/* 全局重置与基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary: #8b5cf6;
    --secondary-hover: #7c3aed;
    --accent: #ec4899;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    --white: #ffffff;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-primary: 0 10px 25px -5px rgba(37, 99, 235, 0.2);
    --transition: all 0.3s ease;
}

body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    color: var(--gray-800);
    background-color: var(--white);
    line-height: 1.5;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

button {
    border: none;
    background: none;
    cursor: pointer;
    font-family: inherit;
    font-size: inherit;
    transition: var(--transition);
}

/* 容器 */
.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 1rem;
}

@media (min-width: 640px) {
    .container {
        padding: 0 1.5rem;
    }
}

@media (min-width: 1024px) {
    .container {
        padding: 0 2rem;
    }
}

/* 导航栏 */
.navbar {
    position: sticky;
    top: 0;
    z-index: 50;
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(4px);
    border-bottom: 1px solid var(--gray-100);
}

.nav-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 3.5rem;
}

.logo {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--gray-900);
}

.nav-links {
    display: none;
    align-items: center;
    gap: 2rem;
}

.nav-links a {
    font-size: 0.875rem;
    color: var(--gray-600);
}

.nav-links a:hover {
    color: var(--primary);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.btn {
    display: inline-block;
    padding: 0.375rem 1rem;
    border-radius: 0.375rem;
    font-size: 0.875rem;
    font-weight: 500;
    text-align: center;
    transition: var(--transition);
}

.btn-primary {
    background-color: var(--primary);
    color: var(--white);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    box-shadow: var(--shadow-primary);
}

.btn-secondary {
    background-color: var(--secondary);
    color: var(--white);
}

.btn-secondary:hover {
    background-color: var(--secondary-hover);
}

.btn-disabled {
    background-color: var(--gray-200);
    color: var(--gray-500);
    cursor: not-allowed;
}

.icon-btn {
    color: var(--gray-600);
    font-size: 1rem;
}

.icon-btn:hover {
    color: var(--gray-900);
}

.mobile-menu-btn {
    display: block;
}

/* 移动端菜单 */
.mobile-menu {
    display: none;
    padding: 0.5rem 1rem 1rem;
    border-top: 1px solid var(--gray-100);
}

.mobile-menu a {
    display: block;
    padding: 0.5rem 0;
    font-size: 0.875rem;
    color: var(--gray-600);
}

.mobile-menu a:hover {
    color: var(--primary);
}

.mobile-menu .btn {
    width: 100%;
    margin-top: 0.5rem;
    padding: 0.5rem 1rem;
}

/* 英雄区 */
.hero {
    padding: 4rem 0;
    background: linear-gradient(135deg, rgba(236, 72, 153, 0.15) 0%, rgba(139, 92, 246, 0.15) 100%);
    text-align: center;
}

.hero h1 {
    font-size: clamp(1.8rem, 5vw, 3rem);
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero p {
    max-width: 42rem;
    margin: 0 auto 1.5rem;
    color: var(--gray-600);
    font-size: 0.875rem;
}

.hero .small-text {
    font-size: 0.75rem;
    color: var(--gray-500);
    margin-bottom: 2rem;
}

.hero .btn {
    padding: 0.625rem 1.5rem;
    box-shadow: var(--shadow-primary);
}

/* 通用区块样式 */
.section {
    padding: 4rem 0;
}

.section-gray {
    background-color: var(--gray-50);
}

.section-title {
    font-size: 1.25rem;
    font-weight: 700;
    text-align: center;
    color: var(--gray-900);
    margin-bottom: 1.5rem;
}

.section-subtitle {
    max-width: 42rem;
    margin: 0 auto 3rem;
    text-align: center;
    color: var(--gray-600);
    font-size: 0.875rem;
    line-height: 1.6;
}

/* 卡片网格 */
.card-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
    max-width: 64rem;
    margin: 0 auto;
}

@media (min-width: 768px) {
    .card-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .card-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.card {
    background-color: var(--white);
    border-radius: 0.5rem;
    box-shadow: var(--shadow-md);
    padding: 1.5rem;
    transition: var(--transition);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.card-icon {
    width: 3rem;
    height: 3rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1rem;
    font-size: 1.25rem;
}

.card-icon-blue {
    background-color: rgba(37, 99, 235, 0.1);
    color: var(--primary);
}

.card-icon-purple {
    background-color: rgba(139, 92, 246, 0.1);
    color: var(--secondary);
}

.card-icon-pink {
    background-color: rgba(236, 72, 153, 0.1);
    color: var(--accent);
}

.card-icon-green {
    background-color: rgba(16, 185, 129, 0.1);
    color: #10b981;
}

.card-icon-yellow {
    background-color: rgba(245, 158, 11, 0.1);
    color: #f59e0b;
}

.card-icon-red {
    background-color: rgba(239, 68, 68, 0.1);
    color: #ef4444;
}

.card h3 {
    font-size: 1.125rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: 0.75rem;
}

.card p {
    font-size: 0.875rem;
    color: var(--gray-600);
    text-align: center;
    margin-bottom: 1rem;
    line-height: 1.6;
}

.card-tag {
    display: block;
    width: fit-content;
    margin: 0 auto 1rem;
    background-color: var(--gray-100);
    color: var(--gray-700);
    font-size: 0.75rem;
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
}

