/* Professional, minimal styles for the to-do app */
:root{
  --bg:#f5f7fb;
  --card:#ffffff;
  --muted:#6b7280;
  --accent:#2563eb;
  --success:#10b981;
  --danger:#ef4444;
  --glass: rgba(255,255,255,0.6);
  --radius:10px;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial;
}
*{box-sizing:border-box}
html,body,#root{height:100%}
body{
  margin:0; padding:32px; background:linear-gradient(180deg,var(--bg),#eef2ff); color:#0f172a;
}
.app{max-width:900px;margin:0 auto}
.app-header{display:flex;flex-direction:column;gap:6px;margin-bottom:18px}
.app-header h1{margin:0;font-weight:700}
.subtitle{margin:0;color:var(--muted)}
.controls{background:var(--card);padding:14px;border-radius:var(--radius);box-shadow:0 6px 18px rgba(16,24,40,0.06);margin-bottom:16px}
.task-form{display:flex;gap:8px;align-items:center}
.task-form input[type="text"]{flex:1;padding:10px 12px;border-radius:8px;border:1px solid #e6e9ef}
.task-form input[type="date"],.task-form select{padding:8px;border-radius:8px;border:1px solid #e6e9ef}
.task-form button{background:var(--accent);color:white;padding:10px 14px;border-radius:8px;border:none;cursor:pointer}
.toolbar{display:flex;gap:12px;align-items:center;margin-top:12px;flex-wrap:wrap}
.filters{display:flex;align-items:center;gap:8px}
.filter-btn{background:transparent;border:1px solid transparent;padding:6px 8px;border-radius:8px;cursor:pointer}
.filter-btn.active{background:var(--accent);color:white}
.search-sort{display:flex;gap:8px;align-items:center}
.search-sort input[type="search"]{padding:8px;border-radius:8px;border:1px solid #e6e9ef}
.import-export{display:flex;gap:8px;align-items:center}
.task-list{list-style:none;padding:0;margin:12px 0}
.task-item{display:flex;align-items:flex-start;gap:12px;background:linear-gradient(180deg,var(--glass),rgba(255,255,255,0.9));padding:12px;border-radius:12px;border:1px solid #f1f5f9;margin-bottom:10px}
.task-left{display:flex;align-items:center;gap:12px;width:100%}
.task-left input[type="checkbox"]{width:20px;height:20px}
.task-meta{flex:1}
.task-title{margin:0;font-weight:600}
.task-title.completed{ text-decoration:line-through;color:var(--muted);font-weight:500 }
.task-details{margin:6px 0;color:var(--muted);font-size:13px}
.task-actions{display:flex;gap:8px;margin-left:auto}
.icon-btn{background:transparent;border:1px solid transparent;padding:6px;border-radius:8px;cursor:pointer}
.icon-btn.danger{color:var(--danger)}
.badge{display:inline-block;padding:4px 8px;border-radius:999px;font-size:12px}
.badge.low{background:#ecfccb;color:#365314}
.badge.normal{background:#e0f2fe;color:#075985}
.badge.high{background:#fee2e2;color:#7f1d1d}
@media (max-width:680px){
  .task-form{flex-direction:column;align-items:stretch}
  .toolbar{flex-direction:column;align-items:stretch}
  .search-sort{width:100%;justify-content:space-between}
}
.footer, .app-footer{margin-top:18px;color:var(--muted);font-size:13px}
.small{font-size:13px;color:var(--muted)}

 :root {
      /* Primary UI Colors */
      --primary: #2563EB;
      --primary-light: #3B82F6;
      
      /* Neutral Colors */
      --background: #F3F4F6;
      --card-bg: #FFFFFF;
      --border: #E5E7EB;
      --text-dark: #1F2937;
      --text-light: #6B7280;
      
      /* Priority Colors */
      --priority-high: #DC2626;
      --priority-normal: #2563EB;
      --priority-low: #10B981;
      
      /* Accent Colors */
      --success: #22C55E;
      --warning: #F59E0B;
      --icons: #4B5563;
      
