:root {
    --primary: #2D3748;
    --secondary: #4A5568;
    --accent: #3182CE;
    --light: #F7FAFC;
    --border: #E2E8F0;
    --radius: 8px;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-hover: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, .05);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--primary);
    background-color: var(--light);
    line-height: 1.7;
}

.section-label {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 18px;
    color: var(--accent);
    font-size: 18px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.section-label:before {
    content: "";
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--accent);
}

h1, h2 {
    font-weight: 800;
    line-height: 1.15;
    color: var(--primary);
    letter-spacing: -0.5px;
    margin-bottom: 20px;
}

h1 {
    font-size: 40px;
}

h2 {
    font-size: 30px;
}

h3 {
    font-weight: 800;
}

h4, h5 {
    font-weight: 700;
}

.section-desc {
    max-width: 800px;
    font-size: 16px;
    color: var(--secondary);
}

.text-highlight {
    color: var(--accent);
}

/* Hero Section */
.hero-section {
    background: var(--light);
    padding: 80px 0;
    border-bottom: 1px solid var(--border);
}
.hero-feature-img {
    width: 100%;
    height: 350px;
    object-fit: cover;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    margin-top: 10px;
    filter: contrast(1.05) saturate(0.9);
}

.hero-form-card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 30px;
    box-shadow: var(--shadow);
}

.btn-primary {
    background: var(--accent);
    color: #fff;
    padding: 12px;
    border: none;
    border-radius: 4px;
    font-weight: 700;
    transition: 0.2s;
}

.btn-primary:hover {
    background: #2C5282;
    color: #fff;
}

/* Content Sections */
.content-section {
    padding: 80px 0;
    background: var(--light);
}

.content-card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 30px;
    box-shadow: var(--shadow);
}

.content-card h3 {
    color: var(--primary);
    margin-bottom: 20px;
}

.content-card p {
    font-size: 16px;
    color: var(--secondary);
    margin-bottom: 20px;
}

/* Technical Specifications Table */
.spec-table {
    width: 100%;
    border-collapse: collapse;
}

.spec-table th {
    background-color: var(--accent);
    color: #fff;
    padding: 12px 15px;
    text-align: left;
    font-size: 14px;
    font-weight: 600;
}

.spec-table td {
    padding: 12px 15px;
    border-bottom: 1px solid var(--border);
    font-size: 14px;
    color: var(--secondary);
}

.spec-table tr:last-child td {
    border-bottom: none;
}

.spec-table tr:hover td {
    background-color: var(--light);
}

/* Product Card */
.product-card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    height: 100%;
    display: flex;
    flex-direction: column;
    transition: all 0.2s ease;
}

.product-card:hover {
    box-shadow: var(--shadow-hover);
    border-color: var(--accent);
    transform: translateY(-3px);
}

.product-img-wrapper {
    position: relative;
    width: 100%;
    padding-top: 66.66%;
    background-color: var(--light);
    overflow: hidden;
}

.product-img-wrapper img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.4s ease;
}

.product-card:hover .product-img-wrapper img {
    transform: scale(1.05);
}

.product-content {
    padding: 20px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.product-content h4 {
    margin-bottom: 8px;
    color: var(--primary);
    font-size: 18px;
}

.product-content p {
    font-size: 13px;
    color: var(--secondary);
    line-height: 1.6;
    margin-bottom: 15px;
}

.product-specs {
    margin-top: auto;
    border-top: 1px solid var(--border);
    padding-top: 12px;
}

.spec-row {
    display: flex;
    justify-content: space-between;
    padding: 5px 0;
    border-bottom: 1px solid #f3f4f6;
    font-size: 12px;
}

.spec-row:last-child {
    border-bottom: none;
}

.spec-label {
    color: var(--secondary);
    font-weight: 600;
}

.spec-value {
    color: var(--accent);
    font-weight: 700;
}

/* Challenge Card - 统一Core Challenges样式 */
.challenge-card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 30px;
    height: 100%;
    box-shadow: var(--shadow);
    transition: all 0.2s ease;
}

.challenge-card:hover {
    box-shadow: var(--shadow-hover);
    border-color: var(--accent);
}

.challenge-card h3 {
    color: var(--primary);
    margin-bottom: 15px;
    font-size: 20px;
}

.challenge-card p {
    font-size: 14px;
    color: var(--secondary);
    margin-bottom: 20px;
    line-height: 1.6;
}

.challenge-card .text-highlight {
    font-size: 16px;
    margin-bottom: 10px;
    display: block;
}

/* Case Study Card */
.case-study-card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 25px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
}

.case-study-card h4 {
    color: var(--primary);
    margin-bottom: 15px;
}

.case-study-card p {
    font-size: 14px;
    line-height: 1.6;
    color: var(--secondary);
    margin-bottom: 10px;
}

/* Selection Guide */
.selection-guide {
    background: var(--light);
    padding: 80px 0;
}

.selection-item {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 25px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
}

.selection-item h4 {
    color: var(--accent);
    margin-bottom: 15px;
}

.selection-item p {
    font-size: 14px;
    line-height: 1.6;
    color: var(--secondary);
    margin-bottom: 10px;
}

/* FAQ Section */
.faq-section {
    background: var(--light);
    padding: 80px 0;
}

.faq-item {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    margin-bottom: 15px;
    overflow: hidden;
}

.faq-header {
    padding: 15px 20px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 700;
    color: var(--primary);
}

.faq-body {
    padding: 0 20px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.faq-body p {
    padding: 15px 0;
    font-size: 14px;
    color: var(--secondary);
    line-height: 1.6;
}

.faq-item.active .faq-body {
    max-height: 500px;
}

/* Trust Section */
.trust-section {
    background: var(--light);
    padding: 80px 0;
}

.trust-item {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
}

.trust-item i {
    color: var(--accent);
    font-size: 24px;
}

.trust-item span {
    font-size: 16px;
    color: var(--primary);
}

/* Responsive */
@media (max-width: 768px) {
    h1 {
        font-size: 32px;
    }

    h2 {
        font-size: 24px;
    }

    .hero-section, .content-section, .selection-guide, .faq-section, .trust-section {
        padding: 60px 0;
    }
}