/* ========== 全局重置与变量 ========== */
:root {
    --color-primary: #C8102E;       /* 中国红 */
    --color-secondary: #005BAC;     /* 科技蓝 */
    --color-accent: #FF6B35;        /* 警示橙 */
    --color-dark: #1a1a2e;          /* 深色背景 */
    --color-dark2: #16213e;         /* 次深背景 */
    --color-bg: #fafafa;            /* 主背景 */
    --color-bg-alt: #f0f4f8;        /* 交替背景 */
    --color-text: #2d3436;          /* 主文字 */
    --color-text-light: #636e72;    /* 次文字 */
    --color-white: #ffffff;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.08);
    --shadow-md: 0 6px 24px rgba(0,0,0,0.12);
    --shadow-lg: 0 12px 40px rgba(0,0,0,0.18);
    --radius: 16px;
    --transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: 70px;
}

body {
    font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.7;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ========== 通用 Section ========== */
.section {
    padding: 90px 0;
    position: relative;
}
.section-alt {
    background: var(--color-bg-alt);
}
.section-dark {
    background: linear-gradient(160deg, var(--color-dark) 0%, var(--color-dark2) 100%);
    color: var(--color-white);
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}
.section-tag {
    display: inline-block;
    font-size: 13px;
    letter-spacing: 3px;
    color: var(--color-primary);
    font-weight: 700;
    padding: 6px 16px;
    background: rgba(200,16,46,0.08);
    border-radius: 20px;
    margin-bottom: 18px;
}
.section-tag.light {
    color: #ff6b6b;
    background: rgba(255,107,107,0.15);
}
.section-title {
    font-size: 38px;
    font-weight: 800;
    color: var(--color-text);
    margin-bottom: 14px;
    letter-spacing: 1px;
}
.section-title.light { color: var(--color-white); }
.section-desc {
    font-size: 17px;
    color: var(--color-text-light);
    max-width: 700px;
    margin: 0 auto;
}
.section-desc.light { color: rgba(255,255,255,0.7); }

/* ========== 滚动渐入动画 ========== */
.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.8s ease, transform 0.8s ease;
    transition-delay: var(--delay, 0s);
}
.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

/* ========== 顶部导航栏 ========== */
.navbar {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 1000;
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(12px);
    box-shadow: 0 1px 0 rgba(0,0,0,0.06);
    transition: var(--transition);
}
.navbar.scrolled {
    box-shadow: var(--shadow-sm);
}
.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.nav-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    font-size: 20px;
    font-weight: 800;
    color: var(--color-primary);
}
.logo-icon { font-size: 24px; }
.nav-menu {
    display: flex;
    list-style: none;
    gap: 6px;
}
.nav-link {
    text-decoration: none;
    color: var(--color-text);
    font-size: 15px;
    font-weight: 500;
    padding: 8px 14px;
    border-radius: 8px;
    transition: var(--transition);
    position: relative;
}
.nav-link:hover { color: var(--color-primary); background: rgba(200,16,46,0.06); }
.nav-link.active { color: var(--color-primary); }
.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: 2px; left: 14px; right: 14px;
    height: 2px;
    background: var(--color-primary);
    border-radius: 2px;
}
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
}
.nav-toggle span {
    width: 24px; height: 2px;
    background: var(--color-text);
    transition: var(--transition);
}

