/* ===== Design Tokens ===== */
:root {
  --c-bg: #f5f7fa;
  --c-surface: #ffffff;
  --c-primary: #1a73e8;
  --c-primary-hover: #1557b0;
  --c-primary-light: #e8f0fe;
  --c-text: #1f2937;
  --c-text-secondary: #6b7280;
  --c-border: #e5e7eb;
  --c-border-light: #f0f2f5;
  --c-success: #10b981;
  --c-warning: #f59e0b;
  --c-error: #ef4444;
  --radius: 10px;
  --radius-sm: 6px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,.08);
  --shadow-lg: 0 8px 30px rgba(0,0,0,.12);
  --sidebar-w: 280px;
  --font: -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,"PingFang SC","Noto Sans SC",sans-serif;
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{font-size:15px;scroll-behavior:smooth}
body{font-family:var(--font);background:var(--c-bg);color:var(--c-text);min-height:100vh;display:flex}
.sidebar{position:fixed;top:0;left:0;width:var(--sidebar-w);height:100vh;background:var(--c-surface);border-right:1px solid var(--c-border);display:flex;flex-direction:column;z-index:100;box-shadow:var(--shadow-sm)}
.sidebar-header{padding:24px 20px 16px;border-bottom:1px solid var(--c-border-light)}
.sidebar-header h1{font-size:1.15rem;font-weight:700;color:var(--c-primary);letter-spacing:-.02em}
.sidebar-header p{font-size:.8rem;color:var(--c-text-secondary);margin-top:4px}
.sidebar-modules{flex:1;overflow-y:auto;padding:12px 0}
.module-btn{display:flex;align-items:center;gap:10px;width:100%;padding:11px 20px;border:none;background:none;font-size:.9rem;font-weight:500;color:var(--c-text-secondary);cursor:pointer;transition:all .15s;text-align:left;border-left:3px solid transparent}
.module-btn:hover{background:var(--c-primary-light);color:var(--c-primary)}
.module-btn.active{background:var(--c-primary-light);color:var(--c-primary);border-left-color:var(--c-primary);font-weight:600}
.module-btn .icon{font-size:1.2rem;width:24px;text-align:center}
.module-btn .badge{margin-left:auto;background:var(--c-border);color:var(--c-text-secondary);font-size:.7rem;padding:2px 8px;border-radius:99px;font-weight:500}
.module-btn.active .badge{background:var(--c-primary);color:#fff}
.sidebar-footer{padding:16px 20px;border-top:1px solid var(--c-border-light)}
.progress-info{display:flex;justify-content:space-between;font-size:.75rem;color:var(--c-text-secondary);margin-bottom:6px}
.progress-bar{height:6px;background:var(--c-border);border-radius:99px;overflow:hidden}
.progress-bar-fill{height:100%;background:var(--c-primary);border-radius:99px;transition:width .4s ease;width:0%}
.main{margin-left:var(--sidebar-w);flex:1;padding:32px 40px 80px;max-width:960px;width:100%}
.main-header{margin-bottom:28px}
.main-header h2{font-size:1.5rem;font-weight:700;margin-bottom:4px}
.main-header p{color:var(--c-text-secondary);font-size:.9rem}
.section-card{background:var(--c-surface);border-radius:var(--radius);box-shadow:var(--shadow-sm);margin-bottom:20px;overflow:hidden;border:1px solid var(--c-border-light)}
.section-header{display:flex;align-items:center;justify-content:space-between;padding:16px 24px;cursor:pointer;user-select:none;transition:background .15s}
.section-header:hover{background:#fafbfc}
.section-header h3{font-size:1rem;font-weight:600;display:flex;align-items:center;gap:8px}
.section-header .num{display:inline-flex;align-items:center;justify-content:center;width:26px;height:26px;border-radius:50%;background:var(--c-primary-light);color:var(--c-primary);font-size:.8rem;font-weight:700}
.section-header .arrow{color:var(--c-text-secondary);transition:transform .2s;font-size:.8rem}
.section-header.open .arrow{transform:rotate(180deg)}
.section-body{display:none;border-top:1px solid var(--c-border-light);padding:20px 24px}
.section-body.open{display:block}
.question-group{margin-bottom:24px;padding-bottom:20px;border-bottom:1px solid var(--c-border-light)}
.question-group:last-child{margin-bottom:0;padding-bottom:0;border-bottom:none}
.question-item{margin-bottom:16px}
.question-item:last-child{margin-bottom:0}
