/* ===== CSS Variables / Design Tokens ===== */
:root {
  --primary: #0891B2;
  --primary-light: #06B6D4;
  --primary-dark: #0E7490;
  --primary-10: rgba(8, 145, 178, 0.1);
  --bg-page: #F0F7FA;
  --bg-card: #FFFFFF;
  --bg-sidebar: #1B2A3D;
  --bg-sidebar-hover: #253B52;
  --bg-sidebar-active: #0891B2;
  --text-primary: #164E63;
  --text-secondary: #5E7A89;
  --text-sidebar: #B0C4D0;
  --text-sidebar-active: #FFFFFF;
  --text-muted: #8CA3B0;
  --border: #D5E3EA;
  --border-focus: #0891B2;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.1);
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;
  --font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", Helvetica, Arial, sans-serif;
  --font-size-sm: 12px;
  --font-size-base: 14px;
  --font-size-md: 15px;
  --font-size-lg: 18px;
  --font-size-xl: 22px;
  --font-size-2xl: 28px;
  --transition-fast: 150ms ease;
  --transition-normal: 200ms ease;
}

*, *::before, *::after { margin:0; padding:0; box-sizing:border-box; }
html, body { height:100%; font-family:var(--font-family); font-size:var(--font-size-base); color:var(--text-primary); background:var(--bg-page); line-height:1.6; -webkit-font-smoothing:antialiased; }
a { text-decoration:none; color:inherit; }
button { font-family:inherit; cursor:pointer; border:none; background:none; }

.app-layout { display:flex; height:100vh; overflow:hidden; }

.sidebar { width:256px; min-width:256px; background:var(--bg-sidebar); color:var(--text-sidebar); display:flex; flex-direction:column; overflow:hidden; }
.sidebar-logo { display:flex; align-items:center; gap:10px; padding:20px 20px 16px; border-bottom:1px solid rgba(255,255,255,0.08); }
.sidebar-logo .logo-icon { width:34px; height:34px; background:var(--primary); border-radius:var(--radius-md); display:flex; align-items:center; justify-content:center; }
.sidebar-logo .logo-icon svg { width:18px; height:18px; color:#fff; }
.sidebar-logo .logo-text { font-size:var(--font-size-lg); font-weight:600; color:#fff; letter-spacing:-0.02em; }
.sidebar-section { padding:16px 12px 8px; }
.sidebar-section-title { font-size:var(--font-size-sm); font-weight:500; text-transform:uppercase; letter-spacing:0.06em; color:rgba(255,255,255,0.35); padding:0 12px; margin-bottom:8px; }
.sidebar-nav { flex:1; overflow-y:auto; padding:0 12px 16px; }
.sidebar-item { display:flex; align-items:center; gap:10px; width:100%; padding:9px 12px; border-radius:var(--radius-md); font-size:var(--font-size-base); color:var(--text-sidebar); transition:background var(--transition-fast),color var(--transition-fast); margin-bottom:2px; }
.sidebar-item:hover { background:var(--bg-sidebar-hover); color:var(--text-sidebar-active); }
.sidebar-item.active { background:var(--bg-sidebar-active); color:var(--text-sidebar-active); font-weight:500; }
.sidebar-item svg { width:18px; height:18px; flex-shrink:0; }
.sidebar-item .arrow { margin-left:auto; opacity:0.4; transition:transform var(--transition-fast); }
.sidebar-item:hover .arrow { transform:translateX(2px); opacity:0.7; }
.sidebar-footer { padding:16px 20px; border-top:1px solid rgba(255,255,255,0.08); font-size:var(--font-size-sm); color:rgba(255,255,255,0.3); }

.main-content { flex:1; overflow-y:auto; background:var(--bg-page); }

.page-header { padding:var(--spacing-xl) var(--spacing-xl) 0; }
.page-header h1 { font-size:var(--font-size-2xl); font-weight:700; color:var(--text-primary); margin-bottom:var(--spacing-xs); }
.page-header p { font-size:var(--font-size-md); color:var(--text-secondary); }

.tool-grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(280px,1fr)); gap:var(--spacing-lg); padding:var(--spacing-xl); }
.tool-card { display:block; background:var(--bg-card); border:1px solid var(--border); border-radius:var(--radius-xl); padding:var(--spacing-lg); transition:transform var(--transition-normal),box-shadow var(--transition-normal); }
.tool-card:hover { transform:translateY(-3px); box-shadow:var(--shadow-md); }
.tool-card .card-icon { width:60px; height:60px; border-radius:var(--radius-lg); background:var(--primary-10); display:flex; align-items:center; justify-content:center; margin-bottom:var(--spacing-md); }
.tool-card .card-icon svg { width:28px; height:28px; color:var(--primary); }
.tool-card h3 { font-size:var(--font-size-lg); font-weight:600; color:var(--text-primary); margin-bottom:var(--spacing-sm); }
.tool-card .card-desc { font-size:var(--font-size-base); color:var(--text-secondary); line-height:1.6; margin-bottom:var(--spacing-md); }
.tool-card .card-action { display:flex; align-items:center; gap:4px; font-size:var(--font-size-base); font-weight:500; color:var(--primary); }
.tool-card .card-action svg { width:14px; height:14px; transition:transform var(--transition-fast); }
.tool-card:hover .card-action svg { transform:translateX(3px); }
.empty-state { text-align:center; padding:80px 40px; color:var(--text-muted); font-size:var(--font-size-md); }

/* ===== 工具页: 左右双栏布局 ===== */
.tool-layout {
  display: flex;
  gap: var(--spacing-lg);
  padding: var(--spacing-xl);
  align-items: flex-start;
}

