:root {
    --bg: #ffffff;
    --bg-alt: #f7f9fc;
    --surface: #ffffff;
    --surface-alt: #f2f6fa;
    --nav-bg: #73b6e6;
    --nav-active: #005792;
    --accent: #005792;
    --accent-light: #2980b9;
    --accent-glow: rgba(0, 87, 146, 0.06);
    --text-primary: #1a2332;
    --text-secondary: #5a6a7e;
    --text-muted: #9aa5b4;
    --border: rgba(0, 0, 0, 0.08);
    --border-accent: rgba(0, 87, 146, 0.18);
    --shadow-sm: 0 1px 4px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 20px rgba(0,0,0,0.07);
    --shadow-accent: 0 4px 24px rgba(0, 87, 146, 0.1);
    --radius: 12px;
    --radius-sm: 8px;
    --transition: 0.35s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
    font-family: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', 'WenQuanYi Micro Hei', sans-serif;
    background: var(--bg);
    color: var(--text-primary);
    line-height: 1.7;
    overflow-x: hidden;
}
a{text-decoration: none;color: inherit;}
/* ========== Navigation ========== */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    padding: 0 5%;
    height: 68px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--nav-bg);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    transition: background var(--transition);
}

.logo {
    font-size: 1.4rem;
    color: #fff;
    cursor: pointer;
    letter-spacing: 0.02em;
    font-weight: 700;
    transition: opacity var(--transition);
}
.logo:hover { opacity: 0.85; }

.nav-links { display: flex; align-items: center; }

.nav-links-li{
    color: rgba(255,255,255,0.88);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 400;
    padding: 0.5rem 1.2rem;
    border-radius: 6px;
    cursor: pointer;
    transition: all var(--transition);
    position: relative;
}

.nav-links-li::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: #fff;
    transform: translateX(-50%);
    transition: width var(--transition);
    border-radius: 1px;
}

.nav-links-li:hover { color: #fff; background: var(--nav-active); }
.nav-links-li.active { color: #fff; background: var(--nav-active); }
.nav-links-li.active::after,
.nav-links-li:hover::after { width: 50%; }

/* Nav Dropdown */
.nav-item { position: relative; }

.nav-dropdown {
    display: none;
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    min-width: 280px;
    background: #fff;
    border-radius: var(--radius);
    box-shadow: 0 8px 30px rgba(0,0,0,0.12);
    border: 1px solid rgba(0,0,0,0.06);
    padding: 0.5rem 0;
    margin-top: 8px;
    z-index: 1001;
}

.nav-item:hover .nav-dropdown {
    display: block;
    animation: dropdownIn 0.2s ease;
}

@keyframes dropdownIn {
    from { opacity: 0; transform: translateX(-50%) translateY(-6px); }
    to   { opacity: 1; transform: translateX(-50%) translateY(0); }
}

.nav-dropdown::before {
    content: '';
    position: absolute;
    top: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    height: 8px;
}

.nav-dropdown-item {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    padding: 0.75rem 1.4rem;
    color: var(--text-primary);
    text-decoration: none;
    font-size: 0.88rem;
    cursor: pointer;
    transition: all 0.2s ease;
    white-space: nowrap;
}

.nav-dropdown-item:hover {
    background: rgba(0, 87, 146, 0.06);
    color: var(--accent);
    padding-left: 1.8rem;
}

.nav-dropdown-item .dropdown-dot {
    width: 6px;
    height: 6px;
    min-width: 6px;
    border-radius: 50%;
    background: var(--border);
    transition: all 0.2s ease;
}

.nav-dropdown-item:hover .dropdown-dot { background: var(--accent); }

.nav-dropdown-divider {
    height: 1px;
    background: rgba(0,0,0,0.06);
    margin: 0.3rem 0;
}

/* ========== Pages ========== */
.pages-container { margin-top: 68px; position: relative; }

.page {
    width: 100%;
    min-height: calc(100vh - 68px);
    flex-direction: column;
    animation: pageIn 0.45s ease forwards;
}

#home { display: flex; }

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

.menu_btn{display: none;width: 20px;height: 20px;cursor: pointer;position: relative;}
.menu_btn span{display: inline-block;width: 100%;height: 2px;background-color: #fff;position: absolute;transition:all .3s linear;}
.menu_btn span:first-child{top: 2px;}
.menu_btn span:nth-child(2){top: 9px;}
.menu_btn span:last-child{top: 16px;}
.menu_btn.toggle span:first-child{top: 9px;transform: rotate(45deg);}
.menu_btn.toggle span:nth-child(2){opacity: 0;}
.menu_btn.toggle span:last-child{top: 9px;transform: rotate(-45deg);}

.nav_m{display: none;}

/* ========== Section Title ========== */
.section-title {
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 3rem;
    color: var(--text-primary);
    text-align: center;
    position: relative;
    padding-bottom: 1.2rem;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 48px;
    height: 2px;
    background: var(--accent);
    border-radius: 1px;
}

