:root {
  /* =========================== */
  /* 粘土拟物化 (Claymorphism) 配色 */
  /* =========================== */
  --bg-color: #f0f0f0;        /* 灰白色背景 */
  --card-bg-color: #e0e0e0;   /* 骨白色/浅灰色卡片背景 */
  --text-color: #333333;      /* 深灰色文字 */
  --primary-color: #ff8c42;   /* 焦橙色 (CTA) */
  --secondary-color: #6a5acd; /* 石板蓝 (CTA) */
  
  /* =========================== */
  /* 粘土拟物化 (Claymorphism) 效果 */
  /* =========================== */
  --clay-shadow-distance: 8px;
  --clay-shadow-blur: 16px;
  --clay-light: rgba(255, 255, 255, 0.8);
  --clay-dark: rgba(0, 0, 0, 0.2);
  --clay-inset-light: rgba(255, 255, 255, 0.6);
  --clay-inset-dark: rgba(0, 0, 0, 0.1);

  /* =========================== */
  /* 通用变量 */
  /* =========================== */
  --container-max: 1200px;
  --container-pad: 1rem;
  --radius-lg: 24px; /* 更圆润的圆角 */
  --radius-md: 16px;
  --radius-sm: 12px;
  --transition-fast: 200ms;
  --transition-slow: 300ms;
  
  /* 组合粘土阴影 */
  --clay-out: 
    var(--clay-shadow-distance) var(--clay-shadow-distance) var(--clay-shadow-blur) var(--clay-dark),
    calc(var(--clay-shadow-distance) * -1) calc(var(--clay-shadow-distance) * -1) var(--clay-shadow-blur) var(--clay-light);
  --clay-in: 
    inset var(--clay-shadow-distance) var(--clay-shadow-distance) var(--clay-shadow-blur) var(--clay-inset-dark),
    inset calc(var(--clay-shadow-distance) * -1) calc(var(--clay-shadow-distance) * -1) var(--clay-shadow-blur) var(--clay-inset-light);
}

/* =========================== */
/* 基础样式 */
/* =========================== */

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

/* 使用几何无衬线字体 */
body {
  font-family: 'Segoe UI', 'Roboto', 'Helvetica Neue', 'Arial', sans-serif;
  margin: 0;
  padding: 0;
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.6;
}

/* =========================== */
/* Header */
/* =========================== */

header {
  background: transparent;
  padding: 1.5rem;
  text-align: center;
}

header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-color);
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 1px;
}

/* =========================== */
/* 顶部导航 */
/* =========================== */

nav {
  background: transparent;
  position: sticky;
  top: 0;
  z-index: 1000;
  padding: 1rem 0;
  display: flex;
  justify-content: center;
  backdrop-filter: blur(10px);
  background-color: rgba(240, 240, 240, 0.7); /* 半透明背景 */
}

nav .nav-wrap {
  max-width: var(--container-max);
  padding: 0 var(--container-pad);
  margin: 0 auto;
  width: 100%;
  display: flex;
  justify-content: center;
  text-align: center;
}

nav ul {
  list-style-type: none;
  padding: 0.75rem;
  margin: 0 auto;
  display: inline-flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  width: max-content;
  background-color: var(--card-bg-color);
  border-radius: 9999px;
  box-shadow: var(--clay-out);
  border: 1px solid var(--clay-light); /* 添加边框增强粘土感 */
}

nav li {
  margin: 0;
}

nav a {
  display: inline-block;
  color: var(--text-color);
  text-decoration: none;
  font-size: 1rem;
  font-weight: 600;
  padding: 0.75rem 1.25rem;
  border-radius: 9999px;
  transition: all var(--transition-fast) ease;
  background-color: var(--card-bg-color);
  box-shadow: var(--clay-out);
  border: 1px solid var(--clay-light); /* 添加边框增强粘土感 */
  position: relative;
  overflow: hidden;
}