      /* Additional derived colors */
      --primary-lighter: rgba(37, 99, 235, 0.1);
      --primary-lighter-hover: rgba(37, 99, 235, 0.2);
      --success-lighter: rgba(34, 197, 94, 0.1);
      --warning-lighter: rgba(245, 158, 11, 0.1);
      --danger-lighter: rgba(220, 38, 38, 0.1);
      --high-lighter: rgba(220, 38, 38, 0.1);
      --low-lighter: rgba(16, 185, 129, 0.1);
      
      /* Shadows for 3D effect */
      --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
      --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);
      --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
      --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.1);
      --shadow-2xl: 0 25px 50px rgba(0, 0, 0, 0.15);
      
      /* Border radius for consistent styling */
      --radius: 12px;
      
      /* Transition for smooth animations */
      --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    body {
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      background-color: var(--background);
      color: var(--text-dark);
      line-height: 1.6;
      perspective: 1000px;
      min-height: 100vh;
      padding: 20px;
    }

    .app {
      max-width: 800px;
      margin: 0 auto;
      background: var(--card-bg);
      border-radius: var(--radius);
      box-shadow: var(--shadow-xl);
      transform-style: preserve-3d;
      transform: rotateX(2deg);
      transition: var(--transition);
      overflow: hidden;
    }

    .app:hover {
      transform: rotateX(0deg) translateY(-5px);
      box-shadow: var(--shadow-2xl);
    }

    .app-header {
      background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
      color: white;
      padding: 2rem;
      text-align: center;
      position: relative;
      overflow: hidden;
    }

    .app-header::before {
      content: '';
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100" preserveAspectRatio="none"><path d="M0,0 L100,0 L100,100 Z" fill="rgba(255,255,255,0.1)"/></svg>');
      background-size: 100% 100%;
    }

    .app-header h1 {
      font-size: 2.5rem;
      margin-bottom: 0.5rem;
      position: relative;
      z-index: 1;
      text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
    }

    .subtitle {
      font-size: 1rem;
      opacity: 0.9;
      max-width: 600px;
      margin: 0 auto;
      position: relative;
      z-index: 1;
    }

    .controls {
      padding: 1.5rem;
      background: var(--card-bg);
      border-bottom: 1px solid var(--border);
    }

    .task-form {
      display: flex;
      gap: 0.75rem;
      margin-bottom: 1.5rem;
      flex-wrap: wrap;
    }

    .task-form input,
    .task-form select,
    .task-form button {
      padding: 0.75rem 1rem;
      border-radius: var(--radius);
      border: 1px solid var(--border);
      background: var(--card-bg);
      transition: var(--transition);
      font-size: 1rem;
    }

    .task-form input:focus,
    .task-form select:focus {
      outline: none;
      border-color: var(--primary);
      box-shadow: 0 0 0 3px var(--primary-lighter);
    }

    #task-title {
      flex: 1;
      min-width: 200px;
    }

    #add-btn {
      background: var(--primary);
      color: white;
      border: none;
      cursor: pointer;
      font-weight: 600;
      box-shadow: var(--shadow-md);
      transform: translateZ(10px);
    }

    #add-btn:hover {
      background: var(--primary-light);
      transform: translateZ(15px) translateY(-2px);
      box-shadow: var(--shadow-lg);
    }

    .toolbar {
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 1rem;
    }

    .filters {
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }

    .filters label {
      color: var(--text-light);
      font-weight: 500;
    }

    .filter-btn {
      padding: 0.5rem 1rem;
      background: var(--card-bg);
      border: 1px solid var(--border);
      border-radius: calc(var(--radius) / 2);
      cursor: pointer;
      transition: var(--transition);
      font-weight: 500;
      color: var(--text-dark);
      transform: translateZ(5px);
    }

    .filter-btn:hover {
      background: var(--primary-lighter);
      transform: translateZ(10px);
    }

    .filter-btn.active {
      background: var(--primary);
      color: white;
      border-color: var(--primary);
      transform: translateZ(10px);
      box-shadow: var(--shadow-md);
    }

    .search-sort {
      display: flex;
      align-items: center;
      gap: 0.75rem;
    }

    #search {
      padding: 0.5rem 1rem;
      border-radius: calc(var(--radius) / 2);
      border: 1px solid var(--border);
      background: var(--card-bg);
      transition: var(--transition);
    }

