* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    }
  
  body {
  font-family: Arial, Helvetica, sans-serif;
  }
  
  /* Main Background */
  .container {
  width: 100%;
  min-height: 100vh;
  background: linear-gradient(135deg, #6fa9a9, #9ac5c5);
  padding: 30px 15px;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  }
  
  /* Todo App */
  .todo-app {
  width: 100%;
  max-width: 550px;
  background: #ffffff;
  margin-top: 70px;
  padding: 35px;
  border-radius: 20px;
  box-shadow: 0 15px 40px rgba(0, 0, 0, 0.15);
  }
  
  /* Header */
  .app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 25px;
  }
  
  .app-header h1 {
  color: #002765;
  font-size: 28px;
  font-weight: 700;
  line-height: 1.2;
  }
  
  .app-header p {
  color: #777;
  font-size: 14px;
  margin-top: 6px;
  }
  
  .app-icon {
  width: 45px;
  height: 45px;
  object-fit: contain;
  margin-left: 15px;
  }
  
  /* Input Row */
  .row {
  display: flex;
  align-items: center;
  width: 100%;
  background: #f1f3f4;
  border-radius: 14px;
  padding: 6px;
  margin-bottom: 20px;
  }
  
  #input-box {
  flex: 1;
  border: none;
  outline: none;
  background: transparent;
  padding: 14px 15px;
  font-size: 16px;
  color: #333;
  min-width: 0;
  }
  
  #input-box::placeholder {
  color: #999;
  }
  
  /* Add Button */
  #add-btn {
  border: none;
  outline: none;
  background: #002765;
  color: white;
  padding: 13px 23px;
  border-radius: 11px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: 0.2s ease;
  }
  
  #add-btn:hover {
  background: #00439c;
  transform: translateY(-1px);
  }
  
  #add-btn:active {
  transform: scale(0.97);
  }
  
  /* Task Information */
  .task-info {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 15px;
  color: #777;
  font-size: 14px;
  }
  
  #clear-completed {
  border: none;
  background: transparent;
  color: #d9534f;
  font-size: 13px;
  cursor: pointer;
  font-weight: 600;
  }
  
  #clear-completed:hover {
  text-decoration: underline;
  }
  
  /* Task List */
  #list-container {
  list-style: none;
  width: 100%;
  }
  
  /* Individual Task */
  #list-container li {
  position: relative;
  display: flex;
  align-items: center;
  width: 100%;
  min-height: 50px;
  background: #f7f8fa;
  border: 1px solid #eeeeee;
  border-radius: 12px;
  padding: 13px 45px 13px 45px;
  margin-bottom: 10px;
  color: #333;
  font-size: 15px;
  word-break: break-word;
  transition: 0.2s ease;
  }
  
  #list-container li:hover {
  background: #f0f3f7;
  transform: translateY(-1px);
  }
  
  /* Custom Checkbox */
  #list-container li::before {
  content: "";
  position: absolute;
  left: 15px;
  top: 50%;
  transform: translateY(-50%);
  width: 21px;
  height: 21px;
  border: 2px solid #002765;
  border-radius: 50%;
  cursor: pointer;
  background: white;
  }
  
  /* Completed Task */
  #list-container li.checked {
  color: #999;
  text-decoration: line-through;
  background: #f2f2f2;
  }
  
  #list-container li.checked::before {
  content: "✓";
  display: flex;
  align-items: center;
  justify-content: center;
  background: #002765;
  border-color: #002765;
  color: white;
  font-size: 13px;
  font-weight: bold;
  text-decoration: none;
  }
  
  /* Delete Button */
  #list-container li span {
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 28px;
  height: 28px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #777;
  font-size: 21px;
  cursor: pointer;
  transition: 0.2s ease;
  }
  
  #list-container li span:hover {
  background: #e5e5e5;
  color: #d9534f;
  }
  
  /* Empty State */
  .empty-state {
  text-align: center;
  padding: 35px 10px 10px;
  color: #888;
  }
  
  .empty-icon {
  width: 50px;
  height: 50px;
  margin: 0 auto 12px;
  border-radius: 50%;
  background: #eef3f9;
  color: #002765;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  font-weight: bold;
  }
  
  .empty-state h3 {
  color: #555;
  font-size: 17px;
  margin-bottom: 6px;
  }
  
  .empty-state p {
  font-size: 14px;
  }
  
  /* Tablet */
  @media (max-width: 600px) {
  

  .container {
      padding: 20px 12px;
  }
  
  .todo-app {
      margin-top: 35px;
      padding: 28px 20px 35px;
      border-radius: 17px;
  }
  
  .app-header h1 {
      font-size: 24px;
  }
  
  .app-icon {
      width: 40px;
      height: 40px;
  }
  
  #input-box {
      font-size: 15px;
      padding: 13px 12px;
  }
  
  #add-btn {
      padding: 12px 18px;
  }

  
  }
  
  /* Standard Smartphones */
  @media (max-width: 480px) {
  

  .container {
      padding: 15px 10px;
  }
  
  .todo-app {
      margin-top: 20px;
      padding: 25px 16px 30px;
      border-radius: 15px;
  }
  
  .app-header {
      margin-bottom: 20px;
  }
  
  .app-header h1 {
      font-size: 21px;
  }
  
  .app-header p {
      font-size: 12px;
  }
  
  .app-icon {
      width: 35px;
      height: 35px;
      margin-left: 8px;
  }
  
  .row {
      padding: 5px;
      border-radius: 12px;
  }
  
  #input-box {
      font-size: 14px;
      padding: 12px 10px;
  }
  
  #add-btn {
      padding: 11px 15px;
      font-size: 14px;
      border-radius: 9px;
  }
  
  #list-container li {
      font-size: 14px;
      padding: 12px 40px 12px 42px;
  }
  
  .task-info {
      font-size: 12px;
  }
  
  #clear-completed {
      font-size: 12px;
  }
  
  }
  
  /* Very Small Phones */
  @media (max-width: 350px) {
  
  .todo-app {
      padding: 20px 12px 25px;
  }
  
  .app-header h1 {
      font-size: 19px;
  }
  
  .app-icon {
      width: 30px;
      height: 30px;
  }
  
  #add-btn {
      padding: 10px 12px;
  }
  
  #input-box {
      font-size: 13px;
  }

  
  }