/* ===== 行星探路者 · 深空主题 (ReactBits-inspired) ===== */

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

:root {
    /* 深空配色 - 纯白极简 */
    --bg-dark: #06060a;
    --bg-card: rgba(14, 14, 20, 0.6);
    --bg-card-solid: #0e0e14;
    --bg-card-light: #16161e;
    --bg-card-hover: rgba(22, 22, 30, 0.7);
    --text-primary: #e8e8ec;
    --text-secondary: #9898a8;
    --text-muted: #6a6a7a;
    --accent: #d0d0d8;
    --accent-soft: #e8e8ec;
    --accent-glow: rgba(255, 255, 255, 0.08);
    --border: rgba(255, 255, 255, 0.06);
    --border-hover: rgba(255, 255, 255, 0.15);
    --border-accent: rgba(255, 255, 255, 0.18);
    --success: #5A7D5A;
    --current: #8a8a98;
    --title-font: 'Ma Shan Zheng', 'STKaiti', 'KaiTi', cursive;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    --spotlight: rgba(255, 255, 255, 0.02);
    --card-radius: 16px;
    --card-shadow: 0 4px 24px rgba(0, 0, 0, 0.4), 0 0 0 1px rgba(255, 255, 255, 0.05) inset;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: "SF Pro Display", -apple-system, BlinkMacSystemFont, "Helvetica Neue", Arial, sans-serif;
    font-size: 16px;
    line-height: 1.7;
    color: var(--text-primary);
    background: var(--bg-dark);
    letter-spacing: 0.01em;
    position: relative;
}

/* 全局背景 - 月球表面 */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    z-index: -2;
    background: url('images/月球表面.jpg') center/cover no-repeat fixed;
    opacity: 0.08;
}

body::after {
    content: '';
    position: fixed;
    inset: 0;
    z-index: -1;
    background: linear-gradient(180deg, rgba(6,6,10,0.88) 0%, rgba(6,6,10,0.94) 40%, rgba(6,6,10,0.97) 100%);
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 32px;
    position: relative;
    z-index: 1;
}

.section {
    padding: 120px 0;
    position: relative;
    z-index: 1;
}

.section-dark {
    background: transparent;
}

/* 标题 - 渐变闪光效果 */
.section-title {
    font-size: 42px;
    font-weight: 600;
    text-align: center;
    margin-bottom: 70px;
    letter-spacing: 0.05em;
    color: var(--text-primary);
}

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(6, 6, 10, 0.8);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    z-index: 1000;
    border-bottom: 1px solid var(--border);
    transition: var(--transition);
}

.navbar.scrolled {
    background: rgba(6, 6, 10, 0.92);
    border-bottom-color: var(--border-hover);
}

.nav-container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 32px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 60px;
}

.logo-text {
    color: var(--text-primary);
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 0.15em;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 4px;
}

.nav-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 13px;
    font-weight: 400;
    padding: 10px 16px;
    transition: var(--transition-fast);
    position: relative;
    border-radius: 6px;
}

.nav-links a:hover {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.03);
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 4px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 1.5px;
    background: var(--accent);
    transition: var(--transition);
    border-radius: 1px;
}

.nav-links a:hover::after {
    width: 60%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    z-index: 1001;
}

.nav-toggle span {
    display: block;
    width: 20px;
    height: 1.5px;
    background: var(--text-secondary);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    transform-origin: center;
}

.nav-toggle:hover span {
    background: var(--text-primary);
}

/* Active state: transform bars into X */
.nav-toggle.active span:nth-child(1) {
    transform: translateY(6.5px) rotate(45deg);
    background: var(--text-primary);
}

.nav-toggle.active span:nth-child(2) {
    opacity: 0;
    transform: scaleX(0);
}

.nav-toggle.active span:nth-child(3) {
    transform: translateY(-6.5px) rotate(-45deg);
    background: var(--text-primary);
}

/* Mobile nav-links open state */
.nav-links.nav-open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: rgba(6, 6, 10, 0.95);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border-bottom: 1px solid var(--border);
    padding: 16px 32px 24px;
    gap: 0;
    animation: navSlideDown 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