/* ========== Banner ========== */
.banner {
    width: 100%;
    background: var(--bg-alt);
}
.banner img{
    width: 100%;
}
.banner .swiper-pagination-bullet{
    background: rgba(115, 182, 230, 0.4);
    border: 1.5px solid rgba(115, 182, 230, 0.6);
    opacity: 1;
}
.banner .swiper-pagination-bullet-active{
    width: 30px;
    border-radius: 4px;
    background: #005792;
    width: 30px;
    border-radius: 5px;
    border-color: #005792;
}

.banner .swiper-pagination-bullet:hover { background: #73b6e6; }

.application{
    width: 60%;
    min-width: 1200px;
    max-width: 1400px;
    margin: 3rem auto;
}


/* ========== 3D Model Viewer ========== */
.model-viewer-wrapper {
    width: 100vw;
    max-width: 100vw;
    margin-left: calc(-50vw + 50%);
    margin-right: calc(-50vw + 50%);
    margin-bottom: 3rem;
    padding: 0 5%;
}
.model-viewer-label { text-align: center; font-size: 1.2rem; font-weight: 600; color: var(--text-primary); margin-bottom: 1rem; }
.model-viewer-hint { text-align: center; font-size: 0.82rem; color: var(--text-muted); margin-top: 0.8rem; }

model-viewer {
    width: 100%;
    height: 1000px;
    background: var(--surface-alt);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    box-shadow: var(--shadow-md);
    --poster-color: transparent;
}

/* ========== Grid & Cards ========== */
.grid-box {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 1.5rem;
    width: 100%;
    max-width: 1100px;
    padding: 0 5%;
    margin: 0 auto;
}

.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2.4rem 2rem;
    text-align: left;
    cursor: pointer;
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    opacity: 0;
    animation: cardIn 0.5s ease forwards;
}

.card:nth-child(1) { animation-delay: 0.05s; }
.card:nth-child(2) { animation-delay: 0.12s; }
.card:nth-child(3) { animation-delay: 0.19s; }

@keyframes cardIn {
    from { opacity: 0; transform: translateY(16px); }
    to   { opacity: 1; transform: translateY(0); }
}

.card::before {
    content: '';
    position: absolute;
    top: 0; left: 0;
    width: 3px; height: 0;
    background: var(--accent);
    transition: height var(--transition);
    border-radius: 0 2px 2px 0;
}

.card:hover { box-shadow: var(--shadow-accent); transform: translateY(-4px); border-color: var(--border-accent); }
.card:hover::before { height: 100%; }
.card h3 { font-size: 1.1rem; font-weight: 600; margin-bottom: 0.7rem; color: var(--text-primary); line-height: 1.4; }
.card p { color: var(--text-secondary); font-size: 0.9rem; line-height: 1.7; }

.card .card-arrow {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    margin-top: 1.4rem;
    color: var(--accent);
    font-size: 0.82rem;
    font-weight: 500;
    opacity: 0;
    transform: translateX(-8px);
    transition: all var(--transition);
}

.card:hover .card-arrow { opacity: 1; transform: translateX(0); }

/* ========== Detail Content ========== */
.detail-content { max-width: 1300px; font-size: 1rem; line-height: 1.9; color: var(--text-secondary); padding: 0 5%; margin: 0 auto; }
.detail-content h3, .detail-content h4 { color: var(--text-primary); margin-bottom: 1rem; }
.detail-content p { margin-bottom: 1rem; }
.detail-content ol { padding-left: 1.8rem; margin: 0.8rem 0; }
.detail-content li { margin-bottom: 0.6rem; }

.product-img { width: 100%; max-width: 1300px; border-radius: var(--radius); margin: 0 auto 2.5rem; display: block; }

.product-img-wrap {
    position: relative;
    width: 100%;
    max-width: 1300px;
    margin: 0 auto 2.5rem;
    border-radius: var(--radius);
    overflow: hidden;
}

.product-img-wrap img {
    width: 100%;
    display: block;
    border-radius: var(--radius);
}

.product-img-consult {
    position: absolute;
    bottom: 24px;
    right: 24px;
    padding: 0.6rem 1.8rem;
    background: rgba(0, 87, 146, 0.88);
    color: #fff;
    border: none;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
    backdrop-filter: blur(4px);
    letter-spacing: 0.03em;
}

.product-img-consult:hover {
    background: rgba(0, 87, 146, 1);
    box-shadow: 0 4px 16px rgba(0, 87, 146, 0.3);
    transform: translateY(-2px);
}

/* ========== Feature Section ========== */
.feature-section {
    display: flex;
    flex-wrap: wrap;
    gap: 2.5rem;
    align-items: center;
    justify-content: center;
    margin: 3rem auto;
    padding: 2.5rem;
    background: var(--surface-alt);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    max-width: 1100px;
}