    #search:focus {
      outline: none;
      border-color: var(--primary);
      box-shadow: 0 0 0 3px var(--primary-lighter);
    }

    #sort {
      padding: 0.5rem 1rem;
      border-radius: calc(var(--radius) / 2);
      border: 1px solid var(--border);
      background: var(--card-bg);
      transition: var(--transition);
    }

    #sort:focus {
      outline: none;
      border-color: var(--primary);
      box-shadow: 0 0 0 3px var(--primary-lighter);
    }

    main {
      padding: 1.5rem;
      min-height: 300px;
    }

    .task-list {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 1rem;
    }

    .task-item {
      background: var(--card-bg);
      border-radius: var(--radius);
      padding: 1rem;
      box-shadow: var(--shadow-md);
      display: flex;
      align-items: center;
      gap: 1rem;
      transition: var(--transition);
      transform-style: preserve-3d;
      border-left: 4px solid transparent;
    }

    .task-item.high-priority {
      border-left-color: var(--priority-high);
    }

    .task-item.normal-priority {
      border-left-color: var(--priority-normal);
    }

    .task-item.low-priority {
      border-left-color: var(--priority-low);
    }

    .task-item:hover {
      transform: translateZ(10px) translateY(-3px);
      box-shadow: var(--shadow-xl);
    }

    .task-checkbox {
      width: 24px;
      height: 24px;
      border-radius: 50%;
      border: 2px solid var(--border);
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: var(--transition);
      flex-shrink: 0;
      position: relative;
    }

    .task-checkbox:hover {
      border-color: var(--primary);
      background: var(--primary-lighter);
    }

    .task-checkbox.checked {
      background: var(--success);
      border-color: var(--success);
    }

    .task-checkbox.checked::after {
      content: '✓';
      color: white;
      font-weight: bold;
      position: absolute;
    }

    .task-content {
      flex: 1;
    }

    .task-title {
      font-weight: 600;
      margin-bottom: 0.25rem;
      color: var(--text-dark);
    }

    .task-meta {
      display: flex;
      gap: 1rem;
      font-size: 0.875rem;
      color: var(--text-light);
    }

    .task-due {
      display: flex;
      align-items: center;
      gap: 0.25rem;
    }

    .task-priority {
      display: flex;
      align-items: center;
      gap: 0.25rem;
      padding: 0.125rem 0.5rem;
      border-radius: calc(var(--radius) / 2);
      font-size: 0.75rem;
      font-weight: 600;
    }

    .priority-high {
      background: var(--high-lighter);
      color: var(--priority-high);
    }

    .priority-normal {
      background: var(--primary-lighter);
      color: var(--priority-normal);
    }

    .priority-low {
      background: var(--low-lighter);
      color: var(--priority-low);
    }

    .task-actions {
      display: flex;
      gap: 0.5rem;
    }

    .task-btn {
      width: 32px;
      height: 32px;
      border-radius: 50%;
      border: none;
      background: var(--card-bg);
      color: var(--icons);
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: var(--transition);
      box-shadow: var(--shadow-sm);
    }

    .task-btn:hover {
      transform: translateZ(5px);
      box-shadow: var(--shadow-md);
    }

    .edit-btn:hover {
      background: var(--primary-lighter);
      color: var(--primary);
    }

    .delete-btn:hover {
      background: var(--danger-lighter);
      color: var(--priority-high);
    }

    .completed .task-title {
      text-decoration: line-through;
      color: var(--text-light);
    }

    .empty-state {
      text-align: center;
      padding: 3rem 1rem;
      color: var(--text-light);
    }

    .empty-state-icon {
      font-size: 3rem;
      margin-bottom: 1rem;
      opacity: 0.5;
    }

    .app-footer {
      padding: 1rem;
      text-align: center;
      color: var(--text-light);
      font-size: 0.875rem;
      background: var(--card-bg);
      border-top: 1px solid var(--border);
    }

    /* Responsive adjustments */
    @media (max-width: 768px) {
      .app {
        border-radius: 0;
        margin: -20px;
        min-height: 100vh;
      }

      .toolbar {
        flex-direction: column;
        align-items: stretch;
      }

      .task-form {
        flex-direction: column;
      }

      #task-title {
        min-width: 100%;
      }
    }