:root {
    --primary-deep: #060e1f;
    --primary: #0f1f3d;
    --primary-light: #1a3558;
    --accent-gold: #c8963e;
    --accent-gold-light: #d4a853;
    --accent-gold-pale: #f5ecd7;
    --white: #ffffff;
    --off-white: #f8f9fb;
    --light-gray: #eef0f4;
    --mid-gray: #d1d5db;
    --text-dark: #1a1d24;
    --text-body: #3a3f4a;
    --text-light: #6b7280;
    --text-muted: #9ca3af;
    --shadow-sm: 0 1px 2px rgba(6,14,31,0.04);
    --shadow-md: 0 4px 16px rgba(6,14,31,0.06);
    --shadow-lg: 0 12px 40px rgba(6,14,31,0.10);
    --shadow-gold: 0 8px 32px rgba(200,150,62,0.20);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --transition-fast: 0.2s ease;
    --transition-smooth: 0.35s ease;
    --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
    --font-display: 'Playfair Display', Georgia, serif;
    --max-width: 1100px;
    --nav-height: 72px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
    font-family: var(--font-sans);
    color: var(--text-body);
    background-color: var(--off-white);
    line-height: 1.7;
    min-height: 100vh;
    padding-top: var(--nav-height);
}

/* NAVIGATION */
.navbar {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    padding: 0 2rem; height: var(--nav-height); display: flex;
    align-items: center; justify-content: space-between;
    background: rgba(255,255,255,0.97); backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: 0 1px 8px rgba(6,14,31,0.04);
}
.navbar .logo { display: flex; align-items: center; text-decoration: none; }
.logo-img { height: 40px; width: auto; object-fit: contain; }
.nav-links { display: flex; gap: 2.2rem; list-style: none; align-items: center; }
.nav-links a {
    text-decoration: none; color: var(--text-dark); font-weight: 500;
    font-size: 0.92rem; transition: color var(--transition-fast);
    position: relative;
}
.nav-links a::after {
    content: ''; position: absolute; bottom: -4px; left: 0; width: 0; height: 2px;
    background: var(--accent-gold); transition: width var(--transition-smooth); border-radius: 1px;
}
.nav-links a:hover::after, .nav-links a.active::after { width: 100%; }
.nav-links a:hover, .nav-links a.active { color: var(--accent-gold); }
.nav-cta {
    padding: 9px 20px; background: var(--accent-gold); color: var(--white);
    border-radius: 50px; font-weight: 600; font-size: 0.88rem; text-decoration: none;
    transition: all var(--transition-smooth); white-space: nowrap;
}
.nav-cta:hover { background: var(--accent-gold-light); transform: translateY(-2px); box-shadow: var(--shadow-gold); }

/* PAGE HEADER */
.page-header {
    background: linear-gradient(165deg, #040b1a 0%, #060e1f 30%, #0a1628 60%, #0f1f3d 100%);
    padding: 5rem 2rem 3.5rem; text-align: center; position: relative; overflow: hidden;
}
.page-header::before {
    content: ''; position: absolute; inset: 0; pointer-events: none; opacity: 0.03;
    background-image: radial-gradient(circle at 20% 30%, #fff 1px, transparent 1px),
                      radial-gradient(circle at 75% 60%, #fff 0.8px, transparent 0.8px);
    background-size: 60px 60px, 80px 80px;
}
.page-header-content { position: relative; z-index: 1; }
.breadcrumb {
    font-size: 0.82rem; color: rgba(255,255,255,0.45); margin-bottom: 1.2rem;
    display: flex; align-items: center; justify-content: center; gap: 8px;
}
.breadcrumb a { color: rgba(255,255,255,0.5); text-decoration: none; transition: color var(--transition-fast); }
.breadcrumb a:hover { color: var(--accent-gold-light); }
.breadcrumb .current { color: var(--accent-gold-light); font-weight: 500; }
.page-header h1 {
    font-family: var(--font-display); font-size: clamp(1.8rem, 3.5vw, 2.6rem);
    font-weight: 700; color: var(--white); margin-bottom: 0.8rem;
}
.page-header h1 .gold-text { color: var(--accent-gold-light); }
.page-header p {
    font-size: 0.95rem; color: rgba(255,255,255,0.55); max-width: 500px; margin: 0 auto;
}

/* MAIN CONTENT */
.main-content {
    max-width: var(--max-width); margin: 0 auto; padding: 0 2rem 5rem;
}
.section-intro {
    text-align: center; padding: 3rem 0 2rem;
}
.section-intro .count-badge {
    display: inline-block; padding: 6px 16px; background: var(--accent-gold-pale);
    color: var(--accent-gold); border-radius: 50px; font-size: 0.75rem;
    font-weight: 600; letter-spacing: 0.05em; text-transform: uppercase;
}