@keyframes navSlideDown {
    from {
        opacity: 0;
        transform: translateY(-8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.nav-links.nav-open a {
    display: block;
    padding: 14px 16px;
    font-size: 15px;
    border-bottom: 1px solid var(--border);
}

.nav-links.nav-open li:last-child a {
    border-bottom: none;
}

/* ===== Spotlight Card 基础 ===== */
/* All interactive cards share this mixin pattern.
   Each card type defines its own ::before with a matching radius.
   JS sets --mouse-x / --mouse-y as px values on mousemove. */
.spotlight-card {
    position: relative;
    overflow: hidden;
    --mouse-x: 50%;
    --mouse-y: 50%;
}

.spotlight-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(
        600px circle at var(--mouse-x) var(--mouse-y),
        var(--spotlight),
        transparent 60%
    );
    opacity: 0;
    transition: opacity 0.5s ease;
    pointer-events: none;
    z-index: 0;
}

.spotlight-card:hover::before {
    opacity: 1;
}

.spotlight-card > * {
    position: relative;
    z-index: 1;
}

/* ===== 英雄区 - 月球表面背景 ===== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    background: url('images/月球表面.jpg') center/cover no-repeat fixed;
}

.hero-overlay {
    position: absolute;
    inset: 0;
    z-index: 0;
    background: linear-gradient(180deg, rgba(6,6,10,0.4) 0%, rgba(6,6,10,0.65) 50%, rgba(6,6,10,0.85) 100%);
}

.hero-content {
    position: relative;
    z-index: 3;
    text-align: center;
    max-width: 850px;
    padding: 0 24px;
}

.hero-title {
    font-family: var(--title-font);
    font-size: 96px;
    font-weight: 400;
    margin-bottom: 14px;
    color: var(--text-primary);
    text-shadow: 0 2px 30px rgba(0, 0, 0, 0.4);
    line-height: 1.3;
    letter-spacing: 0.08em;
}

.hero-title .title-char {
    display: inline-block;
    opacity: 0;
    transform: translateY(20px);
    animation: charReveal 0.6s ease forwards;
}

@keyframes charReveal {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 第二行"探路者"向右偏移，形成错落感 */
.hero-title br + .title-char {
    margin-left: 0.6em;
}

.hero-subtitle {
    font-size: 20px;
    font-weight: 400;
    margin-bottom: 18px;
    color: var(--text-secondary);
    letter-spacing: 0.05em;
}

.hero-description {
    font-size: 15px;
    font-weight: 300;
    margin-bottom: 42px;
    color: var(--text-muted);
    letter-spacing: 0.05em;
}

.hero-buttons {
    display: flex;
    gap: 18px;
    justify-content: center;
    flex-wrap: wrap;
}

.btn-hero {
    display: inline-block;
    background: transparent;
    color: var(--text-primary);
    padding: 14px 42px;
    text-decoration: none;
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 0.08em;
    transition: var(--transition);
    border-radius: 8px;
    border: 1px solid var(--border-hover);
}

.btn-hero:hover {
    border-color: var(--text-secondary);
    background: rgba(255, 255, 255, 0.06);
    transform: translateY(-2px);
}

.btn-hero-outline {
    display: inline-block;
    background: transparent;
    color: var(--text-primary);
    padding: 14px 42px;
    text-decoration: none;
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 0.08em;
    transition: var(--transition);
    border: 1px solid var(--border-hover);
    border-radius: 8px;
}

.btn-hero-outline:hover {
    border-color: var(--text-secondary);
    background: rgba(255, 255, 255, 0.06);
    transform: translateY(-2px);
}

.scroll-indicator {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 3;
    text-align: center;
}

.scroll-indicator span {
    display: block;
    font-size: 10px;
    font-weight: 500;
    letter-spacing: 0.2em;
    color: var(--text-muted);
    margin-bottom: 10px;
}

.scroll-line {
    width: 1px;
    height: 50px;
    background: linear-gradient(180deg, var(--text-muted) 0%, transparent 100%);
    margin: 0 auto;
}

/* ===== 项目介绍 ===== */
.about-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.about-images {
    position: relative;
}

.image-stack {
    position: relative;
    height: 420px;
}

.stack-img {
    position: absolute;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.stack-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.stack-img:hover {
    transform: scale(1.03);
    z-index: 10;
}

