/* ===================================
 *  sidebar.css — 左侧自适应导航栏
 *
 *  默认: 窄栏（仅图标，56px）
 *  宽屏 ≥1024px: 自动展开
 *  点击底部按钮切换
 * =================================== */

.sidebar {
  width: 56px;
  min-width: 56px;
  background: var(--color-sidebar-bg);
  border-right: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  height: 100vh;
  position: sticky;
  top: 0;
  overflow: hidden;
  transition: width 0.25s ease, min-width 0.25s ease;
  z-index: 10;
}

/* ── Expanded state ── */
.sidebar.expanded {
  width: 260px;
  min-width: 260px;
}

/* ── Header / Logo ── */
.sidebar-header {
  padding: 1.5rem 0;
  text-align: center;
  border-bottom: 1px solid var(--color-border);
  white-space: nowrap;
  overflow: hidden;
}

.sidebar.expanded .sidebar-header {
  padding: 1.5rem 1.2rem 1rem;
  text-align: left;
}

.site-logo {
  font-size: 1.3rem;
  font-weight: 700;
  letter-spacing: 1px;
  color: var(--color-text);
}
.site-logo:hover { text-decoration: none; }

.logo-full { display: none; }
.logo-short { display: inline; }

.sidebar.expanded .logo-short { display: none; }
.sidebar.expanded .logo-full { display: inline; }

/* ── Nav list ── */
.nav-list {
  list-style: none;
  padding: 0.5rem 0;
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
}

.nav-item {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0.8rem 0;
  font-size: 0.95rem;
  color: var(--color-text);
  border-left: 3px solid transparent;
  transition: background 0.15s, border-color 0.15s;
  white-space: nowrap;
  overflow: hidden;
}

.sidebar.expanded .nav-item {
  justify-content: flex-start;
  padding: 0.6rem 1.2rem;
  gap: 10px;
}

.nav-item:hover {
  background: #eee;
  text-decoration: none;
  border-left-color: var(--color-text);
}

.nav-item.active {
  background: #eaeaea;
  border-left-color: var(--color-text);
  font-weight: 600;
}

.nav-icon {
  flex-shrink: 0;
  display: block;
}

/* ── Nav label (text) ── */
.nav-label {
  display: none;
}

.sidebar.expanded .nav-label {
  display: inline;
}

/* ── Toggle button ── */
.sidebar-collapse-btn {
  border: none;
  background: transparent;
  cursor: pointer;
  padding: 0.8rem 0;
  color: var(--color-text-lighter);
  display: flex;
  align-items: center;
  justify-content: center;
  border-top: 1px solid var(--color-border);
  transition: color 0.15s;
  flex-shrink: 0;
}
.sidebar-collapse-btn:hover { color: var(--color-text); }

.sidebar:not(.expanded) .sidebar-collapse-btn svg {
  transform: rotate(180deg);
}

.sidebar.expanded .sidebar-collapse-btn {
  justify-content: flex-end;
  padding: 0.8rem 1.2rem;
}