/* ============================================
   瀑布流卡片式网站 - 完整CSS样式文件
   布局: 卡片式瀑布流
   风格: 毛玻璃效果 + 微交互动效 + 渐变背景
   ============================================ */

/* ============================================
   1. CSS变量定义
   ============================================ */
:root {
    /* 主色调 */
    --primary-color: #667eea;
    --primary-light: #889af7;
    --primary-dark: #5a67d8;
    
    /* 渐变色 */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-bg: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    --gradient-text: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    
    /* 毛玻璃效果 */
    --glass-bg: rgba(255, 255, 255, 0.1);
    --glass-border: rgba(255, 255, 255, 0.2);
    --glass-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.37);
    
    /* 中性色 */
    --white: #ffffff;
    --gray-100: #f7fafc;
    --gray-200: #edf2f7;
    --gray-300: #e2e8f0;
    --gray-400: #a0aec0;
    --gray-500: #718096;
    --gray-600: #4a5568;
    --gray-700: #2d3748;
    --gray-800: #1a202c;
    --gray-900: #171923;
    
    /* 间距 */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    /* 圆角 */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;
    
    /* 阴影 */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    /* 过渡 */
    --transition-fast: 150ms ease;
    --transition-normal: 300ms ease;
    --transition-slow: 500ms ease;
    
    /* 字体 */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-display: 'Poppins', var(--font-sans);
    
    /* 容器宽度 */
    --container-max: 1400px;
    --container-narrow: 800px;
}

/* ============================================
   2. 全局重置与基础样式
   ============================================ */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--gray-700);
    background: var(--gradient-bg);
    min-height: 100vh;
    overflow-x: hidden;
}

/* 背景装饰 */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 80%, rgba(102, 126, 234, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(118, 75, 162, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(240, 147, 251, 0.08) 0%, transparent 40%);
    pointer-events: none;
    z-index: -1;
}

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

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

img {
    max-width: 100%;
    height: auto;
    display: block;
}

ul, ol {
    list-style: none;
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

input, textarea, select {
    font-family: inherit;
    font-size: inherit;
}

/* ============================================
   3. 工具类
   ============================================ */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.container--narrow {
    max-width: var(--container-narrow);
}

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

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ============================================
   4. 标题样式
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 700;
    color: var(--white);
    line-height: 1.2;
}

h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
    letter-spacing: -0.02em;
}

h2 {
    font-size: clamp(2rem, 4vw, 3rem);
    letter-spacing: -0.01em;
}

h3 {
    font-size: clamp(1.5rem, 3vw, 2rem);
}

h4 {
    font-size: 1.25rem;
}

h5 {
    font-size: 1.125rem;
}

h6 {
    font-size: 1rem;
}

/* ============================================
   5. 导航栏
   ============================================ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: var(--spacing-md) 0;
    transition: all var(--transition-normal);
}

.navbar--scrolled {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
}

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

.navbar__logo {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    transition: transform var(--transition-fast);
}

.navbar__logo:hover {
    transform: scale(1.05);
}

.navbar__menu {
    display: flex;
    gap: var(--spacing-xl);
}

.navbar__link {
    position: relative;
    color: var(--gray-300);
    font-weight: 500;
    padding: var(--spacing-sm) 0;
    transition: color var(--transition-fast);
}

.navbar__link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: width var(--transition-normal);
}

.navbar__link:hover {
    color: var(--white);
}

.navbar__link:hover::after {
    width: 100%;
}

.navbar__toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: var(--spacing-sm);
}

.navbar__toggle span {
    width: 24px;
    height: 2px;
    background: var(--white);
    border-radius: 2px;
    transition: all var(--transition-fast);
}

/* 移动端菜单 */
@media (max-width: 768px) {
    .navbar__menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 80%;
        max-width: 320px;
        height: 100vh;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: var(--spacing-2xl);
        background: rgba(26, 26, 46, 0.98);
        backdrop-filter: blur(20px);
        transition: right var(--transition-normal);
    }
    