/* 两张图完全相同尺寸 */
.img-1 {
    width: 85%;
    aspect-ratio: 16 / 10;
    top: 0;
    left: 0;
    z-index: 2;
}

/* 祝融号竖图：放大画面内容匹配玉兔号视觉 */
.img-1 img {
    object-fit: cover;
    object-position: center;
    transform: scale(1.6);
}

.img-2 {
    width: 85%;
    aspect-ratio: 16 / 10;
    bottom: 0;
    right: 0;
    z-index: 1;
    opacity: 0.88;
}

.about-text-col {
    display: flex;
    flex-direction: column;
    gap: 0;
}

.about-text {
    font-size: 15px;
    font-weight: 300;
    margin-bottom: 18px;
    color: var(--text-secondary);
    line-height: 1.85;
}

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

.about-text strong {
    color: var(--text-primary);
    font-weight: 500;
}

/* 团队信息行 */
.about-team-row {
    display: flex;
    gap: 24px;
    margin-top: 22px;
    padding-top: 18px;
    border-top: 1px solid var(--border);
}

.about-team-tag {
    font-size: 14px;
    color: var(--text-secondary);
}

.about-team-tag strong {
    color: var(--text-primary);
    font-weight: 600;
    margin-right: 4px;
}

/* ===== 研究方向 ===== */
#research {
    position: relative;
}

#research .container {
    position: relative;
    z-index: 1;
}

.research-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.research-card {
    background: var(--bg-card);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: 40px 28px;
    border-radius: var(--card-radius);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1px solid var(--border);
    position: relative;
    overflow: hidden;
    box-shadow: var(--card-shadow);
}

/* Spotlight glow on research cards */
.research-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(
        500px circle at var(--mouse-x, 50%) var(--mouse-y, 50%),
        var(--spotlight),
        transparent 60%
    );
    opacity: 0;
    transition: opacity 0.5s ease;
    pointer-events: none;
    z-index: 0;
    will-change: opacity;
}

.research-card::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent 0%, var(--accent) 50%, transparent 100%);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.research-card:hover {
    border-color: var(--border-hover);
    transform: translateY(-4px);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(255, 255, 255, 0.08) inset;
}

.research-card:hover::before {
    opacity: 1;
}

.research-card:hover::after {
    opacity: 1;
}

/* CSS 图标 - 月球 */
.research-icon-moon {
    width: 44px;
    height: 44px;
    margin-bottom: 22px;
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-soft) 100%);
    border-radius: 50%;
    position: relative;
    box-shadow: 0 0 20px rgba(255, 255, 255, 0.15), inset -4px -4px 8px rgba(0,0,0,0.3);
}

.research-icon-moon::before {
    content: '';
    position: absolute;
    width: 8px;
    height: 8px;
    background: rgba(0,0,0,0.15);
    border-radius: 50%;
    top: 8px;
    left: 10px;
}

.research-icon-moon::after {
    content: '';
    position: absolute;
    width: 5px;
    height: 5px;
    background: rgba(0,0,0,0.12);
    border-radius: 50%;
    bottom: 10px;
    right: 8px;
}

/* CSS 图标 - 火星 */
.research-icon-mars {
    width: 44px;
    height: 44px;
    margin-bottom: 22px;
    background: linear-gradient(135deg, #B8735A 0%, #C98A6B 100%);
    border-radius: 50%;
    position: relative;
    box-shadow: 0 0 20px rgba(184, 115, 90, 0.15), inset -4px -4px 8px rgba(0,0,0,0.3);
}

.research-icon-mars::before {
    content: '';
    position: absolute;
    width: 10px;
    height: 6px;
    background: rgba(0,0,0,0.15);
    border-radius: 50%;
    top: 12px;
    left: 8px;
}

/* CSS 图标 - 齿轮 */
.research-icon-gear {
    width: 44px;
    height: 44px;
    margin-bottom: 22px;
    background: var(--bg-card-light);
    border: 3px solid var(--text-muted);
    border-radius: 50%;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

.research-icon-gear::before {
    content: '';
    width: 16px;
    height: 16px;
    background: var(--text-muted);
    border-radius: 50%;
}

