:root {
    --bg-color: #ffffff;
    --text-color: #333333;
    --input-bg: #f0f0f0;
    --task-bg: #f9f9f9;
    --task-complete: #888;
    --btn-bg: #4caf50;
    --btn-hover: #45a049;
    --delete-bg: #e74c3c;
    --delete-hover: #c0392b;
  }
  
  body.dark {
    --bg-color: #121212;
    --text-color: #f1f1f1;
    --input-bg: #2a2a2a;
    --task-bg: #1e1e1e;
    --task-complete: #777;
  }
  
  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', sans-serif;
  }
  
  body {
    background: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    padding: 50px;
    min-height: 100vh;
    transition: background 0.3s, color 0.3s;
  }
  
  .todo-container {
    background: var(--input-bg);
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
    width: 100%;
    max-width: 700px;
  }
  
  h1 {
    text-align: center;
    margin-bottom: 20px;
  }
  
  .top-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
  }
  
  .input-section {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 20px;
  }
  
  .input-section input, select {
    padding: 10px;
    border-radius: 5px;
    border: 1px solid #ccc;
    font-size: 14px;
    background: var(--bg-color);
    color: var(--text-color);
    flex: 1;
    min-width: 120px;
  }
  
  #add-task-btn {
    background: var(--btn-bg);
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 5px;
    cursor: pointer;
    white-space: nowrap;
  }
  
  #add-task-btn:hover {
    background: var(--btn-hover);
  }
  
  #export-btn {
    background: #3498db;
    color: white;
    border: none;
    padding: 6px 10px;
    border-radius: 5px;
    cursor: pointer;
  }
  
  #export-btn:hover {
    background: #2980b9;
  }
  
  #task-list {
    list-style: none;
  }
  
  .task-item {
    background: var(--task-bg);
    margin-bottom: 10px;
    padding: 10px 15px;
    border-radius: 5px;
    display: flex;
    flex-direction: column;
    gap: 5px;
  }
  
  .task-item-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
  }
  
  .task-item.completed .task-text {
    text-decoration: line-through;
    color: var(--task-complete);
  }
  
  .task-text {
    cursor: pointer;
  }
  
  .task-meta {
    font-size: 13px;
    color: #777;
  }
  
  .delete-btn {
    background: var(--delete-bg);
    color: white;
    border: none;
    padding: 6px 10px;
    border-radius: 5px;
    cursor: pointer;
  }
  
  .delete-btn:hover {
    background: var(--delete-hover);
  }