/* 按钮内部光泽效果 */
nav a::before {
  content: '';
  position: absolute;
  top: -10%;
  left: -10%;
  width: 120%;
  height: 120%;
  background: radial-gradient(circle at center, rgba(255, 255, 255, 0.4) 0%, rgba(255, 255, 255, 0) 70%);
  opacity: 0;
  transition: opacity var(--transition-fast) ease;
  pointer-events: none;
  border-radius: 9999px;
}

nav a:hover::before {
  opacity: 1;
}

nav a:hover {
  transform: translateY(-2px);
  box-shadow: 
    calc(var(--clay-shadow-distance) * 1.5) calc(var(--clay-shadow-distance) * 1.5) calc(var(--clay-shadow-blur) * 1.2) var(--clay-dark),
    calc(var(--clay-shadow-distance) * -1.5) calc(var(--clay-shadow-distance) * -1.5) calc(var(--clay-shadow-blur) * 1.2) var(--clay-light);
}

nav a.active {
  background: linear-gradient(145deg, var(--primary-color), #e07a30); /* 焦橙色渐变 */
  color: white;
  box-shadow: var(--clay-in);
  border: 1px solid rgba(0, 0, 0, 0.1);
}

nav a:focus-visible {
  outline: none;
  box-shadow: var(--clay-out), 0 0 0 3px rgba(255, 140, 66, 0.5);
}

/* =========================== */
/* 主内容区 */
/* =========================== */

main {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 1.5rem;
}

.category-title {
  font-size: 1.75rem;
  font-weight: 700;
  margin: 2.5rem 0 1.25rem;
  color: var(--text-color);
  padding-left: 0.5rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  position: relative;
}

.category-title::after {
  content: "";
  display: inline-block;
  width: 12px;
  height: 12px;
  margin-left: 10px;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 35%, var(--primary-color), rgba(255, 140, 66, 0.3));
  box-shadow: var(--clay-out);
  vertical-align: middle;
}

/* =========================== */
/* 链接网格 */
/* =========================== */

.link-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(10rem, 1fr));
  gap: 1.5rem;
  margin-bottom: 2.5rem;
}

.link-card {
  background-color: var(--card-bg-color);
  border-radius: var(--radius-lg);
  padding: 1.5rem 1rem;
  text-align: center;
  transition: all var(--transition-fast) ease;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 110px;
  position: relative;
  overflow: hidden;
  box-shadow: var(--clay-out);
  border: 1px solid var(--clay-light); /* 添加边框增强粘土感 */
}

/* 卡片内部光泽效果 */
.link-card::before {
  content: '';
  position: absolute;
  top: -20%;
  left: -20%;
  width: 140%;
  height: 140%;
  background: radial-gradient(circle at center, rgba(255, 255, 255, 0.3) 0%, rgba(255, 255, 255, 0) 70%);
  opacity: 0;
  transition: opacity var(--transition-fast) ease;
  pointer-events: none;
  border-radius: var(--radius-lg);
}

.link-card:hover::before {
  opacity: 1;
}

.link-card:hover {
  transform: translateY(-4px);
  box-shadow: 
    calc(var(--clay-shadow-distance) * 1.5) calc(var(--clay-shadow-distance) * 1.5) calc(var(--clay-shadow-blur) * 1.2) var(--clay-dark),
    calc(var(--clay-shadow-distance) * -1.5) calc(var(--clay-shadow-distance) * -1.5) calc(var(--clay-shadow-blur) * 1.2) var(--clay-light);
}

.link-card:active,
.link-card:has(a:active) {
  transform: translateY(0);
  box-shadow: var(--clay-in);
}

.link-card a {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  text-decoration: none;
  z-index: 12;
  display: block;
}

.link-card i {
  font-size: 2.2rem;
  margin-bottom: 0.8rem;
  color: var(--primary-color);
  transition: transform var(--transition-fast) ease;
  position: relative;
  z-index: 11;
  text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.1);
}

.link-card:hover i {
  transform: scale(1.15);
}

.link-card h3 {
  font-size: 1rem;
  margin: 0;
  color: var(--text-color);
  line-height: 1.4;
  font-weight: 600;
  max-width: 100%;
  height: 2.8em;
  overflow: hidden;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  line-clamp: 2;
  -webkit-box-orient: vertical;
  text-overflow: ellipsis;
  white-space: normal;
  padding: 0 0.4rem;
  position: relative;
  z-index: 11;
}

