/* ============================================================
   layout.css — 头部、导航、页脚、栅格
   ============================================================ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(245, 241, 232, 0.88);
  backdrop-filter: saturate(140%) blur(8px);
  -webkit-backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid var(--line-soft);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-h);
  gap: 16px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
}
.brand:hover { color: var(--ink); }

.brand-mark {
  font-size: 1.5rem;
  color: var(--gold);
  line-height: 1;
  filter: drop-shadow(0 1px 1px rgba(168,130,31,0.3));
}
.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-title { font-family: var(--font-serif); font-size: 1.15rem; font-weight: 600; letter-spacing: 0.06em; }
.brand-sub { font-size: 0.7rem; color: var(--ink-3); letter-spacing: 0.12em; }

.main-nav { display: flex; gap: 4px; }
.main-nav a {
  position: relative;
  padding: 8px 14px;
  color: var(--ink-2);
  font-size: 0.95rem;
  border-radius: var(--radius-sm);
  transition: all 0.18s;
}
.main-nav a:hover { color: var(--gold); background: var(--surface-2); }
.main-nav a.active { color: var(--gold); }
.main-nav a.active::after {
  content: "";
  position: absolute;
  left: 14px; right: 14px; bottom: 2px;
  height: 2px;
  background: var(--gold);
  border-radius: 2px;
}

#app {
  min-height: calc(100vh - var(--header-h) - 120px);
  padding-top: 28px;
  padding-bottom: 48px;
}

.site-footer {
  border-top: 1px solid var(--line-soft);
  background: var(--bg-soft);
  padding: 24px 0 28px;
  text-align: center;
  color: var(--ink-3);
  font-size: 0.85rem;
}
.site-footer p { margin: 0 0 6px; }
.footer-note { font-size: 0.78rem; opacity: 0.85; }

/* 通用视图容器 */
.view { animation: fadein 0.32s ease; }
@keyframes fadein {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

.page-title-row {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 24px;
}
.page-title-row h1 { margin: 0; }
.page-title-row .subtitle { color: var(--ink-3); font-size: 0.92rem; }

/* 栅格 */
.grid {
  display: grid;
  gap: 18px;
}
.grid-2 { grid-template-columns: 1fr 1fr; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

/* 卡片 */
.card {
  background: var(--surface-2);
  border: none;
  border-radius: var(--radius);
  padding: 18px 20px;
  box-shadow: none;
  transition: transform 0.18s;
}
.card:hover { transform: translateY(-2px); }

.section { margin-bottom: 36px; }
.section > h2 { margin-bottom: 14px; }
.section-intro { color: var(--ink-2); margin-bottom: 18px; max-width: 60ch; }

/* 引文块 */
.quote {
  font-family: var(--font-serif);
  background: transparent;
  border-left: 2px solid var(--gold);
  padding: 8px 0 8px 20px;
  border-radius: 0;
  color: var(--ink-2);
  line-height: 1.9;
  box-shadow: none;
}

/* 折叠 */
details.collapse {
  background: var(--surface);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  padding: 4px 18px;
  box-shadow: var(--shadow-sm);
}
details.collapse > summary {
  cursor: pointer;
  padding: 10px 0;
  font-weight: 600;
  list-style: none;
  color: var(--ink);
}
details.collapse > summary::-webkit-details-marker { display: none; }
details.collapse > summary::before {
  content: "▸";
  display: inline-block;
  margin-right: 8px;
  color: var(--gold);
  transition: transform 0.2s;
}
details.collapse[open] > summary::before { transform: rotate(90deg); }

/* 响应式：平板 */
@media (max-width: 900px) {
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
}

/* 响应式：手机 */
@media (max-width: 600px) {
  :root { --header-h: 56px; }
  .header-inner { gap: 8px; }
  .brand-sub { display: none; }
  .brand-title { font-size: 1rem; }
  .main-nav a { padding: 6px 10px; font-size: 0.88rem; }
  h1 { font-size: 1.5rem; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
}