.feature-list { flex: 1; min-width: 300px; }
.feature-list h3 { font-size: 1.4rem; margin-bottom: 1.2rem; color: var(--text-primary); }

.feature-tag {
    display: inline-block;
    background: var(--accent-glow);
    color: var(--accent);
    padding: 0.3rem 0.9rem;
    border-radius: 20px;
    font-size: 0.82rem;
    margin-bottom: 1.2rem;
    border: 1px solid var(--border-accent);
    font-weight: 500;
}

.feature-item { display: flex; align-items: center; margin: 0.7rem 0; font-size: 0.95rem; color: var(--text-secondary); }

.feature-icon {
    width: 26px; height: 26px; min-width: 26px;
    background: var(--accent-glow);
    color: var(--accent);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: 0.8rem;
    font-size: 0.75rem;
    font-weight: 700;
    border: 1px solid var(--border-accent);
}

.feature-highlight { color: var(--accent); font-weight: 600; }
.feature-img { flex: 1; min-width: 300px; text-align: center; }
.feature-img img { max-width: 100%; border-radius: var(--radius-sm); }

/* ========== Feature Section LG ========== */
.feature-section-lg {
    display: flex;
    flex-wrap: wrap;
    gap: 3.5rem;
    align-items: center;
    justify-content: center;
    margin: 3rem auto;
    padding: 3.5rem 4rem;
    background: var(--surface-alt);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    width: 100%;
    max-width: 1300px;
    min-height: 560px;
}

.feature-section-lg .feature-list { flex: 1; min-width: 360px; }
.feature-section-lg .feature-list h3 { font-size: 2.6rem; margin-bottom: 1.5rem; color: var(--text-primary); font-weight: 700; }

.feature-section-lg .feature-tag {
    display: inline-block;
    background: var(--accent-glow);
    color: var(--accent);
    padding: 0.5rem 1.4rem;
    border-radius: 20px;
    font-size: 1.35rem;
    margin-bottom: 1.8rem;
    border: 1px solid var(--border-accent);
    font-weight: 600;
}

.feature-bullet {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    min-width: 36px;
    font-size: 1.6rem;
    color: var(--accent);
    margin-right: 1rem;
    font-weight: 700;
    line-height: 1;
}

.feature-section-lg .feature-item { display: flex; align-items: center; margin: 1.1rem 0; font-size: 1.55rem; color: var(--text-secondary); line-height: 1.6; }

.feature-section-lg .feature-icon {
    width: 36px; height: 36px; min-width: 36px;
    background: var(--accent-glow);
    color: var(--accent);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: 1rem;
    font-size: 0.95rem;
    font-weight: 700;
    border: 1px solid var(--border-accent);
}

.feature-section-lg .feature-hint { font-size: 1.2rem; color: var(--text-muted); margin-top: 0.3rem; }
.feature-section-lg .feature-img { flex: 1; min-width: 360px; text-align: center; }
.feature-section-lg .feature-img video{display: block;}
.feature-section-lg .feature-img img { max-width: 100%; max-height: 600px; border-radius: var(--radius-sm); object-fit: contain; }

/* ========== FIRE Case Section ========== */
.fire-case-section {
    max-width: 1300px;
    margin: 3rem auto;
    padding: 2.5rem 3rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
}

.fire-case-title {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
    text-align: center;
    margin-bottom: 2rem;
    line-height: 1.5;
}

.fire-case-content {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
    align-items: center;
    justify-content: center;
    flex-direction: column;
}

.fire-case-image { flex: 1; min-width: 300px; text-align: center; }
.fire-case-image img { width: 100%; max-height: 450px; object-fit: contain; border-radius: var(--radius-sm); border: 1px solid var(--border); }
.fire-case-spectra { flex: 1; min-width: 300px; text-align: center; }
.fire-case-spectra img { width: 100%; max-height: 450px; object-fit: contain; border-radius: var(--radius-sm); border: 1px solid var(--border); }

/* ========== SNR Section ========== */
.snr-section { margin: 3rem auto; padding: 2.5rem; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); max-width: 1100px; box-shadow: var(--shadow-sm); }
.snr-header { display: flex; align-items: center; justify-content: center; margin-bottom: 1.5rem; gap: 1.2rem; }
.snr-header h4 { font-size: 1.2rem; color: var(--text-primary); }
.snr-header-sample { width: 96px; height: 96px; border-radius: var(--radius-sm); overflow: hidden; flex-shrink: 0; border: 1px solid var(--border); }
.snr-header-sample img { width: 100%; height: 100%; object-fit: cover; }
.snr-desc { font-size: 0.95rem; color: var(--text-secondary); margin-bottom: 1rem; text-align: center; }
.snr-plot { margin-bottom: 1rem; text-align: center; }
.snr-plot img { width: 100%; border-radius: var(--radius-sm); }
.snr-note { font-size: 0.82rem; color: var(--text-muted); display: flex; justify-content: center; gap: 2rem; flex-wrap: wrap; font-family: 'Courier New', 'Consolas', monospace; }

