/* ===== 51视频 全站样式表 ===== */
/* 设计理念：现代影视平台风格，高清质感，沉浸式观影氛围 */

/* ===== CSS变量定义 ===== */
:root {
    /* 主色调 - 科技蓝紫渐变 */
    --brand-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #d946ef 100%);
    --brand-primary: #7c3aed;
    --brand-secondary: #6366f1;
    --brand-accent: #d946ef;
    
    /* 背景色 */
    --bg-primary: #0b0f1a;
    --bg-secondary: #131a2b;
    --bg-tertiary: #1a2338;
    --bg-card: rgba(255, 255, 255, 0.05);
    --bg-glass: rgba(255, 255, 255, 0.08);
    
    /* 文字色 */
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --text-heading: #ffffff;
    
    /* 边框与阴影 */
    --border-color: rgba(255, 255, 255, 0.1);
    --shadow-color: rgba(0, 0, 0, 0.4);
    --shadow-glow: 0 0 30px rgba(124, 58, 237, 0.3);
    
    /* 状态色 */
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    
    /* 圆角 */
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --radius-full: 9999px;
    
    /* 导航 */
    --nav-bg: rgba(11, 15, 26, 0.85);
    --nav-border: rgba(255, 255, 255, 0.08);
    
    /* 页脚 */
    --footer-bg: #060a12;
}

/* ===== 暗色模式变量（默认即暗色，此块兼容） ===== */
[data-theme="dark"] {
    --bg-primary: #0b0f1a;
    --bg-secondary: #131a2b;
    --bg-tertiary: #1a2338;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border-color: rgba(255, 255, 255, 0.1);
    --nav-bg: rgba(11, 15, 26, 0.9);
    --footer-bg: #060a12;
}

/* ===== 重置与基础 ===== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-primary);
    background-image: 
        radial-gradient(ellipse at 20% 0%, rgba(124, 58, 237, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, rgba(99, 102, 241, 0.1) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 50%, rgba(217, 70, 239, 0.05) 0%, transparent 50%);
    background-attachment: fixed;
    color: var(--text-primary);
    line-height: 1.7;
    font-size: 16px;
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

h1, h2, h3, h4, h5, h6 {
    color: var(--text-heading);
    font-weight: 700;
    line-height: 1.3;
    letter-spacing: -0.02em;
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
    background: var(--brand-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

h2 {
    font-size: 2rem;
    margin-top: 3rem;
    margin-bottom: 1.5rem;
    position: relative;
    padding-left: 1.2rem;
}

h2::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 70%;
    background: var(--brand-gradient);
    border-radius: var(--radius-full);
}

h3 {
    font-size: 1.4rem;
    margin-top: 1.5rem;
    margin-bottom: 0.8rem;
}

h4 {
    font-size: 1.1rem;
    font-weight: 600;
}

p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

a {
    color: var(--brand-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease, text-shadow 0.3s ease;
}

a:hover {
    color: var(--brand-accent);
    text-shadow: 0 0 20px rgba(217, 70, 239, 0.3);
}

strong {
    color: var(--text-heading);
    font-weight: 600;
}

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

/* ===== 容器 ===== */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 24px;
    position: relative;
}

/* ===== 滚动条美化 ===== */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, var(--brand-primary), var(--brand-accent));
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(180deg, var(--brand-accent), var(--brand-primary));
}

/* ===== 选择文本 ===== */
::selection {
    background: var(--brand-primary);
    color: white;
    text-shadow: none;
}

/* ===== 导航栏 ===== */
.navbar {
    background: var(--nav-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--nav-border);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: all 0.4s ease;
}

.navbar.scrolled {
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
    background: rgba(11, 15, 26, 0.95);
}

.nav-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    padding: 0.8rem 0;
    min-height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    flex-shrink: 0;
}

.logo a {
    font-size: 1.6rem;
    font-weight: 800;
    background: var(--brand-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
    display: flex;
    align-items: center;
    gap: 0.6rem;
}

.logo svg {
    filter: drop-shadow(0 4px 12px rgba(124, 58, 237, 0.4));
    transition: transform 0.3s ease;
}

.logo:hover svg {
    transform: rotate(10deg) scale(1.1);
}

.nav-links {
    display: flex;
    gap: 2rem;
    align-items: center;
    flex-wrap: wrap;
    list-style: none;
}

