/* ===== 全局重置 & 变量 ===== */
:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --secondary: #8b5cf6;
    --accent: #06b6d4;
    --bg-dark: #0f172a;
    --bg-card: #1e293b;
    --bg-card-hover: #273548;
    --text-light: #f1f5f9;
    --text-muted: #94a3b8;
    --border-color: #334155;
    --gradient-main: linear-gradient(135deg, #6366f1, #8b5cf6, #06b6d4);
    --shadow-card: 0 8px 30px rgba(0,0,0,0.4);
    --radius: 16px;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--bg-dark);
    color: var(--text-light);
    line-height: 1.6;
    min-height: 100vh;
}
a { text-decoration: none; color: inherit; }
img { max-width: 100%; display: block; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(15, 23, 42, 0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid transparent;
    transition: background 0.4s, border-color 0.4s;
}
.navbar.scrolled {
    background: rgba(15, 23, 42, 0.95);
    border-bottom: 1px solid var(--border-color);
}
.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}
.logo {
    font-size: 1.6rem;
    font-weight: 700;
    background: var(--gradient-main);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    display: flex;
    align-items: center;
    gap: 8px;
}
.logo i { font-size: 1.8rem; }
.nav-menu { display: flex; gap: 28px; align-items: center; }
.nav-link {
    color: var(--text-muted);
    font-weight: 500;
    transition: color var(--transition);
    position: relative;
    font-size: 0.95rem;
}
.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-main);
    transition: width var(--transition);
    border-radius: 4px;
}
.nav-link:hover, .nav-link.active { color: var(--text-light); }
.nav-link:hover::after, .nav-link.active::after { width: 100%; }
.menu-toggle { display: none; background: none; border: none; color: var(--text-light); font-size: 1.6rem; cursor: pointer; }

/* ===== Hero ===== */
.hero {
    padding: 140px 0 80px;
    position: relative;
    overflow: hidden;
    min-height: 90vh;
    display: flex;
    align-items: center;
}
.hero::before {
    content: '';
    position: absolute;
    top: -30%;
    right: -20%;
    width: 60%;
    height: 80%;
    background: radial-gradient(circle, rgba(99,102,241,0.15), transparent 70%);
    pointer-events: none;
}
.hero-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 40px;
    flex-wrap: wrap;
}
.hero-text { flex: 1 1 500px; }
.hero-text h1 {
    font-size: 3.2rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 20px;
}
.gradient-text {
    background: var(--gradient-main);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.hero-text p { font-size: 1.2rem; color: var(--text-muted); margin-bottom: 32px; max-width: 500px; }
.search-box {
    display: flex;
    align-items: center;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 60px;
    padding: 6px 6px 6px 20px;
    max-width: 520px;
    transition: border-color var(--transition), box-shadow var(--transition);
}
.search-box:focus-within {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99,102,241,0.3);
}
.search-icon { color: var(--text-muted); margin-right: 8px; font-size: 1.1rem; }
.search-box input {
    flex: 1;
    background: transparent;
    border: none;
    outline: none;
    color: var(--text-light);
    font-size: 1rem;
    padding: 10px 0;
}
.search-box input::placeholder { color: var(--text-muted); }
.search-box button {
    background: var(--gradient-main);
    border: none;
    color: #fff;
    width: 46px;
    height: 46px;
    border-radius: 50%;
    cursor: pointer;
    transition: transform var(--transition), box-shadow var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
}
.search-box button:hover { transform: scale(1.05); box-shadow: 0 4px 20px rgba(99,102,241,0.4); }
.hero-stats { margin-top: 32px; display: flex; gap: 24px; flex-wrap: wrap; }
.hero-stats span { color: var(--text-muted); font-size: 0.95rem; display: flex; align-items: center; gap: 6px; }
.hero-stats strong { color: var(--text-light); font-weight: 700; }
.hero-visual { flex: 1 1 300px; display: flex; justify-content: center; }
.hero-graphic {
    width: 280px;
    height: 280px;
    background: var(--gradient-main);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 6rem;
    color: #fff;
    box-shadow: 0 20px 60px rgba(99,102,241,0.3);
    animation: float 6s ease-in-out infinite;
}
@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

/* ===== 分类标签 ===== */
.categories { padding: 60px 0 20px; }
.section-header { text-align: center; margin-bottom: 40px; }
.section-header h2 { font-size: 2.2rem; font-weight: 700; }
.section-header .highlight { color: var(--accent); font-weight: 300; }
.section-header p { color: var(--text-muted); margin-top: 8px; }
.category-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    justify-content: center;
}
.cate-btn {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    padding: 10px 22px;
    border-radius: 40px;
    cursor: pointer;
    font-size: 0.95rem;
    transition: all var(--transition);
    display: flex;
    align-items: center;
    gap: 6px;
}
.cate-btn .cate-count {
    background: rgba(255,255,255,0.05);
    padding: 0 8px;
    border-radius: 20px;
    font-size: 0.8rem;
}
.cate-btn:hover { border-color: var(--primary); color: var(--text-light); }
.cate-btn.active {
    background: var(--gradient-main);
    border-color: transparent;
    color: #fff;
    box-shadow: 0 4px 20px rgba(99,102,241,0.3);
}
.cate-btn.active .cate-count { background: rgba(255,255,255,0.2); }