/* ========== Hero 首屏 ========== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    text-align: center;
    color: var(--color-white);
    padding: 90px 24px 60px;
}
.hero-bg {
    position: absolute;
    inset: 0;
    background: url('../hero-bg.jpg') center center / cover no-repeat;
    z-index: 0;
}
.hero-bg::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(200,16,46,0.55) 0%, rgba(100,10,30,0.65) 40%, rgba(15,15,30,0.85) 100%);
}
.hero-overlay {
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse at center, rgba(0,0,0,0.15) 0%, rgba(0,0,0,0.45) 100%);
    z-index: 1;
}
.hero-content {
    max-width: 1000px;
    position: relative;
    z-index: 2;
}
.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-size: 14px;
    padding: 8px 22px;
    background: rgba(255,255,255,0.12);
    border: 1px solid rgba(255,255,255,0.25);
    border-radius: 30px;
    margin-bottom: 28px;
    backdrop-filter: blur(8px);
}
.badge-divider { opacity: 0.5; }
.hero-title {
    margin-bottom: 22px;
}
.title-main {
    display: block;
    font-size: 76px;
    font-weight: 900;
    letter-spacing: 8px;
    text-shadow: 0 4px 30px rgba(0,0,0,0.4);
    background: linear-gradient(180deg, #fff 0%, #ffd0d0 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.title-sub {
    display: block;
    font-size: 26px;
    font-weight: 400;
    letter-spacing: 4px;
    margin-top: 8px;
    opacity: 0.95;
}
.hero-slogan {
    font-size: 18px;
    opacity: 0.85;
    margin-bottom: 50px;
    letter-spacing: 1px;
}
.hero-stats {
    display: flex;
    justify-content: center;
    gap: 50px;
    flex-wrap: wrap;
    margin-bottom: 44px;
}
.stat-item {
    position: relative;
}
.stat-number {
    font-size: 52px;
    font-weight: 900;
    color: var(--color-white);
    line-height: 1;
    display: inline-block;
}
.stat-plus, .stat-unit {
    font-size: 28px;
    font-weight: 700;
    color: var(--color-accent);
}
.stat-label {
    font-size: 14px;
    opacity: 0.75;
    margin-top: 8px;
    letter-spacing: 1px;
}
.hero-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}
.btn {
    display: inline-block;
    padding: 14px 36px;
    border-radius: 30px;
    text-decoration: none;
    font-size: 16px;
    font-weight: 600;
    transition: var(--transition);
    cursor: pointer;
    border: 2px solid transparent;
}
.btn-primary {
    background: var(--color-white);
    color: var(--color-primary);
    box-shadow: 0 8px 24px rgba(0,0,0,0.2);
}
.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 12px 32px rgba(0,0,0,0.3);
}
.btn-outline {
    border-color: rgba(255,255,255,0.6);
    color: var(--color-white);
}
.btn-outline:hover {
    background: rgba(255,255,255,0.15);
    transform: translateY(-3px);
}
.scroll-hint {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    text-align: center;
    font-size: 12px;
    opacity: 0.6;
    letter-spacing: 2px;
}
.scroll-arrow {
    width: 20px; height: 32px;
    border: 2px solid rgba(255,255,255,0.5);
    border-radius: 12px;
    margin: 8px auto 0;
    position: relative;
}
.scroll-arrow::after {
    content: '';
    position: absolute;
    top: 6px; left: 50%;
    transform: translateX(-50%);
    width: 4px; height: 8px;
    background: rgba(255,255,255,0.8);
    border-radius: 2px;
    animation: scrollDot 1.8s infinite;
}
@keyframes scrollDot {
    0% { top: 6px; opacity: 1; }
    100% { top: 18px; opacity: 0; }
}

/* ========== 项目背景与痛点 ========== */
.pain-data {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 30px;
    background: linear-gradient(135deg, var(--color-primary) 0%, #a00d24 100%);
    color: var(--color-white);
    padding: 40px;
    border-radius: var(--radius);
    margin-bottom: 50px;
    box-shadow: var(--shadow-md);
}
.pain-data-item {
    text-align: center;
    flex: 1;
}
.pain-data-number {
    font-size: 56px;
    font-weight: 900;
    line-height: 1;
    color: var(--color-accent);
}
.pain-data-number span { font-size: 28px; }
.pain-data-text {
    margin-top: 12px;
    font-size: 15px;
    opacity: 0.9;
}
.pain-data-text small { opacity: 0.7; font-size: 13px; }
.pain-data-divider {
    width: 1px;
    height: 80px;
    background: rgba(255,255,255,0.2);
}
.pain-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 24px;
}
.pain-card {
    background: var(--color-white);
    padding: 36px 28px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    text-align: center;
    transition: var(--transition);
    border-top: 4px solid var(--color-accent);
}
.pain-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
    border-top-color: var(--color-primary);
}
.pain-icon {
    font-size: 48px;
    margin-bottom: 16px;
}
.pain-card h3 {
    font-size: 22px;
    margin-bottom: 12px;
    color: var(--color-text);
}
.pain-card p {
    color: var(--color-text-light);
    font-size: 15px;
    margin-bottom: 16px;
}
.pain-tag {
    display: inline-block;
    padding: 4px 14px;
    background: rgba(255,107,53,0.12);
    color: var(--color-accent);
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
}