.nav-links a {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.95rem;
    padding: 0.5rem 0;
    position: relative;
    transition: color 0.3s ease;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: var(--brand-gradient);
    border-radius: var(--radius-full);
    transition: width 0.3s ease;
}

.nav-links a:hover {
    color: var(--text-heading);
}

.nav-links a:hover::after {
    width: 100%;
}

.nav-controls {
    display: flex;
    gap: 0.8rem;
    align-items: center;
    flex-shrink: 0;
}

.search-bar {
    display: flex;
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-full);
    overflow: hidden;
    transition: all 0.3s ease;
}

.search-bar:focus-within {
    border-color: var(--brand-primary);
    box-shadow: 0 0 20px rgba(124, 58, 237, 0.2);
}

.search-bar input {
    border: none;
    background: transparent;
    padding: 0.6rem 1.2rem;
    color: var(--text-primary);
    width: 200px;
    outline: none;
    font-size: 0.9rem;
}

.search-bar input::placeholder {
    color: var(--text-muted);
}

.search-bar button {
    background: var(--brand-gradient);
    border: none;
    color: white;
    padding: 0.6rem 1.5rem;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

.search-bar button:hover {
    filter: brightness(1.2);
    transform: scale(1.05);
}

.theme-toggle, .menu-toggle {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-full);
    padding: 0.5rem 1.2rem;
    cursor: pointer;
    color: var(--text-primary);
    font-weight: 500;
    font-size: 1.2rem;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover, .menu-toggle:hover {
    border-color: var(--brand-primary);
    box-shadow: 0 0 20px rgba(124, 58, 237, 0.3);
    transform: translateY(-2px);
}

.menu-toggle {
    display: none;
    font-size: 1.4rem;
}

/* ===== Banner 轮播 ===== */
.banner {
    margin: 2rem 0 1rem;
    position: relative;
}

.banner-slide {
    background: linear-gradient(135deg, rgba(124, 58, 237, 0.9) 0%, rgba(99, 102, 241, 0.85) 30%, rgba(217, 70, 239, 0.8) 100%);
    border-radius: var(--radius-lg);
    padding: 3.5rem 3rem;
    color: white;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
    flex-wrap: wrap;
    position: relative;
    overflow: hidden;
    box-shadow: 0 20px 60px rgba(124, 58, 237, 0.3);
    animation: gradientShift 8s ease infinite alternate;
}

@keyframes gradientShift {
    0% {
        background: linear-gradient(135deg, rgba(124, 58, 237, 0.9) 0%, rgba(99, 102, 241, 0.85) 30%, rgba(217, 70, 239, 0.8) 100%);
    }
    100% {
        background: linear-gradient(135deg, rgba(217, 70, 239, 0.8) 0%, rgba(99, 102, 241, 0.85) 50%, rgba(124, 58, 237, 0.9) 100%);
    }
}

.banner-slide::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 60%;
    height: 200%;
    background: rgba(255, 255, 255, 0.1);
    transform: rotate(30deg);
    animation: shine 3s ease infinite;
}

@keyframes shine {
    0%, 100% {
        transform: rotate(30deg) translateX(0);
    }
    50% {
        transform: rotate(30deg) translateX(20%);
    }
}

.banner-text {
    position: relative;
    z-index: 2;
    flex: 1;
    min-width: 300px;
}

.banner-text h2 {
    color: white;
    border-left: none;
    padding-left: 0;
    font-size: 2.5rem;
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    background: none;
    -webkit-text-fill-color: white;
    margin-top: 0;
}

.banner-text p {
    color: rgba(255, 255, 255, 0.9);
    max-width: 600px;
    font-size: 1.1rem;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.banner-btn {
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.4);
    color: white;
    padding: 0.9rem 2.5rem;
    border-radius: var(--radius-full);
    font-weight: 600;
    font-size: 1.1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-block;
    margin-top: 1rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

.banner-btn:hover {
    background: white;
    color: var(--brand-primary);
    transform: translateY(-3px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.3);
}

.banner-slide > svg {
    position: relative;
    z-index: 2;
    filter: drop-shadow(0 10px 30px rgba(0, 0, 0, 0.3));
    animation: float 3s ease-in-out infinite;
}

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

/* ===== 品牌介绍 ===== */
#about {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 3rem;
    margin: 2rem 0;
    position: relative;
    overflow: hidden;
}