.tool-left {
  flex: 1;
  min-width: 0;
}

.tool-right {
  width: 420px;
  min-width: 320px;
  flex-shrink: 0;
}

.tool-right .result-placeholder {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-2xl) var(--spacing-lg);
  text-align: center;
  color: var(--text-muted);
  font-size: var(--font-size-md);
  min-height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.form-card { background:var(--bg-card); border:1px solid var(--border); border-radius:var(--radius-xl); padding:var(--spacing-xl); box-shadow:var(--shadow-sm); }
.form-group { margin-bottom:var(--spacing-xl); }
.form-group:last-child { margin-bottom:0; }
.form-label { display:block; font-size:var(--font-size-md); font-weight:500; color:var(--text-primary); margin-bottom:var(--spacing-sm); }
.form-hint { font-size:var(--font-size-sm); color:var(--text-muted); margin-top:6px; }

.option-group { display:flex; flex-wrap:wrap; gap:8px; }
.option-btn { padding:6px 14px; border-radius:var(--radius-md); font-size:var(--font-size-base); border:1px solid var(--border); background:var(--bg-card); color:var(--text-secondary); transition:all var(--transition-fast); }
.option-btn:hover { border-color:var(--primary); color:var(--text-primary); }
.option-btn.selected { background:var(--primary); color:#fff; border-color:var(--primary); }

.select-wrap { position:relative; display:inline-block; min-width:220px; }
.select-wrap select { width:100%; padding:9px 36px 9px 12px; border-radius:var(--radius-md); border:1px solid var(--border); background:var(--bg-card); color:var(--text-primary); font-size:var(--font-size-base); font-family:inherit; appearance:none; cursor:pointer; transition:border-color var(--transition-fast); }
.select-wrap select:focus { outline:none; border-color:var(--border-focus); box-shadow:0 0 0 3px rgba(8,145,178,0.15); }
.select-wrap::after { content:''; position:absolute; right:12px; top:50%; transform:translateY(-50%); width:0; height:0; border-left:5px solid transparent; border-right:5px solid transparent; border-top:6px solid var(--text-muted); pointer-events:none; }

input[type="date"] { padding:9px 12px; border-radius:var(--radius-md); border:1px solid var(--border); background:var(--bg-card); color:var(--text-primary); font-size:var(--font-size-base); font-family:inherit; cursor:pointer; transition:border-color var(--transition-fast); }
input[type="date"]:focus { outline:none; border-color:var(--border-focus); box-shadow:0 0 0 3px rgba(8,145,178,0.15); }

.btn { display:inline-flex; align-items:center; gap:6px; padding:10px 24px; border-radius:var(--radius-md); font-size:var(--font-size-base); font-weight:500; transition:all var(--transition-fast); }
.btn-primary { background:var(--primary); color:#fff; }
.btn-primary:hover { background:var(--primary-dark); }
.btn-primary:disabled { background:#B0C4D0; cursor:not-allowed; }
.btn-outline { background:transparent; border:1px solid var(--border); color:var(--text-secondary); }
.btn-outline:hover { border-color:var(--primary); color:var(--primary); }
.btn svg { width:16px; height:16px; }
.form-actions { display:flex; align-items:center; gap:12px; padding-top:var(--spacing-sm); }
.form-actions .hint { font-size:var(--font-size-sm); color:var(--text-muted); }

/* 生成结果 */
.result-card { background:var(--bg-card); border:1px solid var(--border); border-radius:var(--radius-xl); padding:var(--spacing-xl); box-shadow:var(--shadow-sm); }
.result-header { display:flex; align-items:center; justify-content:space-between; margin-bottom:var(--spacing-md); }
.result-header h2 { font-size:var(--font-size-lg); font-weight:600; color:var(--text-primary); }
.result-textarea { width:100%; min-height:200px; padding:var(--spacing-md); border-radius:var(--radius-md); border:1px solid var(--border); background:#F8FBFC; font-family:"SF Mono","Fira Code","Cascadia Code",Consolas,monospace; font-size:var(--font-size-base); color:var(--text-primary); line-height:1.7; resize:vertical; }
.result-textarea:focus { outline:none; border-color:var(--border-focus); }

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  /* 双栏折叠为单栏 */
  .tool-layout { flex-direction:column; }
  .tool-right { width:100%; min-width:0; }
}
/* =====
@media (max-width: 768px) {
  .app-layout { flex-direction:column; }
  .sidebar { width:100%; min-width:auto; height:auto; max-height:60px; overflow:hidden; flex-direction:row; align-items:center; }
  .sidebar-nav { overflow-x:auto; gap:4px; padding:8px 12px; }
  .sidebar-section-title, .sidebar-footer, .sidebar-logo { display:none; }
  .tool-grid { grid-template-columns:1fr; padding:var(--spacing-md); }
  .tool-layout { padding:var(--spacing-md); }
}
===== */

@media (max-width: 768px) {  .app-layout {     flex-direction: column;   }    
.sidebar {     width: 100%;     min-width: auto;     height: auto;     max-height: 60px;     overflow: hidden;     flex-direction: row;     align-items: center;   /* 居中显示logo */  }    
.sidebar-nav {     display: none !important; /* 完全隐藏导航菜单 */  }    
 
.sidebar-section-title, .sidebar-footer {     display: none;   }    
.tool-grid {     grid-template-columns: 1fr;     padding: var(--spacing-md);   }    
.tool-layout {     padding: var(--spacing-md);   }}