/* ====== 基础重置与全局变量 ====== */
:root {
    --primary-color: #2b4c65; /* 雅致科技蓝 */
    --bg-light: #ffffff;
    --bg-gray: #f7f9fa;
    --bg-dark: #111417; /* 深空灰黑 */
    --text-dark: #1a1a1a;
    --text-gray: #767676;
    --text-light: #f5f5f5;
    
    /* 字体：使用浏览器/系统默认字体，无需加载外部字体资源 */
    --font-heading: "SimSun", "STSong", "Times New Roman", serif;
    --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    color: var(--text-dark);
    background-color: var(--bg-light);
    line-height: 1.6;
    overflow-x: hidden;
}

/* ====== 排版基础 ====== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 5%;
}

.section {
    padding: 120px 0;
    position: relative;
}

.section-gray { background-color: var(--bg-gray); }
.section-dark { 
    background-color: var(--bg-dark); 
    color: var(--text-light); 
}

h1, h2, h3, h4 {
    font-family: var(--font-heading);
    font-weight: 600;
}

.subtitle-en {
    display: block;
    font-size: 0.75rem;
    letter-spacing: 0.2em;
    color: var(--text-gray);
    text-transform: uppercase;
    margin-bottom: 1.5rem;
}

.section-dark .subtitle-en { color: #a0a0a0; }

.section-title {
    font-size: 2.5rem;
    line-height: 1.3;
    margin-bottom: 2rem;
}

.section-text {
    font-size: 1.1rem;
    color: var(--text-gray);
    max-width: 800px;
    margin-bottom: 1.5rem;
}

.section-dark .section-text { color: #cccccc; }

.section-header { margin-bottom: 4rem; }

/* ====== 导航栏 Navbar ====== */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 100;
    background: #1a5fa8;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255,255,255,0.1);
    box-shadow: 0 2px 12px rgba(0,0,0,0.18);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo {
    display: flex;
    flex-direction: column;
    line-height: 1.2;
}

.logo-zh {
    font-family: var(--font-heading);
    font-size: 1.3rem;
    font-weight: 900;
    color: var(--primary-color);
}

.logo-en {
    font-size: 0.65rem;
    letter-spacing: 0.15em;
    color: var(--text-gray);
}

/* Navbar 蓝色背景下 logo 文字改为白色 */
.navbar .logo-zh {
    color: #ffffff;
}

.navbar .logo-en {
    color: rgba(255,255,255,0.75);
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 2.5rem;
}

.nav-links a {
    text-decoration: none;
    color: rgba(255,255,255,0.9);
    font-size: 0.9rem;
    transition: color 0.3s ease;
}

.nav-links a:hover {
    color: #ffffff;
}

/* ====== 第一屏 Hero ====== */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    /* 使用无版权的高端医疗/科技感图片作为背景，并加上深色遮罩 */
    background: linear-gradient(rgba(17, 20, 23, 0.7), rgba(17, 20, 23, 0.8)), url('hero_bg.png') center/cover no-repeat;
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    padding-top: 80px; /* offset navbar */
}

.hero-title {
    font-size: 4rem;
    margin-bottom: 1.5rem;
}

.hero-desc {
    font-size: 1.2rem;
    color: #e0e0e0;
    margin-bottom: 3rem;
}

.btn-primary {
    display: inline-block;
    padding: 1rem 2.5rem;
    background: transparent;
    color: var(--text-light);
    text-decoration: none;
    border: 1px solid var(--text-light);
    font-size: 0.9rem;
    letter-spacing: 0.1em;
    transition: all 0.4s ease;
}

.btn-primary:hover {
    background: var(--text-light);
    color: var(--text-dark);
}

/* ====== 第二屏 关于我们 ====== */
.about-container {
    display: flex;
    gap: 4rem;
}

.about-left {
    flex: 1;
}

.about-right {
    flex: 2;
}

/* ====== 第三屏 核心业务 ====== */
.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.card {
    background: var(--bg-light);
    padding: 3rem 2rem;
    border: 1px solid #eaeaea;
    transition: transform 0.4s ease, box-shadow 0.4s ease;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0,0,0,0.05);
}

.card-icon {
    font-family: var(--font-heading);
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    opacity: 0.8;
}