/* ========== App Section (Spirit 300) ========== */
.app-section { margin: 3rem auto; max-width: 1100px; }
.app-section h4 { font-size: 1.2rem; margin-bottom: 1.5rem; text-align: center; color: var(--text-primary); }
.app-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.5rem; }
.app-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.8rem; transition: all var(--transition); box-shadow: var(--shadow-sm); }
.app-card:hover { border-color: var(--border-accent); box-shadow: var(--shadow-accent); }
.app-card-header { display: flex; align-items: center; justify-content: center; margin-bottom: 0.8rem; gap: 1rem; }
.app-card-title { flex: 1; text-align: center; }
.app-card-header h5 { font-size: 1.05rem; color: var(--text-primary); margin-bottom: 0.3rem; font-weight: 600; }
.app-card-desc { font-size: 0.88rem; color: var(--text-secondary); }
.app-card-sample { width: 88px; height: 88px; border-radius: var(--radius-sm); overflow: hidden; flex-shrink: 0; border: 1px solid var(--border); }
.app-card-sample img { width: 100%; height: 100%; object-fit: cover; }
.app-card-divider { height: 1px; background: linear-gradient(90deg, transparent, var(--border-accent), transparent); margin: 1rem auto; width: 80%; }
.app-card-plot { width: 100%; text-align: center; }
.app-card-plot img { width: 100%; border-radius: var(--radius-sm); }

/* ========== Param Table ========== */
.param-group { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); margin: 2rem auto; overflow: hidden; max-width: 1100px; box-shadow: var(--shadow-sm); }
.param-group h4 { background: var(--accent); color: #fff; padding: 0.9rem 1.5rem; margin: 0; font-size: 1rem; font-weight: 500; }

.param-table { width: 100%; border-collapse: collapse; font-family: 'Microsoft YaHei', 'PingFang SC', sans-serif; }
.param-table th { background: #005792; color: #fff; padding: 10px 16px; text-align: left; font-weight: 600; font-size: 0.9rem; border: 1px solid #005792; }
.param-table th:first-child { width: 180px; min-width: 180px; }
.param-table td { padding: 9px 16px; border: 1px solid #d0d8e0; text-align: left; font-size: 0.9rem; color: var(--text-primary); }
.param-table tr:nth-child(even) td { background: #f2f6fa; }
.param-table tr:nth-child(odd) td { background: #fff; }
.param-table td:first-child { font-weight: 500; color: var(--text-primary); width: 180px; min-width: 180px; }
.param-table td:not(:first-child) { color: var(--text-primary); font-family: 'Microsoft YaHei', 'PingFang SC', sans-serif; }

/* ========== About ========== */
.about-img { width: 100%; max-width: 820px; border-radius: var(--radius); margin: 0 auto 2.5rem; display: block; box-shadow: var(--shadow-md); }
.about-text { max-width: 860px; margin: 0 auto; font-size: 1rem; line-height: 1.9; color: var(--text-secondary); padding: 0 5%; }

/* ========== Contact Modal ========== */
.contact-modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.45);
    z-index: 2000;
    justify-content: center;
    align-items: center;
}

.contact-modal-overlay.show { display: flex; }

.contact-modal {
    background: #fff;
    border-radius: 16px;
    width: 380px;
    max-width: 92vw;
    padding: 0;
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.18);
    overflow: hidden;
    animation: modalSlideUp 0.3s ease;
}

@keyframes modalSlideUp {
    from { transform: translateY(20px); opacity: 0; }
    to   { transform: translateY(0); opacity: 1; }
}

.contact-modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.2rem 1.5rem;
    border-bottom: 1px solid rgba(0, 0, 0, 0.06);
}

.contact-modal-header h3 {
    font-size: 1.05rem;
    font-weight: 600;
    color: #1a2332;
    margin: 0;
}

.contact-modal-close {
    width: 30px;
    height: 30px;
    border: none;
    background: #f0f2f5;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    color: #666;
    transition: all 0.2s ease;
    line-height: 1;
    padding: 0;
}

.contact-modal-close:hover { background: #e0e0e0; color: #333; }

.contact-modal-body { padding: 0.5rem 1.5rem 1.5rem; }

.contact-modal-item {
    display: flex;
    align-items: flex-start;
    gap: 0.9rem;
    padding: 1rem 0;
    border-bottom: 1px solid rgba(0, 0, 0, 0.04);
}

.contact-modal-item:last-child { border-bottom: none; }

.contact-modal-icon {
    width: 36px;
    height: 36px;
    min-width: 36px;
    border-radius: 50%;
    background: rgba(0, 87, 146, 0.08);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    margin-top: 0.1rem;
}

