/* ===== 全局重置 & 变量 ===== */
:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --bg: #f8fafc;
    --card-bg: #ffffff;
    --text: #1e293b;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --shadow: 0 4px 24px rgba(0,0,0,0.06);
    --radius: 16px;
    --radius-sm: 10px;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --font: 'Segoe UI', system-ui, -apple-system, sans-serif;
}

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

body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
}

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

a:hover {
    color: var(--primary-dark);
}

img {
    max-width: 100%;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ===== 导航 ===== */
.navbar {
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: var(--transition);
}

.nav-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 64px;
}

.logo {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--primary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo i {
    font-size: 1.5rem;
}

.nav-links {
    display: flex;
    gap: 8px;
}

.nav-links a {
    padding: 8px 18px;
    border-radius: 30px;
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--text-muted);
    transition: var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
    background: var(--primary);
    color: #fff;
}

.hamburger {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text);
    cursor: pointer;
    padding: 8px;
}

/* ===== Hero ===== */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    text-align: center;
    padding: 80px 24px 60px;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.05) 1px, transparent 1px);
    background-size: 30px 30px;
    animation: floatBg 20s linear infinite;
}

@keyframes floatBg {
    0% { transform: translate(0,0); }
    100% { transform: translate(30px,30px); }
}

.hero h1 {
    font-size: 2.8rem;
    margin-bottom: 16px;
    position: relative;
    z-index: 1;
}

.hero h1 i {
    margin-right: 12px;
}

.hero p {
    font-size: 1.15rem;
    max-width: 600px;
    margin: 0 auto 32px;
    opacity: 0.9;
    position: relative;
    z-index: 1;
}

.hero-actions {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    position: relative;
    z-index: 1;
}

/* ===== 按钮 ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 28px;
    border-radius: 30px;
    font-weight: 600;
    font-size: 0.95rem;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
}

.btn-primary {
    background: var(--primary);
    color: #fff;
    box-shadow: 0 4px 14px rgba(99,102,241,0.35);
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99,102,241,0.45);
}

.btn-outline {
    background: transparent;
    color: var(--primary);
    border: 2px solid var(--primary);
}

.btn-outline:hover {
    background: var(--primary);
    color: #fff;
    transform: translateY(-2px);
}

.btn-sm {
    padding: 6px 16px;
    font-size: 0.85rem;
}

.btn-block {
    width: 100%;
    justify-content: center;
}

.btn-danger {
    background: #ef4444;
    color: #fff;
}

.btn-danger:hover {
    background: #dc2626;
}

/* ===== 筛选栏 ===== */
.filter-bar {
    margin-bottom: 32px;
}

.search-form {
    display: flex;
    max-width: 480px;
    margin-bottom: 16px;
    background: var(--card-bg);
    border-radius: 30px;
    border: 1px solid var(--border);
    overflow: hidden;
    transition: var(--transition);
}

.search-form:focus-within {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99,102,241,0.15);
}

.search-form input {
    flex: 1;
    padding: 12px 20px;
    border: none;
    outline: none;
    font-size: 1rem;
    background: transparent;
}

.search-form button {
    padding: 12px 20px;
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    font-size: 1.1rem;
}

.category-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tab {
    padding: 8px 20px;
    border-radius: 30px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-muted);
    transition: var(--transition);
}

.tab:hover,
.tab.active {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}

/* ===== 卡片网格 ===== */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}

.card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
    transition: var(--transition);
    position: relative;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(0,0,0,0.1);
}

.card-badge {
    position: absolute;
    top: 16px;
    right: 16px;
    background: var(--primary-light);
    color: #fff;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
}

.card h3 {
    font-size: 1.15rem;
    margin-bottom: 10px;
    padding-right: 80px;
}

.card p {
    color: var(--text-muted);
    font-size: 0.9rem;
    line-height: 1.5;
    margin-bottom: 16px;
}

.card-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.card-meta i {
    margin-right: 4px;
}

/* ===== 空状态 ===== */
.empty-state {
    grid-column: 1 / -1;
    text-align: center;
    padding: 60px 20px;
    color: var(--text-muted);
}

.empty-state i {
    font-size: 3rem;
    margin-bottom: 16px;
    opacity: 0.5;
}

/* ===== 弹窗 ===== */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    backdrop-filter: blur(4px);
    z-index: 200;
    opacity: 0;
    pointer-events: none;
    transition: var(--transition);
}

.modal-overlay.active {
    opacity: 1;
    pointer-events: all;
}

.modal {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0.9);
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 32px;
    max-width: 560px;
    width: 90%;
    z-index: 210;
    box-shadow: 0 20px 60px rgba(0,0,0,0.2);
    opacity: 0;
    pointer-events: none;
    transition: var(--transition);
}

.modal.active {
    opacity: 1;
    pointer-events: all;
    transform: translate(-50%, -50%) scale(1);
}

.modal-close {
    position: absolute;
    top: 16px;
    right: 16px;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-muted);
    cursor: pointer;
    transition: var(--transition);
}

.modal-close:hover {
    color: var(--text);
    transform: rotate(90deg);
}

.modal h2 {
    margin-bottom: 12px;
    padding-right: 40px;
}

.modal-meta {
    display: flex;
    gap: 12px;
    align-items: center;
    margin-bottom: 16px;
    font-size: 0.9rem;
    color: var(--text-muted);
}

.modal .badge {
    background: var(--primary-light);
    color: #fff;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
}

/* ===== 页脚 ===== */
.footer {
    text-align: center;
    padding: 32px 24px;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-top: 40px;
}

/* ===== 工具页面 ===== */
.filter-tool {
    max-width: 960px;
    margin: 0 auto;
}

.filter-tool h2 {
    font-size: 1.8rem;
    margin-bottom: 8px;
}

.text-muted {
    color: var(--text-muted);
    margin-bottom: 24px;
}

.filter-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

@media (max-width: 768px) {
    .filter-layout {
        grid-template-columns: 1fr;
    }
}

.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 6px;
    font-size: 0.9rem;
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 0.95rem;
    background: var(--card-bg);
    transition: var(--transition);
    font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99,102,241,0.15);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.output-box {
    background: #f1f5f9;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 16px;
    min-height: 200px;
    white-space: pre-wrap;
    word-break: break-word;
    font-size: 0.95rem;
    line-height: 1.7;
}

.highlight {
    background: #fef08a;
    padding: 2px 4px;
    border-radius: 4px;
    font-weight: 600;
}

.stats {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-top: 12px;
}

.stats strong {
    color: var(--text);
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2rem;
    }

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

    .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 64px;
        left: 0;
        width: 100%;
        background: var(--card-bg);
        border-bottom: 1px solid var(--border);
        padding: 16px;
        box-shadow: var(--shadow);
        gap: 4px;
    }

    .nav-links.open {
        display: flex;
    }

    .hamburger {
        display: block;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

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

@media (max-width: 480px) {
    .hero {
        padding: 60px 16px 40px;
    }

    .hero h1 {
        font-size: 1.6rem;
    }

    .container {
        padding: 0 16px;
    }
}