/* ========== 核心创新：四阶闭环 ========== */
.loop-diagram {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 50px;
    padding: 40px 20px;
    background: var(--color-white);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    position: relative;
}
.loop-stage {
    text-align: center;
    padding: 16px;
    cursor: pointer;
    transition: var(--transition);
    border-radius: 12px;
    min-width: 160px;
}
.loop-stage:hover { background: var(--color-bg-alt); transform: scale(1.05); }
.stage-circle {
    width: 80px; height: 80px;
    margin: 0 auto 12px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: var(--color-white);
    box-shadow: 0 8px 20px rgba(200,16,46,0.3);
    position: relative;
}
.stage-num { font-size: 12px; opacity: 0.8; font-weight: 700; }
.stage-icon { font-size: 28px; }
.loop-stage h3 { font-size: 18px; margin-bottom: 6px; color: var(--color-text); }
.stage-problem { font-size: 13px; color: var(--color-text-light); }
.loop-arrow {
    font-size: 24px;
    color: var(--color-primary);
    font-weight: 700;
}
.loop-back {
    width: 100%;
    text-align: center;
    margin-top: 16px;
    color: var(--color-primary);
    font-weight: 600;
    font-size: 14px;
}

.stage-details {
    background: var(--color-white);
    border-radius: var(--radius);
    padding: 40px;
    box-shadow: var(--shadow-md);
    margin-bottom: 30px;
    min-height: 240px;
}
.stage-detail {
    display: none;
    grid-template-columns: 2fr 1fr;
    gap: 40px;
    align-items: center;
}
.stage-detail.active { display: grid; animation: fadeIn 0.5s ease; }
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}
.detail-badge {
    display: inline-block;
    padding: 6px 16px;
    background: rgba(200,16,46,0.1);
    color: var(--color-primary);
    border-radius: 20px;
    font-size: 13px;
    font-weight: 700;
    margin-bottom: 14px;
}
.stage-detail h3 {
    font-size: 24px;
    margin-bottom: 14px;
    color: var(--color-text);
}
.stage-detail p {
    color: var(--color-text-light);
    margin-bottom: 18px;
}
.detail-list {
    list-style: none;
}
.detail-list li {
    padding: 6px 0;
    color: var(--color-text);
    font-size: 15px;
}
.detail-right { text-align: center; }
.detail-stat {
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    color: var(--color-white);
    padding: 36px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
}
.ds-number {
    font-size: 60px;
    font-weight: 900;
    line-height: 1;
}
.ds-number span { font-size: 26px; }
.ds-label {
    margin-top: 10px;
    opacity: 0.9;
    font-size: 14px;
}
.stage-tabs {
    display: flex;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
}
.stage-tab {
    padding: 12px 28px;
    border: 2px solid var(--color-bg-alt);
    background: var(--color-white);
    border-radius: 30px;
    cursor: pointer;
    font-size: 15px;
    font-weight: 600;
    color: var(--color-text-light);
    transition: var(--transition);
}
.stage-tab:hover { border-color: var(--color-primary); color: var(--color-primary); }
.stage-tab.active {
    background: var(--color-primary);
    border-color: var(--color-primary);
    color: var(--color-white);
    box-shadow: 0 6px 18px rgba(200,16,46,0.3);
}

/* ========== 工科教具展示 ========== */
.aids-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 28px;
    margin-bottom: 50px;
}
.aid-card {
    perspective: 1000px;
    height: 280px;
    cursor: pointer;
}
.aid-card-inner {
    position: relative;
    width: 100%; height: 100%;
    transition: transform 0.7s;
    transform-style: preserve-3d;
}
.aid-card.flipped .aid-card-inner {
    transform: rotateY(180deg);
}
.aid-front, .aid-back {
    position: absolute;
    inset: 0;
    backface-visibility: hidden;
    border-radius: var(--radius);
    padding: 32px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    box-shadow: var(--shadow-sm);
}
.aid-front {
    background: linear-gradient(160deg, var(--color-white) 0%, #f7f9fc 100%);
    border: 1px solid #eee;
}
.aid-back {
    background: linear-gradient(160deg, var(--color-secondary) 0%, #003d73 100%);
    color: var(--color-white);
    transform: rotateY(180deg);
    text-align: left;
    align-items: flex-start;
}
.aid-icon {
    font-size: 56px;
    margin-bottom: 16px;
}
.aid-front h3 {
    font-size: 20px;
    margin-bottom: 8px;
    color: var(--color-text);
}
.aid-front p {
    color: var(--color-text-light);
    font-size: 14px;
    margin-bottom: 16px;
}
.aid-flip-hint {
    font-size: 12px;
    color: var(--color-primary);
    font-weight: 600;
}
.aid-patent {
    display: inline-block;
    padding: 4px 12px;
    background: rgba(255,255,255,0.2);
    border-radius: 16px;
    font-size: 12px;
    margin-bottom: 12px;
}
.aid-back h3 { font-size: 20px; margin-bottom: 10px; }
.aid-back p { font-size: 14px; opacity: 0.9; margin-bottom: 14px; }
.aid-back ul { list-style: none; font-size: 13px; opacity: 0.85; }
.aid-back ul li { padding: 3px 0; }