.contact-modal-info { flex: 1; }
.contact-modal-info .modal-label { font-size: 0.78rem; color: #9aa5b4; margin-bottom: 0.3rem; }
.contact-modal-info .modal-value { font-size: 0.92rem; color: #1a2332; font-weight: 500; line-height: 1.5; }
.contact-modal-info .modal-value a { color: #005792; text-decoration: none; transition: color 0.2s ease; }
.contact-modal-info .modal-value a:hover { color: #2980b9; }

.contact-modal-footer { padding: 0 1.5rem 1.5rem; }

.contact-modal-more {
    display: block;
    width: 100%;
    padding: 0.75rem;
    background: var(--accent);
    color: #fff;
    border: none;
    border-radius: 10px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.25s ease;
    font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
    text-align: center;
    letter-spacing: 0.03em;
}

.contact-modal-more:hover {
    background: var(--accent-light);
    box-shadow: 0 4px 16px rgba(0, 87, 146, 0.2);
    transform: translateY(-1px);
}

/* ========== Contact Page ========== */
.contact-wrapper { display: flex; justify-content: center; align-items: center; gap: 3rem; flex-wrap: wrap; padding: 0 5%; }
.contact-info { min-width: 300px; line-height: 2.4; }
.contact-info p { color: var(--text-secondary); }
.contact-info strong { color: var(--text-primary); font-weight: 500; }
.contact-info a { color: var(--accent); text-decoration: none; transition: color var(--transition); }
.contact-info a:hover { color: var(--accent-light); }
.map-box { width: 500px; height: 400px; background: var(--bg-alt); border-radius: var(--radius); overflow: hidden; border: 1px solid var(--border); box-shadow: var(--shadow-sm); }

/* ========== Back Button ========== */
.back-btn {
    margin: 3rem auto 2rem;
    padding: 11px 30px;
    background: transparent;
    color: var(--accent);
    border: 1.5px solid var(--accent);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.88rem;
    font-weight: 500;
    transition: all var(--transition);
    display: block;
    font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

.back-btn:hover { background: var(--accent); color: #fff; box-shadow: var(--shadow-accent); }

/* ========== Footer ========== */
footer {
    background: #1a2332;
    color: #c0c8d4;
    padding: 0;
    font-size: 0.88rem;
}

.footer-main {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 2.5rem;
    max-width: 1200px;
    margin: 0 auto;
    padding: 3.5rem 5% 2.5rem;
}

.footer-brand { min-width: 240px; max-width: 300px; }

.footer-brand .footer-logo {
    font-size: 1.3rem;
    font-weight: 700;
    color: #fff;
    margin-bottom: 1rem;
    letter-spacing: 0.02em;
}

.footer-brand p { color: #8a95a5; font-size: 0.85rem; line-height: 1.8; margin-bottom: 1.2rem; }

.footer-brand .footer-contact-line {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    margin-bottom: 0.6rem;
    font-size: 0.82rem;
    color: #8a95a5;
}

.footer-brand .footer-contact-line a { color: #8a95a5; text-decoration: none; transition: color 0.3s ease; }
.footer-brand .footer-contact-line a:hover { color: #73b6e6; }

.footer-col h4 { color: #fff; font-size: 0.95rem; font-weight: 600; margin-bottom: 1.2rem; letter-spacing: 0.03em; }
.footer-col ul { list-style: none; padding: 0; margin: 0; }
.footer-col ul li { margin-bottom: 0.65rem; }

.footer-col ul li a {
    color: #8a95a5;
    text-decoration: none;
    font-size: 0.85rem;
    transition: all 0.25s ease;
    position: relative;
    padding-left: 0;
    cursor: pointer;
}

.footer-col ul li a:hover { color: #73b6e6; padding-left: 6px; }

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    text-align: center;
    padding: 1.2rem 5%;
    font-size: 0.78rem;
    color: #5a6a7e;
    background: #151d28;
}

@media (max-width: 900px) {
    .footer-main { flex-direction: column; gap: 2rem; }
    .footer-brand { max-width: 100%; }
}

/* ========== App Tab (Homepage) ========== */
.app-tab {
    padding: 0.5rem 1.5rem;
    background: var(--surface-alt);
    color: var(--text-secondary);
    border-radius: 20px;
    font-size: 0.9rem;
    cursor: pointer;
    border: 1px solid var(--border);
    transition: all var(--transition);
}

.app-tab.active { background: var(--accent); color: #fff; border-color: var(--accent); }
.app-tab:hover:not(.active) { border-color: var(--accent); color: var(--accent); }

/* ========== Article Layout with Sidebar ========== */
.article-layout {
    display: flex;
    gap: 3rem;
    width: 100%;
    max-width: 1300px;
    margin: 0 auto;
    padding: 3rem 5% 2rem;
    align-items: flex-start;
}

.article-sidebar {
    width: 260px;
    min-width: 260px;
    min-height: 200px;
    position: sticky;
    top: 88px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.sidebar-header {
    padding: 1.2rem 1.5rem;
    background: var(--accent);
    color: #fff;
    font-size: 0.95rem;
    font-weight: 600;
    letter-spacing: 0.03em;
}

