/* 基础样式重置与优化 - 使用CSS变量 */

/* 导入变量 */
@import url('variables.css');

/* ========== 样式重置 ========== */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  -ms-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  padding: 0;
  background-color: var(--color-bg);
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  line-height: var(--line-height-base);
  color: var(--color-text);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ========== 排版优化 ========== */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-family-heading);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-heading);
  margin-top: 0;
  margin-bottom: var(--spacing-base);
  color: var(--color-secondary);
}

h1 { font-size: var(--font-size-xxxl); }
h2 { font-size: var(--font-size-xxl); }
h3 { font-size: var(--font-size-xl); }
h4 { font-size: var(--font-size-lg); }
h5 { font-size: var(--font-size-md); }
h6 { font-size: var(--font-size-base); }

p {
  margin-bottom: var(--spacing-base);
}

a {
  color: var(--color-link);
  text-decoration: none;
  background-color: transparent;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-link-hover);
  text-decoration: underline;
}

a:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ========== 列表样式 ========== */
ul, ol {
  margin-bottom: var(--spacing-base);
  padding-left: var(--spacing-lg);
}

li {
  margin-bottom: var(--spacing-sm);
}

/* ========== 图片优化 ========== */
img {
  max-width: 100%;
  height: auto;
  vertical-align: middle;
  border-style: none;
}

figure {
  margin: 0 0 var(--spacing-base);
}

figcaption {
  font-size: var(--font-size-sm);
  color: var(--color-text-light);
  text-align: center;
  padding-top: var(--spacing-sm);
}

/* ========== 表格样式 ========== */
table {
  width: 100%;
  margin-bottom: var(--spacing-base);
  border-collapse: collapse;
  background-color: var(--color-bg);
}

th, td {
  padding: var(--table-cell-padding);
  border: 1px solid var(--table-border-color);
  text-align: left;
}

th {
  background-color: var(--color-bg-light);
  font-weight: var(--font-weight-bold);
}

/* ========== 表单元素 ========== */
input,
button,
select,
optgroup,
textarea {
  margin: 0;
  font-family: inherit;
  font-size: inherit;
  line-height: inherit;
}

button,
input {
  overflow: visible;
}

button,
select {
  text-transform: none;
}

button,
[type="button"],
[type="reset"],
[type="submit"] {
  -webkit-appearance: button;
}

button:not(:disabled),
[type="button"]:not(:disabled),
[type="reset"]:not(:disabled),
[type="submit"]:not(:disabled) {
  cursor: pointer;
}

/* ========== 辅助类 ========== */
.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.text-primary { color: var(--color-primary); }
.text-secondary { color: var(--color-secondary); }
.text-success { color: var(--color-success); }
.text-warning { color: var(--color-warning); }
.text-error { color: var(--color-error); }
.text-info { color: var(--color-info); }

.bg-primary { background-color: var(--color-primary); }
.bg-secondary { background-color: var(--color-secondary); }
.bg-light { background-color: var(--color-bg-light); }
.bg-dark { background-color: var(--color-bg-dark); }

/* ========== 间距工具类 ========== */
.m-0 { margin: 0 !important; }
.mt-0 { margin-top: 0 !important; }
.mr-0 { margin-right: 0 !important; }
.mb-0 { margin-bottom: 0 !important; }
.ml-0 { margin-left: 0 !important; }

.m-1 { margin: var(--spacing-xs) !important; }
.mt-1 { margin-top: var(--spacing-xs) !important; }
.mr-1 { margin-right: var(--spacing-xs) !important; }
.mb-1 { margin-bottom: var(--spacing-xs) !important; }
.ml-1 { margin-left: var(--spacing-xs) !important; }

.m-2 { margin: var(--spacing-sm) !important; }
.mt-2 { margin-top: var(--spacing-sm) !important; }
.mr-2 { margin-right: var(--spacing-sm) !important; }
.mb-2 { margin-bottom: var(--spacing-sm) !important; }
.ml-2 { margin-left: var(--spacing-sm) !important; }

.m-3 { margin: var(--spacing-base) !important; }
.mt-3 { margin-top: var(--spacing-base) !important; }
.mr-3 { margin-right: var(--spacing-base) !important; }
.mb-3 { margin-bottom: var(--spacing-base) !important; }
.ml-3 { margin-left: var(--spacing-base) !important; }