.card .btn {
    width: 100%;
    padding: 0.5rem 1rem;
}

/* 流程步骤 */
.steps-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    max-width: 64rem;
    margin: 0 auto 2rem;
}

@media (min-width: 640px) {
    .steps-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .steps-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

.step {
    text-align: center;
    padding: 1rem;
}

.step-icon {
    width: 2.5rem;
    height: 2.5rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 0.75rem;
    font-size: 1rem;
}

.step h3 {
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.step p {
    font-size: 0.75rem;
    color: var(--gray-600);
    line-height: 1.5;
}

.disclaimer {
    max-width: 42rem;
    margin: 0 auto;
    text-align: center;
    font-size: 0.75rem;
    color: var(--gray-500);
    line-height: 1.6;
}

/* 优势网格 */
.features-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    max-width: 64rem;
    margin: 0 auto;
}

@media (min-width: 640px) {
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .features-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.feature-card {
    background-color: var(--white);
    border-radius: 0.5rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--gray-100);
    padding: 1.25rem;
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.feature-icon {
    width: 2rem;
    height: 2rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 0.75rem;
    font-size: 0.875rem;
}

.feature-card h3 {
    font-size: 0.875rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: 0.5rem;
}

.feature-card p {
    font-size: 0.75rem;
    color: var(--gray-600);
    text-align: center;
    line-height: 1.5;
}

/* 用户评价 */
.testimonials-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    max-width: 64rem;
    margin: 0 auto;
}

@media (min-width: 768px) {
    .testimonials-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.testimonial-card {
    background-color: var(--white);
    border-radius: 0.5rem;
    box-shadow: var(--shadow-sm);
    padding: 1.25rem;
}

.testimonial-card h4 {
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.stars {
    color: #f59e0b;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
}

.testimonial-card p {
    font-size: 0.75rem;
    color: var(--gray-600);
    line-height: 1.5;
}

/* FAQ */
.faq-container {
    max-width: 42rem;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.faq-item {
    border: 1px solid var(--gray-200);
    border-radius: 0.375rem;
    overflow: hidden;
}

.faq-toggle {
    width: 100%;
    text-align: left;
    padding: 0.75rem 1rem;
    background-color: var(--white);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.875rem;
    font-weight: 500;
}

.faq-toggle:hover {
    background-color: var(--gray-50);
}

.faq-icon {
    color: var(--gray-400);
    font-size: 0.75rem;
    transition: transform 0.3s ease;
}

.faq-icon.rotate {
    transform: rotate(180deg);
}

.faq-content {
    padding: 0.75rem 1rem;
    background-color: var(--gray-50);
    font-size: 0.75rem;
    color: var(--gray-600);
    line-height: 1.6;
    display: none;
}

.faq-content.show {
    display: block;
}

/* CTA区域 */
.cta {
    padding: 4rem 0;
    background: linear-gradient(135deg, rgba(236, 72, 153, 0.15) 0%, rgba(139, 92, 246, 0.15) 100%);
    text-align: center;
}

.cta h2 {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 1rem;
}

.cta p {
    max-width: 40rem;
    margin: 0 auto 2rem;
    color: var(--gray-600);
    font-size: 0.875rem;
}

.cta .btn {
    padding: 0.625rem 1.5rem;
    box-shadow: var(--shadow-primary);
}

/* 页脚 */
.footer {
    background-color: var(--gray-50);
    padding: 2.5rem 0;
    border-top: 1px solid var(--gray-200);
}

.footer-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

@media (min-width: 768px) {
    .footer-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

.footer-column h3 {
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.footer-column p {
    font-size: 0.75rem;
    color: var(--gray-600);
    line-height: 1.5;
}

.footer-column ul {
    list-style: none;
}

.footer-column ul li {
    margin-bottom: 0.5rem;
}

.footer-column ul li a {
    font-size: 0.75rem;
    color: var(--gray-600);
}

.footer-column ul li a:hover {
    color: var(--primary);
}

.footer-bottom {
    border-top: 1px solid var(--gray-200);
    padding-top: 1.5rem;
    text-align: center;
    font-size: 0.75rem;
    color: var(--gray-500);
}

/* 回到顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: 1.5rem;
    right: 1.5rem;
    width: 2.5rem;
    height: 2.5rem;
    background-color: var(--primary);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    font-size: 0.875rem;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

/* 修复：为什么选择我们 字体大小 */
.why-choose-item h3 {
    font-size: 1rem !important;
    font-weight: 600;
    margin-bottom: 0.5rem;
    text-align: center;
}

.why-choose-item p {
    font-size: 0.875rem !important;
    color: var(--gray-600);
    text-align: center;
    line-height: 1.5;
}

/* 修复：探索我们平台的力量 居中+间距 */
.platform-title-desc {
    text-align: center;
    font-size: 1rem;
    font-weight: 500;
    margin: 0 auto 2rem !important;
    max-width: 42rem;
}

/* 响应式调整 */
@media (min-width: 768px) {
    .nav-links {
        display: flex;
    }

    .mobile-menu-btn {
        display: none;
    }

    .section {
        padding: 5rem 0;
    }

    .hero {
        padding: 6rem 0;
    }

    .section-title {
        font-size: 1.5rem;
    }
}