.aids-summary {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 24px;
    background: linear-gradient(135deg, var(--color-secondary), #003d73);
    padding: 40px;
    border-radius: var(--radius);
    color: var(--color-white);
    box-shadow: var(--shadow-md);
}
.summary-item { text-align: center; }
.si-number {
    font-size: 48px;
    font-weight: 900;
    color: var(--color-accent);
    line-height: 1;
}
.si-number span { font-size: 24px; }
.si-label { margin-top: 8px; opacity: 0.85; font-size: 14px; }

/* ========== 数据驾驶舱 ========== */
.kpi-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 20px;
    margin-bottom: 40px;
}
.kpi-card {
    background: rgba(255,255,255,0.06);
    border: 1px solid rgba(255,255,255,0.12);
    border-radius: var(--radius);
    padding: 26px 16px;
    text-align: center;
    backdrop-filter: blur(10px);
    transition: var(--transition);
}
.kpi-card:hover {
    transform: translateY(-6px);
    background: rgba(255,255,255,0.1);
    border-color: var(--color-accent);
}
.kpi-icon { font-size: 32px; margin-bottom: 10px; }
.kpi-value {
    font-size: 42px;
    font-weight: 900;
    color: var(--color-accent);
    line-height: 1;
}
.kpi-unit { font-size: 15px; color: rgba(255,255,255,0.7); margin: 4px 0; }
.kpi-label { font-size: 13px; color: rgba(255,255,255,0.6); }

.charts-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}
.chart-box {
    background: rgba(255,255,255,0.05);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: var(--radius);
    padding: 24px;
    backdrop-filter: blur(10px);
}
.chart-title {
    font-size: 16px;
    color: rgba(255,255,255,0.9);
    margin-bottom: 16px;
    font-weight: 600;
}
.chart-canvas {
    width: 100%;
    height: 340px;
}

/* ========== 典型案例与社会认可 ========== */
.case-highlight {
    background: linear-gradient(135deg, var(--color-primary) 0%, #8B0000 100%);
    color: var(--color-white);
    padding: 44px;
    border-radius: var(--radius);
    margin-bottom: 50px;
    box-shadow: var(--shadow-lg);
    position: relative;
    overflow: hidden;
}
.case-highlight::before {
    content: '';
    position: absolute;
    top: -40px; right: -40px;
    width: 200px; height: 200px;
    background: rgba(255,255,255,0.05);
    border-radius: 50%;
}
.case-badge {
    display: inline-block;
    padding: 6px 16px;
    background: rgba(255,255,255,0.2);
    border-radius: 20px;
    font-size: 13px;
    font-weight: 700;
    margin-bottom: 16px;
}
.case-highlight h3 { font-size: 28px; margin-bottom: 16px; }
.case-highlight p { opacity: 0.9; font-size: 16px; margin-bottom: 20px; }
.case-quote {
    font-size: 18px;
    font-style: italic;
    opacity: 0.95;
    padding-left: 20px;
    border-left: 3px solid rgba(255,255,255,0.4);
}
.quote-mark { font-size: 28px; opacity: 0.6; }

.recognition-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 28px;
}
.recog-block {
    background: var(--color-white);
    padding: 32px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}
.recog-block:hover { transform: translateY(-6px); box-shadow: var(--shadow-md); }
.recog-title { font-size: 20px; margin-bottom: 20px; color: var(--color-text); }
.recog-list { display: flex; flex-direction: column; gap: 14px; }
.recog-item {
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--color-text);
    font-size: 15px;
}
.recog-icon { font-size: 22px; }
.media-wall {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 14px;
}
.media-tag {
    padding: 8px 16px;
    background: linear-gradient(135deg, var(--color-secondary), #003d73);
    color: var(--color-white);
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
}
.media-count { font-size: 14px; color: var(--color-text-light); }

