/*!
 * 现代响应式布局系统 - CSS Grid & Flexbox
 * 为Jekyll博客项目提供现代化的响应式布局支持
 */

/* ===== CSS变量定义 ===== */
:root {
  /* 断点定义 */
  --breakpoint-xs: 480px;
  --breakpoint-sm: 768px;
  --breakpoint-md: 992px;
  --breakpoint-lg: 1200px;
  --breakpoint-xl: 1400px;
  
  /* 间距系统 */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-xxl: 3rem;
  
  /* 容器最大宽度 */
  --container-max-width: 1200px;
  --content-max-width: 800px;
  
  /* 网格间距 */
  --grid-gap: var(--spacing-md);
  --grid-gap-lg: var(--spacing-lg);
}

/* ===== 现代容器系统 ===== */
.responsive-container {
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
  .responsive-container {
    padding: 0 var(--spacing-lg);
  }
}

@media (min-width: 1200px) {
  .responsive-container {
    padding: 0 var(--spacing-xl);
  }
}

/* ===== CSS Grid 布局系统 ===== */
.grid-container {
  display: grid;
  gap: var(--grid-gap);
  width: 100%;
}

/* 主要布局网格 */
.main-layout-grid {
  display: grid;
  gap: var(--grid-gap-lg);
  grid-template-areas: 
    "header"
    "main"
    "sidebar"
    "footer";
  grid-template-rows: auto 1fr auto auto;
  min-height: 100vh;
}

@media (min-width: 992px) {
  .main-layout-grid {
    grid-template-areas: 
      "header header"
      "main sidebar"
      "footer footer";
    grid-template-columns: 1fr 300px;
    grid-template-rows: auto 1fr auto;
  }
}

@media (min-width: 1200px) {
  .main-layout-grid {
    grid-template-columns: 1fr 350px;
  }
}

/* 网格区域定义 */
.grid-header {
  grid-area: header;
}

.grid-main {
  grid-area: main;
  min-width: 0; /* 防止内容溢出 */
}

.grid-sidebar {
  grid-area: sidebar;
}

.grid-footer {
  grid-area: footer;
}

/* 文章列表网格 */
.posts-grid {
  display: grid;
  gap: var(--spacing-lg);
  grid-template-columns: 1fr;
}

@media (min-width: 768px) {
  .posts-grid {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  }
}

/* ===== Flexbox 组件系统 ===== */
.flex-container {
  display: flex;
  gap: var(--spacing-md);
}

.flex-row {
  flex-direction: row;
  flex-wrap: wrap;
}

.flex-column {
  flex-direction: column;
}

.flex-center {
  justify-content: center;
  align-items: center;
}

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

.flex-around {
  justify-content: space-around;
  align-items: center;
}

.flex-start {
  justify-content: flex-start;
  align-items: flex-start;
}

.flex-end {
  justify-content: flex-end;
  align-items: flex-end;
}

/* Flex项目控制 */
.flex-1 {
  flex: 1;
}

.flex-2 {
  flex: 2;
}

.flex-3 {
  flex: 3;
}

.flex-none {
  flex: none;
}

.flex-auto {
  flex: auto;
}

/* ===== 响应式导航系统 ===== */
.responsive-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md);
  position: relative;
}

.nav-brand {
  flex: none;
  font-weight: bold;
  font-size: 1.25rem;
}

.nav-menu {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: var(--spacing-lg);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-sm);
}

@media (max-width: 767px) {
  .nav-toggle {
    display: block;
  }
  
  .nav-menu {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: white;
    flex-direction: column;
    padding: var(--spacing-md);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
  }
  
  .nav-menu.active {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }
}

/* ===== 响应式卡片系统 ===== */
.card-container {
  display: grid;
  gap: var(--spacing-lg);
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}

.responsive-card {
  background: white;
  border-radius: 8px;
  padding: var(--spacing-lg);
  box-shadow: 0 2px 10px rgba(0,0,0,0.1);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.responsive-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(0,0,0,0.15);
}

/* ===== 响应式媒体容器 ===== */
.responsive-media {
  position: relative;
  width: 100%;
  height: 0;
  overflow: hidden;
}

.responsive-media.ratio-16-9 {
  padding-bottom: 56.25%; /* 16:9 */
}

.responsive-media.ratio-4-3 {
  padding-bottom: 75%; /* 4:3 */
}

.responsive-media.ratio-1-1 {
  padding-bottom: 100%; /* 1:1 */
}

.responsive-media img,
.responsive-media iframe,
.responsive-media video {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* ===== 响应式文本系统 ===== */
.responsive-text {
  font-size: clamp(1rem, 2.5vw, 1.25rem);
  line-height: 1.6;
}

.responsive-heading {
  font-size: clamp(1.5rem, 4vw, 2.5rem);
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
}

.responsive-subheading {
  font-size: clamp(1.25rem, 3vw, 1.75rem);
  line-height: 1.3;
  margin-bottom: var(--spacing-sm);
}

/* ===== 响应式间距系统 ===== */
.spacing-xs { margin: var(--spacing-xs); }
.spacing-sm { margin: var(--spacing-sm); }
.spacing-md { margin: var(--spacing-md); }
.spacing-lg { margin: var(--spacing-lg); }
.spacing-xl { margin: var(--spacing-xl); }
.spacing-xxl { margin: var(--spacing-xxl); }

.padding-xs { padding: var(--spacing-xs); }
.padding-sm { padding: var(--spacing-sm); }
.padding-md { padding: var(--spacing-md); }
.padding-lg { padding: var(--spacing-lg); }
.padding-xl { padding: var(--spacing-xl); }
.padding-xxl { padding: var(--spacing-xxl); }

/* 方向性间距 */
.mt-auto { margin-top: auto; }
.mb-auto { margin-bottom: auto; }
.ml-auto { margin-left: auto; }
.mr-auto { margin-right: auto; }

/* ===== 响应式显示控制 ===== */
.hide-xs { display: none; }
.hide-sm { display: none; }
.hide-md { display: none; }
.hide-lg { display: none; }
.hide-xl { display: none; }

@media (min-width: 480px) {
  .hide-xs { display: initial; }
  .show-xs-only { display: none; }
}

@media (min-width: 768px) {
  .hide-sm { display: initial; }
  .show-sm-only { display: none; }
}

@media (min-width: 992px) {
  .hide-md { display: initial; }
  .show-md-only { display: none; }
}

@media (min-width: 1200px) {
  .hide-lg { display: initial; }
  .show-lg-only { display: none; }
}

@media (min-width: 1400px) {
  .hide-xl { display: initial; }
  .show-xl-only { display: none; }
}

/* ===== 性能优化 ===== */
.gpu-accelerated {
  transform: translateZ(0);
  will-change: transform;
}

.smooth-scroll {
  scroll-behavior: smooth;
}

/* ===== 打印样式 ===== */
@media print {
  .responsive-container {
    max-width: none;
    padding: 0;
  }
  
  .main-layout-grid {
    display: block;
  }
  
  .grid-sidebar {
    display: none;
  }
  
  .responsive-nav {
    display: none;
  }
}