/* --- 全局设置 --- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

/* V2.1 颜色变量定义 (不变) */
:root {
    --sky-blue: #5CACEE;
    --light-blue-bg: #EBF5FF;
    --dark-text: #343A40;
    --medium-text: #6C757D;
    --light-gray-border: #DEE2E6;
    --white-bg: #FFFFFF;
    --light-bg: #F8F9FA;
}

body {
    background-color: var(--white-bg);
    color: var(--dark-text);
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", "Arial", sans-serif;
    line-height: 1.7;
    overflow-x: hidden;
}

a {
    color: var(--sky-blue);
    text-decoration: none;
    transition: opacity 0.3s ease; /* V2.2: 保持基础过渡 */
}
a:hover {
    opacity: 0.7;
}

/* --- 导航栏 (V2.2: 增加 scrolled 样式) --- */
.main-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--light-gray-border);
    transition: background 0.3s ease, box-shadow 0.3s ease; /* V2.2: 添加过渡 */
}
/* V2.2: 导航栏滚动时样式 */
.main-nav.scrolled {
     background: rgba(255, 255, 255, 0.95);
     box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

.nav-content {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 30px;
    height: 56px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.nav-brand {
    font-weight: 600;
    color: var(--dark-text);
}
.nav-links {
    list-style: none;
    display: flex;
}
.nav-links li {
    margin-left: 35px;
}
.nav-links a {
    color: var(--medium-text);
    font-size: 0.85rem;
    transition: color 0.3s ease; /* V2.2: 悬停颜色过渡 */
}
.nav-links a:hover {
    color: var(--sky-blue);
}

/* --- 主内容区 --- */
main {
    padding-top: 56px;
}

/* --- 通用 Section 样式 --- */
section {
    min-height: 80vh; /* V2.2: 恢复稍高的高度 */
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 100px 30px; /* V2.2: 恢复稍大边距 */
    text-align: center;
    border-bottom: 1px solid var(--light-gray-border);
    position: relative;
    overflow: hidden; /* V2.2: 确保动画元素不溢出 */
}
section:last-of-type {
    border-bottom: none;
}
section:nth-of-type(even) {
     background-color: var(--light-bg);
}

section h2 {
    font-size: 2.5rem; /* V2.2: 恢复稍大字号 */
    font-weight: 700;
    margin-bottom: 50px; /* V2.2: 恢复稍大间距 */
    color: var(--dark-text);
}

/* --- Section 1: Hero (V2.2: 恢复动画) --- */
.hero {
    min-height: calc(100vh - 56px);
    background: linear-gradient(135deg, #EBF5FF 0%, #BDE0FE 100%);
    color: var(--dark-text);
    border-bottom: none; /* Hero 无需边框 */
    position: relative; /* V2.2: 为滚动提示定位 */
}
.hero-title {
    font-size: 4rem; /* V2.2: 恢复稍大字号 */
    font-weight: 700;
    color: #212529;
    letter-spacing: -1px;
    margin-bottom: 10px;
    opacity: 0;
    /* V2.2: 恢复入场动画 */
    animation: fadeInUp 1s 0.5s forwards cubic-bezier(0.2, 0.8, 0.2, 1);
}
.hero-subtitle {
    font-size: 1.6rem; /* V2.2: 恢复稍大字号 */
    font-weight: 400;
    color: var(--medium-text);
    margin-bottom: 30px;
    opacity: 0;
    /* V2.2: 恢复入场动画 */
    animation: fadeInUp 1s 0.8s forwards cubic-bezier(0.2, 0.8, 0.2, 1);
}
.hero-slogan {
    font-size: 1.2rem; /* V2.2: 恢复稍大字号 */
    color: #495057;
    max-width: 600px;
    opacity: 0;
    /* V2.2: 恢复入场动画 */
    animation: fadeInUp 1s 1.1s forwards cubic-bezier(0.2, 0.8, 0.2, 1);
}
/* V2.2: 恢复向下滚动提示 */
.scroll-down-prompt {
    position: absolute;
    bottom: 30px;
    color: rgba(92, 172, 238, 0.5);
    animation: pulse 2s infinite ease-in-out;
}
.scroll-down-prompt svg { width: 30px; height: 30px; }
/* V2.2: 恢复动画定义 */
@keyframes pulse {
    0% { opacity: 0.3; transform: scale(0.9); }
    50% { opacity: 0.8; transform: scale(1); }
    100% { opacity: 0.3; transform: scale(0.9); }
}
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}


