-lang { border-color: rgba(255,255,255,0.3); font-size: 12px; padding: 0.5rem 1rem;}
.navbar.scrolled .nav-links .btn-primary {
    border-color: var(--primary-color);
    color: var(--primary-color) !important;
}
.navbar.scrolled .nav-links .btn-lang {
    border-color: #ddd;
    color: #888 !important;
}
.nav-links .btn-primary:hover, .navbar.scrolled .nav-links .btn-primary:hover { 
    background: var(--primary-color); 
    color: #fff !important;
    border-color: var(--primary-color);
}
.nav-links .btn-lang:hover, .navbar.scrolled .nav-links .btn-lang:hover {
    border-color: var(--primary-color);
    color: var(--primary-color) !important;
}

/* ================= 首屏 ================= */
.hero {
    height: 100vh;
    /* 替换为极具科技和数据网络出海感的背景（地球网络数据流） */
    background-image: url('https://images.unsplash.com/photo-1451187580459-43490279c0fa?auto=format&fit=crop&q=80&w=1920');
    background-size: cover;
    background-position: center top;
    background-attachment: fixed;
    position: relative;
    display: flex; justify-content: center; align-items: center;
    text-align: center;
}
.hero-overlay {
    position: absolute; top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(21, 29, 42, 0.65); 
}
.hero-content { position: relative; z-index: 10; color: #fff; padding: 0 2rem;}
.hero-content h1 { 
    color: #fff;
    font-size: 4.5rem; font-weight: 700; 
    text-transform: uppercase; letter-spacing: 4px; 
    margin-bottom: 10px; 
}
body.lang-zh .hero-content h1 { letter-spacing: 8px; }

.hero-content .subtitle { 
    font-size: 16px; font-weight: 400; 
    letter-spacing: 2px; margin-bottom: 2.5rem; 
    color: #e0e0e0;
    text-transform: uppercase;
}
.hero-buttons { margin-top: 2rem; }
.btn-ghost {
    display: inline-block;
    padding: 12px 30px;
    border: 2px solid #fff;
    color: #fff;
    font-size: 14px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin: 0 10px;
    border-radius: 2px;
    transition: all 0.3s;
}
.btn-ghost:hover { background: #fff; color: var(--primary-color) !important; border-color: #fff;}

/* ================= 通用区域 ================= */
.section { padding: 100px 0; background: var(--bg-white); }
.bg-light { background: var(--bg-light); border-top: 1px solid #f0f0f0; border-bottom: 1px solid #f0f0f0;}
.container { max-width: 1100px; margin: 0 auto; padding: 0 20px; }

.section-title { text-align: center; margin-bottom: 70px; }
.section-title span {
    font-size: 26px; font-weight: 600; text-transform: uppercase; 
    position: relative; padding-bottom: 15px; display: inline-block;
    color: var(--text-main); letter-spacing: 2px;
}
.section-title span::after {
    content: ''; position: absolute; bottom: 0; left: 50%; transform: translateX(-50%);
    width: 40px; height: 2px; background: var(--primary-color);
}

/* ================= 关于我网格 ================= */
.about-grid {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 60px;
}
.about-image {
    flex: 0 0 35%;
    max-width: 350px;
}
.image-wrapper {
    position: relative;
    border-radius: 4px;
    padding: 10px;
    background: #fff;
    box-shadow: 0 10px 40px rgba(0,0,0,0.08);
}
.image-wrapper img {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 2px;
}
.about-text {
    flex: 1;
    font-size: 15px;
    color: var(--text-muted);
    line-height: 1.9;
}
body.lang-en .about-text { font-size: 14.5px; }

.about-text p { margin-bottom: 15px; text-align: justify; }

.contact-info-grid { 
    display: flex; gap: 20px; margin-top: 40px; flex-wrap: wrap;
    border-top: 1px solid #e5e5e5; padding-top: 30px;
}
.info-item { font-size: 14px;}
.info-item strong { margin-right: 8px; color: var(--primary-color); text-transform: uppercase; letter-spacing: 1px;}

/* ================= 履历 ================= */
.timeline { position: relative; max-width: 900px; margin: 0 auto; }
.timeline::before {
    content: ''; position: absolute; top: 0; bottom: 0; left: 50%; width: 1px; background: #ddd; transform: translateX(-50%);
}
.timeline-item {
    display: flex; justify-content: space-between; align-items: flex-start;
    margin-bottom: 60px; position: relative; width: 100%;
}
.timeline-meta { width: 50%; text-align: right; padding-right: 45px; position: relative;}
.timeline-content { width: 50%; text-align: left; padding-left: 45px; position: relative; }

.timeline-item:nth-child(even) { flex-direction: row-reverse; }
.timeline-item:nth-child(even) .timeline-meta { text-align: left; padding-right: 0; padding-left: 45px; }
.timeline-item:nth-child(even) .timeline-content { text-align: right; padding-left: 0; padding-right: 45px; }