/* =========================== */
/* Footer */
/* =========================== */

footer {
  background: transparent;
  color: #666666;
  text-align: center;
  padding: 1.5rem;
  font-size: 0.85rem;
  margin-top: 2rem;
}

footer nav {
  margin-top: 0.8rem;
  background-color: transparent;
}

footer nav a {
  color: #666666;
  margin: 0 0.8rem;
  font-size: 0.85rem;
  display: inline-block;
  padding: 0.5rem 0.8rem;
  border-radius: 9999px;
  background-color: var(--card-bg-color);
  box-shadow: var(--clay-out);
  transition: all var(--transition-fast) ease;
  border: 1px solid var(--clay-light); /* 添加边框增强粘土感 */
}

footer nav a:hover {
  transform: translateY(-2px);
  box-shadow: 
    calc(var(--clay-shadow-distance) * 1.2) calc(var(--clay-shadow-distance) * 1.2) calc(var(--clay-shadow-blur) * 1.1) var(--clay-dark),
    calc(var(--clay-shadow-distance) * -1.2) calc(var(--clay-shadow-distance) * -1.2) calc(var(--clay-shadow-blur) * 1.1) var(--clay-light);
}

footer nav a:focus-visible {
  outline: none;
  box-shadow: var(--clay-out), 0 0 0 3px rgba(255, 140, 66, 0.4);
}

/* =========================== */
/* 响应式 */
/* =========================== */

@media (max-width: 1200px) {
  :root {
    --container-max: 95vw;
  }
  main {
    padding: 1.25rem;
  }
  .link-grid {
    grid-template-columns: repeat(auto-fill, minmax(9rem, 1fr));
    gap: 1.25rem;
  }
}

@media (max-width: 768px) {
  html {
    font-size: 15px;
  }

  main {
    padding: 1rem;
  }

  .link-grid {
    grid-template-columns: repeat(auto-fill, minmax(8rem, 1fr));
    gap: 1rem;
  }

  nav {
    padding: 0.75rem;
  }

  nav a {
    padding: 0.6rem 1rem;
    font-size: 0.95rem;
  }

  .category-title {
    font-size: 1.5rem;
    margin: 2rem 0 1rem;
  }

  .link-card {
    padding: 1.25rem 0.8rem;
    min-height: 95px;
  }

  .link-card i {
    font-size: 2rem;
    margin-bottom: 0.6rem;
  }

  .link-card h3 {
    font-size: 0.9rem;
    height: 2.6em;
  }
}

@media (max-width: 480px) {
  html {
    font-size: 14px;
  }

  main {
    padding: 0.8rem;
  }

  .link-grid {
    grid-template-columns: repeat(auto-fill, minmax(7rem, 1fr));
    gap: 0.8rem;
  }

  header h1 {
    font-size: 2rem;
  }

  nav li {
    margin: 0.3rem;
  }

  nav a {
    padding: 0.5rem 0.8rem;
    font-size: 0.9rem;
  }

  .category-title {
    font-size: 1.4rem;
    margin: 1.8rem 0 1rem;
  }

  .link-card {
    padding: 1rem 0.6rem;
    min-height: 85px;
  }

  .link-card i {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
  }

  .link-card h3 {
    font-size: 0.85rem;
    padding: 0 0.3rem;
    height: 2.4em;
  }

  footer {
    padding: 1rem;
  }

  footer nav a {
    margin: 0 0.5rem;
    font-size: 0.8rem;
    padding: 0.4rem 0.6rem;
  }
}

@media (max-width: 360px) {
  html {
    font-size: 13px;
  }

  .link-grid {
    grid-template-columns: repeat(auto-fill, minmax(6.5rem, 1fr));
    gap: 0.7rem;
  }

  header h1 {
    font-size: 1.8rem;
  }

  .link-card {
    padding: 0.9rem 0.5rem;
    min-height: 80px;
  }

  .link-card i {
    font-size: 1.6rem;
    margin-bottom: 0.4rem;
  }

  .link-card h3 {
    font-size: 0.8rem;
    padding: 0 0.2rem;
    height: 2.2em;
  }
}