    .navbar__menu--active {
        right: 0;
    }
    
    .navbar__toggle {
        display: flex;
        z-index: 1001;
    }
}

/* ============================================
   6. 头部区域
   ============================================ */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: var(--spacing-3xl) var(--spacing-lg);
    position: relative;
}

.hero__content {
    max-width: 900px;
}

.hero__title {
    margin-bottom: var(--spacing-lg);
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease forwards;
}

.hero__subtitle {
    font-size: clamp(1.125rem, 2vw, 1.5rem);
    color: var(--gray-400);
    margin-bottom: var(--spacing-2xl);
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease 0.2s forwards;
}

.hero__cta {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease 0.4s forwards;
}

/* 几何装饰 */
.hero__decoration {
    position: absolute;
    pointer-events: none;
}

.hero__decoration--1 {
    top: 20%;
    left: 10%;
    width: 100px;
    height: 100px;
    border: 2px solid var(--glass-border);
    border-radius: 50%;
    animation: float 6s ease-in-out infinite;
}

.hero__decoration--2 {
    top: 60%;
    right: 15%;
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    opacity: 0.3;
    border-radius: var(--radius-md);
    transform: rotate(45deg);
    animation: float 8s ease-in-out infinite reverse;
}

.hero__decoration--3 {
    bottom: 25%;
    left: 20%;
    width: 80px;
    height: 80px;
    border: 2px solid var(--glass-border);
    border-radius: var(--radius-lg);
    animation: float 7s ease-in-out infinite;
}

/* ============================================
   7. 瀑布流布局
   ============================================ */
.masonry {
    padding: var(--spacing-3xl) 0;
}

.masonry__header {
    text-align: center;
    margin-bottom: var(--spacing-3xl);
}

.masonry__filter {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    margin-top: var(--spacing-lg);
    flex-wrap: wrap;
}

.masonry__filter-btn {
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    color: var(--gray-400);
    font-weight: 500;
    transition: all var(--transition-fast);
}

.masonry__filter-btn:hover,
.masonry__filter-btn--active {
    background: var(--gradient-primary);
    border-color: transparent;
    color: var(--white);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

/* 瀑布流网格 */
.masonry__grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    grid-auto-rows: 10px;
    gap: var(--spacing-lg);
}

@media (min-width: 768px) {
    .masonry__grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .masonry__grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (min-width: 1400px) {
    .masonry__grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* ============================================
   8. 卡片组件
   ============================================ */
.card {
    position: relative;
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all var(--transition-normal);
    cursor: pointer;
}

.card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--glass-shadow), 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    border-color: var(--primary-light);
}

.card__image-wrapper {
    position: relative;
    overflow: hidden;
}

.card__image {
    width: 100%;
    height: auto;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.card:hover .card__image {
    transform: scale(1.1);
}

.card__overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(to top, rgba(0, 0, 0, 0.6) 0%, transparent 50%);
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.card:hover .card__overlay {
    opacity: 1;
}

.card__content {
    padding: var(--spacing-lg);
}

.card__tag {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--gradient-primary);
    border-radius: var(--radius-sm);
    color: var(--white);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-sm);
}

.card__title {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
    color: var(--white);
    transition: color var(--transition-fast);
}

.card:hover .card__title {
    color: var(--primary-light);
}

.card__description {
    color: var(--gray-400);
    font-size: 0.9rem;
    line-height: 1.6;
    margin-bottom: var(--spacing-md);
}

.card__footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--glass-border);
}

.card__author {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.card__avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    border: 2px solid var(--glass-border);
}

.card__author-name {
    font-size: 0.875rem;
    color: var(--gray-300);
    font-weight: 500;
}

.card__date {
    font-size: 0.75rem;
    color: var(--gray-500);
}

.card__actions {
    display: flex;
    gap: var(--spacing-sm);
    opacity: 0;
    transform: translateY(10px);
    transition: all var(--transition-normal);
}

.card:hover .card__actions {
    opacity: 1;
    transform: translateY(0);
}

.card__action-btn {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 50%;
    color: var(--gray-400);
    transition: all var(--transition-fast);
}

