/* ==================== 全局样式 ==================== */
:root {
    /* 亮色主题 */
    --bg-primary: #f5f7fa;
    --bg-secondary: #ffffff;
    --bg-hover: #f0f2f5;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-tertiary: #9ca3af;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-success: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
}

[data-theme="dark"] {
    /* 暗色主题 */
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-hover: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-tertiary: #94a3b8;
    --border-color: #334155;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background 0.3s ease, color 0.3s ease;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

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

/* ==================== 顶部导航 ==================== */
.header {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
}

.logo-icon {
    font-size: 2rem;
}

.logo-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.theme-toggle {
    background: var(--bg-hover);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1.2rem;
}

.theme-toggle:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-md);
}

/* ==================== 主内容区 ==================== */
.main {
    flex: 1;
    padding: 3rem 0;
}

/* 搜索区域 */
.search-section {
    text-align: center;
    margin-bottom: 3rem;
}

.search-box {
    max-width: 600px;
    margin: 0 auto 0.5rem;
    position: relative;
}

.search-icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    font-size: 1.2rem;
    color: var(--text-tertiary);
}

.search-input {
    width: 100%;
    padding: 1rem 1rem 1rem 3rem;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 50px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    transition: all 0.3s ease;
    outline: none;
}

.search-input:focus {
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.search-tip {
    color: var(--text-tertiary);
    font-size: 0.9rem;
}

/* 工具分类 */
.category {
    margin-bottom: 3rem;
}

.category-title {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.category-icon {
    font-size: 1.8rem;
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

/* 工具卡片 */
.tool-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 2rem;
    text-decoration: none;
    color: var(--text-primary);
    transition: all 0.3s ease;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.tool-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: #667eea;
}

.tool-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 700;
}

.tool-name {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.tool-desc {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* 空状态 */
.empty-state {
    text-align: center;
    padding: 4rem 2rem;
}

.empty-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

.empty-text {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.empty-tip {
    color: var(--text-tertiary);
    font-size: 0.9rem;
}

/* ==================== 页脚 ==================== */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    margin-top: auto;
}

.footer-text {
    text-align: center;
    color: var(--text-tertiary);
    font-size: 0.9rem;
}

/* ==================== 响应式设计 ==================== */
@media (max-width: 768px) {
    .tools-grid {
        grid-template-columns: 1fr;
    }
    
    .logo-text {
        font-size: 1.2rem;
    }
    
    .category-title {
        font-size: 1.3rem;
    }
    
    .search-input {
        font-size: 0.9rem;
    }
}

/* ==================== 动画效果 ==================== */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.tool-card {
    animation: fadeIn 0.5s ease;
}

.category:nth-child(1) .tool-card { animation-delay: 0.1s; }
.category:nth-child(2) .tool-card { animation-delay: 0.2s; }
.category:nth-child(3) .tool-card { animation-delay: 0.3s; }
.category:nth-child(4) .tool-card { animation-delay: 0.4s; }