.card-title {
    font-size: 1.3rem;
    margin-bottom: 1rem;
}

.card-tags {
    margin-bottom: 1.5rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.card-tags span {
    font-size: 0.75rem;
    background: var(--bg-gray);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    color: var(--primary-color);
}

.card-desc {
    font-size: 0.95rem;
    color: var(--text-gray);
    line-height: 1.7;
}

/* ====== 第四屏 生态系统 ====== */
.timeline {
    border-left: 1px solid rgba(255,255,255,0.2);
    padding-left: 3rem;
    margin-left: 1rem;
}

.timeline-item {
    position: relative;
    margin-bottom: 4rem;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -3.35rem; /* align to border */
    top: 5px;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--text-light);
}

.timeline-title {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.timeline-desc {
    font-size: 1rem;
    color: #cccccc;
    max-width: 600px;
}

/* ====== 第五屏 优势 ====== */
.advantage-list {
    display: flex;
    flex-direction: column;
    gap: 3rem;
}

.adv-item h3 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    display: flex;
    align-items: baseline;
    gap: 1rem;
}

.adv-item h3 span {
    font-family: var(--font-body);
    font-size: 0.85rem;
    font-weight: 400;
    color: var(--text-gray);
    letter-spacing: 0.1em;
}

.adv-item p {
    font-size: 1.05rem;
    color: var(--text-gray);
    max-width: 800px;
}

.adv-line {
    width: 100%;
    height: 1px;
    background: #eaeaea;
    margin-bottom: 2rem;
}

/* ====== 第六屏 愿景 ====== */
.vision {
    display: flex;
    align-items: center;
    min-height: 80vh;
}

.vision-bg {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    background: linear-gradient(to right, rgba(17,20,23,0.95) 20%, rgba(17,20,23,0.4)), url('vision_bg.png') center/cover no-repeat;
    z-index: 1;
}

.vision-content {
    position: relative;
    z-index: 2;
}

.vision-quote {
    margin-top: 3rem;
    font-family: var(--font-heading);
    font-size: 1.5rem;
    color: var(--primary-color);
    background: rgba(255,255,255,0.9);
    display: inline-block;
    padding: 0.5rem 1.5rem;
}

/* ====== 页脚 Footer ====== */
.footer {
    padding: 60px 0 30px;
    background: var(--bg-light);
    border-top: 1px solid #eaeaea;
}

.footer-container {
    display: flex;
    justify-content: space-between;
    margin-bottom: 4rem;
    flex-wrap: wrap;
    gap: 2rem;
}

.footer-desc {
    margin-top: 1rem;
    font-size: 0.9rem;
    color: var(--text-gray);
}

.footer-right p {
    font-size: 0.9rem;
    color: var(--text-gray);
    margin-bottom: 0.5rem;
}

.footer-bottom {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    gap: 0.5rem;
    border-top: 1px solid #eaeaea;
    padding-top: 2rem;
    font-size: 0.8rem;
    color: #999;
    flex-wrap: wrap;
}

.disclaimer {
    font-style: italic;
}

/* ====== 动画 Scroll Reveal ====== */
.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: all 0.8s cubic-bezier(0.5, 0, 0, 1);
}

.reveal-delay-1 { opacity: 0; transform: translateY(40px); transition: all 0.8s cubic-bezier(0.5, 0, 0, 1) 0.1s; }
.reveal-delay-2 { opacity: 0; transform: translateY(40px); transition: all 0.8s cubic-bezier(0.5, 0, 0, 1) 0.2s; }
.reveal-delay-3 { opacity: 0; transform: translateY(40px); transition: all 0.8s cubic-bezier(0.5, 0, 0, 1) 0.3s; }

.active {
    opacity: 1;
    transform: translateY(0);
}

/* ====== 响应式设计 (手机端) ====== */
@media (max-width: 768px) {
    .hero-title { font-size: 2.5rem; }
    .section-title { font-size: 2rem; }
    .about-container { flex-direction: column; gap: 2rem; }
    .grid-3 { grid-template-columns: 1fr; }
    .nav-links { display: none; /* 手机端简化，隐藏菜单 */ }
    .timeline { padding-left: 1.5rem; }
    .timeline-item::before { left: -1.85rem; }
    .footer-container { flex-direction: column; }
}