/* ================================
   包豪斯极简主义风格样式表
   Bauhaus Minimalist Design
   ================================ */

/* 基础重置和变量 */
:root {
    /* 配色系统 - Bauhaus Color Palette */
    --bg-primary: #f4f4f0;          /* 奶油白背景 */
    --bg-secondary: #ffffff;         /* 纯白卡片背景 */
    --bg-card: #ffffff;
    --text-primary: #0a0a0a;        /* 纯黑文字 */
    --text-secondary: #8a8a8a;      /* 辅助灰文字 */
    --border-color: #0a0a0a;        /* 黑色边框 */
    --grid-color: #e5e5e5;          /* 网格线颜色 */

    /* 强调色 - Bauhaus Accent Colors */
    --accent-orange: #FF4D00;       /* 警示橙 */
    --accent-blue: #0047AB;         /* 克莱因蓝 */
    --accent-green: #059669;        /* 增长绿 */
    --accent-red: #E63946;          /* 强调红 */
    --accent-yellow: #FFD60A;       /* 明黄 */

    /* 间距系统 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;

    /* 硬边框和阴影 */
    --border-width: 1px;
    --shadow-small: 4px 4px 0 var(--border-color);
    --shadow-medium: 8px 8px 0 var(--border-color);
    --shadow-large: 12px 12px 0 var(--border-color);

    /* 过渡效果 */
    --transition: all 0.3s ease;
    --transition-fast: all 0.15s ease;
}

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

body {
    font-family: 'Noto Sans SC', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI',
                 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 1rem;
}

@media (min-width: 768px) {
    .container {
        padding: 0 2rem;
    }
}

/* ================================
   导航栏 - Bauhaus Navigation
   ================================ */
.nav {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: var(--bg-primary);
    border-bottom: var(--border-width) solid var(--border-color);
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) 0;
}

.logo {
    font-size: 1.75rem;
    font-weight: 900;
    color: var(--text-primary);
    text-decoration: none;
    letter-spacing: -0.02em;
    transition: var(--transition-fast);
}

.logo:hover {
    color: var(--accent-orange);
}

.nav-links {
    display: flex;
    gap: 1.5rem;
    list-style: none;
    align-items: center;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition-fast);
    font-weight: 600;
    font-size: 1rem;
    position: relative;
}

.nav-links a.active {
    color: var(--text-primary);
    font-weight: 600;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-orange);
    transition: var(--transition-fast);
}

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

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

.search-btn {
    background: var(--bg-secondary);
    border: var(--border-width) solid var(--border-color);
    color: var(--text-primary);
    padding: 0.5rem 1rem;
    cursor: pointer;
    transition: var(--transition-fast);
    font-size: 1.2rem;
}

.search-btn:hover {
    background: var(--text-primary);
    color: var(--bg-secondary);
    transform: translate(-2px, -2px);
    box-shadow: 2px 2px 0 var(--border-color);
}

/* ================================
   Hero 区域 - Bauhaus Hero
   ================================ */
.hero {
    min-height: 80vh;
    display: flex;
    align-items: center;
    position: relative;
    padding: var(--spacing-xl) 0;
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
}

.hero-title {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: -0.02em;
    margin-bottom: var(--spacing-md);
}

.gradient-text {
    color: var(--text-primary);
    position: relative;
    display: inline-block;
}

/* 包豪斯风格的强调标记 */
.gradient-text::after {
    content: '';
    position: absolute;
    bottom: 0.1em;
    left: 0;
    width: 100%;
    height: 0.3em;
    background: var(--accent-orange);
    opacity: 0.3;
    z-index: -1;
}

.typing-text {
    color: var(--text-secondary);
    font-size: clamp(1.2rem, 3vw, 2rem);
    font-weight: 400;
}

.hero-description {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.btn {
    padding: 1rem 2rem;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    display: inline-block;
    border: var(--border-width) solid var(--border-color);
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.btn-primary {
    background: var(--accent-orange);
    color: white;
    border-color: var(--border-color);
}

.btn-primary:hover {
    transform: translate(-4px, -4px);
    box-shadow: var(--shadow-small);
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: var(--border-width) solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--text-primary);
    color: var(--bg-secondary);
    transform: translate(-4px, -4px);
    box-shadow: var(--shadow-small);
}

/* ================================
   文章部分 - Bento Card Layout
   ================================ */
.featured {
    padding: var(--spacing-xl) 0;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: var(--spacing-lg);
    text-align: center;
    line-height: 1.1;
    letter-spacing: -0.02em;
}

.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
}

.article-card-link {
    text-decoration: none;
    color: inherit;
    display: block;
}

/* Bento Card 风格 */
.article-card {
    background: var(--bg-card);
    border: var(--border-width) solid var(--border-color);
    padding: var(--spacing-md);
    transition: var(--transition);
    cursor: pointer;
    position: relative;
}

.article-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--accent-orange);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.4s ease;
}

.article-card-link:hover .article-card {
    transform: translate(-4px, -4px);
    box-shadow: var(--shadow-medium);
}

.article-card-link:hover .article-card::before {
    transform: scaleX(1);
}

.article-tag {
    display: inline-block;
    padding: 0.3rem 0.8rem;
    background: var(--accent-blue);
    color: white;
    font-size: 0.85rem;
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    border: var(--border-width) solid var(--border-color);
}

.article-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
    line-height: 1.3;
    letter-spacing: -0.01em;
}

.article-excerpt {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    line-height: 1.6;
}

.article-meta {
    display: flex;
    gap: var(--spacing-sm);
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* ================================
   关于预览 - About Section
   ================================ */
.about-preview {
    padding: var(--spacing-xl) 0;
    background: var(--bg-secondary);
    border-top: var(--border-width) solid var(--border-color);
    border-bottom: var(--border-width) solid var(--border-color);
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.about-text {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
}

/* ================================
   页脚 - Footer
   ================================ */
.footer {
    padding: var(--spacing-lg) 0;
    border-top: var(--border-width) solid var(--border-color);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.social-links {
    display: flex;
    gap: var(--spacing-md);
}

.social-links a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition-fast);
    font-weight: 500;
}

.social-links a:hover {
    color: var(--accent-orange);
}

/* ================================
   响应式设计 - Responsive
   ================================ */
@media (max-width: 768px) {
    .nav-links {
        gap: var(--spacing-sm);
    }

    .hero {
        min-height: 60vh;
        padding: var(--spacing-lg) 0;
    }

    .articles-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        flex-direction: column;
        text-align: center;
    }
}

/* ================================
   滚动条样式 - Scrollbar
   ================================ */
::-webkit-scrollbar {
    width: 8px;
}

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

::-webkit-scrollbar-thumb {
    background: var(--text-primary);
    border-radius: 0;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--accent-orange);
}

/* ================================
   回到顶部按钮 - Back to Top
   ================================ */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--bg-card);
    border: var(--border-width) solid var(--border-color);
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: var(--transition);
    z-index: 999;
}

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

.back-to-top:hover {
    background: var(--text-primary);
    transform: translate(-4px, -4px);
    box-shadow: var(--shadow-small);
}

.back-to-top::before {
    content: '↑';
    font-size: 1.5rem;
    color: var(--text-primary);
}

.back-to-top:hover::before {
    color: var(--bg-secondary);
}

/* ================================
   阅读进度条 - Reading Progress
   ================================ */
.reading-progress-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: transparent;
    z-index: 1001;
    pointer-events: none;
}

.reading-progress-bar {
    height: 100%;
    width: 0%;
    background: var(--accent-orange);
    transition: width 0.1s ease;
}