#about::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: var(--brand-gradient);
}

#about p {
    font-size: 1.05rem;
    line-height: 2;
}

/* ===== 统计数据 ===== */
.stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin: 3rem 0;
    padding: 2rem;
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
}

.stat-item {
    text-align: center;
    padding: 1.5rem;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
    cursor: default;
}

.stat-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(124, 58, 237, 0.2);
    border-color: var(--brand-primary);
}

.stat-number {
    font-size: 2.8rem;
    font-weight: 800;
    background: var(--brand-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    display: block;
    margin-bottom: 0.5rem;
    line-height: 1.2;
}

.stat-item p {
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-bottom: 0;
}

/* ===== 网格卡片 ===== */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin: 2.5rem 0;
}

.card {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 2rem 1.8rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    transition: all 0.4s cubic-bezier(0.165, 0.84, 0.44, 1);
    position: relative;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--brand-gradient);
    opacity: 0;
    transition: opacity 0.4s ease;
    z-index: -1;
}

.card:hover {
    transform: translateY(-10px) scale(1.02);
    box-shadow: 0 20px 50px rgba(124, 58, 237, 0.3);
    border-color: var(--brand-primary);
}

.card:hover::before {
    opacity: 0.05;
}

.card svg {
    margin-bottom: 1.2rem;
    filter: drop-shadow(0 4px 12px rgba(124, 58, 237, 0.3));
    transition: transform 0.3s ease;
}

.card:hover svg {
    transform: scale(1.1) rotate(5deg);
}

.card h3 {
    margin-top: 0;
    font-size: 1.3rem;
}

.card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 0;
}

/* ===== 解决方案 ===== */
#solutions .card {
    background: var(--bg-glass);
    border-left: 3px solid var(--brand-primary);
}

/* ===== 客户案例 ===== */
#cases .card {
    background: var(--bg-glass);
    border-top: 3px solid var(--brand-gradient);
}

#cases .card p:first-child {
    font-style: italic;
    font-size: 1.05rem;
    line-height: 1.9;
}

#cases .card p:last-child {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-top: 1rem;
    font-style: normal;
}

/* ===== 新闻中心 ===== */
#news {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 3rem;
    margin: 2rem 0;
}

.article-list {
    margin: 2rem 0;
}

.article-item {
    border-bottom: 1px solid var(--border-color);
    padding: 2rem 0;
    transition: all 0.3s ease;
    position: relative;
    padding-left: 1.5rem;
}

.article-item:last-child {
    border-bottom: none;
}

.article-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 2.5rem;
    width: 4px;
    height: 40px;
    background: var(--brand-gradient);
    border-radius: var(--radius-full);
    opacity: 0.3;
    transition: all 0.3s ease;
}

.article-item:hover::before {
    height: 70px;
    opacity: 1;
}

.article-item h3 {
    margin-bottom: 0.5rem;
    font-size: 1.2rem;
    transition: color 0.3s ease;
}

.article-item:hover h3 {
    color: var(--brand-accent);
}

.meta {
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-bottom: 0.8rem;
}

.article-item p:not(.meta) {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 1rem;
}

.btn {
    display: inline-block;
    background: var(--brand-gradient);
    color: white;
    padding: 0.7rem 1.8rem;
    border-radius: var(--radius-full);
    font-weight: 600;
    border: none;
    cursor: pointer;
    text-decoration: none;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(124, 58, 237, 0.3);
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 25px rgba(124, 58, 237, 0.5);
    color: white;
    text-decoration: none;
}

.btn-secondary {
    background: var(--bg-glass);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    box-shadow: none;
}

.btn-secondary:hover {
    border-color: var(--brand-primary);
    color: var(--brand-accent);
    box-shadow: 0 4px 15px rgba(124, 58, 237, 0.2);
}

/* ===== FAQ ===== */
#faq {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 3rem;
    margin: 2rem 0;
}

.faq-item {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 1.5rem 2rem;
    margin-bottom: 1rem;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
    cursor: pointer;
}

.faq-item:hover {
    border-color: var(--brand-primary);
    box-shadow: 0 4px 20px rgba(124, 58, 237, 0.1);
}

.faq-question {
    font-weight: 600;
    color: var(--text-heading);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1.05rem;
    transition: color 0.3s ease;
}