/* ===== 工具卡片 ===== */
.tools-section { padding: 40px 0 80px; }
.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}
.tool-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 24px;
    border: 1px solid var(--border-color);
    transition: all var(--transition);
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: hidden;
}
.tool-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient-main);
    opacity: 0;
    transition: opacity var(--transition);
}
.tool-card:hover {
    transform: translateY(-6px);
    border-color: var(--primary);
    box-shadow: var(--shadow-card);
    background: var(--bg-card-hover);
}
.tool-card:hover::before { opacity: 1; }
.tool-card-header {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 16px;
}
.tool-icon {
    width: 48px;
    height: 48px;
    background: var(--gradient-main);
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: #fff;
    flex-shrink: 0;
}
.tool-card h3 { font-size: 1.15rem; font-weight: 600; }
.tool-category {
    background: rgba(99,102,241,0.15);
    color: var(--primary);
    font-size: 0.75rem;
    padding: 2px 10px;
    border-radius: 20px;
    display: inline-block;
    margin-top: 4px;
}
.tool-desc {
    color: var(--text-muted);
    font-size: 0.9rem;
    line-height: 1.5;
    margin: 8px 0 16px;
    flex: 1;
}
.tool-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: auto;
    padding-top: 12px;
    border-top: 1px solid var(--border-color);
}
.tool-meta span { font-size: 0.8rem; color: var(--text-muted); }
.tool-link {
    background: var(--gradient-main);
    color: #fff;
    padding: 6px 16px;
    border-radius: 30px;
    font-size: 0.85rem;
    transition: transform var(--transition), box-shadow var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.tool-link:hover { transform: scale(1.05); box-shadow: 0 4px 16px rgba(99,102,241,0.4); }
.load-more { text-align: center; margin-top: 40px; }
.btn-outline {
    background: transparent;
    border: 2px solid var(--border-color);
    color: var(--text-light);
    padding: 12px 40px;
    border-radius: 60px;
    font-size: 1rem;
    cursor: pointer;
    transition: all var(--transition);
}
.btn-outline:hover { border-color: var(--primary); background: rgba(99,102,241,0.1); }

/* ===== 热门排行 ===== */
.hot-section {
    padding: 60px 0 100px;
    background: rgba(15,23,42,0.5);
}
.hot-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 20px;
}
.hot-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 20px;
    border: 1px solid var(--border-color);
    transition: all var(--transition);
    display: flex;
    align-items: center;
    gap: 16px;
}
.hot-card:hover {
    transform: translateY(-4px);
    border-color: var(--accent);
    box-shadow: 0 8px 24px rgba(6,182,212,0.15);
}
.hot-rank {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--text-muted);
    min-width: 36px;
    text-align: center;
}
.hot-rank.top1 { color: #f59e0b; }
.hot-rank.top2 { color: #94a3b8; }
.hot-rank.top3 { color: #d97706; }
.hot-info h4 { font-size: 1rem; }
.hot-info p { color: var(--text-muted); font-size: 0.8rem; margin-top: 4px; }

/* ===== 页脚 ===== */
.footer {
    border-top: 1px solid var(--border-color);
    padding: 40px 0;
    text-align: center;
}
.footer-content { display: flex; flex-direction: column; gap: 16px; align-items: center; }
.footer-brand { font-size: 1.2rem; font-weight: 600; display: flex; align-items: center; gap: 8px; }
.footer-links { display: flex; gap: 20px; }
.footer-links a { color: var(--text-muted); transition: color var(--transition); }
.footer-links a:hover { color: var(--primary); }
.footer-copy { color: var(--text-muted); font-size: 0.85rem; }

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: rgba(15,23,42,0.98);
        backdrop-filter: blur(12px);
        flex-direction: column;
        padding: 24px 20px;
        gap: 20px;
        transform: translateY(-120%);
        transition: transform 0.4s;
        border-bottom: 1px solid var(--border-color);
    }
    .nav-menu.open { transform: translateY(0); }
    .menu-toggle { display: block; }
    .hero-text h1 { font-size: 2.2rem; }
    .hero { padding: 120px 0 60px; min-height: auto; }
    .hero-visual { display: none; }
    .tool-grid { grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); }
    .hot-grid { grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); }
}
@media (max-width: 480px) {
    .hero-text h1 { font-size: 1.8rem; }
    .search-box { max-width: 100%; }
    .category-tabs { gap: 8px; }
    .cate-btn { padding: 8px 16px; font-size: 0.85rem; }
}