/* ==========================================================================
   基础样式：重置、排版、滚动条、可访问性
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body,
h1, h2, h3, h4, h5, h6,
p, figure, blockquote, dl, dd, ul, ol, pre {
  margin: 0;
  padding: 0;
}

ul[class],
ol[class] {
  list-style: none;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-app);
  background-image: var(--bg-app-gradient);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
  overflow-x: hidden;
  transition: background-color var(--dur-slow) var(--ease-out), color var(--dur-normal) var(--ease-out);
}

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

button, input, select, textarea {
  font: inherit;
  color: inherit;
}

button {
  background: none;
  border: none;
  cursor: pointer;
}

a {
  color: var(--brand-500);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease-out);
}

a:hover {
  color: var(--brand-400);
}

/* ---------- 标题排版 ---------- */
.h1 { font-size: var(--text-3xl); font-weight: 700; letter-spacing: -0.02em; line-height: 1.2; }
.h2 { font-size: var(--text-2xl); font-weight: 700; letter-spacing: -0.015em; line-height: 1.25; }
.h3 { font-size: var(--text-xl); font-weight: 650; letter-spacing: -0.01em; }
.h4 { font-size: var(--text-lg); font-weight: 620; }

.text-secondary { color: var(--text-secondary); }
.text-tertiary { color: var(--text-tertiary); }
.text-mono { font-family: var(--font-mono); font-size: 0.92em; }
.text-xs { font-size: var(--text-xs); }
.text-sm { font-size: var(--text-sm); }
.text-lg { font-size: var(--text-lg); }
.text-center { text-align: center; }
.text-right { text-align: right; }
.font-medium { font-weight: 500; }
.font-semibold { font-weight: 600; }
.font-bold { font-weight: 700; }

/* ---------- 布局工具类 ---------- */
.row { display: flex; align-items: center; gap: var(--space-3); }
.row-between { display: flex; align-items: center; justify-content: space-between; gap: var(--space-3); }
.row-wrap { display: flex; flex-wrap: wrap; align-items: center; gap: var(--space-3); }
.col { display: flex; flex-direction: column; gap: var(--space-3); }
.grow { flex: 1 1 auto; min-width: 0; }
.shrink-0 { flex-shrink: 0; }
.wrap-anywhere { overflow-wrap: anywhere; }
.truncate { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.clamp-2 {
  display: -webkit-box;
  -webkit-line-clamp: 2;
  line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.hidden { display: none !important; }
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.mt-1 { margin-top: var(--space-1); } .mt-2 { margin-top: var(--space-2); }
.mt-3 { margin-top: var(--space-3); } .mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); } .mt-8 { margin-top: var(--space-8); }
.mb-2 { margin-bottom: var(--space-2); } .mb-3 { margin-bottom: var(--space-3); }
.mb-4 { margin-bottom: var(--space-4); } .mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }
.gap-1 { gap: var(--space-1); } .gap-2 { gap: var(--space-2); }
.gap-4 { gap: var(--space-4); } .gap-6 { gap: var(--space-6); }

/* ---------- 网格 ---------- */
.grid { display: grid; gap: var(--space-4); }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.grid-4 { grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); }
.grid-form { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }

/* ---------- 滚动条 ---------- */
* {
  scrollbar-width: thin;
  scrollbar-color: var(--scrollbar-thumb) transparent;
}

::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb);
  border-radius: var(--radius-full);
  border: 3px solid transparent;
  background-clip: content-box;
  transition: background var(--dur-fast) var(--ease-out);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--scrollbar-thumb-hover);
  background-clip: content-box;
}

/* ---------- 可访问性：焦点环 ---------- */
:focus {
  outline: none;
}

:focus-visible {
  outline: 2px solid var(--brand-400);
  outline-offset: 2px;
  border-radius: var(--radius-xs);
}

::selection {
  background: rgba(99, 102, 241, 0.28);
  color: var(--text-primary);
}

/* ---------- 打印 ---------- */
@media print {
  .app-sidebar, .app-topbar, .no-print { display: none !important; }
  body { background: #fff; }
}