.sidebar-item {
    display: block;
    width: 100%;
    padding: 0.9rem 1.5rem;
    font-size: 0.88rem;
    color: var(--text-secondary);
    background: transparent;
    border: none;
    border-bottom: 1px solid var(--border);
    cursor: pointer;
    text-align: left;
    line-height: 1.6;
    transition: all 0.25s ease;
    position: relative;
    font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

.sidebar-item:last-child { border-bottom: none; }

.sidebar-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 3px;
    height: 0;
    background: var(--accent);
    transition: height 0.3s ease;
    border-radius: 0 2px 2px 0;
}

.sidebar-item:hover { background: var(--accent-glow); color: var(--accent); }
.sidebar-item:hover::before { height: 100%; }

.sidebar-item.active { background: var(--accent-glow); color: var(--accent); font-weight: 600; }
.sidebar-item.active::before { height: 100%; }

.sidebar-item .sidebar-index {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 22px;
    height: 22px;
    min-width: 22px;
    background: var(--border);
    color: var(--text-muted);
    border-radius: 50%;
    font-size: 0.72rem;
    font-weight: 600;
    margin-right: 0.7rem;
    transition: all 0.25s ease;
}

.sidebar-item.active .sidebar-index { background: var(--accent); color: #fff; }
.sidebar-item:hover .sidebar-index { background: var(--accent); color: #fff; }

.article-main { flex: 1; min-width: 0; text-align: left; }

/* ========== Article Detail Page ========== */
.article-hero-title {
    font-size: 2.4rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.35;
    margin-bottom: 1rem;
    text-align: left;
}

.article-body { font-size: 1.05rem; line-height: 2; color: var(--text-secondary); }

.article-body h3 {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 2.5rem 0 1rem;
    padding-left: 1rem;
    border-left: 3px solid var(--accent);
}

.article-body h4 {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 1.8rem 0 0.8rem;
    padding-left: 1rem;
    border-left: 3px solid var(--accent);
}

.article-body p { margin-bottom: 1.2rem; text-align: justify; }

.article-body img {
    width: 100%;
    height: auto;
    border-radius: var(--radius-sm);
    margin: 1.8rem 0;
    display: block;
}

.article-body ul { padding-left: 1.5rem; margin-bottom: 1.2rem; }
.article-body ul li { margin-bottom: 0.5rem; color: var(--text-secondary); }

.article-body .highlight-box {
    background: var(--surface-alt);
    border: 1px solid var(--border-accent);
    border-radius: var(--radius-sm);
    padding: 1.5rem 1.8rem;
    margin: 1.8rem 0;
    color: var(--text-primary);
    font-size: 0.95rem;
    line-height: 1.9;
}

.article-body .highlight-box strong { color: var(--accent); }

.article-body blockquote {
    margin: 1.8rem 0;
    padding: 1.2rem 1.5rem;
    border-left: 3px solid var(--accent);
    background: var(--accent-glow);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    color: var(--text-primary);
    font-style: italic;
    font-size: 0.98rem;
    line-height: 1.9;
}

.article-nav-bottom {
    display: flex;
    justify-content: space-between;
    gap: 1.5rem;
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
}

.article-nav-item {
    flex: 1;
    padding: 1.2rem 1.5rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
}

.article-nav-item:hover { border-color: var(--border-accent); box-shadow: var(--shadow-accent); }
.article-nav-item .nav-label { font-size: 0.78rem; color: var(--text-muted); margin-bottom: 0.3rem; text-transform: uppercase; letter-spacing: 0.05em; }
.article-nav-item .nav-title { font-size: 0.92rem; color: var(--text-primary); font-weight: 500; line-height: 1.5; }
.article-nav-item.next { text-align: right; }

.related-articles { margin-top: 3rem; padding-top: 2rem; border-top: 1px solid var(--border); }
.related-articles h4 { font-size: 1.1rem; font-weight: 600; color: var(--text-primary); margin-bottom: 1.2rem; }
.related-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 1rem; }

.related-card {
    padding: 1.2rem;
    background: var(--surface-alt);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
}

.related-card:hover { border-color: var(--border-accent); box-shadow: var(--shadow-accent); transform: translateY(-2px); }
.related-card .rc-cat { font-size: 0.72rem; color: var(--accent); font-weight: 500; margin-bottom: 0.35rem; }
.related-card .rc-title { font-size: 0.88rem; color: var(--text-primary); font-weight: 500; line-height: 1.5; }

/* ========== App Article Item ========== */
.app-article-item {
    display: flex;
    align-items: flex-start;
    line-height: 2.4;
    font-size: 0.95rem;
    cursor: pointer;
    padding: 0.2rem 0.4rem;
    border-radius: 6px;
    transition: all 0.25s ease;
}

.app-article-item:hover { background: rgba(255,255,255,0.12); padding-left: 0.8rem; }