.research-icon-gear::after {
    content: '';
    position: absolute;
    width: 4px;
    height: 4px;
    background: var(--text-muted);
    top: -2px;
    left: 50%;
    transform: translateX(-50%);
    border-radius: 1px;
}

.research-card h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.research-card p {
    color: var(--text-secondary);
    margin-bottom: 18px;
    line-height: 1.6;
    font-size: 14px;
}

.research-list {
    list-style: none;
    padding: 0;
    margin-bottom: 20px;
}

.research-list li {
    padding: 7px 0;
    color: var(--text-muted);
    font-size: 13px;
    padding-left: 14px;
    position: relative;
}

.research-list li::before {
    content: '';
    position: absolute;
    left: 0;
    width: 4px;
    height: 4px;
    background: var(--accent);
    border-radius: 50%;
    top: 50%;
    transform: translateY(-50%);
}

.card-link {
    display: inline-block;
    color: var(--accent);
    text-decoration: none;
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.05em;
    transition: var(--transition-fast);
}

.card-link:hover {
    color: var(--accent-soft);
}


/* ===== 时代窗口 ===== */
.era-bg-section {
    position: relative;
}

#era .container {
    position: relative;
    z-index: 2;
}

.era-intro {
    text-align: center;
    color: var(--text-secondary);
    font-size: 17px;
    margin-bottom: 50px;
    line-height: 1.8;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* ===== 加入我们 ===== */
.join-slogan-section {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 60vh;
    text-align: center;
}

.join-slogan {
    font-size: 36px;
    font-weight: 400;
    line-height: 2;
    color: var(--text-primary);
    margin-bottom: 56px;
    letter-spacing: 0.05em;
}

.join-slogan-accent {
    color: #8EA8E8;
    font-weight: 600;
    background: linear-gradient(90deg, #8EA8E8 0%, #B8C8F0 50%, #8EA8E8 100%);
    background-size: 200% auto;
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: shimmer 4s linear infinite;
}

@keyframes shimmer {
    0% { background-position: 0% center; }
    100% { background-position: 200% center; }
}

/* StarBorder button */
.star-border-wrapper {
    display: inline-block;
    cursor: pointer;
}

.star-border-container {
    display: inline-block;
    position: relative;
    border-radius: 20px;
    padding: 2px;
    overflow: hidden;
}

.border-gradient-bottom {
    position: absolute;
    width: 300%;
    height: 50%;
    opacity: 0.7;
    bottom: -12px;
    right: -250%;
    border-radius: 50%;
    animation: star-movement-bottom 6s linear infinite alternate;
    z-index: 0;
}

.border-gradient-top {
    position: absolute;
    opacity: 0.7;
    width: 300%;
    height: 50%;
    top: -12px;
    left: -250%;
    border-radius: 50%;
    animation: star-movement-top 6s linear infinite alternate;
    z-index: 0;
}

.star-border-inner {
    position: relative;
    border: none;
    background: rgba(14, 14, 20, 0.85);
    backdrop-filter: blur(8px);
    color: var(--text-primary);
    font-size: 20px;
    font-weight: 700;
    letter-spacing: 0.15em;
    text-align: center;
    padding: 20px 64px;
    border-radius: 18px;
    z-index: 1;
    transition: all 0.3s ease;
}

.star-border-wrapper:hover .star-border-inner {
    background: rgba(14, 14, 20, 0.92);
    box-shadow: 0 0 30px rgba(255, 255, 255, 0.25);
}

@keyframes star-movement-bottom {
    0% {
        transform: translate(0%, 0%);
        opacity: 1;
    }
    100% {
        transform: translate(-100%, 0%);
        opacity: 0;
    }
}

@keyframes star-movement-top {
    0% {
        transform: translate(0%, 0%);
        opacity: 1;
    }
    100% {
        transform: translate(100%, 0%);
        opacity: 0;
    }
}

/* 行星探测路线图 - 三栏 */
.roadmap-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-bottom: 50px;
}

.roadmap-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--card-radius);
    padding: 28px 24px;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
    box-shadow: var(--card-shadow);
}