/* INSTRUMENTS LIST */
.instruments-list {
    display: flex; flex-direction: column; gap: 1px;
    background: var(--mid-gray); border-radius: var(--radius-xl); overflow: hidden;
    box-shadow: var(--shadow-md);
}
.instrument-item {
    background: var(--white); padding: 1.6rem 2rem;
    display: flex; align-items: center; justify-content: space-between;
    gap: 2rem; cursor: pointer; transition: all var(--transition-smooth);
    text-decoration: none; color: inherit; position: relative;
    border-left: 3px solid transparent;
}
.instrument-item:hover {
    background: #fafbfc; border-left-color: var(--accent-gold);
    padding-left: 2.4rem;
}
.instrument-item:first-child { border-radius: var(--radius-xl) var(--radius-xl) 0 0; }
.instrument-item:last-child { border-radius: 0 0 var(--radius-xl) var(--radius-xl); }
.instrument-item:only-child { border-radius: var(--radius-xl); }

.instrument-left {
    display: flex; align-items: center; gap: 1.4rem; flex: 1; min-width: 0;
}
.instrument-index {
    width: 40px; height: 40px; border-radius: 50%; display: flex;
    align-items: center; justify-content: center; font-weight: 700;
    font-size: 0.85rem; flex-shrink: 0;
    background: var(--off-white); color: var(--text-muted);
    transition: all var(--transition-smooth);
}
.instrument-item:hover .instrument-index {
    background: var(--accent-gold-pale); color: var(--accent-gold);
}
.instrument-info { min-width: 0; }
.instrument-info h3 {
    font-size: 1.08rem; font-weight: 700; color: var(--primary-deep);
    margin-bottom: 0.2rem; transition: color var(--transition-fast);
}
.instrument-item:hover .instrument-info h3 { color: var(--accent-gold); }
.instrument-info .model {
    font-size: 0.78rem; color: var(--text-muted); font-weight: 400;
    letter-spacing: 0.02em;
}
.instrument-meta {
    display: flex; align-items: center; gap: 1rem; flex-shrink: 0;
}
.instrument-category {
    font-size: 0.68rem; padding: 4px 12px; border-radius: 50px;
    font-weight: 600; letter-spacing: 0.04em; text-transform: uppercase;
    white-space: nowrap;
}
.cat-materials { background: #eef2ff; color: #4f46e5; }
.cat-chemical { background: #fef3e4; color: #d97706; }
.cat-biomedical { background: #ecfdf5; color: #059669; }
.cat-mechanical { background: #f1f5f9; color: #475569; }
.instrument-arrow {
    color: var(--text-muted); font-size: 1.1rem; transition: all var(--transition-smooth);
    flex-shrink: 0;
}
.instrument-item:hover .instrument-arrow {
    color: var(--accent-gold); transform: translateX(4px);
}

/* CTA BANNER */
.cta-banner {
    margin-top: 3rem; padding: 2.8rem 2.5rem;
    background: linear-gradient(135deg, var(--primary-deep) 0%, var(--primary-light) 100%);
    border-radius: var(--radius-2xl); text-align: center; position: relative; overflow: hidden;
}
.cta-banner h3 {
    font-family: var(--font-display); font-size: 1.6rem; font-weight: 700;
    color: var(--white); margin-bottom: 0.6rem; position: relative; z-index: 1;
}
.cta-banner p {
    color: rgba(255,255,255,0.55); margin-bottom: 1.5rem; position: relative; z-index: 1; font-size: 0.9rem;
}
.cta-banner .btn {
    display: inline-block; padding: 12px 28px; background: var(--accent-gold);
    color: var(--white); border-radius: 50px; font-weight: 600; text-decoration: none;
    transition: all var(--transition-smooth); position: relative; z-index: 1;
}
.cta-banner .btn:hover { background: var(--accent-gold-light); transform: translateY(-2px); box-shadow: var(--shadow-gold); }

/* FOOTER */
.site-footer {
    background: var(--primary-deep); color: rgba(255,255,255,0.55);
    padding: 3rem 2rem 2rem; margin-top: 0;
}
.footer-grid {
    display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 2rem;
    max-width: var(--max-width); margin: 0 auto;
}
.footer-grid h4 { color: var(--white); font-weight: 600; margin-bottom: 0.8rem; font-size: 0.95rem; }
.footer-grid ul { list-style: none; }
.footer-grid ul li { margin-bottom: 0.35rem; font-size: 0.85rem; }
.footer-grid ul li a { color: inherit; text-decoration: none; transition: color var(--transition-fast); }
.footer-grid ul li a:hover { color: var(--accent-gold-light); }
.footer-bottom {
    max-width: var(--max-width); margin: 2rem auto 0; padding-top: 1.5rem;
    border-top: 1px solid rgba(255,255,255,0.08); text-align: center;
    font-size: 0.8rem; color: rgba(255,255,255,0.35);
}