.faq-item:hover .faq-question {
    color: var(--brand-accent);
}

.faq-question span {
    font-size: 1.5rem;
    font-weight: 300;
    color: var(--brand-primary);
    transition: transform 0.3s ease;
    flex-shrink: 0;
    margin-left: 1rem;
}

.faq-item.active .faq-question span {
    transform: rotate(45deg);
}

.faq-answer {
    margin-top: 1rem;
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.8;
    border-top: 1px solid var(--border-color);
    padding-top: 1rem;
}

/* ===== 新手指南 ===== */
#howto {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 3rem;
    margin: 2rem 0;
}

.howto-step {
    background: var(--bg-card);
    border-left: 4px solid var(--brand-primary);
    padding: 1.5rem 2rem;
    margin: 1.2rem 0;
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    transition: all 0.3s ease;
}

.howto-step:hover {
    border-left-width: 6px;
    background: var(--bg-glass);
    transform: translateX(5px);
}

.howto-step h3 {
    margin-top: 0;
    margin-bottom: 0.8rem;
    font-size: 1.1rem;
    color: var(--brand-accent);
}

.howto-step p {
    margin-bottom: 0;
    font-size: 0.95rem;
}

/* ===== 联系我们 ===== */
#contact {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 3rem;
    margin: 2rem 0;
}

#contact p {
    font-size: 1.05rem;
    padding: 0.8rem 0;
    border-bottom: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

#contact p:last-child {
    border-bottom: none;
}

#contact p:hover {
    padding-left: 1rem;
    border-bottom-color: var(--brand-primary);
}

#contact strong {
    color: var(--brand-accent);
    margin-right: 0.5rem;
}

/* ===== 页脚 ===== */
footer {
    background: var(--footer-bg);
    color: var(--text-secondary);
    padding: 4rem 0 2rem;
    margin-top: 4rem;
    border-top: 1px solid var(--border-color);
    position: relative;
}

footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 1px;
    background: var(--brand-gradient);
    opacity: 0.5;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 3rem;
}

footer h4 {
    color: var(--text-heading);
    font-size: 1.1rem;
    margin-bottom: 1.2rem;
    position: relative;
}

footer h4::after {
    content: '';
    position: absolute;
    bottom: -0.5rem;
    left: 0;
    width: 30px;
    height: 2px;
    background: var(--brand-gradient);
    border-radius: var(--radius-full);
}

footer a {
    color: var(--text-muted);
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

footer a:hover {
    color: var(--brand-accent);
    text-shadow: 0 0 20px rgba(217, 70, 239, 0.3);
}

.copyright {
    border-top: 1px solid var(--border-color);
    margin-top: 3rem;
    padding-top: 2rem;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.85rem;
}

.copyright p {
    margin-bottom: 0.5rem;
    color: var(--text-muted);
}

/* ===== 返回顶部按钮 ===== */
.back-to-top {
    position: fixed;
    bottom: 2.5rem;
    right: 2.5rem;
    background: var(--brand-gradient);
    color: white;
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    font-size: 1.4rem;
    cursor: pointer;
    box-shadow: 0 4px 20px rgba(124, 58, 237, 0.4);
    z-index: 1000;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(124, 58, 237, 0.6);
}

/* ===== 滚动动画 ===== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== 表格 ===== */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
    background: var(--bg-glass);
    border-radius: var(--radius-md);
    overflow: hidden;
}

th, td {
    border: 1px solid var(--border-color);
    padding: 1rem 1.2rem;
    text-align: left;
}

th {
    background: var(--bg-tertiary);
    color: var(--text-heading);
    font-weight: 600;
}

td {
    color: var(--text-secondary);
}

tr:hover td {
    background: var(--bg-card);
}

/* ===== 辅助类 ===== */
.text-muted {
    color: var(--text-muted);
}

.text-secondary {
    color: var(--text-secondary);
}

.text-center {
    text-align: center;
}

.mt-1 { margin-top: 1rem; }
.mt-2 { margin-top: 2rem; }
.mt-3 { margin-top: 3rem; }
.mb-1 { margin-bottom: 1rem; }
.mb-2 { margin-bottom: 2rem; }
.mb-3 { margin-bottom: 3rem; }