/* Spotlight for roadmap cards */
.roadmap-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(
        400px circle at var(--mouse-x, 50%) var(--mouse-y, 50%),
        var(--spotlight),
        transparent 60%
    );
    opacity: 0;
    transition: opacity 0.5s ease;
    pointer-events: none;
    will-change: opacity;
}

/* Gradient top accent line */
.roadmap-card::after {
    content: '';
    position: absolute;
    top: 0;
    left: 20%;
    right: 20%;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--accent), transparent);
    opacity: 0.4;
    transition: opacity 0.3s ease;
}

.roadmap-card:hover {
    border-color: var(--border-hover);
    transform: translateY(-4px);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(255, 255, 255, 0.08) inset;
}

.roadmap-card:hover::before {
    opacity: 1;
}

.roadmap-card:hover::after {
    opacity: 0.8;
    left: 10%;
    right: 10%;
}

.roadmap-card > * {
    position: relative;
    z-index: 1;
}

.roadmap-flag {
    display: inline-block;
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 8px;
    padding: 3px 10px;
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 4px;
}

.roadmap-card h4 {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 16px;
    letter-spacing: 0.02em;
}

.roadmap-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.roadmap-list li {
    display: flex;
    gap: 10px;
    padding: 9px 0;
    border-bottom: 1px solid var(--border);
    color: var(--text-secondary);
    font-size: 13px;
    line-height: 1.5;
    transition: var(--transition-fast);
}

.roadmap-list li:last-child {
    border-bottom: none;
}

.roadmap-list li:hover {
    color: var(--text-primary);
}

.roadmap-year {
    flex-shrink: 0;
    font-weight: 600;
    color: var(--accent);
    font-variant-numeric: tabular-nums;
    min-width: 42px;
}

.why-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.why-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--card-radius);
    padding: 36px 28px;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
    box-shadow: var(--card-shadow);
}

/* Spotlight for why cards */
.why-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(
        400px circle at var(--mouse-x, 50%) var(--mouse-y, 50%),
        var(--spotlight),
        transparent 60%
    );
    opacity: 0;
    transition: opacity 0.5s ease;
    pointer-events: none;
    will-change: opacity;
}

/* Top accent gradient line */
.why-card::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent 0%, var(--accent) 50%, transparent 100%);
    opacity: 0.4;
    transition: opacity 0.3s ease;
}

.why-card:hover {
    border-color: var(--border-hover);
    transform: translateY(-6px);
    box-shadow: 0 24px 60px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(255, 255, 255, 0.08) inset;
}

.why-card:hover::before {
    opacity: 1;
}

.why-card:hover::after {
    opacity: 1;
}

.why-card > * {
    position: relative;
    z-index: 1;
}

.why-data {
    font-size: 34px;
    font-weight: 700;
    margin-bottom: 16px;
    font-variant-numeric: tabular-nums;
    letter-spacing: -0.02em;
    color: var(--accent);
}

.why-unit {
    font-size: 18px;
    font-weight: 500;
    opacity: 0.7;
}

.why-card h4 {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.why-card p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.75;
}

.join-requirements {
    display: flex;
    justify-content: center;
    gap: 48px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.req-item {
    font-size: 14px;
    color: var(--text-secondary);
    padding: 8px 16px;
    background: rgba(255, 255, 255, 0.02);
    border-radius: 8px;
    border: 1px solid var(--border);
}

.req-item strong {
    color: var(--accent);
    margin-right: 6px;
}

.btn-apply-center {
    display: block;
    margin: 0 auto;
}

/* ===== 联系我们 ===== */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
    max-width: 680px;
    margin: 0 auto;
}

.contact-item {
    background: var(--bg-card);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: 40px 28px;
    border-radius: var(--card-radius);
    text-align: center;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1px solid var(--border);
    position: relative;
    overflow: hidden;
    box-shadow: var(--card-shadow);
}

/* Spotlight for contact cards */
.contact-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(
        300px circle at var(--mouse-x, 50%) var(--mouse-y, 50%),
        var(--spotlight),
        transparent 60%
    );
    opacity: 0;
    transition: opacity 0.5s ease;
    pointer-events: none;
    will-change: opacity;
}

