/* ... 基础变量 ... */
:root {
    --bg-primary: #f8f9fa; --bg-secondary: #ffffff; --text-primary: #1a1a1a; --text-secondary: #666666;
    --accent-color: #4a90e2; --border-color: rgba(0, 0, 0, 0.08);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04); --shadow-hover: 0 8px 24px rgba(0, 0, 0, 0.12);
    --sidebar-width: 260px;
}
[data-theme="dark"] {
    --bg-primary: #0f0f0f; --bg-secondary: #1a1a1a; --text-primary: #e8e8e8; --text-secondary: #a0a0a0;
    --border-color: rgba(255, 255, 255, 0.1); --shadow-hover: 0 8px 24px rgba(0, 0, 0, 0.5);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, system-ui, sans-serif; background: var(--bg-primary); color: var(--text-primary); line-height: 1.6; transition: 0.3s; }
html { scroll-behavior: smooth; }

/* 侧边栏 */
.sidebar { position: fixed; left: 0; top: 0; width: var(--sidebar-width); height: 100vh; background: var(--bg-secondary); border-right: 1px solid var(--border-color); padding: 30px 20px; display: flex; flex-direction: column; transition: transform 0.3s ease; z-index: 1000; }
.sidebar.collapsed { transform: translateX(-100%); }

/* 主内容 */
.main-content { margin-left: var(--sidebar-width); padding: 40px 60px; min-height: 100vh; transition: margin-left 0.3s ease; }
.main-content.expanded { margin-left: 0; }

/* 悬浮展开按钮 */
.desktop-toggle-btn { 
    position: fixed; bottom: 20px; left: 20px; z-index: 2000; 
    width: 44px; height: 44px; border-radius: 50%; 
    background: var(--bg-secondary); color: var(--text-primary); 
    border: 1px solid var(--border-color); box-shadow: var(--shadow-hover);
    cursor: pointer; display: none; align-items: center; justify-content: center; font-size: 20px;
    transition: 0.3s;
}
.desktop-toggle-btn:hover { background: var(--accent-color); color: white; transform: scale(1.1); }
.desktop-toggle-btn.active { display: flex; animation: popIn 0.3s; }
@keyframes popIn { from { transform: scale(0); } to { transform: scale(1); } }

.logo { display: flex; align-items: center; gap: 10px; margin-bottom: 40px; font-size: 22px; font-weight: 700; padding: 0 10px; }
.nav-menu { flex: 1; overflow-y: auto; }
.nav-link { display: flex; align-items: center; gap: 12px; padding: 12px 16px; color: var(--text-secondary); text-decoration: none; border-radius: 10px; margin-bottom: 4px; transition: 0.2s; }
.nav-link:hover, .nav-link.active { background: rgba(74, 144, 226, 0.1); color: var(--accent-color); font-weight: 600; }
.sidebar-footer { padding-top: 20px; border-top: 1px solid var(--border-color); }
.theme-toggle { width: 100%; padding: 12px; background: transparent; border: 1px solid var(--border-color); border-radius: 10px; color: var(--text-primary); cursor: pointer; transition: 0.2s; text-align: center; font-size: 14px; }
.theme-toggle:hover { border-color: var(--accent-color); color: var(--accent-color); }

.page-header { margin-bottom: 30px; }
.page-title { font-size: 32px; font-weight: 700; margin-bottom: 8px; }
.search-wrapper { margin-bottom: 40px; position: sticky; top: 20px; z-index: 90; }
.search-input { width: 100%; padding: 16px 24px; border-radius: 14px; border: 1px solid var(--border-color); background: var(--bg-secondary); color: var(--text-primary); font-size: 16px; box-shadow: var(--shadow-sm); outline: none; transition: 0.3s; backdrop-filter: blur(10px); }
.search-input:focus { border-color: var(--accent-color); box-shadow: 0 4px 12px rgba(74, 144, 226, 0.15); transform: translateY(-1px); }

/* 折叠相关 */
.content-section { margin-bottom: 50px; scroll-margin-top: 100px; }
.section-title { font-size: 22px; margin-bottom: 20px; display: flex; align-items: center; gap: 10px; cursor: pointer; user-select: none; }
.section-title:hover { color: var(--accent-color); }
.toggle-icon { font-size: 14px; color: var(--text-secondary); transition: transform 0.2s; margin-right: 5px; width: 20px; text-align: center; }

.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 20px; transition: all 0.3s ease; opacity: 1; max-height: 10000px; overflow: hidden; transform-origin: top; }
/* 隐藏逻辑：使用 max-height 做动画，opacity 做隐形 */
.card-grid.hidden { opacity: 0; max-height: 0; margin: 0; padding: 0; gap: 0; transform: scaleY(0.95); pointer-events: none; }

.card { display: flex; align-items: center; gap: 15px; padding: 18px; background: var(--bg-secondary); border: 1px solid var(--border-color); border-radius: 16px; text-decoration: none; transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1); position: relative; overflow: hidden; }
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-hover); border-color: transparent; }
.card-icon { width: 54px; height: 54px; border-radius: 14px; display: flex; align-items: center; justify-content: center; font-size: 24px; color: white; font-weight: 600; flex-shrink: 0; overflow: hidden; }
.card-icon img { width: 100%; height: 100%; object-fit: cover; }
.card-info { flex: 1; min-width: 0; }
.card-title { font-size: 16px; font-weight: 600; color: var(--text-primary); margin-bottom: 4px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.card-desc { font-size: 13px; color: var(--text-secondary); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.card-arrow { color: var(--border-color); transition: 0.2s; opacity: 0; transform: translateX(-10px); }
.card:hover .card-arrow { opacity: 1; transform: translateX(0); color: var(--accent-color); }

.mobile-menu-btn { display: none; position: fixed; top: 20px; right: 20px; z-index: 1001; width: 44px; height: 44px; background: var(--bg-secondary); border-radius: 50%; border: none; box-shadow: var(--shadow-sm); flex-direction: column; justify-content: center; align-items: center; gap: 5px; cursor: pointer; }
.mobile-menu-btn span { width: 20px; height: 2px; background: var(--text-primary); transition: 0.3s; }
.mobile-menu-btn.active span:nth-child(2) { opacity: 0; }
.mobile-menu-btn.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.mobile-menu-btn.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

@media (max-width: 768px) {
    .sidebar { transform: translateX(-100%); box-shadow: 2px 0 20px rgba(0,0,0,0.1); }
    .sidebar.active { transform: translateX(0); }
    .main-content { margin-left: 0; padding: 80px 20px 40px; }
    .mobile-menu-btn { display: flex; }
    .search-wrapper { top: 80px; }
    .card-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
    .card { padding: 12px; gap: 10px; border-radius: 12px; }
    .card-icon { width: 40px; height: 40px; font-size: 18px; border-radius: 10px; }
    .card-title { font-size: 14px; margin-bottom: 2px; }
    .card-desc { font-size: 12px; -webkit-line-clamp: 1; display: -webkit-box; -webkit-box-orient: vertical; }
    .card-arrow { display: none; }
    .desktop-toggle-btn.active { display: none; } /* 移动端禁用悬浮按钮 */
}