.app-content-li{display: none;min-height: 480px;}
.app-content-li.active{display: block;}

.app-learn-more-btn {
    display: inline-block;
    padding: 0.6rem 2rem;
    border: 1.5px solid #fff;
    color: #fff;
    border-radius: 8px;
    font-size: 0.88rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

.app-learn-more-btn:hover { background: rgba(255,255,255,0.18); transform: translateY(-1px); }

/* ========== News Card Styles ========== */
.news-card { animation-delay: 0.05s; }
.news-card:nth-child(1) { animation-delay: 0.05s; }
.news-card:nth-child(2) { animation-delay: 0.1s; }
.news-card:nth-child(3) { animation-delay: 0.15s; }
.news-card:nth-child(4) { animation-delay: 0.2s; }
.news-card:nth-child(5) { animation-delay: 0.25s; }
.news-card:nth-child(6) { animation-delay: 0.3s; }

.news-card .card-category {
    display: inline-block;
    background: var(--accent-glow);
    color: var(--accent);
    padding: 0.2rem 0.7rem;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 500;
    border: 1px solid var(--border-accent);
    margin-bottom: 0.8rem;
}

.news-card .card-summary {
    color: var(--text-secondary);
    font-size: 0.88rem;
    line-height: 1.7;
    margin-top: 0.5rem;
}

/* ========== 科研计算器 ========== */
.calc-section {
    width: 60%;
    margin: 2rem auto 4rem;
    padding: 0;
}
.calc-section-title {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    text-align: center;
    margin-bottom: 0.3rem;
}
.calc-section-subtitle {
    font-size: 1rem;
    color: var(--text-secondary);
    text-align: center;
    margin-bottom: 2rem;
    letter-spacing: 0.03em;
}
.calc-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2.5rem 3rem;
    box-shadow: var(--shadow-md);
}
.calc-tabs {
    display: flex;
    gap: 0.6rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    justify-content: center;
}
.calc-tab {
    padding: 0.45rem 1.2rem;
    background: var(--surface-alt);
    color: var(--text-secondary);
    border: 1px solid var(--border);
    border-radius: 20px;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all var(--transition);
    font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
}
.calc-tab.active {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
}
.calc-tab:hover:not(.active) {
    border-color: var(--accent);
    color: var(--accent);
}
.calc-body {
    display: flex;
    flex-wrap: wrap;
    gap: 3rem;
    align-items: flex-start;
}
.calc-input-area {
    flex: 1;
    min-width: 280px;
}
.calc-input-group {
    margin-bottom: 1.5rem;
}
.calc-label {
    display: block;
    font-size: 0.88rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    font-weight: 500;
}
.calc-input {
    width: 100%;
    padding: 0.7rem 1rem;
    border: 1.5px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    color: var(--text-primary);
    background: var(--bg);
    transition: border-color var(--transition);
    font-family: 'DM Mono', 'Consolas', 'Courier New', monospace;
    outline: none;
}
.calc-input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}
.calc-select {
    width: 100%;
    padding: 0.7rem 1rem;
    border: 1.5px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    color: var(--text-primary);
    background: var(--bg);
    cursor: pointer;
    transition: border-color var(--transition);
    font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
    outline: none;
    appearance: none;
    -webkit-appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath d='M2 4l4 4 4-4' fill='none' stroke='%235a6a7e' stroke-width='1.5' stroke-linecap='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 1rem center;
    padding-right: 2.5rem;
}
.calc-select:focus {
    border-color: var(--accent);
}
.calc-btn {
    width: 100%;
    padding: 0.8rem 2rem;
    background: var(--accent);
    color: #fff;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
    letter-spacing: 0.05em;
}
.calc-btn:hover {
    background: var(--accent-light);
    box-shadow: var(--shadow-accent);
    transform: translateY(-1px);
}
.calc-result-area {
    flex: 1;
    min-width: 280px;
}
.calc-result-title {
    font-size: 0.88rem;
    color: var(--text-secondary);
    margin-bottom: 0.8rem;
    font-weight: 500;
}
.calc-result-table {
    width: 100%;
    border-collapse: collapse;
    border-radius: var(--radius-sm);
    overflow: hidden;
    margin-bottom: 1.5rem;
}
.calc-result-table tr {
    border-bottom: 1px solid var(--border);
}
.calc-result-table tr:last-child {
    border-bottom: none;
}
.calc-result-table td {
    padding: 0.7rem 1rem;
    font-size: 0.95rem;
}
.calc-result-table td:first-child {
    color: var(--text-secondary);
    font-weight: 500;
    width: 80px;
}
.calc-result-table td:last-child {
    color: var(--text-primary);
    font-family: 'DM Mono', 'Consolas', 'Courier New', monospace;
    font-weight: 500;
    text-align: right;
}
.calc-result-table tr:nth-child(odd) td {
    background: var(--surface-alt);
}
.calc-result-table tr:nth-child(even) td {
    background: var(--surface);
}
.calc-formulas {
    background: var(--surface-alt);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 1.2rem 1.5rem;
}
.calc-formulas-title {
    font-size: 0.82rem;
    color: var(--text-muted);
    margin-bottom: 0.6rem;
    font-weight: 500;
}
.calc-formula-line {
    font-size: 0.88rem;
    color: var(--text-secondary);
    margin-bottom: 0.3rem;
    font-family: 'DM Mono', 'Consolas', 'Courier New', monospace;
    line-height: 1.8;
}
.calc-note {
    font-size: 0.78rem;
    color: var(--text-muted);
    margin-top: 0.8rem;
    font-family: 'DM Mono', 'Consolas', 'Courier New', monospace;
    line-height: 1.8;
}