.contact-item::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent 0%, var(--accent) 50%, transparent 100%);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.contact-item:hover {
    border-color: var(--border-hover);
    transform: translateY(-4px);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(255, 255, 255, 0.08) inset;
}

.contact-item:hover::before {
    opacity: 1;
}

.contact-item:hover::after {
    opacity: 0.8;
}

.contact-item > * {
    position: relative;
    z-index: 1;
}

/* CSS 图标 - 邮件 */
.contact-icon-mail {
    width: 36px;
    height: 28px;
    margin: 0 auto 18px;
    border: 2px solid var(--text-muted);
    border-radius: 3px;
    position: relative;
}

.contact-icon-mail::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    border-left: 9px solid transparent;
    border-right: 9px solid transparent;
    border-top: 7px solid var(--text-muted);
}

/* CSS 图标 - 对话 */
.contact-icon-chat {
    width: 38px;
    height: 32px;
    margin: 0 auto 18px;
    border: 2px solid var(--text-muted);
    border-radius: 8px;
    position: relative;
}

.contact-icon-chat::before {
    content: '';
    position: absolute;
    bottom: -6px;
    left: 8px;
    border-left: 6px solid transparent;
    border-right: 6px solid var(--text-muted);
    border-top: 6px solid var(--text-muted);
}

.contact-icon-chat::after {
    content: '';
    position: absolute;
    bottom: -6px;
    left: 9px;
    border-left: 5px solid transparent;
    border-right: 5px solid var(--bg-card);
    border-top: 5px solid var(--bg-card);
}

.contact-item h4 {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.contact-item p {
    color: var(--text-secondary);
    font-size: 14px;
    line-height: 1.7;
}


/* ===== 页脚 ===== */
.footer {
    background: var(--bg-card-solid);
    color: var(--text-muted);
    padding: 50px 0;
    text-align: center;
    border-top: 1px solid var(--border);
    position: relative;
    z-index: 1;
}

.footer p {
    font-size: 12px;
    margin-bottom: 8px;
}

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

/* ===== 动画 ===== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    opacity: 0;
    transform: translateY(25px);
    transition: opacity 0.6s cubic-bezier(0.4, 0, 0.2, 1), transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== 响应式 ===== */
@media (max-width: 968px) {
    .research-grid,
    .contact-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 20px;
    }

    .why-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .about-layout {
        grid-template-columns: 1fr;
        gap: 36px;
    }

    .about-images {
        order: -1;
    }

    .image-stack {
        height: 320px;
    }

    .about-team-row {
        flex-direction: column;
        gap: 8px;
    }

    .why-card {
        padding: 28px 24px;
    }

    .roadmap-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .hero-title {
        font-size: 72px;
        line-height: 1.25;
    }

    .section-title {
        font-size: 36px;
        margin-bottom: 50px;
    }

    .section {
        padding: 90px 0;
    }

    .era-intro {
        font-size: 16px;
        margin-bottom: 40px;
    }
}

@media (max-width: 640px) {
    .research-grid,
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 16px;
    }

    .research-card {
        padding: 28px 20px;
    }

    .roadmap-grid {
        gap: 16px;
    }

    .roadmap-card {
        padding: 24px 20px;
    }

    .why-grid {
        gap: 16px;
    }

    .why-card {
        padding: 24px 20px;
    }

    .why-data {
        font-size: 28px;
    }

    .hero-title {
        font-size: 42px;
        line-height: 1.15;
    }

    .hero-subtitle {
        font-size: 17px;
    }

    .section-title {
        font-size: 30px;
        margin-bottom: 40px;
    }

    .nav-links {
        display: none;
    }

    .nav-toggle {
        display: flex;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
        gap: 12px;
    }

    .btn-hero,
    .btn-hero-outline {
        width: 100%;
        max-width: 260px;
        text-align: center;
    }