.card__action-btn:hover {
    background: var(--gradient-primary);
    border-color: transparent;
    color: var(--white);
    transform: scale(1.1);
}

/* 卡片尺寸变体 */
.card--large {
    grid-row-end: span 45;
}

.card--medium {
    grid-row-end: span 35;
}

.card--small {
    grid-row-end: span 25;
}

/* 特色卡片 */
.card--featured {
    grid-column: span 2;
    grid-row-end: span 50;
}

@media (max-width: 768px) {
    .card--featured {
        grid-column: span 1;
    }
}

/* ============================================
   9. 按钮样式
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    font-weight: 600;
    font-size: 1rem;
    border-radius: var(--radius-md);
    transition: all var(--transition-normal);
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

.btn--primary {
    background: var(--gradient-primary);
    color: var(--white);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.btn--primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.5);
}

.btn--secondary {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    color: var(--white);
    backdrop-filter: blur(10px);
}

.btn--secondary:hover {
    background: rgba(255, 255, 255, 0.2);
    border-color: var(--primary-light);
    transform: translateY(-3px);
}

.btn--ghost {
    background: transparent;
    color: var(--gray-300);
}

.btn--ghost:hover {
    color: var(--white);
    background: var(--glass-bg);
}

.btn--icon {
    width: 48px;
    height: 48px;
    padding: 0;
    border-radius: 50%;
}

.btn--sm {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.875rem;
}

.btn--lg {
    padding: var(--spacing-lg) var(--spacing-2xl);
    font-size: 1.125rem;
}

/* 按钮组 */
.btn-group {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

/* ============================================
   10. 表单样式
   ============================================ */
.form {
    max-width: 500px;
}

.form__group {
    margin-bottom: var(--spacing-lg);
}

.form__label {
    display: block;
    margin-bottom: var(--spacing-sm);
    color: var(--gray-300);
    font-weight: 500;
    font-size: 0.9rem;
}

.form__input,
.form__textarea,
.form__select {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    color: var(--white);
    font-size: 1rem;
    transition: all var(--transition-fast);
}

.form__input::placeholder,
.form__textarea::placeholder {
    color: var(--gray-500);
}

.form__input:focus,
.form__textarea:focus,
.form__select:focus {
    outline: none;
    border-color: var(--primary-light);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.2);
    background: rgba(255, 255, 255, 0.15);
}

.form__textarea {
    min-height: 150px;
    resize: vertical;
}

.form__select {
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='%23a0aec0'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M19 9l-7 7-7-7'%3E%3C/path%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    background-size: 20px;
    padding-right: 40px;
}

.form__select option {
    background: var(--gray-800);
    color: var(--white);
}

/* 输入框组 */
.form__input-group {
    display: flex;
    gap: var(--spacing-sm);
}

.form__input-group .form__input {
    flex: 1;
}

/* 复选框和单选框 */
.form__checkbox,
.form__radio {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    cursor: pointer;
}

.form__checkbox input,
.form__radio input {
    display: none;
}

.form__checkbox-box,
.form__radio-box {
    width: 20px;
    height: 20px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.form__radio-box {
    border-radius: 50%;
}

.form__checkbox input:checked + .form__checkbox-box,
.form__radio input:checked + .form__radio-box {
    background: var(--gradient-primary);
    border-color: transparent;
}

.form__checkbox-box::after {
    content: '✓';
    color: var(--white);
    font-size: 0.75rem;
    opacity: 0;
    transform: scale(0);
    transition: all var(--transition-fast);
}

.form__checkbox input:checked + .form__checkbox-box::after {
    opacity: 1;
    transform: scale(1);
}

/* ============================================
   11. 特色区块
   ============================================ */
.section {
    padding: var(--spacing-3xl) 0;
}

.section--alt {
    background: rgba(0, 0, 0, 0.2);
}

.section__header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto var(--spacing-3xl);
}

