/* ============================================================
   Base · Reset + 全局样式
   ============================================================ */

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

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-size-adjust: 100%;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: var(--lh-normal);
  color: var(--text-primary);
  background: var(--bg-canvas);
  overscroll-behavior-y: none;
}

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

ul, ol { list-style: none; }

h1 { font-size: var(--fs-h1); font-weight: var(--fw-semibold); line-height: var(--lh-tight); }
h2 { font-size: var(--fs-h2); font-weight: var(--fw-semibold); line-height: var(--lh-tight); }
h3 { font-size: var(--fs-h3); font-weight: var(--fw-semibold); line-height: var(--lh-snug); }
h4 { font-size: var(--fs-h4); font-weight: var(--fw-semibold); line-height: var(--lh-snug); }
h5 { font-size: var(--fs-h5); font-weight: var(--fw-semibold); line-height: var(--lh-normal); }

a {
  color: var(--text-link);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease);
}
a:hover { text-decoration: underline; }

button {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
}
button:disabled { cursor: not-allowed; opacity: 0.5; }

input, textarea, select {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
}

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

code, pre {
  font-family: var(--font-mono);
  font-size: 0.92em;
}

/* 滚动条 */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
  background: var(--border-default);
  border-radius: 8px;
  border: 2px solid transparent;
  background-clip: padding-box;
}
::-webkit-scrollbar-thumb:hover { background: var(--border-strong); background-clip: padding-box; border: 2px solid transparent; }

/* 文本选中 */
::selection { background: rgba(16, 163, 127, 0.35); color: var(--text-primary); }

/* 焦点 */
:focus-visible {
  outline: 2px solid var(--border-strong);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* 工具类 */
.u-flex { display: flex; }
.u-flex-col { display: flex; flex-direction: column; }
.u-flex-1 { flex: 1; min-width: 0; }
.u-items-center { align-items: center; }
.u-justify-between { justify-content: space-between; }
.u-justify-center { justify-content: center; }
.u-gap-1 { gap: 4px; }
.u-gap-2 { gap: 8px; }
.u-gap-3 { gap: 12px; }
.u-gap-4 { gap: 16px; }
.u-gap-6 { gap: 24px; }
.u-text-center { text-align: center; }
.u-text-secondary { color: var(--text-secondary); }
.u-text-tertiary { color: var(--text-tertiary); }
.u-caption { font-size: var(--fs-caption); color: var(--text-tertiary); }
.u-truncate { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.u-hidden { display: none !important; }

/* 屏幕响应工具 */
@media (max-width: 767px) {
  .u-md-only { display: none !important; }
}
@media (min-width: 768px) {
  .u-sm-only { display: none !important; }
}
@media (max-width: 1023px) {
  .u-lg-only { display: none !important; }
}