    .scroll-indicator {
        bottom: 24px;
    }

    .container {
        padding: 0 20px;
    }

    .section {
        padding: 70px 0;
    }

    .era-intro {
        font-size: 15px;
        margin-bottom: 36px;
    }

    .join-intro {
        font-size: 15px;
        margin-bottom: 36px;
    }

    .join-slogan {
        font-size: 24px;
        line-height: 1.9;
    }

    .join-slogan-section {
        min-height: 50vh;
    }

    .contact-grid {
        max-width: 100%;
    }

    .contact-item {
        padding: 28px 20px;
    }

}

/* ===== 移动端性能优化 ===== */
@media (max-width: 640px) {
    /* Disable card hover transforms on mobile (no hover state on touch) */
    .research-card,
    .roadmap-card,
    .why-card,
    .contact-item {
        transform: none !important;
    }

    .research-card:hover,
    .roadmap-card:hover,
    .why-card:hover,
    .contact-item:hover {
        transform: none !important;
        box-shadow: var(--card-shadow);
    }
}

/* ===== 模态框系统 - 方案 A 精致现代风 ===== */
.modal {
    display: none;
    position: fixed;
    z-index: 9999;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.75);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    align-items: center;
    justify-content: center;
    overflow-y: auto;
    padding: 20px;
    opacity: 0;
    transition: opacity 0.2s ease;
}

.modal.show {
    opacity: 1;
}

.modal-content {
    background: var(--bg-card-solid);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 40px;
    max-width: 680px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    position: relative;
    box-shadow: 0 24px 64px rgba(0, 0, 0, 0.6), 0 0 0 1px rgba(255, 255, 255, 0.05) inset;
    transform: scale(0.96) translateY(10px);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    animation: modalEnter 0.3s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

@keyframes modalEnter {
    from {
        opacity: 0;
        transform: scale(0.96) translateY(10px);
    }
    to {
        opacity: 1;
        transform: scale(1) translateY(0);
    }
}

.modal-close {
    position: absolute;
    top: 16px;
    right: 20px;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: 300;
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.2s ease;
    line-height: 1;
    border-radius: 50%;
    background: rgba(255,255,255,0.03);
}

.modal-close:hover {
    color: var(--accent);
    background: rgba(201,166,107,0.1);
    transform: rotate(90deg);
}

.modal-content h2 {
    font-size: 26px;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.modal-content h3 {
    font-size: 22px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

.modal-subtitle {
    color: var(--text-secondary);
    font-size: 14px;
    margin-bottom: 30px;
    line-height: 1.6;
}

/* 提交成功提示 */
.submit-success {
    text-align: center;
    padding: 40px 20px;
}

.submit-success-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 20px;
    background: rgba(90, 125, 90, 0.2);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    color: #7DA87D;
}

.submit-success-title {
    font-size: 22px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.submit-success-text {
    color: var(--text-secondary);
    font-size: 14px;
    line-height: 1.6;
}

.submit-success-close {
    margin-top: 24px;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 18px;
    margin-bottom: 18px;
}

.form-group {
    margin-bottom: 18px;
}

.form-group label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
    letter-spacing: 0.03em;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 14px;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border);
    border-radius: 10px;
    color: var(--text-primary);
    font-size: 14px;
    font-family: inherit;
    transition: all 0.2s ease;
    -webkit-appearance: none;
    appearance: none;
}

/* Select dropdown arrow */
.form-group select {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' fill='none'%3E%3Cpath d='M1 1.5l5 5 5-5' stroke='%239898a8' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 14px center;
    padding-right: 36px;
    cursor: pointer;
}

/* Fix browser autofill colors on dark background */
.form-group input:-webkit-autofill,
.form-group select:-webkit-autofill,
.form-group textarea:-webkit-autofill {
    -webkit-box-shadow: 0 0 0 1000px var(--bg-card) inset;
    -webkit-text-fill-color: var(--text-primary);
    caret-color: var(--text-primary);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--border-accent);
    background: rgba(255, 255, 255, 0.05);
    box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.08);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-muted);
}

.form-group textarea {
    resize: vertical;
    min-height: 80px;
    line-height: 1.6;
}

.form-actions {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
    margin-top: 28px;
    padding-top: 24px;
    border-top: 1px solid var(--border);
}

.btn-secondary {
    padding: 11px 24px;
    background: transparent;
    border: 1px solid var(--border-hover);
    border-radius: 10px;
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.btn-secondary:hover {
    border-color: var(--text-muted);
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
}