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
    .container {
        padding: 0 20px;
    }
    
    h1 {
        font-size: 2.2rem;
    }
    
    h2 {
        font-size: 1.8rem;
    }
    
    .banner-slide {
        padding: 2.5rem 2rem;
    }
    
    .banner-text h2 {
        font-size: 2rem;
    }
}

@media (max-width: 768px) {
    body {
        font-size: 15px;
    }
    
    h1 {
        font-size: 1.8rem;
    }
    
    h2 {
        font-size: 1.5rem;
    }
    
    .container {
        padding: 0 16px;
    }
    
    .nav-links {
        display: none;
        width: 100%;
        flex-direction: column;
        align-items: flex-start;
        gap: 0.8rem;
        margin-top: 1rem;
        padding: 1rem 0;
        border-top: 1px solid var(--border-color);
        background: var(--nav-bg);
        backdrop-filter: blur(20px);
    }
    
    .nav-links.active {
        display: flex;
    }
    
    .nav-links a {
        width: 100%;
        padding: 0.8rem 0;
        border-bottom: 1px solid var(--border-color);
    }
    
    .nav-links a:last-child {
        border-bottom: none;
    }
    
    .menu-toggle {
        display: flex;
    }
    
    .search-bar {
        display: none;
    }
    
    .banner-slide {
        padding: 2rem 1.5rem;
        flex-direction: column;
        text-align: center;
    }
    
    .banner-text h2 {
        font-size: 1.6rem;
    }
    
    .banner-text p {
        font-size: 0.95rem;
    }
    
    .banner-slide > svg {
        display: none;
    }
    
    .stats {
        grid-template-columns: repeat(2, 1fr);
        gap: 1rem;
        padding: 1rem;
    }
    
    .stat-number {
        font-size: 2rem;
    }
    
    .grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    #about, #news, #faq, #howto, #contact {
        padding: 2rem 1.5rem;
    }
    
    .banner-btn {
        padding: 0.8rem 2rem;
        font-size: 1rem;
    }
    
    .back-to-top {
        bottom: 1.5rem;
        right: 1.5rem;
        width: 44px;
        height: 44px;
        font-size: 1.2rem;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}

@media (max-width: 480px) {
    .stats {
        grid-template-columns: 1fr;
    }
    
    .banner-slide {
        padding: 1.5rem 1rem;
    }
    
    .banner-text h2 {
        font-size: 1.4rem;
    }
    
    .banner-text p {
        font-size: 0.9rem;
    }
    
    .card {
        padding: 1.5rem;
    }
    
    .faq-item {
        padding: 1.2rem 1.5rem;
    }
    
    .faq-question {
        font-size: 0.95rem;
    }
    
    .howto-step {
        padding: 1.2rem 1.5rem;
    }
}

/* ===== 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 scaleIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* ===== 滚动动画应用 ===== */
section {
    animation: fadeInUp 0.8s ease both;
}

section:nth-child(2) { animation-delay: 0.1s; }
section:nth-child(3) { animation-delay: 0.2s; }
section:nth-child(4) { animation-delay: 0.3s; }
section:nth-child(5) { animation-delay: 0.4s; }
section:nth-child(6) { animation-delay: 0.5s; }
section:nth-child(7) { animation-delay: 0.6s; }
section:nth-child(8) { animation-delay: 0.7s; }
section:nth-child(9) { animation-delay: 0.8s; }

/* ===== 卡片悬停特效 ===== */
.card:hover .card-icon {
    animation: pulse 0.5s ease;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.2); }
    100% { transform: scale(1); }
}

/* ===== 玻璃拟态增强 ===== */
.glass-effect {
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

/* ===== 渐变文字 ===== */
.gradient-text {
    background: var(--brand-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ===== 装饰性背景粒子 ===== */
.particles {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: -1;
    overflow: hidden;
}

.particle {
    position: absolute;
    background: var(--brand-gradient);
    border-radius: 50%;
    opacity: 0.3;
    animation: float-particle 20s infinite;
}

@keyframes float-particle {
    0%, 100% {
        transform: translateY(0) scale(1);
        opacity: 0.3;
    }
    50% {
        transform: translateY(-100px) scale(1.2);
        opacity: 0.6;
    }
}

/* ===== 打印样式 ===== */
@media print {
    .navbar, .back-to-top, .search-bar, .theme-toggle, .menu-toggle, .banner-btn {
        display: none !important;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .card, .article-item, .faq-item, .howto-step {
        break-inside: avoid;
        border: 1px solid #ccc;
        box-shadow: none;
    }
}