.question-label{display:block;font-size:.88rem;font-weight:500;margin-bottom:6px;line-height:1.5;color:var(--c-text)}
.question-label .tag{display:inline-block;font-size:.7rem;padding:1px 8px;border-radius:99px;background:var(--c-border-light);color:var(--c-text-secondary);margin-left:6px;font-weight:400}
.question-input{width:100%}
.question-input textarea{width:100%;padding:10px 14px;border:1px solid var(--c-border);border-radius:var(--radius-sm);font-size:.88rem;font-family:var(--font);line-height:1.6;resize:vertical;min-height:48px;transition:border-color .15s,box-shadow .15s}
.question-input textarea:focus{outline:none;border-color:var(--c-primary);box-shadow:0 0 0 3px rgba(26,115,232,.12)}
.question-input input[type="text"]{width:100%;padding:8px 14px;border:1px solid var(--c-border);border-radius:var(--radius-sm);font-size:.88rem;font-family:var(--font);transition:border-color .15s,box-shadow .15s}
.question-input input[type="text"]:focus{outline:none;border-color:var(--c-primary);box-shadow:0 0 0 3px rgba(26,115,232,.12)}
.checkbox-group{display:flex;flex-wrap:wrap;gap:8px}
.checkbox-group label{display:inline-flex;align-items:center;gap:6px;padding:6px 12px;border:1px solid var(--c-border);border-radius:var(--radius-sm);cursor:pointer;transition:all .15s;font-size:.85rem}
.checkbox-group label:hover{border-color:var(--c-primary);background:var(--c-primary-light)}
.checkbox-group label:has(input:checked){border-color:var(--c-primary);background:var(--c-primary-light)}
.volume-row{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.actions-bar{position:fixed;bottom:0;left:var(--sidebar-w);right:0;background:var(--c-surface);border-top:1px solid var(--c-border);padding:14px 40px;display:flex;align-items:center;gap:12px;box-shadow:0 -2px 10px rgba(0,0,0,.06);z-index:50}
.actions-bar .save-status{margin-left:auto;font-size:.8rem;color:var(--c-text-secondary);display:flex;align-items:center;gap:6px}
.status-dot{display:inline-block;width:8px;height:8px;border-radius:50%}
.status-dot.saved{background:var(--c-success)}
.status-dot.saving{background:var(--c-warning);animation:pulse 1s infinite}
.status-dot.error{background:var(--c-error)}
@keyframes pulse{0%,100%{opacity:1}50%{opacity:.4}}
.btn{display:inline-flex;align-items:center;gap:6px;padding:9px 20px;border:none;border-radius:var(--radius-sm);font-size:.88rem;font-weight:500;cursor:pointer;transition:all .15s;font-family:var(--font)}
.btn-primary{background:var(--c-primary);color:#fff}
.btn-primary:hover{background:var(--c-primary-hover)}
.btn-secondary{background:var(--c-border-light);color:var(--c-text)}
.btn-secondary:hover{background:var(--c-border)}
.btn-success{background:var(--c-success);color:#fff}
.btn-success:hover{background:#059669}
.modal-overlay{position:fixed;inset:0;background:rgba(0,0,0,.4);display:none;align-items:center;justify-content:center;z-index:200}
.modal-overlay.show{display:flex}
.modal{background:var(--c-surface);border-radius:var(--radius);padding:32px;max-width:480px;width:90%;box-shadow:var(--shadow-lg)}
.modal h3{font-size:1.15rem;margin-bottom:12px}
.modal p{font-size:.9rem;color:var(--c-text-secondary);margin-bottom:20px;line-height:1.6}
.modal .btn-group{display:flex;gap:10px;justify-content:flex-end}
@media(max-width:768px){
  .sidebar{width:100%;height:auto;position:relative;border-right:none;border-bottom:1px solid var(--c-border)}
  .sidebar-modules{display:flex;overflow-x:auto;padding:8px;gap:4px}
  .module-btn{white-space:nowrap;padding:8px 14px;border-left:none;border-bottom:3px solid transparent;flex-shrink:0}
  .module-btn.active{border-left:none;border-bottom-color:var(--c-primary)}
  .sidebar-header{padding:16px}
  .sidebar-footer{display:none}
  .main{margin-left:0;padding:24px 16px 100px}
  .actions-bar{left:0;padding:12px 16px;flex-wrap:wrap}
  .actions-bar .save-status{margin-left:0;width:100%;order:-1}
  .section-body{padding:16px}
  .volume-row{grid-template-columns:1fr}
}