.btn-primary {
    padding: 11px 24px;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.15) 0%, rgba(255, 255, 255, 0.1) 100%);
    border: 1px solid var(--border-accent);
    border-radius: 10px;
    color: var(--accent);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.btn-primary:hover {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.25) 0%, rgba(255, 255, 255, 0.2) 100%);
    border-color: var(--accent);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(255, 255, 255, 0.15);
}

/* ===== Toast 提示 - 精致现代风 ===== */
.toast-container {
    position: fixed;
    top: 80px;
    right: 24px;
    z-index: 10000;
    display: flex;
    flex-direction: column;
    gap: 12px;
    pointer-events: none;
}

.toast {
    min-width: 320px;
    max-width: 420px;
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border);
    border-left: 3px solid var(--accent);
    border-radius: 12px;
    padding: 16px 20px;
    box-shadow: 0 12px 40px rgba(0,0,0,0.5);
    display: flex;
    align-items: center;
    gap: 14px;
    transform: translateX(120%);
    opacity: 0;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    pointer-events: auto;
}

.toast.show {
    transform: translateX(0);
    opacity: 1;
}

.toast.hide {
    transform: translateX(120%);
    opacity: 0;
}

.toast-icon {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    flex-shrink: 0;
}

.toast-icon.success {
    background: rgba(90, 125, 90, 0.3);
    color: #7DA87D;
}

.toast-icon.error {
    background: rgba(220, 53, 69, 0.2);
    color: #dc3545;
}

.toast-icon.warning {
    background: rgba(255, 255, 255, 0.2);
    color: var(--accent);
}

.toast-icon.info {
    background: rgba(100, 150, 200, 0.2);
    color: #6496c8;
}

.toast-message {
    flex: 1;
    color: var(--text-primary);
    font-size: 14px;
    line-height: 1.5;
}

.toast-close {
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    color: var(--text-muted);
    cursor: pointer;
    transition: all 0.2s ease;
    border-radius: 50%;
    background: transparent;
}

.toast-close:hover {
    color: var(--text-primary);
    background: rgba(255,255,255,0.05);
}

/* ===== 确认对话框 - 精致现代风 ===== */
.confirm-overlay {
    display: none;
    position: fixed;
    z-index: 9998;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(3px);
    -webkit-backdrop-filter: blur(3px);
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.2s ease;
}

.confirm-overlay.show {
    opacity: 1;
}

.confirm-dialog {
    background: var(--bg-card-solid);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 32px;
    max-width: 420px;
    width: 90%;
    box-shadow: 0 24px 64px rgba(0,0,0,0.6), 0 0 0 1px rgba(255, 255, 255, 0.05) inset;
    transform: scale(0.96) translateY(10px);
    animation: modalEnter 0.3s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.confirm-icon {
    width: 48px;
    height: 48px;
    margin: 0 auto 20px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
}

.confirm-icon.warning {
    background: rgba(255, 255, 255, 0.15);
    color: var(--accent);
}

.confirm-icon.danger {
    background: rgba(220, 53, 69, 0.15);
    color: #dc3545;
}

.confirm-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
    text-align: center;
    margin-bottom: 12px;
}

.confirm-message {
    font-size: 14px;
    color: var(--text-secondary);
    text-align: center;
    line-height: 1.6;
    margin-bottom: 28px;
}

.confirm-actions {
    display: flex;
    gap: 12px;
    justify-content: center;
}

.confirm-actions .btn-secondary,
.confirm-actions .btn-primary {
    flex: 1;
    max-width: 140px;
}

/* 响应式优化 */
@media (max-width: 640px) {
    .modal-content {
        padding: 30px 20px;
    }

    .form-row {
        grid-template-columns: 1fr;
        gap: 0;
    }

    .form-actions {
        flex-direction: column;
    }

    .btn-secondary,
    .btn-primary {
        width: 100%;
    }

    .toast-container {
        left: 16px;
        right: 16px;
    }

    .toast {
        min-width: auto;
        width: 100%;
    }

    .confirm-dialog {
        padding: 28px 20px;
    }

    .confirm-actions {
        flex-direction: column;
    }

    .confirm-actions .btn-secondary,
    .confirm-actions .btn-primary {
        max-width: none;
        width: 100%;
    }
}