* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: 14px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

input[type="search"]::-webkit-search-cancel-button,
input[type="search"]::-webkit-search-decoration {
  -webkit-appearance: none;
  appearance: none;
}

/* ===== 三段式布局 ===== */
.layout {
  display: grid;
  grid-template-columns: var(--sidebar-width) 1fr;
  grid-template-rows: var(--header-height) 1fr auto;
  grid-template-areas:
    "header  header"
    "sidebar content"
    "footer  footer";
  height: 100vh;
}

/* ===== Header ===== */
.header {
  grid-area: header;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-6);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
  z-index: 100;
}

.header__brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 16px;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: .3px;
}

.header__brand-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--color-primary);
  box-shadow: 0 0 0 4px var(--color-primary-soft);
}

.header__time {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--color-text-secondary);
  padding: 6px 12px;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  letter-spacing: .5px;
}

/* ===== Sidebar ===== */
.sidebar {
  grid-area: sidebar;
  background: var(--color-surface);
  border-right: 1px solid var(--color-border);
  padding: var(--space-3) 0;
  overflow-y: auto;
}

.menu { list-style: none; margin: 0; padding: 0; }

.menu__item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: 10px var(--space-6);
  margin: 2px var(--space-2);
  border-radius: var(--radius-sm);
  color: var(--color-text-secondary);
  text-decoration: none;
  font-size: 14px;
  cursor: pointer;
  transition: background var(--duration) var(--ease),
              color var(--duration) var(--ease);
}

.menu__item:hover {
  background: var(--color-primary-soft);
  color: var(--color-primary);
}

.menu__item.is-active {
  background: var(--color-primary-soft);
  color: var(--color-primary);
  font-weight: 600;
}

.menu__icon {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 15px;
}

/* ===== Content ===== */
.content {
  grid-area: content;
  padding: var(--space-6);
  overflow-y: auto;
}

.footer {
  grid-area: footer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-4);
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  font-size: 12px;
  color: var(--color-text-muted);
}

.footer__links {
  display: flex;
  gap: var(--space-3);
}

.footer a {
  color: var(--color-text-secondary);
  text-decoration: none;
}
.footer a:hover { color: var(--color-primary); }

/* ===== 响应式 ===== */
@media (max-width: 768px) {
  .layout {
    grid-template-columns: 1fr;
    grid-template-rows: var(--header-height) minmax(0, 1fr) auto;
    grid-template-areas:
      "header"
      "content"
      "footer";
    height: 100dvh;
  }

  .sidebar {
    position: fixed;
    top: var(--header-height);
    left: 0;
    bottom: 0;
    width: var(--sidebar-width);
    transform: translateX(-100%);
    transition: transform .25s var(--ease);
    z-index: 200;
    box-shadow: var(--shadow-lg);
  }
  .sidebar.is-open { transform: translateX(0); }

  .content { padding: var(--space-4); }

  .footer {
    padding: var(--space-3) var(--space-4);
    font-size: 11px;
    flex-wrap: wrap;
    justify-content: center;
    text-align: center;
  }
}