/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 根变量定义 - 黑白水墨画风格 */
:root {
    /* 主色调 - 黑白灰 */
    --primary-black: #1a1a1a;
    --secondary-black: #2d2d2d;
    --light-gray: #f5f5f5;
    --medium-gray: #e0e0e0;
    --dark-gray: #666666;
    --text-gray: #333333;
    --border-gray: #d0d0d0;
    
    /* 水墨效果色彩 */
    --ink-black: #000000;
    --ink-gray: #808080;
    --paper-white: #ffffff;
    --smoke-gray: #f8f8f8;
    
    /* 字体 */
    --font-primary: 'Microsoft YaHei', 'PingFang SC', 'Helvetica Neue', Arial, sans-serif;
    --font-mono: 'Consolas', 'Monaco', 'Courier New', monospace;
    
    /* 间距 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 4rem;
    
    /* 阴影 */
    --shadow-light: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-medium: 0 4px 16px rgba(0, 0, 0, 0.15);
    --shadow-heavy: 0 8px 32px rgba(0, 0, 0, 0.2);
    
    /* 边框半径 */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    
    /* 过渡 */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* 基础元素样式 */
body {
    font-family: var(--font-primary);
    line-height: 1.6;
    color: var(--text-gray);
    background-color: var(--paper-white);
    overflow-x: hidden;
}

/* 容器 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-gray);
    z-index: 1000;
    transition: var(--transition-normal);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.nav-logo a {
    text-decoration: none;
    color: var(--primary-black);
}

.logo-text {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 0.2rem;
    background: linear-gradient(135deg, var(--primary-black), var(--dark-gray));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo-subtitle {
    font-size: 0.75rem;
    color: var(--dark-gray);
    letter-spacing: 1px;
}

.nav-menu {
    display: flex;
}

.nav-list {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
}

.nav-link {
    text-decoration: none;
    color: var(--text-gray);
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-black);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--primary-black);
    transition: var(--transition-fast);
    transform: translateX(-50%);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

/* 移动端导航切换 */
.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.bar {
    width: 25px;
    height: 3px;
    background: var(--primary-black);
    margin: 3px 0;
    transition: var(--transition-fast);
    border-radius: 2px;
}

/* 主要内容区域 */
.main-content {
    margin-top: 70px;
    min-height: calc(100vh - 70px);
}

/* 消息提示 */
.messages-container {
    position: fixed;
    top: 80px;
    right: var(--spacing-md);
    z-index: 1001;
    max-width: 400px;
}

.alert {
    padding: var(--spacing-sm) var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-medium);
    position: relative;
    background: var(--paper-white);
    border-left: 4px solid var(--primary-black);
}

.alert-success {
    border-left-color: #28a745;
    background: #f8fff9;
}

.alert-error {
    border-left-color: #dc3545;
    background: #fff8f8;
}

.close-btn {
    position: absolute;
    top: var(--spacing-xs);
    right: var(--spacing-sm);
    background: none;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    color: var(--dark-gray);
    transition: var(--transition-fast);
}

.close-btn:hover {
    color: var(--primary-black);
}

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    text-decoration: none;
    border-radius: var(--radius-md);
    font-weight: 500;
    text-align: center;
    transition: var(--transition-normal);
    cursor: pointer;
    border: 2px solid transparent;
    font-size: 1rem;
    line-height: 1.4;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: var(--transition-slow);
}

.btn:hover::before {
    left: 100%;
}

.btn-primary {
    background: var(--primary-black);
    color: var(--paper-white);
}

.btn-primary:hover {
    background: var(--secondary-black);
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

.btn-secondary {
    background: var(--paper-white);
    color: var(--primary-black);
    border-color: var(--primary-black);
}

.btn-secondary:hover {
    background: var(--primary-black);
    color: var(--paper-white);
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

.btn-outline {
    background: transparent;
    color: var(--primary-black);
    border-color: var(--border-gray);
}

.btn-outline:hover {
    background: var(--primary-black);
    color: var(--paper-white);
    border-color: var(--primary-black);
}

.btn-large {
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1.1rem;
}

.btn-full {
    width: 100%;
}

/* 页脚 */
.footer {
    background: var(--primary-black);
    color: var(--light-gray);
    margin-top: var(--spacing-xxl);
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-xxl) var(--spacing-md) var(--spacing-lg);
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-title {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--paper-white);
}

.footer-subtitle {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-sm);
    color: var(--paper-white);
}

.footer-description {
    line-height: 1.8;
    color: var(--medium-gray);
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: var(--spacing-xs);
}

.footer-links a {
    color: var(--medium-gray);
    text-decoration: none;
    transition: var(--transition-fast);
}

.footer-links a:hover {
    color: var(--paper-white);
}

.contact-info p {
    margin-bottom: var(--spacing-xs);
    color: var(--medium-gray);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--secondary-black);
    color: var(--dark-gray);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: var(--paper-white);
        flex-direction: column;
        justify-content: flex-start;
        align-items: center;
        padding-top: var(--spacing-xl);
        transition: var(--transition-normal);
        box-shadow: var(--shadow-medium);
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-list {
        flex-direction: column;
        gap: var(--spacing-lg);
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .nav-toggle.active .bar:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }
    
    .nav-toggle.active .bar:nth-child(2) {
        opacity: 0;
    }
    
    .nav-toggle.active .bar:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -6px);
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .messages-container {
        right: var(--spacing-sm);
        left: var(--spacing-sm);
        max-width: none;
    }
}

@media (max-width: 480px) {
    .logo-text {
        font-size: 1.5rem;
    }
    
    .logo-subtitle {
        font-size: 0.7rem;
    }
    
    .nav-container {
        height: 60px;
    }
    
    .main-content {
        margin-top: 60px;
    }
    
    .nav-menu {
        top: 60px;
        height: calc(100vh - 60px);
    }
}

/* 水墨画效果 */
.ink-effect {
    position: relative;
    overflow: hidden;
}

.ink-effect::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 30% 70%, rgba(0, 0, 0, 0.05) 0%, transparent 50%),
                radial-gradient(circle at 70% 30%, rgba(0, 0, 0, 0.03) 0%, transparent 50%);
    pointer-events: none;
}

/* 纸张纹理效果 */
.paper-texture {
    background-image: 
        radial-gradient(circle at 1px 1px, rgba(0, 0, 0, 0.02) 1px, transparent 0);
    background-size: 20px 20px;
}

/* 毛笔字效果 */
.brush-text {
    font-weight: 700;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.1);
    letter-spacing: 1px;
}