.p-0 { padding: 0 !important; }
.pt-0 { padding-top: 0 !important; }
.pr-0 { padding-right: 0 !important; }
.pb-0 { padding-bottom: 0 !important; }
.pl-0 { padding-left: 0 !important; }

.p-1 { padding: var(--spacing-xs) !important; }
.pt-1 { padding-top: var(--spacing-xs) !important; }
.pr-1 { padding-right: var(--spacing-xs) !important; }
.pb-1 { padding-bottom: var(--spacing-xs) !important; }
.pl-1 { padding-left: var(--spacing-xs) !important; }

.p-2 { padding: var(--spacing-sm) !important; }
.pt-2 { padding-top: var(--spacing-sm) !important; }
.pr-2 { padding-right: var(--spacing-sm) !important; }
.pb-2 { padding-bottom: var(--spacing-sm) !important; }
.pl-2 { padding-left: var(--spacing-sm) !important; }

.p-3 { padding: var(--spacing-base) !important; }
.pt-3 { padding-top: var(--spacing-base) !important; }
.pr-3 { padding-right: var(--spacing-base) !important; }
.pb-3 { padding-bottom: var(--spacing-base) !important; }
.pl-3 { padding-left: var(--spacing-base) !important; }

/* ========== 显示与隐藏 ========== */
.d-none { display: none !important; }
.d-block { display: block !important; }
.d-inline { display: inline !important; }
.d-inline-block { display: inline-block !important; }
.d-flex { display: flex !important; }

/* ========== 响应式工具类 ========== */
@media (max-width: 575.98px) {
  .d-sm-none { display: none !important; }
  .d-sm-block { display: block !important; }
  .d-sm-inline { display: inline !important; }
  .d-sm-inline-block { display: inline-block !important; }
  .d-sm-flex { display: flex !important; }
}

@media (min-width: 576px) and (max-width: 767.98px) {
  .d-md-none { display: none !important; }
  .d-md-block { display: block !important; }
  .d-md-inline { display: inline !important; }
  .d-md-inline-block { display: inline-block !important; }
  .d-md-flex { display: flex !important; }
}

@media (min-width: 768px) and (max-width: 991.98px) {
  .d-lg-none { display: none !important; }
  .d-lg-block { display: block !important; }
  .d-lg-inline { display: inline !important; }
  .d-lg-inline-block { display: inline-block !important; }
  .d-lg-flex { display: flex !important; }
}

@media (min-width: 992px) {
  .d-xl-none { display: none !important; }
  .d-xl-block { display: block !important; }
  .d-xl-inline { display: inline !important; }
  .d-xl-inline-block { display: inline-block !important; }
  .d-xl-flex { display: flex !important; }
}

/* ========== 打印样式 ========== */
@media print {
  *,
  *::before,
  *::after {
    text-shadow: none !important;
    box-shadow: none !important;
  }
  
  a:not(.btn) {
    text-decoration: underline;
  }
  
  abbr[title]::after {
    content: " (" attr(title) ")";
  }
  
  pre {
    white-space: pre-wrap !important;
  }
  
  pre,
  blockquote {
    border: 1px solid #999;
    page-break-inside: avoid;
  }
  
  thead {
    display: table-header-group;
  }
  
  tr,
  img {
    page-break-inside: avoid;
  }
  
  p,
  h2,
  h3 {
    orphans: 3;
    widows: 3;
  }
  
  h2,
  h3 {
    page-break-after: avoid;
  }
}

/* ========== 焦点样式 ========== */
:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

:focus:not(:focus-visible) {
  outline: none;
}

:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ========== 减少运动 ========== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ========== 高对比度模式 ========== */
@media (prefers-contrast: high) {
  :root {
    --color-primary: #006400;
    --color-secondary: #000080;
    --color-text: #000000;
  }
}

/* ========== 暗黑模式支持 ========== */
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #1a1a1a;
    --color-text: #f0f0f0;
    --color-text-light: #cccccc;
    --color-border: #444444;
  }
  
  img {
    opacity: 0.9;
  }
  
  img:hover {
    opacity: 1;
  }
}