/* CSS Reset & Variables */
:root {
    --primary-color: #007bff;
    --primary-hover: #0056b3;
    --bg-color: #f8f9fa;
    --card-bg: #ffffff;
    --text-main: #333333;
    --text-muted: #666666;
    --border-color: #eaeaea;
    --shadow: 0 4px 12px rgba(0,0,0,0.05);
    --hover-shadow: 0 8px 24px rgba(0,123,255,0.15);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
    position: relative;
    overflow-x: hidden;
}

/* Background Canvas */
#bg-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    pointer-events: none;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}
.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}
.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 10px;
}
.logo-img {
    height: 36px;
    width: auto;
}
.header nav a {
    margin-left: 20px;
    text-decoration: none;
    color: var(--text-main);
    font-weight: 500;
    transition: color 0.3s;
}
.header nav a:hover {
    color: var(--primary-color);
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 100px 20px;
}
.hero h1 {
    font-size: 3rem;
    margin-bottom: 20px;
}
.hero .highlight {
    color: var(--primary-color);
}
.hero p {
    font-size: 1.2rem;
    color: var(--text-muted);
    margin-bottom: 40px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 30px;
    font-size: 1.1rem;
    font-weight: bold;
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
}
.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
    border: 2px solid var(--primary-color);
}
.btn-primary:hover {
    background-color: var(--primary-hover);
    border-color: var(--primary-hover);
    box-shadow: 0 4px 12px rgba(0,123,255,0.4);
}
.btn-outline {
    background-color: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}
.btn-outline:hover {
    background-color: var(--primary-color);
    color: #fff;
}

/* Section Headings */
section {
    padding: 60px 0;
}
section h2 {
    text-align: center;
    font-size: 2.2rem;
    margin-bottom: 40px;
    color: var(--text-main);
}

/* Pricing */
.pricing-cards {
    display: flex;
    justify-content: center;
    gap: 30px;
    flex-wrap: wrap;
}
.card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 40px 30px;
    width: 350px;
    text-align: center;
    position: relative;
    transition: transform 0.3s, box-shadow 0.3s;
    box-shadow: var(--shadow);
}
.card:hover {
    transform: translateY(-10px);
    box-shadow: var(--hover-shadow);
}
.card.popular {
    border-color: var(--primary-color);
    transform: scale(1.05);
}
.card.popular:hover {
    transform: scale(1.05) translateY(-10px);
}
.badge {
    position: absolute;
    top: -15px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary-color);
    color: #fff;
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: bold;
}
.card h3 {
    font-size: 1.5rem;
    margin-bottom: 20px;
}
.price {
    font-size: 3rem;
    font-weight: bold;
    color: var(--text-main);
    margin-bottom: 30px;
}
.price span {
    font-size: 1.2rem;
    color: var(--text-muted);
}
.card ul {
    list-style: none;
    margin-bottom: 40px;
    text-align: left;
}
.card ul li {
    margin-bottom: 15px;
    color: var(--text-main);
    display: flex;
    align-items: center;
}
.card ul li.disabled {
    color: #aaa;
}
.icon {
    margin-right: 10px;
    font-weight: bold;
}
.icon.check { color: #28a745; }
.icon.cross { color: #dc3545; }
.card .btn { width: 100%; }

/* Reviews */
.review-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}
.review-card {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 10px;
    box-shadow: var(--shadow);
    font-style: italic;
    transition: box-shadow 0.3s;
}
.review-card:hover {
    box-shadow: var(--hover-shadow);
}
.review-card .content {
    margin-bottom: 20px;
    color: var(--text-muted);
}
.review-card .author {
    font-weight: bold;
    text-align: right;
    color: var(--primary-color);
}

/* FAQ */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}
.faq-item {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    margin-bottom: 15px;
    overflow: hidden;
}
.faq-question {
    padding: 20px;
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
    background: #fdfdfd;
    transition: background 0.3s;
    position: relative;
}
.faq-question:hover {
    background: #f1f8ff;
}
.faq-question::after {
    content: '+';
    position: absolute;
    right: 20px;
    font-size: 1.5rem;
    transition: transform 0.3s;
}
.faq-item.active .faq-question::after {
    transform: rotate(45deg);
}
.faq-answer {
    padding: 0 20px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
    color: var(--text-muted);
}
.faq-item.active .faq-answer {
    padding: 20px;
    max-height: 200px; /* 展开的高度 */
    border-top: 1px solid var(--border-color);
}

/* Articles Section */
.articles p {
    text-align: center;
    color: var(--text-muted);
    margin-bottom: 30px;
}
.article-links {
    list-style: none;
    max-width: 800px;
    margin: 0 auto;
}
.article-links li {
    margin-bottom: 10px;
}
.article-links a {
    display: block;
    padding: 15px 20px;
    background: var(--card-bg);
    color: var(--text-main);
    text-decoration: none;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}
.article-links a:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    box-shadow: var(--shadow);
    transform: translateX(5px);
}

/* Article Page Layout (for inner articles) */
.article-content {
    background: var(--card-bg);
    padding: 50px;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-top: 40px;
    margin-bottom: 40px;
}
.article-content h1 {
    font-size: 2.5rem;
    margin-bottom: 15px;
    color: var(--text-main);
}
.article-meta {
    color: #888;
    font-size: 0.95rem;
    margin-bottom: 40px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 15px;
}
.article-body p {
    font-size: 1.1rem;
    line-height: 1.8;
    color: #444;
    margin-bottom: 25px;
    text-indent: 2em;
}
.kw {
    color: var(--primary-color);
    font-weight: 500;
}
.article-footer {
    margin-top: 60px;
    border-top: 1px solid var(--border-color);
    padding-top: 30px;
}
.article-footer h3 {
    margin-bottom: 20px;
}
.related-links {
    list-style: none;
}
.related-links li {
    margin-bottom: 10px;
}
.related-links a {
    color: var(--primary-color);
    text-decoration: none;
}
.related-links a:hover {
    text-decoration: underline;
}
.cta-banner {
    background: linear-gradient(135deg, #e3f2fd, #f1f8ff);
    padding: 40px;
    border-radius: 10px;
    text-align: center;
    margin-top: 50px;
}
.cta-banner h2 {
    margin-bottom: 10px;
}
.cta-banner p {
    margin-bottom: 20px;
    color: var(--text-muted);
}

/* Footer */
footer {
    text-align: center;
    padding: 30px 20px;
    background: #fff;
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
}

/* Responsive */
@media (max-width: 768px) {
    .header .container {
        flex-direction: column;
        height: auto;
        padding: 15px 20px;
    }
    .header nav {
        margin-top: 10px;
    }
    .hero h1 {
        font-size: 2rem;
    }
    .card {
        width: 100%;
        max-width: 400px;
    }
    .card.popular {
        transform: scale(1);
    }
    .card.popular:hover {
        transform: translateY(-10px);
    }
    .article-content {
        padding: 30px 20px;
    }
}