/**
 * CSS Reset - 基础样式重置
 *
 * 职责：规范化浏览器默认样式，建立一致的基础
 * 作用域：全局
 * 依赖：variables.css（可选，主要用于一致性）
 */

/* ==================== Box Model 规范 ==================== */

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

/* ==================== HTML & Body 基础设置 ==================== */

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  -webkit-text-size-adjust: 100%;
  text-rendering: optimizeLegibility;
}

body {
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-base);
  color: var(--color-text-primary);
  background-color: var(--color-bg-base);
  overflow-x: hidden;
}

/* ==================== 语义化标签重置 ==================== */

h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-weight-semibold);
  line-height: var(--line-height-tight);
}

p {
  margin-bottom: 0;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-hover);
}

ul, ol {
  list-style: none;
}

/* ==================== 表单元素重置 ==================== */

button,
input,
textarea,
select {
  font-family: inherit;
  font-size: inherit;
  line-height: inherit;
  color: inherit;
  border: none;
  background: none;
  outline: none;
}

button {
  cursor: pointer;
  user-select: none;
}

button:disabled {
  opacity: var(--disabled-opacity);
  cursor: var(--disabled-cursor);
}

input:focus,
textarea:focus,
select:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ==================== 图片与媒体 ==================== */

img,
svg,
video,
canvas {
  display: block;
  max-width: 100%;
  height: auto;
}

/* ==================== 表格重置 ==================== */

table {
  border-collapse: collapse;
  border-spacing: 0;
  width: 100%;
}

th,
td {
  text-align: left;
  vertical-align: top;
}

/* ==================== 其他元素 ==================== */

hr {
  border: 0;
  border-top: 1px solid var(--color-border-light);
  margin: var(--spacing-md) 0;
}

code,
pre {
  font-family: var(--font-family-monospace);
  font-size: 0.9em;
}

blockquote {
  margin: 0;
  padding-left: var(--spacing-md);
  border-left: 4px solid var(--color-border-medium);
}

/* ==================== 滚动条样式（Webkit） ==================== */

::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

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

::-webkit-scrollbar-thumb {
  background: var(--color-border-medium);
  border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-border-dark);
}

/* ==================== 文本选择 ==================== */

::selection {
  background-color: var(--color-selection-bg);
  color: var(--color-text-primary);
}

::-moz-selection {
  background-color: var(--color-selection-bg);
  color: var(--color-text-primary);
}

/* ==================== 辅助功能 ==================== */

/* 隐藏但对屏幕阅读器可见 */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* 移除 focus 时的 outline（仅在非键盘导航时） */
:focus:not(:focus-visible) {
  outline: none;
}

/* ==================== 打印样式 ==================== */

@media print {
  *,
  *::before,
  *::after {
    background: transparent !important;
    color: #000 !important;
    box-shadow: none !important;
    text-shadow: none !important;
  }

  a,
  a:visited {
    text-decoration: underline;
  }

  a[href]::after {
    content: " (" attr(href) ")";
  }

  abbr[title]::after {
    content: " (" attr(title) ")";
  }

  pre,
  blockquote {
    border: 1px solid #999;
    page-break-inside: avoid;
  }

  thead {
    display: table-header-group;
  }

  tr,
  img {
    page-break-inside: avoid;
  }

  img {
    max-width: 100% !important;
  }

  p,
  h2,
  h3 {
    orphans: 3;
    widows: 3;
  }

  h2,
  h3 {
    page-break-after: avoid;
  }
}