.section__title {
    margin-bottom: var(--spacing-md);
}

.section__subtitle {
    color: var(--gray-400);
    font-size: 1.125rem;
}

/* 统计数据 */
.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-xl);
    padding: var(--spacing-3xl) 0;
}

.stat {
    text-align: center;
    padding: var(--spacing-xl);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(10px);
    transition: all var(--transition-normal);
}

.stat:hover {
    transform: translateY(-5px);
    border-color: var(--primary-light);
    box-shadow: var(--glass-shadow);
}

.stat__number {
    font-family: var(--font-display);
    font-size: clamp(2.5rem, 5vw, 3.5rem);
    font-weight: 700;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1;
    margin-bottom: var(--spacing-sm);
}

.stat__label {
    color: var(--gray-400);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

/* 特色卡片网格 */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-xl);
}

.feature-card {
    padding: var(--spacing-xl);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(10px);
    text-align: center;
    transition: all var(--transition-normal);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--glass-shadow);
    border-color: var(--primary-light);
}

.feature-card__icon {
    width: 64px;
    height: 64px;
    margin: 0 auto var(--spacing-lg);
    background: var(--gradient-primary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    transition: transform var(--transition-normal);
}

.feature-card:hover .feature-card__icon {
    transform: rotateY(180deg);
}

.feature-card__title {
    margin-bottom: var(--spacing-sm);
    color: var(--white);
}

.feature-card__description {
    color: var(--gray-400);
    font-size: 0.9rem;
}

/* ============================================
   12. 页脚
   ============================================ */
.footer {
    background: rgba(0, 0, 0, 0.3);
    border-top: 1px solid var(--glass-border);
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

.footer__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
}

.footer__brand {
    max-width: 300px;
}

.footer__logo {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-md);
}

.footer__description {
    color: var(--gray-400);
    font-size: 0.9rem;
    line-height: 1.7;
}

.footer__title {
    color: var(--white);
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
}

.footer__links {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.footer__link {
    color: var(--gray-400);
    font-size: 0.9rem;
    transition: color var(--transition-fast);
}

.footer__link:hover {
    color: var(--primary-light);
}

.footer__social {
    display: flex;
    gap: var(--spacing-sm);
}

.footer__social-link {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 50%;
    color: var(--gray-400);
    transition: all var(--transition-fast);
}

.footer__social-link:hover {
    background: var(--gradient-primary);
    border-color: transparent;
    color: var(--white);
    transform: translateY(-3px);
}

.footer__bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--glass-border);
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.footer__copyright {
    color: var(--gray-500);
    font-size: 0.875rem;
}

.footer__legal {
    display: flex;
    gap: var(--spacing-lg);
}

.footer__legal a {
    color: var(--gray-500);
    font-size: 0.875rem;
}

.footer__legal a:hover {
    color: var(--gray-300);
}

/* ============================================
   13. 模态框
   ============================================ */
.modal {
    position: fixed;
    inset: 0;
    z-index: 2000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-lg);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
}

.modal--active {
    opacity: 1;
    visibility: visible;
}

.modal__backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
}

.modal__content {
    position: relative;
    width: 100%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    background: rgba(26, 26, 46, 0.95);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    transform: scale(0.9) translateY(20px);
    transition: transform var(--transition-normal);
}

.modal--active .modal__content {
    transform: scale(1) translateY(0);
}

.modal__close {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 50%;
    color: var(--gray-400);
    font-size: 1.25rem;
    transition: all var(--transition-fast);
}

.modal__close:hover {
    background: var(--gradient-primary);
    border-color: transparent;
    color: var(--white);
    transform: rotate(90deg);
}

.modal__header {
    margin-bottom: var(--spacing-xl);
}

.modal__title {
    font-size: 1.5rem;
}

.modal__body {
    color: var(--gray-300);
    line-height: 1.7;
}

.modal__footer {
    display: flex;
    justify-content: flex-end;
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--glass-border);
}

/* ============================================
   14. 加载状态
   ============================================ */
.loading {
    display: flex;
    justify-content: center;
    padding: var(--spacing-2xl);
}

.loading__spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--glass-border);
    border-top-color: var(--primary-light);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