/* ========== 焦距单位切换按钮 ========== */
.gauss-unit-group {
    display: flex;
    gap: 0.4rem;
    margin-top: 0.5rem;
}
.gauss-unit-btn {
    padding: 0.3rem 1rem;
    background: var(--surface-alt);
    color: var(--text-secondary);
    border: 1px solid var(--border);
    border-radius: 20px;
    font-size: 0.82rem;
    cursor: pointer;
    transition: all var(--transition);
    font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
}
.gauss-unit-btn.active {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
}
.gauss-unit-btn:hover:not(.active) {
    border-color: var(--accent);
    color: var(--accent);
}

/* ========== Responsive ========== */


@media (max-width: 1270px) {
    .application{
        width: 92%;
        min-width: 92%;
        max-width: 92%;
    }
}
@media (max-width: 900px) {
    .block-1, .block-3 { flex-direction: column; min-height: auto; }
    .block-1 img, .block-3 img { max-width: 100%; max-height: 300px; }
    .app-grid { grid-template-columns: 1fr; }
    .contact-wrapper { flex-direction: column; }
    .map-box { width: 100%; height: 300px; }
    .nav-links-li { padding: 0.4rem 0.7rem; font-size: 0.8rem; }
    .feature-section, .feature-section-lg { flex-direction: column; min-height: auto; }
    model-viewer { height: 600px !important; }
    .fire-case-content { flex-direction: column; }
    .fire-case-image img, .fire-case-spectra img { max-height: 350px; }
    .article-hero-title { font-size: 1.8rem; }
    .article-nav-bottom { flex-direction: column; }
    .article-nav-item.next { text-align: left; }
    .article-layout { flex-direction: column; gap: 1.5rem; }
    .article-sidebar { width: 100%; min-width: 100%; position: static; }
    .calc-section { width: 92%; }
    .calc-body { flex-direction: column; gap: 2rem; align-items: center;}
    .calc-card { padding: 1.8rem 20px; }

    .wp_tb{width: 100%;overflow-x: auto;}
    .wp_tb1 table{min-width: 600px;}
}

@media (max-width: 600px) {
    .section-title { font-size: 1.6rem; }
    .grid-box { grid-template-columns: 1fr; }
    .nav-links-li { padding: 0.35rem 0.5rem; font-size: 0.76rem; }
    model-viewer { height: 400px !important; }
    .feature-section-lg{padding:  20px;}
    .fire-case-section{padding:  20px;}
    .feature-section{padding:  20px;}
    .feature-list{min-width: 100% !important;width: 100% !important;}
    .feature-img{min-width: 100% !important;width: 100% !important;}
    .feature-section-lg .feature-list h3 { font-size: 1.5rem; }
    .feature-section-lg .feature-item { font-size: 1.05rem; flex-wrap: wrap;}
    .feature-section-lg .feature-hint{font-size: inherit;}
    .fire-case-title { font-size: 1.3rem; }
    .article-hero-title { font-size: 1.4rem; }
    .related-grid { grid-template-columns: 1fr; }
    .nav-dropdown { display: none !important; }
    .nav-item:hover .nav-dropdown { display: none !important; }
    .detail-content{padding: 0;}
    .app-content-li>div:nth-child(2){padding: 2.5rem 20px !important;}
    .app-article-item{line-height: 1.5;margin: 10px 0;}

    .nav-links{display: none;}
    .menu_btn{display: block;}
    
    .nav_m{position: fixed;top: 68px;right: -400px;width: 370px;max-width: 100%;height: calc(100% - 68px);background: #fff;display: block;z-index: 99999;box-shadow: 0 0 10px #ccc;padding: 20px;transition: all .3s ease-out;opacity: 0;}
    .nav_m ul{width: 100%;height: 100%;overflow-y: auto;}
    .nav_m li{list-style: none;border-bottom: 1px solid #eee;}
    .nav_m li a{display: block;padding: 8px;}
    .nav_m li .children a{border-top: 1px solid #eee;font-size: 14px;padding: 5px 0 5px 20px;color: #706e6e;}
    .nav_m.toggle{right: 0;opacity: 1;}
    .nav_m a.active{color: #005792 !important;}
}