/* ========== 发展规划时间轴 ========== */
.roadmap-timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
    padding-left: 40px;
}
.roadmap-line {
    position: absolute;
    left: 12px; top: 0; bottom: 0;
    width: 3px;
    background: linear-gradient(180deg, var(--color-primary), var(--color-accent), var(--color-secondary));
    border-radius: 2px;
}
.roadmap-item {
    position: relative;
    margin-bottom: 50px;
}
.roadmap-dot {
    position: absolute;
    left: -34px; top: 6px;
    width: 18px; height: 18px;
    background: var(--color-white);
    border: 4px solid var(--color-primary);
    border-radius: 50%;
    box-shadow: 0 0 0 4px rgba(200,16,46,0.15);
}
.roadmap-content {
    background: var(--color-white);
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}
.roadmap-content:hover { box-shadow: var(--shadow-md); transform: translateX(6px); }
.roadmap-phase {
    display: inline-block;
    padding: 4px 14px;
    background: rgba(200,16,46,0.1);
    color: var(--color-primary);
    border-radius: 16px;
    font-size: 13px;
    font-weight: 700;
    margin-bottom: 8px;
}
.roadmap-year { font-size: 26px; color: var(--color-text); margin-bottom: 16px; }
.roadmap-goals { list-style: none; }
.roadmap-goals li {
    padding: 6px 0;
    color: var(--color-text-light);
    font-size: 15px;
}
.roadmap-goals strong { color: var(--color-primary); font-size: 17px; }

/* ========== 团队介绍 ========== */
.team-intro {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
    background: var(--color-white);
    padding: 50px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
    margin-bottom: 40px;
}
.team-badge {
    display: inline-block;
    padding: 8px 20px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    color: var(--color-white);
    border-radius: 20px;
    font-size: 14px;
    font-weight: 700;
    margin-bottom: 20px;
}
.team-intro h3 { font-size: 28px; margin-bottom: 18px; color: var(--color-text); }
.team-desc {
    color: var(--color-text-light);
    font-size: 16px;
    margin-bottom: 30px;
    text-align: left;
}
.team-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}
.tf-item {
    display: flex;
    align-items: center;
    gap: 10px;
    justify-content: center;
    padding: 14px;
    background: var(--color-bg-alt);
    border-radius: 12px;
    font-size: 14px;
    color: var(--color-text);
}
.tf-icon { font-size: 22px; }

.contact-box {
    text-align: center;
    padding: 36px;
    background: linear-gradient(135deg, var(--color-secondary), #003d73);
    color: var(--color-white);
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
}
.contact-box h3 { font-size: 22px; margin-bottom: 14px; }
.contact-box p { opacity: 0.9; margin: 4px 0; }

/* ========== 页脚 ========== */
.footer {
    background: var(--color-dark);
    color: rgba(255,255,255,0.7);
    padding: 50px 0 30px;
    text-align: center;
}
.footer-logo {
    font-size: 24px;
    font-weight: 800;
    color: var(--color-white);
    margin-bottom: 14px;
    display: flex;
    align-items: center;
    gap: 8px;
    justify-content: center;
}
.footer-slogan { font-size: 15px; margin-bottom: 20px; opacity: 0.8; }
.footer-copy { font-size: 13px; opacity: 0.5; }

/* ========== 返回顶部 ========== */
.back-to-top {
    position: fixed;
    bottom: 30px; right: 30px;
    width: 48px; height: 48px;
    background: var(--color-primary);
    color: var(--color-white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    cursor: pointer;
    box-shadow: var(--shadow-md);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 999;
}
.back-to-top.show { opacity: 1; visibility: visible; }
.back-to-top:hover { transform: translateY(-4px); background: var(--color-accent); }

/* ========== 响应式适配 ========== */
@media (max-width: 900px) {
    .charts-grid { grid-template-columns: 1fr; }
    .stage-detail { grid-template-columns: 1fr; }
    .detail-right { order: -1; }
    .title-main { font-size: 52px; }
    .title-sub { font-size: 20px; }
    .hero-stats { gap: 30px; }
    .stat-number { font-size: 40px; }
    .pain-data { flex-direction: column; gap: 20px; }
    .pain-data-divider { width: 80px; height: 1px; }
}
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 64px; left: 0; right: 0;
        background: var(--color-white);
        flex-direction: column;
        padding: 16px;
        gap: 4px;
        box-shadow: var(--shadow-md);
        transform: translateY(-150%);
        transition: var(--transition);
    }
    .nav-menu.open { transform: translateY(0); }
    .nav-toggle { display: flex; }
    .nav-toggle.open span:nth-child(1) { transform: rotate(45deg) translate(5px,5px); }
    .nav-toggle.open span:nth-child(2) { opacity: 0; }
    .nav-toggle.open span:nth-child(3) { transform: rotate(-45deg) translate(5px,-5px); }
    .section { padding: 60px 0; }
    .section-title { font-size: 28px; }
    .loop-diagram { flex-direction: column; }
    .loop-arrow { transform: rotate(90deg); }
    .stage-tabs { flex-direction: column; align-items: stretch; }
    .hero-badge { font-size: 12px; flex-wrap: wrap; justify-content: center; }
}