.skeleton {
    background: linear-gradient(90deg, 
        var(--glass-bg) 25%, 
        rgba(255, 255, 255, 0.1) 50%, 
        var(--glass-bg) 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
    border-radius: var(--radius-md);
}

/* ============================================
   15. 提示消息
   ============================================ */
.toast {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    padding: var(--spacing-md) var(--spacing-xl);
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    color: var(--white);
    box-shadow: var(--glass-shadow);
    transform: translateX(120%);
    transition: transform var(--transition-normal);
    z-index: 3000;
}

.toast--active {
    transform: translateX(0);
}

.toast--success {
    border-color: #48bb78;
}

.toast--error {
    border-color: #f56565;
}

.toast--warning {
    border-color: #ecc94b;
}

/* ============================================
   16. 动画关键帧
   ============================================ */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes float {
    0%, 100% {
        transform: translateY(0) rotate(0deg);
    }
    50% {
        transform: translateY(-20px) rotate(5deg);
    }
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

@keyframes shimmer {
    0% {
        background-position: -200% 0;
    }
    100% {
        background-position: 200% 0;
    }
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

@keyframes bounce {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
}

/* ============================================
   17. 响应式媒体查询
   ============================================ */

/* 超大屏幕 */
@media (min-width: 1920px) {
    :root {
        font-size: 18px;
    }
    
    .container {
        max-width: 1600px;
    }
}

/* 大屏幕 */
@media (max-width: 1199px) {
    .card--featured {
        grid-column: span 1;
    }
}

/* 平板 */
@media (max-width: 991px) {
    :root {
        font-size: 15px;
    }
    
    .section {
        padding: var(--spacing-2xl) 0;
    }
    
    .stats {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* 大手机 */
@media (max-width: 767px) {
    :root {
        font-size: 14px;
    }
    
    .container {
        padding: 0 var(--spacing-md);
    }
    
    .hero {
        padding: var(--spacing-2xl) var(--spacing-md);
    }
    
    .hero__cta {
        flex-direction: column;
        align-items: center;
    }
    
    .hero__decoration {
        display: none;
    }
    
    .masonry__grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .card {
        grid-row-end: auto !important;
    }
    
    .feature-grid {
        grid-template-columns: 1fr;
    }
    
    .footer__grid {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .footer__brand {
        max-width: 100%;
    }
    
    .footer__social {
        justify-content: center;
    }
    
    .footer__bottom {
        flex-direction: column;
        text-align: center;
    }
    
    .modal__content {
        padding: var(--spacing-lg);
    }
    
    .toast {
        left: var(--spacing-md);
        right: var(--spacing-md);
        bottom: var(--spacing-md);
    }
}

/* 小手机 */
@media (max-width: 479px) {
    .btn {
        width: 100%;
    }
    
    .btn-group {
        flex-direction: column;
    }
    
    .form__input-group {
        flex-direction: column;
    }
    
    .stats {
        grid-template-columns: 1fr;
    }
    
    .masonry__filter {
        flex-direction: column;
        align-items: stretch;
    }
    
    .masonry__filter-btn {
        text-align: center;
    }
}

/* ============================================
   18. 打印样式
   ============================================ */
@media print {
    body {
        background: white;
        color: black;
    }
    
    .navbar,
    .footer,
    .btn,
    .card__actions,
    .toast {
        display: none !important;
    }
    
    .card {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ddd;
    }
}

/* ============================================
   19. 辅助功能 - 焦点样式
   ============================================ */
:focus-visible {
    outline: 2px solid var(--primary-light);
    outline-offset: 2px;
}

button:focus-visible,
a:focus-visible {
    outline: 2px solid var(--primary-light);
    outline-offset: 2px;
}

/* 减少动画（无障碍） */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    html {
        scroll-behavior: auto;
    }
}

/* 高对比度模式 */
@media (prefers-contrast: high) {
    :root {
        --glass-bg: rgba(0, 0, 0, 0.8);
        --glass-border: rgba(255, 255, 255, 0.6);
    }
}
```