/* ============================================================
   墨氪科技 — Utility Layer (u-*)
   与主设计系统共存：前缀 u- 避免与 .container / .card / .grid 冲突
   只收录实际会用到的原子类，未使用者不产生体积
   ============================================================ */

/* ---------- 布局 ---------- */
.u-flex { display: flex; }
.u-inline-flex { display: inline-flex; }
.u-flex-col { flex-direction: column; }
.u-flex-wrap { flex-wrap: wrap; }
.u-items-start { align-items: flex-start; }
.u-items-center { align-items: center; }
.u-items-end { align-items: flex-end; }
.u-justify-start { justify-content: flex-start; }
.u-justify-center { justify-content: center; }
.u-justify-between { justify-content: space-between; }
.u-justify-end { justify-content: flex-end; }
.u-flex-1 { flex: 1 1 0%; }
.u-flex-none { flex: none; }
.u-block { display: block; }
.u-hidden { display: none; }
.u-relative { position: relative; }
.u-overflow-hidden { overflow: hidden; }

/* ---------- 网格 ---------- */
.u-grid { display: grid; }
.u-grid-2 { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); }
.u-grid-3 { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); }
.u-grid-4 { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); }
.u-col-span-2 { grid-column: span 2 / span 2; }

/* ---------- 间距 ---------- */
.u-gap-4 { gap: 4px; }
.u-gap-8 { gap: 8px; }
.u-gap-12 { gap: 12px; }
.u-gap-16 { gap: 16px; }
.u-gap-20 { gap: 20px; }
.u-gap-24 { gap: 24px; }
.u-gap-32 { gap: 32px; }
.u-gap-40 { gap: 40px; }

.u-mt-8 { margin-top: 8px; }
.u-mt-12 { margin-top: 12px; }
.u-mt-16 { margin-top: 16px; }
.u-mt-20 { margin-top: 20px; }
.u-mt-24 { margin-top: 24px; }
.u-mt-32 { margin-top: 32px; }
.u-mt-40 { margin-top: 40px; }
.u-mb-8 { margin-bottom: 8px; }
.u-mb-12 { margin-bottom: 12px; }
.u-mb-16 { margin-bottom: 16px; }
.u-mb-24 { margin-bottom: 24px; }
.u-mb-32 { margin-bottom: 32px; }
.u-mx-auto { margin-left: auto; margin-right: auto; }

.u-p-16 { padding: 16px; }
.u-p-20 { padding: 20px; }
.u-p-24 { padding: 24px; }
.u-p-32 { padding: 32px; }
.u-py-8 { padding-top: 8px; padding-bottom: 8px; }
.u-py-16 { padding-top: 16px; padding-bottom: 16px; }
.u-py-24 { padding-top: 24px; padding-bottom: 24px; }

/* ---------- 尺寸 ---------- */
.u-w-full { width: 100%; }
.u-w-auto { width: auto; }
.u-max-w-sm { max-width: 480px; }
.u-max-w-md { max-width: 680px; }
.u-max-w-lg { max-width: 860px; }

/* ---------- 文字 ---------- */
.u-text-xs { font-size: 12.5px; line-height: 1.5; }
.u-text-sm { font-size: 14px; line-height: 1.6; }
.u-text-base { font-size: 16px; line-height: 1.75; }
.u-text-lg { font-size: 18px; line-height: 1.7; }
.u-text-xl { font-size: 22px; line-height: 1.5; }
.u-font-500 { font-weight: 500; }
.u-font-600 { font-weight: 600; }
.u-font-700 { font-weight: 700; }
.u-font-800 { font-weight: 800; }
.u-text-left { text-align: left; }
.u-text-center { text-align: center; }
.u-text-right { text-align: right; }
.u-uppercase { text-transform: uppercase; letter-spacing: .12em; }
.u-leading-relaxed { line-height: 1.85; }
.u-truncate { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* ---------- 颜色 ---------- */
.u-text-ink { color: var(--ink); }
.u-text-body { color: var(--ink-2); }
.u-text-muted { color: var(--ink-3); }
.u-text-faint { color: var(--ink-4); }
.u-text-brand { color: var(--brand); }
.u-text-white { color: #fff; }
.u-bg-white { background: #fff; }
.u-bg-soft { background: var(--soft); }
.u-bg-dark { background: var(--dark); color: #aebbd0; }
.u-bg-brand-soft { background: var(--brand-soft); }

/* ---------- 边框与阴影 ---------- */
.u-border { border: 1px solid var(--line); }
.u-border-0 { border: 0; }
.u-rounded { border-radius: var(--r-sm); }
.u-rounded-lg { border-radius: var(--r-md); }
.u-rounded-xl { border-radius: var(--r-lg); }
.u-rounded-full { border-radius: 999px; }
.u-shadow-sm { box-shadow: var(--sh-sm); }
.u-shadow-md { box-shadow: var(--sh-md); }

/* ---------- 小部件 ---------- */
.u-badge {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 5px 11px; border-radius: 999px;
  background: var(--brand-soft); color: var(--brand);
  font-size: 12.5px; font-weight: 600;
}
.u-divider { height: 1px; background: var(--line); border: 0; margin: 24px 0; }
.u-kbd {
  display: inline-block; padding: 2px 7px; border-radius: 6px;
  background: var(--soft-2); border: 1px solid var(--line);
  font-size: 12.5px; font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}

/* ---------- 响应式 ---------- */
@media (max-width: 860px) {
  .u-grid-2, .u-grid-3, .u-grid-4 { grid-template-columns: 1fr; }
  .u-col-span-2 { grid-column: span 1 / span 1; }
  .u-md-flex-col { flex-direction: column; }
}