/* RESPONSIVE */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .navbar { padding: 0 1.5rem; }
    .page-header { padding: 4rem 1.5rem 2.5rem; }
    .main-content { padding: 0 1rem 3rem; }
    .instrument-item { flex-direction: column; align-items: flex-start; gap: 0.8rem; padding: 1.2rem 1.5rem; }
    .instrument-item:hover { padding-left: 1.8rem; }
    .instrument-meta { width: 100%; justify-content: space-between; }
    .footer-grid { grid-template-columns: 1fr; gap: 1.5rem; }
}
/* ===== 反馈表单区块样式 ===== */
.feedback-section {
    padding: 60px 36px 80px;
    background: #f7f8fa;
}
.feedback-container {
    max-width: 1200px;
    margin: 0 auto;
}
.feedback-grid {
    display: grid;
    grid-template-columns: 1.15fr 0.85fr;
    gap: 40px;
    align-items: start;
}
.feedback-form-card {
    background: #fff;
    border: 1px solid rgba(0,0,0,0.06);
    border-radius: 18px;
    padding: 40px 36px;
    box-shadow: 0 4px 16px rgba(0,0,0,0.04);
}
.feedback-form-card h3 {
    font-family: 'Playfair Display', serif;
    font-size: 1.55rem;
    color: #111;
    margin-bottom: 6px;
}
.form-subtitle {
    color: #4a4a4a;
    font-size: 0.9rem;
    margin-bottom: 28px;
}
.form-group {
    margin-bottom: 20px;
}
.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: #1a1a1a;
    margin-bottom: 6px;
}
.required-star {
    color: #d44;
}
.form-group input,
.form-group textarea {
    width: 100%;
    padding: 13px 16px;
    background: #f9fafb;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    font-family: 'Inter', sans-serif;
    font-size: 0.95rem;
    transition: border-color 0.2s, box-shadow 0.2s;
    outline: none;
}
.form-group textarea {
    min-height: 160px;
    resize: vertical;
}
.form-group input:focus,
.form-group textarea:focus {
    border-color: #b2924b;
    box-shadow: 0 0 0 3px rgba(178,146,75,0.1);
    background: #fff;
}
.form-group input.error,
.form-group textarea.error {
    border-color: #e05555;
}
.error-msg {
    font-size: 0.78rem;
    color: #e05555;
    display: none;
    margin-top: 4px;
}
.error-msg.show {
    display: block;
}
.form-submit-row {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-top: 24px;
    flex-wrap: wrap;
}
.btn-submit {
    background: #b2924b;
    color: #fff;
    font-weight: 600;
    font-size: 0.95rem;
    border: none;
    padding: 14px 36px;
    border-radius: 12px;
    cursor: pointer;
    transition: background 0.2s, transform 0.2s;
}
.btn-submit:hover {
    background: #9a7b3a;
    transform: translateY(-2px);
}
.form-note {
    font-size: 0.8rem;
    color: #8a8a8a;
}

/* 右侧联系卡片 */
.feedback-info-cards {
    display: flex;
    flex-direction: column;
    gap: 18px;
}
.info-card {
    background: #fff;
    border: 1px solid rgba(0,0,0,0.06);
    border-radius: 14px;
    padding: 26px 24px;
    text-decoration: none;
    color: inherit;
    display: flex;
    align-items: flex-start;
    gap: 16px;
    transition: box-shadow 0.3s, transform 0.3s;
}
.info-card:hover {
    box-shadow: 0 8px 24px rgba(0,0,0,0.06);
    transform: translateY(-2px);
}
.info-card-icon {
    flex-shrink: 0;
    width: 46px;
    height: 46px;
    border-radius: 12px;
    background: rgba(178,146,75,0.08);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #b2924b;
}
.info-card-icon svg {
    width: 22px;
    height: 22px;
    stroke: #b2924b;
}
.info-card-content h4 {
    font-family: 'Playfair Display', serif;
    font-size: 1.05rem;
    color: #111;
    margin-bottom: 3px;
}
.info-detail {
    font-size: 0.9rem;
    color: #4a4a4a;
    word-break: break-all;
}
.info-sub {
    font-size: 0.78rem;
    color: #8a8a8a;
    margin-top: 2px;
}
.info-highlight-card {
    background: rgba(178,146,75,0.04);
    border: 1px solid rgba(178,146,75,0.2);
    border-radius: 14px;
    padding: 28px 24px;
    text-align: center;
}
.info-highlight-card .highlight-icon {
    display: block;
    margin-bottom: 8px;
}
.info-highlight-card .highlight-icon svg {
    width: 32px;
    height: 32px;
    stroke: #b2924b;
}
.info-highlight-card h4 {
    font-family: 'Playfair Display', serif;
    font-size: 1.15rem;
    color: #111;
}
.info-highlight-card p {
    color: #4a4a4a;
    font-size: 0.9rem;
}

/* 响应式 */
@media (max-width: 1024px) {
    .feedback-grid {
        grid-template-columns: 1fr;
    }
}
@media (max-width: 768px) {
    .feedback-section {
        padding: 40px 20px 60px;
    }
    .feedback-form-card {
        padding: 28px 20px;
    }
    .form-submit-row {
        flex-direction: column;
        align-items: stretch;
    }
    .btn-submit {
        text-align: center;
        justify-content: center;
    }
    .form-note {
        text-align: center;
    }
}


/* 仪器简介 */
.instrument-info .instrument-desc {
    font-size: 0.85rem;
    color: var(--text-light);          /* #6b7280，与整体协调 */
    margin-top: 0.4rem;
    line-height: 1.5;
    /* 限制最多显示两行，超出显示省略号 */
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}