/* --- Section 2: Ethos (V2.2: 恢复动画和交互) --- */
.ethos {
     background-color: var(--light-bg);
}
.ethos-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: 60px; /* V2.2: 恢复较大间距 */
    max-width: 900px;
    align-items: center;
    width: 100%;
}
.ethos-text {
    text-align: left;
    color: var(--medium-text);
}
.ethos-text h2 { text-align: left; margin-bottom: 30px; }
.ethos-text p {
    margin-bottom: 1.5em;
    font-size: 1.05rem; /* V2.2: 恢复稍大字号 */
}
/* 技能标签 (V2.2: 恢复悬停效果) */
.skills span {
    display: inline-block;
    background: var(--light-blue-bg);
    color: var(--sky-blue);
    font-size: 0.8rem;
    padding: 5px 12px;
    border-radius: 15px;
    margin: 5px;
    border: 1px solid rgba(92, 172, 238, 0.2);
    font-family: 'SF Mono', 'Menlo', monospace;
    transition: all 0.3s ease; /* V2.2: 添加过渡 */
}
.skills span:hover { /* V2.2: 恢复悬停 */
    background: var(--sky-blue);
    color: #fff;
    transform: translateY(-2px); /* V2.2: 增加轻微上浮 */
}
/* 右侧视觉元素 (V2.2: 恢复动画) */
.ethos-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}
.lens-svg {
    width: 200px; /* V2.2: 恢复稍大尺寸 */
    height: 200px;
    opacity: 0.6; /* V2.2: 恢复稍暗透明度 */
}
.lens-svg circle, .lens-svg line { stroke: #CED4DA; stroke-width: 0.5; }
.lens-svg .focus-rect {
    stroke: var(--sky-blue);
    stroke-width: 1;
    fill: none;
    /* V2.2: 恢复焦点框呼吸动画 */
    animation: focus-breathing 3s infinite ease-in-out;
    transform-origin: center;
}
/* V2.2: 恢复动画定义 */
@keyframes focus-breathing {
    0% { stroke-width: 1; transform: scale(1); }
    50% { stroke-width: 1.5; transform: scale(1.05); stroke: #87CEFA; }
    100% { stroke-width: 1; transform: scale(1); }
}
@media (min-width: 768px) {
    .ethos-content {
        grid-template-columns: 1.5fr 1fr;
    }
}


