:root {
    --primary-color: #6366f1;
    --secondary-color: #8b5cf6;
    --background-color: #f8fafc;
    --text-color: #1e293b;
    --card-background: #ffffff;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --sidebar-width: 250px;
    --header-height: 60px;
}

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

body {
    font-family: 'Noto Sans SC', sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
}

/* 顶部导航 */
.header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px var(--shadow-color);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    color: white;
    font-size: 1.5rem;
    font-weight: 700;
}

.search-box {
    display: flex;
    gap: 0.5rem;
}

.search-box input {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: 25px;
    width: 300px;
    font-size: 1rem;
    outline: none;
}

.search-box button {
    padding: 0.5rem 1.5rem;
    border: none;
    border-radius: 25px;
    background-color: white;
    color: var(--primary-color);
    font-weight: 500;
    cursor: pointer;
    transition: transform 0.2s;
}

.search-box button:hover {
    transform: scale(1.05);
}

/* 首页标题 */
.hero-section {
    text-align: center;
    padding: 3rem 2rem;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1), rgba(139, 92, 246, 0.1));
}

.hero-section h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-section p {
    font-size: 1.2rem;
    color: #64748b;
}

/* 分类导航 */
.category-nav {
    background-color: white;
    padding: 1rem 0;
    box-shadow: 0 2px 10px var(--shadow-color);
    position: sticky;
    top: 70px;
    z-index: 900;
}

.category-buttons {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    justify-content: center;
}

.category-btn {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: 20px;
    background-color: #f1f5f9;
    color: var(--text-color);
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.category-btn:hover {
    background-color: #e2e8f0;
}

.category-btn.active {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
}

/* 主内容区 */
.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 2rem;
}

.tool-section {
    display: none;
    margin-bottom: 3rem;
}

.tool-section.active {
    display: block;
}

.section-header {
    margin-bottom: 2rem;
}

.section-header h2 {
    font-size: 1.8rem;
    color: var(--text-color);
    margin-bottom: 0.5rem;
}

.section-header p {
    color: #64748b;
}

.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.tool-card {
    background: var(--card-background);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: 0 4px 20px var(--shadow-color);
    transition: transform 0.3s ease;
}

.tool-card:hover {
    transform: translateY(-5px);
}

.tool-card h3 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.tool-card p {
    color: #64748b;
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

.tool-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    align-items: center;
    justify-content: space-between;
}

.tag {
    padding: 0.25rem 0.75rem;
    border-radius: 15px;
    font-size: 0.85rem;
}

.tag.free {
    background-color: #dcfce7;
    color: #166534;
}

.tag.pro {
    background-color: #dbeafe;
    color: #1e40af;
}

.visit-link {
    padding: 0.25rem 1rem;
    border-radius: 15px;
    font-size: 0.85rem;
    text-decoration: none;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    transition: all 0.3s ease;
}

.visit-link:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.2);
}

/* 页脚 */
footer {
    background-color: var(--text-color);
    color: white;
    padding: 2rem 0;
    margin-top: 4rem;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    text-align: center;
    padding: 0 2rem;
}

footer a {
    color: #a5b4fc;
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
        gap: 1rem;
    }

    .search-box input {
        width: 100%;
    }

    .category-buttons {
        flex-wrap: nowrap;
        overflow-x: auto;
        justify-content: flex-start;
        padding-bottom: 0.5rem;
    }

    .category-btn {
        white-space: nowrap;
    }

    .tool-grid {
        grid-template-columns: 1fr;
    }

    .hero-section h1 {
        font-size: 2rem;
    }

    .hero-section p {
        font-size: 1rem;
    }
}