/* ========================================
   前台通用样式
   ======================================== */

/* 重置样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB',
        'Microsoft YaHei', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 14px;
    line-height: 1.6;
    color: #333;
    background-color: #f5f7fa;
}

ul, li {
    list-style: none;
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.3s ease;
}

/* ========================================
   Logo 组件
   ======================================== */

/* Logo 基础样式 */
.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    transition: all 0.3s ease;
    position: relative;
}

/* Logo 图标容器 */
.logo::before {
    content: '\f06e';  /* Font Awesome eye 图标的 Unicode */
    font-family: 'FontAwesome';
    display: flex;
    align-items: center;
    justify-content: center;
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 12px;
    color: white;
    flex-shrink: 0;  /* 防止被压缩 */
}

/* Logo 链接样式 */
a .logo {
    text-decoration: none;
}

a .logo:hover {
    transform: scale(1.05);
}

a .logo:hover::before {
    transform: scale(1.05);
}

/* 小尺寸 Logo */
.logo.logo-small::before {
    width: 40px;
    height: 40px;
    font-size: 18px;
}

/* 大尺寸 Logo */
.logo.logo-large::before {
    width: 80px;
    height: 80px;
    font-size: 32px;
}

/* Logo 无背景版本 */
.logo.logo-no-bg::before {
    background: none;
    color: #667eea;
}

.logo.logo-no-bg:hover::before {
    color: #764ba2;
}

/* ========================================
   品牌 Logo（导航栏使用）
   ======================================== */

.brand-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    transition: all 0.3s ease;
}

.brand-logo:hover {
    opacity: 0.9;
}

.brand-text {
    font-size: 30px;
    font-weight: 700;
    color: #2c3e50;
    letter-spacing: 1px;
    padding: 0px;
}

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

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

/* 容器  margin: 0 auto; */
.container {
    width:100%; 
    max-width: 2180px; 
    margin: 0 auto;
    padding: 0 20px;
}
/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 10px 24px;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 500;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    border: none;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 16px rgba(102, 126, 234, 0.3);
}

.btn-outline {
    background: transparent;
    color: #667eea;
    border: 2px solid #667eea;
}

.btn-outline:hover {
    background: #667eea;
    color: #fff;
}

.btn-large {
    padding: 14px 32px;
    font-size: 16px;
}

/* 章节通用样式 */
section {
    padding: 35px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-title {
    font-size: 36px;
    font-weight: 700;
    color: #2c3e50;
    margin-bottom: 16px;
}

.section-desc {
    font-size: 16px;
    color: #7f8c8d;
}

/* 渐变文字 */
.gradient-text {
    /* background: linear-gradient(135deg, #4f61b4 0%, #69438f 100%);*/
    background: linear-gradient(277.09deg, #4d88ff, #dc79ff  100%);/*667eea 667eea */
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* 响应式 */
@media (max-width: 768px) {
    section {
        padding: 50px 0;
    }

    .section-title {
        font-size: 28px;
    }

    .container {
        padding: 0 15px;
    }

    .btn {
        width: 100%;
    }

    .btn-large {
        width: 100%;
        padding: 12px 24px;
        font-size: 15px;
    }
}

/* ========================================
   返回顶部按钮
   ======================================== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 1.2rem;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    box-shadow: 0 4px 20px rgba(102, 126, 234, 0.4);
    z-index: 999;
    border: none;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 25px rgba(102, 126, 234, 0.5);
}