.timeline-meta::after {
    content: ''; position: absolute; top: 6px; right: -7px;
    width: 15px; height: 15px; background: var(--primary-color);
    border-radius: 50%; z-index: 10;
    transition: transform 0.3s;
}
.timeline-item:nth-child(even) .timeline-meta::after { right: auto; left: -8px; }
.timeline-item:hover .timeline-meta::after { transform: scale(1.3); } /* 动效点缀 */

.timeline-meta .date { font-size: 16px; font-weight: 600; color: var(--primary-color); margin-top: -3px; letter-spacing: 1px;}
.timeline-content h3 { font-size: 18px; font-weight: 600; margin-bottom: 5px; color: var(--text-main); text-transform: uppercase;}
.timeline-content h4 { font-size: 14px; font-weight: 500; color: var(--text-muted); margin-bottom: 15px; font-style: italic; text-transform: capitalize;}
.timeline-content ul { list-style: none; }
.timeline-item:nth-child(odd) .timeline-content li { position: relative; padding-left: 15px; margin-bottom: 10px; color: var(--text-muted); font-size: 14px; line-height: 1.6;}
.timeline-item:nth-child(odd) .timeline-content li::before { content: '-'; position: absolute; left: 0; color: var(--primary-color); font-weight: bold;}
.timeline-item:nth-child(even) .timeline-content li { position: relative; padding-right: 15px; margin-bottom: 10px; color: var(--text-muted); font-size: 14px; line-height: 1.6;}
.timeline-item:nth-child(even) .timeline-content li::after { content: '-'; position: absolute; right: 0; color: var(--primary-color); top: 0; font-weight: bold;}

.timeline-content .highlight { color: var(--primary-color); font-weight: 600; }

/* ================= 紧凑单列模式 ================= */
.timeline-single::before { left: 0; transform: none; }
.timeline-single .timeline-item { flex-direction: column !important; margin-bottom: 30px;}
.timeline-single .timeline-meta { width: 100%; text-align: left; padding: 0 0 0 35px; margin-bottom: 5px;}
.timeline-single .timeline-content { width: 100%; text-align: left; padding: 0 0 0 35px; }
.timeline-single .timeline-meta::after { right: auto; left: -7px; }
.timeline-single .timeline-item:nth-child(even) .timeline-meta, .timeline-single .timeline-item:nth-child(even) .timeline-content { text-align: left; padding-right: 0; padding-left: 35px; }
.timeline-single .timeline-item:nth-child(even) .timeline-content li { padding-right: 0; padding-left: 15px; }
.timeline-single .timeline-item:nth-child(even) .timeline-content li::after { display: none;}
.timeline-single .timeline-item:nth-child(even) .timeline-content li::before { content: '-'; position: absolute; left: 0; color: var(--primary-color); display: block; font-weight: bold;}

/* ================= 尾页 ================= */
.site-footer { background: var(--primary-color); color: #fff; padding: 90px 0 50px; text-align: center; }
.footer-title { margin-bottom: 20px; color: #ffffff; font-size: 26px; font-weight: 600; text-transform: uppercase; letter-spacing: 2px;}
.site-footer p { color: rgba(255,255,255,0.7); margin-bottom: 40px; font-size: 14px; max-width: 600px; margin-left: auto; margin-right: auto;}
.site-footer .btn-primary { 
    background: #fff; border: 2px solid #fff; color: var(--primary-color); 
    padding: 12px 30px; font-weight: 600; border-radius: 2px; 
    display: inline-block; margin: 0 10px; text-transform: uppercase; font-size: 14px;
    transition: all 0.3s;
}
.site-footer .btn-primary:hover { background: transparent; color: #fff; }
.site-footer .btn-ghost { border-color: rgba(255,255,255,0.3); background: transparent;}
.copyright { border-top: 1px solid rgba(255,255,255,0.1); padding-top: 30px; margin-top: 60px; }
.copyright p {font-size: 13px; margin-bottom: 0; color: rgba(255,255,255,0.4);}

/* ================= 动态自适应 ================= */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .hero-content h1 { font-size: 3rem; }
    body.lang-zh .hero-content h1 { letter-spacing: 4px; }
    
    .about-grid { flex-direction: column; gap: 30px;}
    .about-text { text-align: left;}
    
    .timeline::before { left: 0; transform: none; }
    .timeline-item, .timeline-item:nth-child(even) { flex-direction: column; margin-bottom: 40px;}
    .timeline-meta, .timeline-item:nth-child(even) .timeline-meta { width: 100%; text-align: left; padding: 0 0 0 30px; margin-bottom: 10px;}
    .timeline-content, .timeline-item:nth-child(even) .timeline-content { width: 100%; text-align: left; padding: 0 0 0 30px; }
    .timeline-meta::after, .timeline-item:nth-child(even) .timeline-meta::after { left: -7px; right: auto; }
    .timeline-item:nth-child(even) .timeline-content li { padding-left: 15px; padding-right: 0; text-align: left;}
    .timeline-item:nth-child(even) .timeline-content li::after { display: none; }
    .timeline-item:nth-child(even) .timeline-content li::before { content: '-'; position: absolute; left: 0; color: var(--primary-color); display: block;}
    .contact-info-grid { flex-direction: column; gap: 10px; }
}