/* --- Section 3: Project (V2.2: 恢复交互) --- */
.project-card {
    display: grid;
    grid-template-columns: 1fr;
    gap: 40px; /* V2.2: 恢复较大间距 */
    max-width: 1000px;
    background: var(--white-bg);
    border: 1px solid var(--light-gray-border);
    border-radius: 12px; /* V2.2: 恢复稍大圆角 */
    overflow: hidden;
    padding: 40px; /* V2.2: 恢复稍大内边距 */
    width: 100%;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
    transition: box-shadow 0.3s ease, transform 0.3s ease; /* V2.2: 添加过渡 */
}
.project-card:hover { /* V2.2: 恢复悬停阴影和上浮 */
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(92, 172, 238, 0.15);
}
.project-visual img {
    display: block;
    width: 100%;
    border-radius: 8px; /* V2.2: 恢复稍大圆角 */
}
.project-details {
    text-align: left;
}
.project-details h3 {
    font-size: 1.8rem; /* V2.2: 恢复稍大字号 */
    color: var(--dark-text);
    margin-bottom: 5px;
}
.project-details h4 {
    font-size: 0.9rem; /* V2.2: 恢复稍大字号 */
    color: var(--medium-text);
    margin-bottom: 25px; /* V2.2: 恢复稍大间距 */
    font-weight: 400;
}
.project-points details {
    border: 1px solid var(--light-gray-border);
    border-radius: 6px;
    margin-bottom: 25px; /* V2.2: 恢复稍大间距 */
}
.project-points summary {
    padding: 12px;
    cursor: pointer;
    font-weight: 500;
    color: #495057;
    display: flex; justify-content: space-between; align-items: center;
}
.project-points summary .arrow { color: var(--medium-text); transition: transform 0.3s ease; /* V2.2: 添加箭头旋转动画 */}
.project-points details[open] summary .arrow { transform: rotate(180deg); }
.project-points ul {
    list-style: none;
    padding: 0 12px 12px;
    color: var(--medium-text);
    font-size: 0.9rem; /* V2.2: 恢复稍大字号 */
    line-height: 1.6; /* V2.2: 调整行高 */
}
.project-links a { margin-right: 15px; font-weight: 500; }
@media (min-width: 992px) {
    .project-card {
        grid-template-columns: 1fr 1fr;
        padding: 50px; /* V2.2: 恢复稍大内边距 */
    }
}


/* --- Section 4: Connect (V2.2: 恢复交互) --- */
.connect { min-height: auto; padding-bottom: 80px; background-color: var(--light-bg); }
.connect-intro {
    color: var(--medium-text);
    margin-bottom: 30px;
    max-width: 600px;
    font-size: 1.05rem; /* V2.2: 恢复稍大字号 */
}
.connect-methods {
    display: flex; flex-direction: column; align-items: center;
    gap: 25px; margin-bottom: 30px;
}
.connect-email {
    font-size: 1.3rem; /* V2.2: 恢复稍大字号 */
    font-weight: 500;
    color: var(--dark-text);
}
.connect-email a { color: inherit; }
.social-links a { /* (V2.2: 恢复悬停效果) */
    display: inline-block; width: 36px; height: 36px;
    background: #E9ECEF; border-radius: 50%;
    color: var(--medium-text); text-align: center; line-height: 36px;
    margin: 0 8px; font-size: 1rem;
    transition: background 0.3s ease, color 0.3s ease, transform 0.2s ease; /* V2.2: 添加过渡 */
}
.social-links a:hover { /* V2.2: 恢复悬停 */
    background: var(--sky-blue);
    color: #fff;
    transform: scale(1.1); /* V2.2: 增加放大效果 */
}
.team-contact-link { color: #ADB5BD; font-size: 0.85rem; }
.team-contact-link a { color: #6C757D; text-decoration: underline; }


/* --- Footer (V2.1 不变) --- */
.footer {
    padding: 25px 20px;
    text-align: center;
    color: #ADB5BD;
    font-size: 0.8rem;
    background-color: var(--light-bg);
    border-top: 1px solid var(--light-gray-border);
}
.footer p { margin: 0; }

/* --- V2.2: 恢复滚动淡入动画 --- */
.fade-in {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 1.2s cubic-bezier(0.2, 0.8, 0.2, 1), transform 1.2s cubic-bezier(0.2, 0.8, 0.2, 1);
}
.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}
/* V2.2: 恢复延迟效果 */
.ethos.visible .ethos-text,
.project.visible .project-details {
    transition-delay: 0.2s;
}


/* --- 响应式设计 (V2.1 不变) --- */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .hero-title { font-size: 2.5rem; } /* V2.2: 调整 */
    .hero-subtitle { font-size: 1.1rem; }
    .hero-slogan { font-size: 1rem; }
    section h2 { font-size: 1.8rem; }
    .ethos-text p { font-size: 0.95rem; } /* V2.2: 调整 */
    .project-card { padding: 20px; }
    .project-details h3 { font-size: 1.4rem; }
    .connect-email { font-size: 1.1rem; }
}